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Main
Date: 05 Sep 2007 00:32:17
From: Artemisia
Subject: Dark Side Trike: 81 Gears Useful?
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Me again, one more question.
I am assuming that I will order the Scorpion FX with the option of a
Sram Dualdrive on the back and a three-speed cassette on the front.
The Price List stipulates:
"drivetrain DualDrive XT-81 81 speed rear derailleur XT / cassette
XT / DualDrive 3 speed hub / bar end shifters / grip shifter for
DualDrive gear development 0,98 - 9,81 m (3'3'' - 32'3')"
I will be taking this trike up some very steep hills. I'm looking
forward to being able to use very low gears, much lower than would
allow me to remain upright on a 2-wheeler.
However, when I spoke to a dealer in Angers about this option, he told
me he didn't think it was very useful, insofar as the gear range would
not be that much greater than with the SRAM Dualdrive alone, that is
fitted as standard, and that most of the gears would be overlapping
anyway.
Flyzipper has the simple SRAM Dualdrive three by seven. Admittedly I
have never used the lowest of his 24 gears. I do find myself spinning
out on his highest gears, however, on some of those long smooth Czech
descents.
It also appears that the front gears would not be changeable at a
standstill, which is a disadvantage in comparison to the Greenspeed
GT0 setup which combines a SRAM DualDrive in the back with a Sturmey
Archer in the front. The Scorpion 81-speed would have only the three
SRAM levels on the back that could be shifted at a standstill.
Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
sounds like it could be the option delivering the widest range.
Anyway, what do does the ng think? Does this 81 speed setup really
deliver an advantage over the standard 24 speed?
Thanks again for all your expertise.
EFR
In hilly Ile de France
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Date: 07 Sep 2007 08:12:25
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On 5 sep, 22:40, Artemisia <nos...@free.fr > wrote:
> I have of course contacted SRAM to see what they say. If it turns out
> that they won't even guarantee the DualDrive on recumbent trikes despite
> the DD being standard fitting on many in that class of machines, then I
> may have to rethink the whole project.
Still haven't heard from SRAM. I phoned HPV this morning. The guy told
me they had had a lot of problems with the SRAM drives and that SRAM
was over there non-stop, checking and revising, but that they have
solved the glitches now. Still, the guy sounded nervous, like he felt
I was grilling him on a known issue...
EFR
Ile de France
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Date: 07 Sep 2007 17:43:45
From: Nigel Cliffe
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Artemisia wrote:
> On 5 sep, 22:40, Artemisia <nos...@free.fr> wrote:
>
>> I have of course contacted SRAM to see what they say. If it turns out
>> that they won't even guarantee the DualDrive on recumbent trikes
>> despite the DD being standard fitting on many in that class of
>> machines, then I may have to rethink the whole project.
>
> Still haven't heard from SRAM. I phoned HPV this morning. The guy told
> me they had had a lot of problems with the SRAM drives and that SRAM
> was over there non-stop, checking and revising, but that they have
> solved the glitches now. Still, the guy sounded nervous, like he felt
> I was grilling him on a known issue...
Given the way your conversations are heading, suggesting problems with the
SRAM dual-drive, why not explore the other "fairly simple" options, even if
they require a rear wheel which isn't on the standard HPV list:
Schlumpf + 9 speed rear.
Schlumpf + cheaper hub gear, such as Shimano 8, or SRAM 7. This has the
"change when stopped" functionality of hub gears. Schlumpf's website shows
High-Speed-Drive + SRAM 7 combined to give 1.3m to 9.9m fairly evenly spaced
on a 20" wheel.
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
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Date: 07 Sep 2007 19:07:16
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Nigel Cliffe wrote:
> Given the way your conversations are heading, suggesting problems with the
> SRAM dual-drive, why not explore the other "fairly simple" options, even if
> they require a rear wheel which isn't on the standard HPV list:
Because it would actually cost more than to go with the standard
fitting. The base price (which includes the SRAM) stays the same, and
then we'd have to add not only the Schlumpf but the Nexus as well.
Also, I might not be happy running with just a Nexus until such a time
as I can afford the Schlumpf. Between now and Schlumpf I do want to ride
the bike...
Schlumpf's website shows
> High-Speed-Drive + SRAM 7 combined to give 1.3m to 9.9m fairly evenly spaced
> on a 20" wheel.
That is a good range. I wish I could figure out what it would be with
the SRAM DD. I'm a little put off by the fact that the gain in gears
comes entirely at the low end. The top developments of the SRAM DD could
use some good boosting as well. I should like to be able to at least
equal the range of the "Baroque" 81 speed setup, which is 0.98M to 9.81m.
EFR
Ile de France
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Date: 07 Sep 2007 22:22:32
From: Nigel Cliffe
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Artemisia wrote:
> Nigel Cliffe wrote:
>> Given the way your conversations are heading, suggesting problems with
>> the SRAM dual-drive, why not explore the other "fairly simple" options,
>> even if they require a rear wheel which isn't on the standard HPV list:
> Because it would actually cost more than to go with the standard fitting.
> The base price (which includes the SRAM) stays the same, and then we'd
> have to add not only the Schlumpf but the Nexus as well.
Is that because nobody will supply you a bike without a rear wheel, or
credit you at least some of the value of the unused rear wheel components ?
>> Schlumpf's website shows
>> High-Speed-Drive + SRAM 7 combined to give 1.3m to 9.9m fairly
>> evenly spaced on a 20" wheel.
