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Main
Date: 17 May 2007 16:31:17
From: John Verheul
Subject: Increase trail or longer front center
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Since moving out west (US) a couple years ago, practice as I might I just
can't quite descend with riders who are otherwise of my ability. Recently,
I've also been having a hard time cornering in criteriums at high speeds
(over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
and getting caught when I attack because I'm just not carrying as much speed
as my competition.
I practice plenty (have a 14 mile climb behind my house with switchbacks,
and a local training crit), and it's my 21st season of racing, so I'm going
to assume I've maximized the skills area as much as I can. The bike is also
fine when at training speeds, it's just in relatively high speed
descending/cornering situations I cannot get around the turns as quickly as
I'd like.
I'm slightly taller than average at 6'1", and don't use a lot of setback on
my road bike (7-8cm), so I suspected I might have too much weight on the
front wheel. Bathroom scale measurements indicate I don't. It's right around
43/57 front/rear.
So now I'm looking at frame geometry. I'm using a frame that has a steep
74' head angle, and a 45mm raked fork. With a 23c tire that's only about
4.9cm of trail, very low by most standards. Bike also has a pretty short
front-center of 60cm (on a 60cm frame).
My options to improve handling as I see it are:
1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
respectively, more in what most people seem to feel is a more average range
for a racing bike.
2) Get a frame with a longer front center to move cg even further back in
the wheelbase, thus keeping more weight off the front wheel in steep
descending corners (but perhaps leading to front wheel washout in flat crit
corners?).
Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
why?
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Date: 24 May 2007 17:44:40
From: John Verheul
Subject: Re: Increase trail or longer front center
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Followup: Replaced the 45mm fork with a 40, same model. Bike feels 100%
better after the last 3 days of deliberately finding fast descents with
tight turns (I live in the southern Rockies). Solid & stable, much like the
last bike I really felt that way on. Trail on that bike as well as the bike
now is 54 (close to Tim M's "ideal" of 55).
Thanks everyone for the thoughts and helping me hash it out, it helped a
lot.
John Verheul
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Date: 22 May 2007 17:03:15
From: Michael Press
Subject: Re: Increase trail or longer front center
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In article <464cd7e9$0$509$815e3792@news.qwest.net >,
"John Verheul" <vjohn1020@qwest.net > wrote:
> Since moving out west (US) a couple years ago, practice as I might I just
> can't quite descend with riders who are otherwise of my ability. Recently,
> I've also been having a hard time cornering in criteriums at high speeds
> (over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
> and getting caught when I attack because I'm just not carrying as much speed
> as my competition.
>
> I practice plenty (have a 14 mile climb behind my house with switchbacks,
> and a local training crit), and it's my 21st season of racing, so I'm going
> to assume I've maximized the skills area as much as I can. The bike is also
> fine when at training speeds, it's just in relatively high speed
> descending/cornering situations I cannot get around the turns as quickly as
> I'd like.
>
> I'm slightly taller than average at 6'1", and don't use a lot of setback on
> my road bike (7-8cm), so I suspected I might have too much weight on the
> front wheel. Bathroom scale measurements indicate I don't. It's right around
> 43/57 front/rear.
>
> So now I'm looking at frame geometry. I'm using a frame that has a steep
> 74' head angle, and a 45mm raked fork. With a 23c tire that's only about
> 4.9cm of trail, very low by most standards. Bike also has a pretty short
> front-center of 60cm (on a 60cm frame).
>
> My options to improve handling as I see it are:
>
> 1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
> respectively, more in what most people seem to feel is a more average range
> for a racing bike.
>
> 2) Get a frame with a longer front center to move cg even further back in
> the wheelbase, thus keeping more weight off the front wheel in steep
> descending corners (but perhaps leading to front wheel washout in flat crit
> corners?).
>
> Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
> why?
Another comment from a non-racer in northern
California. I have an old steel frame and a new steel
frame, both with ~71 deg angles. Old is a Raleigh
International, it is slower into corners, but feels
rock solid. The new oversize steel frame is quick into
corners, and rock solid. The fork offsets are 55 and 45
mm respectively.
My technique. Unload the inside pedal, get fully out of
the saddle, unload the outside hand, put my attention
on the two contact patches, and watch where I want to
go. The feeling is that I am light on the bicycle and
not forcing anything. It is at the point when I unload
the outside hand that the turn begins in earnest.
I practice this at low speed, 15-25 km/hr on my
residential street doing U-turns in mid-block and
dOnuts in intersections, creeping up on the absolute
maximum tilt and rate of turn. My music teacher said
that if I want to play it fast, first I must be able to
play it slow. Through practice I am taking turns flat
out where I used to back off, and catching up
(temporarily!) with riders on full out race frames who
are much faster than me.
--
Michael Press
(not a pot smoker)
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Date: 21 May 2007 00:05:44
From: bjw@mambo.ucolick.org
Subject: Re: Increase trail or longer front center
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On May 18, 8:27 am, "John Verheul" <vjohn1...@qwest.net > wrote:
> "Tim McNamara" <tim...@bitstream.net> wrote in message
>
> That's kind of the thing, the last bike I won a crit on (and felt more
> comfortable cornering on) was my 2004 Cannondale team bike, which had a bit
> more trail at 73.5 w/45mm rake. It's only in the last year or so I've been
> able to choose my own bike, I always had a team bike before this.
>
> > How does if feel in fast corners? Do you feel like the front end is
> > going to wash out? Does if feel like the rear wheel is going to come
> > around and slide out?
>
> The latter, I feel like any line adjustment I have to make I'm going to put
> too much weight on the front wheel and wash the rear. Last tough descent I
> raced was a couple weeks ago (points as steep as 17%, with switchbacks),
> and I literally did slide the rear around a couple of the corners, which
> didn't help my confidence. To be fair, the guy dropping me is an ex-euro
> pro, but other local nobodies like me are able to hang better than I.
>
A lot of descending and cornering is mental. If you
think it's the trail, then changing the trail is likely
to help. I don't know if this is a placebo effect
or if that's unfair since it's a genuine confidence
issue. That said, I never liked bikes with a steep
front end that are harder to ride no hands, and think
this also makes descending sketchier. That said, I am
a crummy descender anyway (for a racer; in the
century-rider population there are even worse).
Another thing. You mentioned not hanging with the locals.
This doesn't apply to crits, just hills, but some places
in the US just have way more long technical descents
than others and so the locals get more practice. In
Norcal there are plenty of tight twisty roads that drop
1000-2000+ feet elevation. I'm sure there are some in
New England, but not so much in some other places
(like Pennsylvania).
And one last thing. I never could hang with the locals
on sketchy descents in Norcal (Alpine Road in particular),
but they gave me a great piece of advice: "Never follow
a pot smoker downhill."
Ben
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Date: 21 May 2007 22:01:19
From: Dan Connelly
Subject: Re: Increase trail or longer front center
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bjw@mambo.ucolick.org wrote:
> And one last thing. I never could hang with the locals
> on sketchy descents in Norcal (Alpine Road in particular),
I'm fine on Alpine. But follow Dave Stahl or Kevin Merritt down Kings or Page? No way.
Dan
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Date: 19 May 2007 13:44:56
From: Callistus Valerius
Subject: Re: Increase trail or longer front center
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> Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
> why?
>
-----------
from someone who is not a racer, and doesn't like to descend.
wider tires help, especially in the front.
always counter-steer, don't lean.
always descend on the hoods, not the drops (this helped the most, as the
upright position does most of the braking, can actually see the road) With
the wind pushing on your torso it pushes the weight back, as opposed to
braking which puts the weight up front. Also you can ride on the pedals,
instead of the saddle, and helps when you hit bumps. It took me a long time
to figure this one out.
I have bikes with less trail, and more trail. The more trail one is harder
to turn, but gives you confidence because you really have to be active on
the bike. With less trail the bike can turn on it's own, but sometimes
makes you feel uneasy because you feel like a passenger on a run-away train.
I perfer more trail, even though it's harder to turn, because it makes you
feel like you are in control, also it seems to put the weight farther back.