>
> That is a good range. I wish I could figure out what it would be with
> the SRAM DD.
Sheldon Brown will give you the figures:
http://sheldonbrown.com/gears/
Put in the wheel size, then select cassette and the hub gear, and a tooth
count for the front chainring.
An 8 (24 total) speed SRAM DD, with an 11-30 cassette and 50T front ring
gives 1.8 to 9.2m
A 9 (27 total) speed SRAM DD, with an 11-32 cassette and 50T front ring
gives 1.7 to 9.2
> I'm a little put off by the fact that the gain in gears
> comes entirely at the low end. The top developments of the SRAM DD
> could use some good boosting as well.
The SRAM DD is limited by the fixed ratios of the 3-speed hub component.
You can alter the top and bottom at the same time by replacing the front
chainring. Larger for higher ratio, or smaller for lower, but all gears will
move.
The only way to widen the range is to fit a wide-range cassette onto the
drive. I don't know the maximum cassette which will fit the SRAM hub. The
maximum 8-speed cassette range from Shimano would be an 11-34 "mega-range".
Assuming that cassette would fit the SRAM hub, the lowest gear drops to 1.6m
(leaving the top at 9.2m). But mega-range cassettes are often criticised
for the large jump in ratio, making the change to the bottom ratio rather
abrupt.
> I should like to be able to at
> least equal the range of the "Baroque" 81 speed setup, which is 0.98M
> to 9.81m.
I doubt this is possible with the DD on its own. It is designed to achieve
a 500-odd percent range, which is the same as most wide-ratio touring bikes
with derraileur gears.
If you are sticking with the SRAM DD, then the practical way to extend the
range is one of the following:
The Schlumpf.
A 2-ring chainset (rather than 3), with something such as a 53/39 "racing
road" ratio, which would give an overall range of 1.3 to 9.8m.
Either of the above isn't quite as complicated as a triple front, but still
gives more combinations than I think sensible when combined with 24 or 27 at
the rear and the SRAM DD.
- Nigel
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
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Date: 08 Sep 2007 19:28:37
From: Artemisia
Subject: Dark Side Trike: Final Specks
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Nigel Cliffe wrote:
> If you are sticking with the SRAM DD, then the practical way to extend the
> range is one of the following:
>
> The Schlumpf.
> A 2-ring chainset (rather than 3), with something such as a 53/39 "racing
> road" ratio, which would give an overall range of 1.3 to 9.8m.
Thanks for all the maths. Today the Darth at Rando-Cycles came up with
similar figures.
I have now officially ordered the trike with the standard 24-speed SRAM
DD and option of adding a Schlumpf next year.
I've settled on:
** standard suspension (when I spoke to HPV yesterday they mentioned
that the DT Swiss was so that I could regulate the suspension when I
carried luggage; but since I'm in the range of the stiffest spring
whether I take luggage or not it seemed unnecessary expense)
** Magura Big hydraulic brakes, button activated Avid parking brake on
the rear wheel, and one hand actuation of brakes and shifters. We found
a reason why the latter is absolutely necessary. If I have any shifters
on the left side of the headset, I cannot have the Mirrycle mirror and
computer mount there. If the computer is _not_ mounted there, the
computer has to go on the boom where it is invisible while riding, IOW
useless!
** Short pedal cranks. I'm 5'7" and these are supposedly more
comfortable at that height, and better for spinning, although they do
apparently shift the gearing upwards.
** No dynamo or lights at all. I figure a great many Cateye LEDs can fit
into the price of a SON. Also the Darth reassured me that there was no
problem retrofitting a bottle dynamo if I later decided I wanted one, or
even a hub dynamo - and he recommended the Shimano as much better
rapport qualité-prix than the SON.
** Water bottles, mudguards, baggage rack, Mirrycle mirror and computer
on the left, flag.
I was extra pleased that the Darth said he could deliver. I was worrying
about how I'd get the Scorpion home from Picpus, on the metro (not).
He's also fairly sure that it can arrive by mid-October. I really really
need it to be present for its official birth on Nov. 3rd.
Now to think up a proper birthing ceremony that can be performed at 6:40
am on a Saturday in an underground garage without attracting the
attention of the police.
Ouf! Glad it's over and I can think about something else. Thanks to all
the wonderful people on these lists who have brought me so much valuable
information and discussion.
EFR
Ile de France
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Date: 09 Sep 2007 10:18:14
From: Alan Braggins
Subject: Re: Dark Side Trike: Final Specks
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In article <46e2dbc0$0$8933$426a74cc@news.free.fr >, Artemisia wrote:
>
>** No dynamo or lights at all. I figure a great many Cateye LEDs can fit
>into the price of a SON. Also the Darth reassured me that there was no
>problem retrofitting a bottle dynamo if I later decided I wanted one, or
>even a hub dynamo - and he recommended the Shimano as much better
>rapport qualité-prix than the SON.
How does he propose retrofitting fitting a Shimano hub dynamo to a tadpole
trike? I suspect many people with not-Scorpion trikes would be interested
in the answer if he has a plausible plan.
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Date: 09 Sep 2007 18:23:49
From: Artemisia
Subject: Re: Dark Side Trike: Final Specks
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Alan Braggins wrote:
> How does he propose retrofitting fitting a Shimano hub dynamo to a tadpole
> trike? I suspect many people with not-Scorpion trikes would be interested
> in the answer if he has a plausible plan.
I suppose it would require rebuilding a wheel. This particular Darth is
actually a maker of custom bikes, so I expect he has a clue. I didn't
inquire into details though.
EFR
Ile de France
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Date: 09 Sep 2007 20:15:03
From: Alan Braggins
Subject: Re: Dark Side Trike: Final Specks
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In article <46e41e11$0$32207$426a34cc@news.free.fr >, Artemisia wrote:
>Alan Braggins wrote:
>
>> How does he propose retrofitting fitting a Shimano hub dynamo to a tadpole
>> trike? I suspect many people with not-Scorpion trikes would be interested
>> in the answer if he has a plausible plan.
>
>I suppose it would require rebuilding a wheel.
That's the trivial part. Rebuilding a Shimano hub which is designed for use
in a fork so it can be mounted single sided is the tricky bit.
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Date: 09 Sep 2007 10:45:38
From: Tosspot
Subject: Re: Dark Side Trike: Final Specks
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Artemisia wrote:
<snip >
> ** Magura Big hydraulic brakes, button activated Avid parking brake on
> the rear wheel, and one hand actuation of brakes and shifters. We found
> a reason why the latter is absolutely necessary. If I have any shifters
> on the left side of the headset, I cannot have the Mirrycle mirror and
> computer mount there. If the computer is _not_ mounted there, the
> computer has to go on the boom where it is invisible while riding, IOW
> useless!
I have Magura Bigs on my Anthrotech and I don't like them. Parts seem
diffilcult to obtain because they are not cycle brakes, the levers are
nasty platic things, but they do work. I would have thought 'ordinary'
tandem rated brakes would be enough.
The rest looks quite fine though. Whatever you do, I'm sure it will
bring a smile every time you ride it. Mine does.
<snip >
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Date: 08 Sep 2007 21:43:27
From: Steve Gravrock
Subject: Re: Dark Side Trike: Final Specks
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On 2007-09-08, Artemisia <nospam@free.fr > wrote:
> ** Short pedal cranks. I'm 5'7" and these are supposedly more
> comfortable at that height, and better for spinning, although they do
> apparently shift the gearing upwards.
Just how short did you go?
My experience is that shorter cranks tend to push the cadence at which
I'm comfortable up noticeably, which is a good thing if you have bad
kees like I do. The effect on my cadence seems out of proportion to the
slightly higher effective gearing.
In any case you can always adjust your overall gearing by putting on a
smaller or larger chainring. That's especially easy if you stick with a
single-ring setup.
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Date: 06 Sep 2007 22:35:56
From: Mike A Schwab
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On Sep 5, 3:40 pm, Artemisia <nos...@free.fr > wrote:
> Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
> just had an alarming report from someone off-list that SRAM themselves
> don't warranty DualDrives on trikes and that he fried two of them on his
> trike and would never have one again.
>
> I have of course contacted SRAM to see what they say. If it turns out
> that they won't even guarantee the DualDrive on recumbent trikes despite
> the DD being standard fitting on many in that class of machines, then I
> may have to rethink the whole project.
>
> EFR
> Ile de France
I have an EZ-1 recumbent 16/20. Came with a 3 * 8 derailer, LBS had a
DD from a wheel that blew a rim, they built a wheel around it, with a
11-34 megarange cassette. I almost always stay in the middle internal
gear, the internal losses are quite noticable in high and low gear.
Even when I spin out the top gear, shifting the internal into
overdrive slows me down. But the underdrive on steep hills or if I
stop in a mid to high gear is quite useful.
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Date: 06 Sep 2007 03:10:01
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On 6 sep, 10:45, "Dave Larrington" <smert.spamio...@privacy.net >
wrote:
> If that was Ian Fardoe, I wouldn't worry too much. He's a big strong lad...
Don't know who he was. Wish he'd fess up in the ng rather than
contacting me via the back door.
BTW, glad to have you back! We were a bit worried about you for a
moment there.
EFR
Ile de France
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Date: 06 Sep 2007 01:50:50
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On 6 sep, 10:07, Peter Clinch <p.j.cli...@dundee.ac.uk > wrote:
> Artemisia wrote:
> > I don't think it's the extra wheels; rather the extra weight
>
> I doubt that. Weight is listed as "from 16.6 Kg" which is really not
> especially heavy in the wider context of "all bikes", and you don't have
> to look very hard to find bikes in the same weight range.
I meant _rider_ weight and load. The Scorpion has a rather limited
load capacity, only around 275 lbs, and I can easily see myself going
near or over that, especially with luggage.
The guy tells me he's a furious spinner, and puts a lot of torque on
his trike.
I'll try writing to HPV as well. But it's SRAM I'm really interested
in hearing from, especially if they have arguments for officially not
supporting trikes and tandems.
EFR
Ile de France
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Date: 06 Sep 2007 09:59:17
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Artemisia wrote:
> I meant _rider_ weight and load.
Actually easier to carry heavy loads on a Streetmachine, because there's
more space for panniers. And a rider on one can be the rider on the
other: shouldn't make any difference.
> The guy tells me he's a furious spinner, and puts a lot of torque on
> his trike.
And are you a furious spinner putting lots of torque on too? ICBW, but
my impression is probably not.
> I'll try writing to HPV as well. But it's SRAM I'm really interested
> in hearing from, especially if they have arguments for officially not
> supporting trikes and tandems.