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Date: 19 May 2007 10:30:24
From: John Verheul
Subject: Re: Increase trail or longer front center
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"Callistus Valerius" <jazzyboss@hotmail.com > wrote in message
news:sbD3i.8089$296.4237@newsread4.news.pas.earthlink.net...
> With less trail the bike can turn on it's own, but sometimes
> makes you feel uneasy because you feel like a passenger on a run-away
> train.
This is the sensation I have...I'm thinking more and more it's the trail.
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Date: 21 May 2007 22:04:11
From: Dan Connelly
Subject: Re: Increase trail or longer front center
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John Verheul wrote:
> "Callistus Valerius" <jazzyboss@hotmail.com> wrote in message
> news:sbD3i.8089$296.4237@newsread4.news.pas.earthlink.net...
>> With less trail the bike can turn on it's own, but sometimes
>> makes you feel uneasy because you feel like a passenger on a run-away
>> train.
>
> This is the sensation I have...I'm thinking more and more it's the trail.
>
>
Interestingly, this discussion motivated me to try keeping my weight further back when I descend, reducing front wheel load. I think it helped.
Dan
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Date: 18 May 2007 18:42:48
From: almost_fast@yahoo.com
Subject: Re: Increase trail or longer front center
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On May 17, 5:31 pm, "John Verheul" <vjohn1...@qwest.net > wrote:
> Since moving out west (US) a couple years ago, practice as I might I just
> can't quite descend with riders who are otherwise of my ability. Recently,
> I've also been having a hard time cornering in criteriums at high speeds
> (over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
> and getting caught when I attack because I'm just not carrying as much speed
> as my competition.
>
> I practice plenty (have a 14 mile climb behind my house with switchbacks,
> and a local training crit), and it's my 21st season of racing, so I'm going
> to assume I've maximized the skills area as much as I can. The bike is also
> fine when at training speeds, it's just in relatively high speed
> descending/cornering situations I cannot get around the turns as quickly as
> I'd like.
>
> I'm slightly taller than average at 6'1", and don't use a lot of setback on
> my road bike (7-8cm), so I suspected I might have too much weight on the
> front wheel. Bathroom scale measurements indicate I don't. It's right around
> 43/57 front/rear.
>
> So now I'm looking at frame geometry. I'm using a frame that has a steep
> 74' head angle, and a 45mm raked fork. With a 23c tire that's only about
> 4.9cm of trail, very low by most standards. Bike also has a pretty short
> front-center of 60cm (on a 60cm frame).
>
> My options to improve handling as I see it are:
>
> 1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
> respectively, more in what most people seem to feel is a more average range
> for a racing bike.
>
> 2) Get a frame with a longer front center to move cg even further back in
> the wheelbase, thus keeping more weight off the front wheel in steep
> descending corners (but perhaps leading to front wheel washout in flat crit
> corners?).
>
> Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
> why?
As others have said, there may be more to it than geometry, like
adequate frame stiffness. What bike are you on now?
As far as steering geometry goes, I've ridden tons of different bikes
and can relate. Skidding the rear in tight switchbacks too: I did that
a couple of times a month or so ago in Mallorca while on a club
training week there. Scared by teammates, and me too!
I'd 1) get a stiffer frame (Scott and Cannondale measure stiffer than
many others; the CAAD 5 a bit stiffer than the CAAD7), or 2) try a
fork with less offset to get more trail (more like your old bike). I
wouldn't mess around with 43 mm; go for 40 or so. IMHO, 2 mm just
isn't enough of a change to know if adjusting trail is what you're
after.
Just looked up the head angles on Scott (73 or 73.3 on the larger
sizes) and Cannondale (73.5 on the CAAD5). Both of these, especially
the Cannondale, are closer to what you said your old bike was.
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Date: 19 May 2007 10:33:23
From: John Verheul
Subject: Re: Increase trail or longer front center
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<almost_fast@yahoo.com > wrote in message
news:1179538968.402600.304910@y80g2000hsf.googlegroups.com...
> As others have said, there may be more to it than geometry, like
> adequate frame stiffness. What bike are you on now?
Specialized E5. Oversized aluminum.