If SRAM do say "no" it would then be worth asking HPVel why they're
using them if they're not supported. Bear in mind that an email answer
is not necessarily a definitive technical answer, it could just be a
case of someone punting a query up to the legal boys who don't know and
are having a busy day so they say "no" just to be safe, which is why I'd
follow up a "no" carefully with HPVel, who are rather smaller than SRAM
so you can pretty much guarantee you'll end up talking to an engineer
with Clues after a short chain.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 06 Sep 2007 10:02:54
From: Brendan Halpin
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Peter Clinch <p.j.clinch@dundee.ac.uk > writes:
> Artemisia wrote:
>> The guy tells me he's a furious spinner, and puts a lot of torque on
>> his trike.
>
> And are you a furious spinner putting lots of torque on too? ICBW, but
> my impression is probably not.
That's backwards, isn't it: it's the mashers that put out high
torque, not the spinners.
Brendan
--
Brendan Halpin, Department of Sociology, University of Limerick, Ireland
Tel: w +353-61-213147 f +353-61-202569 h +353-61-338562; Room F2-025 x 3147
mailto:brendan.halpin@ul.ie http://www.ul.ie/sociology/brendan.halpin.html
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Date: 06 Sep 2007 10:59:29
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Brendan Halpin wrote:
> Peter Clinch <p.j.clinch@dundee.ac.uk> writes:
>
>> Artemisia wrote:
>>> The guy tells me he's a furious spinner, and puts a lot of torque on
>>> his trike.
>> And are you a furious spinner putting lots of torque on too? ICBW, but
>> my impression is probably not.
>
> That's backwards, isn't it: it's the mashers that put out high
> torque, not the spinners.
All else being equal, yes. But I imagine, say, Lance Armstrong probably
puts more torque through his gears than I do at 2/3 the cadence...
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 05 Sep 2007 23:18:32
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On 6 sep, 01:41, Daniel Barlow <d...@coruskate.net > wrote:
> Artemisia wrote:
> Not a trike, but we've got one on a four-wheeled bike (Brox). Why
> should the extra wheels fry them, though?
I don't think it's the extra wheels; rather the extra weight, and the
fact that one can attempt a greater range of tracks including much
steeper uphills and downhills. In addition to being very heavy myself
I want to take this trike on laden tours.
EFR
Ile de France
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Date: 06 Sep 2007 09:07:06
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Artemisia wrote:
> I don't think it's the extra wheels; rather the extra weight
I doubt that. Weight is listed as "from 16.6 Kg" which is really not
especially heavy in the wider context of "all bikes", and you don't have
to look very hard to find bikes in the same weight range.
The Streetmachine is "from 15.2 Kg" for example, and if you look at
bikes where no real attempt has been made on lightness I think you could
easily get over that.
> and the
> fact that one can attempt a greater range of tracks including much
> steeper uphills and downhills.
And I doubt that too. You can attempt anything on anything, spinning
out on the downhills puts no pressure on the gears and uphill most
people run out of muscle before they topple over from balance.
> In addition to being very heavy myself
> I want to take this trike on laden tours.
There's no shortage of big people touring on /very/ well laden bikes.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 06 Sep 2007 14:03:35
From: Alan Braggins
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
In article <5k9qooF2orogU1@mid.individual.net >, Peter Clinch wrote:
> uphill most
>people run out of muscle before they topple over from balance.
They mostly don't have 81 gear bikes though.
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Date: 06 Sep 2007 23:16:48
From: Aeek
Subject: Re: Dark Side Trike: 81 Gears Useful?
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On 06 Sep 2007 14:03:35 +0100 (BST), armb@chiark.greenend.org.uk (Alan
Braggins) wrote:
>In article <5k9qooF2orogU1@mid.individual.net>, Peter Clinch wrote:
>> uphill most
>>people run out of muscle before they topple over from balance.
>
>They mostly don't have 81 gear bikes though.
I have a 24-32 granny on the 700c tourer, good for 4kmh up hill.
No problems with balance.
Taking a rest is the problem, I can't get up to 4kmh fast enough to
get going again in the granny.
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Date: 06 Sep 2007 14:13:00
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Alan Braggins wrote:
> In article <5k9qooF2orogU1@mid.individual.net>, Peter Clinch wrote:
>> uphill most
>> people run out of muscle before they topple over from balance.
>
> They mostly don't have 81 gear bikes though.
It's not really relevant how many gears you have, it's how fast you're
going that will determine if you topple a bike over up a steep hill.
And IME people just get fed up and walk before they reach that point.
I recall one incident when a pal and I were taking our MTBs up a fairly
steep grassy field. I got bored at walking pace, and decided I'd walk.
While walking, I soon overtook my pal, still spinning happily in 1st...
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 06 Sep 2007 15:18:53
From: Alan Braggins
Subject: Re: Dark Side Trike: 81 Gears Useful?
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In article <5kacmaF2qoipU1@mid.individual.net >, Peter Clinch wrote:
>Alan Braggins wrote:
>> In article <5k9qooF2orogU1@mid.individual.net>, Peter Clinch wrote:
>>> uphill most
>>> people run out of muscle before they topple over from balance.
>>
>> They mostly don't have 81 gear bikes though.
>
>It's not really relevant how many gears you have, it's how fast you're
>going that will determine if you topple a bike over up a steep hill.
Right, and with lower gears and the same amount of muscle, you can
more easily not run out of muscle by going slower.
>And IME people just get fed up and walk before they reach that point.
Less so if they have a recumbent trike to walk, I suspect.