> I'd 1) get a stiffer frame (Scott and Cannondale measure stiffer than
> many others; the CAAD 5 a bit stiffer than the CAAD7),
CAAD5 was my team bike in 2001 - 2002, then we got CAAD7's from '03 - '04
(and I kept riding through 2006, until a friend of mine fell on it and
creased the seatstay). Yeah, these were better...but I don't have access to
a C-Dale deal right now, so I was hoping to make the E5 a little better.
> or 2) try a
> fork with less offset to get more trail (more like your old bike). I
> wouldn't mess around with 43 mm; go for 40 or so. IMHO, 2 mm just
> isn't enough of a change to know if adjusting trail is what you're
> after.
Since I can get a fork for pretty cheap, I think I'm going to try this.
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Date: 18 May 2007 12:54:07
From: Scott
Subject: Re: Increase trail or longer front center
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On May 18, 9:27 am, "John Verheul" <vjohn1...@qwest.net > wrote:
> "Tim McNamara" <tim...@bitstream.net> wrote in message
>
> news:timmcn-30DA12.23222617052007@news.iphouse.com...
>
> > I think the issue may be other than trail. Before you commit to
> > spending money for changing your bike, borrow one with the front end
> > geometry you're thinking and give it a try. 45 mm fork offset with 74
> > degree head angle and 700 x 23s is a bit unusual but not beyond the
> > pale. After all, lots of perfectly ridable bikes have trail numbers
> > down into the 35 mm range (and up to 60 mm or so).
>
> That's kind of the thing, the last bike I won a crit on (and felt more
> comfortable cornering on) was my 2004 Cannondale team bike, which had a bit
> more trail at 73.5 w/45mm rake. It's only in the last year or so I've been
> able to choose my own bike, I always had a team bike before this.
>
> > How does if feel in fast corners? Do you feel like the front end is
> > going to wash out? Does if feel like the rear wheel is going to come
> > around and slide out?
>
> The latter, I feel like any line adjustment I have to make I'm going to put
> too much weight on the front wheel and wash the rear. Last tough descent I
> raced was a couple weeks ago (points as steep as 17%, with switchbacks),
> and I literally did slide the rear around a couple of the corners, which
> didn't help my confidence. To be fair, the guy dropping me is an ex-euro
> pro, but other local nobodies like me are able to hang better than I.
>
> This is what got me thinking about the front center distance. But the weight
> distribution tells me that's not so much the issue.
>
> > Are you faster around left hand bends than right
> > hand bends (or voce versa)?
>
> Not really.
>
> > Have you tried different tires (e.g., 700 x 25 slicks)? Have you played
> > with tore pressure (100 psi vs 110 psi vs 120) to see if that
> > beneficially changes the feel of the bike?
>
> Yes on all accounts, and no not really any difference.
>
> > Are your shoulders tense? Death grip on the bars? Craning your neck to
> > see the line through the corner? All of those can slow you down. Some
> > fine tuning of your position might benefit.
>
> My front end is already pretty high for a racer (drop to bars is 10cm, has
> been as much as 13 at points in my life), and the position is great for
> everything else. I should mention I do professional bike fits myself.
>
> Relaxing in corners...yeah I practice that, and I know that staying loose on
> the bike is key. Sliding the rear wheel doesn't help with that (although I
> caught the slides and stayed up), there just seems to be some feedback
> coming from the bike, the "too far forward" sensation that's making me less
> comfortable in high speed corners.
>
> I should add, I'm fine on straight descents...get up over 50mph no problem,
> feel comfortable, typically can move up in groups in these situations. Same
> for low speed (<25mph) corners in crits. It's just when we go fast (and
> selections are made), I'm closing gaps after every corner.
I've thought of one other thing. I heard once that one of the
Carney's (the brothers, not folks who travel with carnivals) suggested
setting up your brakes so that they don't really grab all that well
until just before the levers contact the bars. That way when you
'panic' you don't make things worse by over-breaking. It may help if
you don't brake so much and loosening your brakes may help with that.
I don't really suggest disconnecting them altogether.
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Date: 18 May 2007 11:43:05
From: Ron Ruff
Subject: Re: Increase trail or longer front center
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John Verheul wrote:
> "Tim McNamara" <timmcn@bitstream.net> wrote in message
> > How does if feel in fast corners? Do you feel like the front end is
> > going to wash out? Does if feel like the rear wheel is going to come
> > around and slide out?