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Date: 06 Sep 2007 18:43:34
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
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Alan Braggins wrote:
> In article <5kacmaF2qoipU1@mid.individual.net>, Peter Clinch wrote:
>>And IME people just get fed up and walk before they reach that point.
> Less so if they have a recumbent trike to walk, I suspect.
If only because they have such a hard time getting up!
EFR
Ile de France
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Date: 06 Sep 2007 15:56:28
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Alan Braggins wrote:
> Right, and with lower gears and the same amount of muscle, you can
> more easily not run out of muscle by going slower.
If you run out more easily or less easily, if you still run out before
you'd topple it's a moot point.
> Less so if they have a recumbent trike to walk, I suspect.
But as further discussions have demonstrated you can actually get a
bigger overall range and attendant lower gears in other ways than having
81 gears via a triple front and DD at the back. 81 gears is a possible
approach but a rather baroque and not optimum one.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 06 Sep 2007 16:04:08
From: Clive George
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
"Peter Clinch" <p.j.clinch@dundee.ac.uk > wrote in message
news:5kaioaF2r3v2U1@mid.individual.net...
> But as further discussions have demonstrated you can actually get a
> bigger overall range and attendant lower gears in other ways than having
> 81 gears via a triple front and DD at the back. 81 gears is a possible
> approach but a rather baroque and not optimum one.
Greenspeed (used to?) do it. He said he didn't want to use a huge ring on
the front to compensate for the little back wheel, since it wouldn't shift
as well. This was about 10 years ago mind. OTOH it's rather cheaper than the
mountain/speed drive options.
cheers,
clive
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Date: 06 Sep 2007 18:45:02
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Clive George wrote:
> Greenspeed (used to?) do it.
They still do on the GT0, SRAM DD on the back and Sturmey Archer on the
front.
EFR
Ile de France
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Date: 06 Sep 2007 14:20:48
From: Clive George
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
"Peter Clinch" <p.j.clinch@dundee.ac.uk > wrote in message
news:5kacmaF2qoipU1@mid.individual.net...
> I recall one incident when a pal and I were taking our MTBs up a fairly
> steep grassy field. I got bored at walking pace, and decided I'd walk.
> While walking, I soon overtook my pal, still spinning happily in 1st...
What is it about going up grassy fields which makes them such hard work?
(yes, I know the answer really, but it still amuses me that such innocuous
looking terrain takes so much effort).
cheers,
clive
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Date: 05 Sep 2007 22:40:45
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
just had an alarming report from someone off-list that SRAM themselves
don't warranty DualDrives on trikes and that he fried two of them on his
trike and would never have one again.
I have of course contacted SRAM to see what they say. If it turns out
that they won't even guarantee the DualDrive on recumbent trikes despite
the DD being standard fitting on many in that class of machines, then I
may have to rethink the whole project.
EFR
Ile de France
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Date: 06 Sep 2007 09:45:00
From: Dave Larrington
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
In news:46df1449$0$6117$426a74cc@news.free.fr,
Artemisia <nospam@free.fr > tweaked the Babbage-Engine to tell us:
> Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
> just had an alarming report from someone off-list that SRAM themselves
> don't warranty DualDrives on trikes and that he fried two of them on
> his trike and would never have one again.
If that was Ian Fardoe, I wouldn't worry too much. He's a big strong lad...
--
Dave Larrington
<http://www.legslarry.beerdrinkers.co.uk >
Odd, is it not, how all roads lead inexorably to David Icke?
|
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Date: 06 Sep 2007 08:56:44
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
> just had an alarming report from someone off-list that SRAM themselves
> don't warranty DualDrives on trikes and that he fried two of them on his
> trike and would never have one again.
While nobody has actually owned up here, I would think in the wider
context the answer is "probably the majority of Scorpion riders", since
it is HPVel's default gearing setup.
I suspect that (a) they tested it fairly well, (b) wouldn't supply
something that they can't back up, (c) wouldn't persist in using
something that's inherently unreliable and (d) know the track record of
quite a lot of vehicles fitted with it via warranty claims they get sent.
So I'd ask them, and make sure they'll stand behind what they supply.
The report you have is a single anecdote. When it comes to
mass-produced complex engineering you can /always/ find someone who
doesn't get on with something, and even Rolls Royce will make the odd lemon.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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Date: 06 Sep 2007 00:41:28
From: Daniel Barlow
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
> just had an alarming report from someone off-list that SRAM themselves
> don't warranty DualDrives on trikes and that he fried two of them on his
> trike and would never have one again.
Not a trike, but we've got one on a four-wheeled bike (Brox). Why
should the extra wheels fry them, though?
-dan
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Date: 05 Sep 2007 22:50:03
From: Nigel Cliffe
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Does anyone actually have a SRAM DualDrive on a recumbent trike? I've
> just had an alarming report from someone off-list that SRAM themselves
> don't warranty DualDrives on trikes and that he fried two of them on
> his trike and would never have one again.
No idea.
I had a 3x7 version on a recumbent bike (sold some years ago). The
three-speed hub bit proved very useful if I forgot to change down at
junctions. But I did notice transmission drag when in gears 1 or 3 on the
hub gear.
I had no mechanical issues with it, but I am fairly light at 68kg and didn't
take the bike on laden tours.
> I have of course contacted SRAM to see what they say. If it turns out
> that they won't even guarantee the DualDrive on recumbent trikes
> despite the DD being standard fitting on many in that class of
> machines, then I may have to rethink the whole project.
Sensible given the cost of the project.
- Nigel
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
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Date: 05 Sep 2007 14:43:15
From: bluezfolk
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
On Sep 5, 2:32 am, Artemisia <e.rose...@free.fr > wrote:
> Me again, one more question.
>
> I am assuming that I will order the Scorpion FX with the option of a
> Sram Dualdrive on the back and a three-speed cassette on the front.
> The Price List stipulates:
>
> "drivetrain DualDrive XT-81 81 speed rear derailleur XT / cassette
> XT / DualDrive 3 speed hub / bar end shifters / grip shifter for
> DualDrive gear development 0,98 - 9,81 m (3'3'' - 32'3')"
>
> I will be taking this trike up some very steep hills. I'm looking
> forward to being able to use very low gears, much lower than would
> allow me to remain upright on a 2-wheeler.
>
> However, when I spoke to a dealer in Angers about this option, he told
> me he didn't think it was very useful, insofar as the gear range would
> not be that much greater than with the SRAM Dualdrive alone, that is
> fitted as standard, and that most of the gears would be overlapping
> anyway.
>
> Flyzipper has the simple SRAM Dualdrive three by seven. Admittedly I
> have never used the lowest of his 24 gears. I do find myself spinning
> out on his highest gears, however, on some of those long smooth Czech
> descents.
>
> It also appears that the front gears would not be changeable at a
> standstill, which is a disadvantage in comparison to the Greenspeed
> GT0 setup which combines a SRAM DualDrive in the back with a Sturmey
> Archer in the front. The Scorpion 81-speed would have only the three
> SRAM levels on the back that could be shifted at a standstill.
>
> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
> sounds like it could be the option delivering the widest range.
>
> Anyway, what do does the ng think? Does this 81 speed setup really
> deliver an advantage over the standard 24 speed?
>
> Thanks again for all your expertise.
>
> EFR
> In hilly Ile de France
Isn't 81 gears a bit much?
Eric
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Date: 05 Sep 2007 20:27:56
From: Mark Pearson
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
In article <1189003395.854195.75060@y42g2000hsy.googlegroups.com >,
ericreh@yahoo.com says...
>
> Isn't 81 gears a bit much?
>
> Eric
>
I've got 82 but that's on 4 cycles.
--
Cheers,
the.Mark
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Date: 05 Sep 2007 06:53:18
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
On 5 sep, 10:17, "Nigel Cliffe" <m...@privacy.net > wrote:
> So, I assumed a 40T front and a 20inch rear wheel, the range is 1.4m to
> 7.4m.
Would it be possible to use a SRAM DD with a Sclumpf Mountain, but to
change the sprocket range on the DD so as to gear higher? Because I'm
assuming the Schlumpf will fill in a lot of speeds _underneath_ the
SRAM setup (24sp, not 27 as I initially mistook), but nothing _over_.
So moving the SRAM into an overall higher speed range with a Schlumpf
might give an overall wider range than with the existent SRAM, a
little deficient at the high end?
EFR
Ile de France
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Date: 05 Sep 2007 15:59:23
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Would it be possible to use a SRAM DD with a Sclumpf Mountain, but to
> change the sprocket range on the DD so as to gear higher?
I guess it would take a different cassette, but it would be /much/
easier to just put a bigger chainwheel on the front end, which should be
no big deal at all on a Mountain Drive.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
|
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Date: 05 Sep 2007 02:09:46
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
On 5 sep, 10:17, "Nigel Cliffe" <m...@privacy.net > wrote:
> > Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
> > sounds like it could be the option delivering the widest range.
>
> This should be retro-fittable by a competant dealer.
and
On 5 sep, 10:13, Peter Clinch <p.j.cli...@dundee.ac.uk > wrote:
> Replace the front
> derailleur with a Schlumpf to pretty much eliminate maintenance other
> than a new chain every one in a while and to give you practically zero
> chance of throwing a chain.
So if I'm reading this correctly, you both think the provided 81-gear
setup is a redundant mess, but that I could probably do quite well
ordering the standard SRAM 27-gear setup and getting a Schlumpf
mountain gear retrofitted at a later date if needed?
This would have the added advantage that I could split the payments.
The Schlumpf part could come next year, after my bank account has
recovered a little, and I could lighten up the bill to be paid up by
the end of 2007.
(Can't afford a Rohloff, Peter, alas.)
EFR
Ile de France
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Date: 05 Sep 2007 22:52:37
From: Don Whybrow
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
>
> So if I'm reading this correctly, you both think the provided 81-gear
> setup is a redundant mess, but that I could probably do quite well
> ordering the standard SRAM 27-gear setup and getting a Schlumpf
> mountain gear retrofitted at a later date if needed?
Just a thought on the Shlumpf option. IIRC the only one suitable for a
Rohloff is the Speed Drive. The Mountain and High Speed drives can
exceed the design limits of the Rholoff. Do any similar limitations
apply to the SRAM system?
--
Don Whybrow
Sequi Bonum Non Time
Give your child mental blocks for Christmas.
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Date: 05 Sep 2007 18:12:31
From: Tosspot
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> On 5 sep, 10:17, "Nigel Cliffe" <m...@privacy.net> wrote:
>
>>> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
>>> sounds like it could be the option delivering the widest range.
>>
>> This should be retro-fittable by a competant dealer.
>
>
> and
>
> On 5 sep, 10:13, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
>
>> Replace the front derailleur with a Schlumpf to pretty much
>> eliminate maintenance other than a new chain every one in a while
>> and to give you practically zero chance of throwing a chain.
The Schlumpf, while a good solution, is bloody expensive. ~400 euros to
get it delivered.
> So if I'm reading this correctly, you both think the provided 81-gear
> setup is a redundant mess, but that I could probably do quite well
> ordering the standard SRAM 27-gear setup and getting a Schlumpf
> mountain gear retrofitted at a later date if needed?
>
> This would have the added advantage that I could split the payments.
> The Schlumpf part could come next year, after my bank account has
> recovered a little, and I could lighten up the bill to be paid up by
> the end of 2007.
>
> (Can't afford a Rohloff, Peter, alas.)
You're in danger of spending the same amount of money a Rohloff would
cost in the first place imho.
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Date: 05 Sep 2007 22:33:53
From: Artemisia
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Tosspot wrote:
> The Schlumpf, while a good solution, is bloody expensive. ~400 euros to
> get it delivered.
>
> You're in danger of spending the same amount of money a Rohloff would
> cost in the first place imho.
Doesn't look like it - the Rohloff option on the HPV price-list costs
1049€, considerably more than the Schlumpf! And I'm thinking Schlumpf +
Dualdrive might give me more range than a Rohloff.
EFR
Ile de France
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Date: 05 Sep 2007 22:53:20
From: Tosspot
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Tosspot wrote:
>
>> The Schlumpf, while a good solution, is bloody expensive. ~400 euros
>> to get it delivered.
>
>
>>
>> You're in danger of spending the same amount of money a Rohloff would
>> cost in the first place imho.
>
>
> Doesn't look like it - the Rohloff option on the HPV price-list costs
> 1049€, considerably more than the Schlumpf! And I'm thinking Schlumpf +
> Dualdrive might give me more range than a Rohloff.
My thought[1] was wouldn't the rohloff with a single ring do the job?
Like I said, I've not run up the spread sheet to do the gear
inches/metres developed/squirrels flattened calculation.
Actually, I do have the schlumpf drive on my trike, not to lower the
ratio, but to stop it spinning out at around 25-30 kph, so I guess I'm
not one to comment :(
But the rohloffs are nice....
[1] I've had a few beers >:)=
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Date: 05 Sep 2007 10:36:31
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> On 5 sep, 10:17, "Nigel Cliffe" <m...@privacy.net> wrote:
>>> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
>>> sounds like it could be the option delivering the widest range.
>> This should be retro-fittable by a competant dealer.
>
> and
>
> On 5 sep, 10:13, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
>> Replace the front
>> derailleur with a Schlumpf to pretty much eliminate maintenance other
>> than a new chain every one in a while and to give you practically zero
>> chance of throwing a chain.
>
> So if I'm reading this correctly, you both think the provided 81-gear
> setup is a redundant mess
I can't speak for Nigel, but I'd put my own position not at "redundant
mess", but rather "there /are/ clear benefits but it seems excessively
baroque for what those benefits are", and it is not an avenue I would
choose myself. I'd just keep it simpler with a DD, and freewheel on the
really big downs.
> but that I could probably do quite well
> ordering the standard SRAM 27-gear setup and getting a Schlumpf
> mountain gear retrofitted at a later date if needed?
Yes.
> (Can't afford a Rohloff, Peter, alas.)
I know /exactly/ how you feel! ;-/
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
|
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Date: 05 Sep 2007 22:55:45
From: Nigel Cliffe
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Peter Clinch wrote:
> Artemisia wrote:
>> On 5 sep, 10:17, "Nigel Cliffe" <m...@privacy.net> wrote:
>>>> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
>>>> sounds like it could be the option delivering the widest range.
>>> This should be retro-fittable by a competant dealer.
>>
>> and
>>
>> On 5 sep, 10:13, Peter Clinch <p.j.cli...@dundee.ac.uk> wrote:
>>> Replace the front
>>> derailleur with a Schlumpf to pretty much eliminate maintenance
>>> other than a new chain every one in a while and to give you
>>> practically zero chance of throwing a chain.
>>
>> So if I'm reading this correctly, you both think the provided 81-gear
>> setup is a redundant mess
>
> I can't speak for Nigel, but I'd put my own position not at "redundant
> mess", but rather "there /are/ clear benefits but it seems excessively
> baroque for what those benefits are", and it is not an avenue I would
> choose myself. I'd just keep it simpler with a DD, and freewheel on
> the really big downs.
I concur, 81 gears is a very complicated system which struggles to justify
its benefits.
I might look at the costs and benefits of few other "simple" options as
well:
Rohloff alone (even if expensive).
Conventional 8/9 speed derraileur rear + Schlumpf front.
8/9 speed hub rear (Shimano/SRAM) + Schlumpf front.
8/9 speed hub rear + 2-ring derraileur front (probably barmy, but I would
think about it).
- Nigel
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
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Date: 05 Sep 2007 09:17:04
From: Nigel Cliffe
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> Me again, one more question.
>
> I am assuming that I will order the Scorpion FX with the option of a
> Sram Dualdrive on the back and a three-speed cassette on the front.
> The Price List stipulates:
>
> "drivetrain DualDrive XT-81 81 speed rear derailleur XT / cassette
> XT / DualDrive 3 speed hub / bar end shifters / grip shifter for
> DualDrive gear development 0,98 - 9,81 m (3'3'' - 32'3')"
>
> I will be taking this trike up some very steep hills. I'm looking
> forward to being able to use very low gears, much lower than would
> allow me to remain upright on a 2-wheeler.
>
> However, when I spoke to a dealer in Angers about this option, he told
> me he didn't think it was very useful, insofar as the gear range would
> not be that much greater than with the SRAM Dualdrive alone, that is
> fitted as standard, and that most of the gears would be overlapping
> anyway.
Putting all you have said into Sheldon Brown's gear calculator
(http://sheldonbrown.com/gears/) gives a massive table of gears, but
essentially:
The Dual Drive system on its own, with an 11-32 cassette at the rear gives
about a 500% gear range. This is comparable to the range in a Rohloff hub,
or a wide-range touring road bike.
How this manifests itself depends on the tooth count of the front chainring
and the diameter of the rear wheel.
So, I assumed a 40T front and a 20inch rear wheel, the range is 1.4m to
7.4m.
1.4m is pretty low for bottom gear. However, on a trike you can go as low as
you like without falling off !
For most people on a two-wheeled machine they would have trouble balancing
at 1.4m, 1.8 being a more typical bottom range of a mountain bike.
7.4m is moderately low for top gear. I would expect to be able to just pedal
to 50kph with a 7.4m gear on a downhill, though my legs would be spinning
very very quickly. I would prefer a top gear nearer to 8.5-9m. I would see
no reason to go massively above 9m for a touring bike.
From the above, my personal choice would be to use a front sprocket of 48T,
making the overall gearing a bit higher (1.6 to 8.9). But in making that
decision, you'd need to take into account the exact rear wheel size (which I
may have estimated incorrectly) and your personal preference for bottom and
top gears.
Adding a triple front chain ring set, whilst this gives you 81 gears, about
75 of them are within the range offered by the Dual-Drive on its own. You
only gain three or four steps at the extremes. I doubt that many of the 75
in the middle offer any advantage over 27; most will be indistinguishable
from the gears already present. Therefore, I tend to agree with your dealer
that the extra steps offered by combining both is marginal.
> Flyzipper has the simple SRAM Dualdrive three by seven. Admittedly I
> have never used the lowest of his 24 gears. I do find myself spinning
> out on his highest gears, however, on some of those long smooth Czech
> descents.
A problem which could be corrected by changing the front chain-ring for a
larger size. Thus the lowest gears would be a bit higher, and the largest
gear even higher.
> It also appears that the front gears would not be changeable at a
> standstill, which is a disadvantage in comparison to the Greenspeed
> GT0 setup which combines a SRAM DualDrive in the back with a Sturmey
> Archer in the front. The Scorpion 81-speed would have only the three
> SRAM levels on the back that could be shifted at a standstill.
Correct.
> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
> sounds like it could be the option delivering the widest range.
This should be retro-fittable by a competant dealer.
> Anyway, what do does the ng think? Does this 81 speed setup really
> deliver an advantage over the standard 24 speed?
>
> Thanks again for all your expertise.
>
> EFR
> In hilly Ile de France
--
Nigel Cliffe,
Webmaster at http://www.2mm.org.uk/
|
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Date: 05 Sep 2007 09:13:05
From: Peter Clinch
Subject: Re: Dark Side Trike: 81 Gears Useful?
|
Artemisia wrote:
> "drivetrain DualDrive XT-81 81 speed rear derailleur XT / cassette
> XT / DualDrive 3 speed hub / bar end shifters / grip shifter for
> DualDrive gear development 0,98 - 9,81 m (3'3'' - 32'3')"
>
> I will be taking this trike up some very steep hills. I'm looking
> forward to being able to use very low gears, much lower than would
> allow me to remain upright on a 2-wheeler.
>
> However, when I spoke to a dealer in Angers about this option, he told
> me he didn't think it was very useful, insofar as the gear range would
> not be that much greater than with the SRAM Dualdrive alone, that is
> fitted as standard, and that most of the gears would be overlapping
> anyway.
He's right about the overlapping (and then some), but wrong about the
overall range. The front triple is 60/52/40, so that gives a 60/40 =
1.5 difference in gearing from using the big ring or small ring, so
that's half as much gear range again as without the front triple.
But it's a rather odd setup... You could have, say, a 50/34 compact
double at the front for pretty much the same degree of useful effect,
less weight, less confusion and less cost.
> Unfortunately HPV doesn't offer Schlumpf Mountain Gearing, which
> sounds like it could be the option delivering the widest range.
Not in their standard price list, but a Schlumpf dealer should be able
to fit one for you. I know that Kinetics have put several Schlumpfs
into HPVels so there's nothing intrinsically problematical about it.
> Anyway, what do does the ng think? Does this 81 speed setup really
> deliver an advantage over the standard 24 speed?
Up to a point. I think it's an odd selection of front rings and will be
rather complicated and fussy in use to get optimum gearing. I'd be much
more inclined to put in a Rohloff with a twin front derailleur to give
you that sort of range as it will be much easier to use and maintain and
probably be more efficient and lighter too. Replace the front
derailleur with a Schlumpf to pretty much eliminate maintenance other
than a new chain every one in a while and to give you practically zero
chance of throwing a chain.
Pete.
--
Peter Clinch Medical Physics IT Officer
Tel 44 1382 660111 ext. 33637 Univ. of Dundee, Ninewells Hospital
Fax 44 1382 640177 Dundee DD1 9SY Scotland UK
net p.j.clinch@dundee.ac.uk http://www.dundee.ac.uk/~pjclinch/
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