>
> The latter, I feel like any line adjustment I have to make I'm going to put
> too much weight on the front wheel and wash the rear. Last tough descent I
> raced was a couple weeks ago (points as steep as 17%, with switchbacks),
> and I literally did slide the rear around a couple of the corners, which
> didn't help my confidence.
Whoa! Sliding the rear on smooth clean pavement? Assuming that you are
using good tires, I don't know what to say about that... unless maybe
you are really leaning over the front or using the brakes... or just
going too fast for the line. You aren't pedaling I hope...
Steep technical descents are extreme, but it puzzles me more that you
are having the same problem in crits. I can't remember any crits I've
been in where a turn could not be taken at 35+ mph, if I could pick my
line. I'm sure they exist but they are not common.
You've tried different tires and pressures... have you tried a
different rear wheel?
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Date: 17 May 2007 23:22:26
From: Tim McNamara
Subject: Re: Increase trail or longer front center
|
In article <464cd7e9$0$509$815e3792@news.qwest.net >,
"John Verheul" <vjohn1020@qwest.net > wrote:
> Since moving out west (US) a couple years ago, practice as I might I
> just can't quite descend with riders who are otherwise of my ability.
> Recently, I've also been having a hard time cornering in criteriums
> at high speeds (over 30mph). Lower speed laps I'm fine, but I'm
> closing gaps on fast laps, and getting caught when I attack because
> I'm just not carrying as much speed as my competition.
>
> I practice plenty (have a 14 mile climb behind my house with
> switchbacks, and a local training crit), and it's my 21st season of
> racing, so I'm going to assume I've maximized the skills area as much
> as I can. The bike is also fine when at training speeds, it's just in
> relatively high speed descending/cornering situations I cannot get
> around the turns as quickly as I'd like.
>
> I'm slightly taller than average at 6'1", and don't use a lot of
> setback on my road bike (7-8cm), so I suspected I might have too much
> weight on the front wheel. Bathroom scale measurements indicate I
> don't. It's right around 43/57 front/rear.
>
> So now I'm looking at frame geometry. I'm using a frame that has a
> steep 74' head angle, and a 45mm raked fork. With a 23c tire that's
> only about 4.9cm of trail, very low by most standards. Bike also has
> a pretty short front-center of 60cm (on a 60cm frame).
>
> My options to improve handling as I see it are:
>
> 1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or
> 5.4 respectively, more in what most people seem to feel is a more
> average range for a racing bike.
>
> 2) Get a frame with a longer front center to move cg even further
> back in the wheelbase, thus keeping more weight off the front wheel
> in steep descending corners (but perhaps leading to front wheel
> washout in flat crit corners?).
>
> Any opinions? If I pick option 1, would you get a 40 or 43 rake fork,
> and why?
I think the issue may be other than trail. Before you commit to
spending money for changing your bike, borrow one with the front end
geometry you're thinking and give it a try. 45 mm fork offset with 74
degree head angle and 700 x 23s is a bit unusual but not beyond the
pale. After all, lots of perfectly ridable bikes have trail numbers
down into the 35 mm range (and up to 60 mm or so).
How does if feel in fast corners? Do you feel like the front end is
going to wash out? Does if feel like the rear wheel is going to come
around and slide out? Are you faster around left hand bends than right
hand bends (or voce versa)?
Have you tried different tires (e.g., 700 x 25 slicks)? Have you played
with tore pressure (100 psi vs 110 psi vs 120) to see if that
beneficially changes the feel of the bike?
Are your shoulders tense? Death grip on the bars? Craning your neck to
see the line through the corner? All of those can slow you down. Some
fine tuning of your position might benefit.
|
| | |
Date: 18 May 2007 09:27:48
From: John Verheul
Subject: Re: Increase trail or longer front center
|
"Tim McNamara" <timmcn@bitstream.net > wrote in message
news:timmcn-30DA12.23222617052007@news.iphouse.com...
> I think the issue may be other than trail. Before you commit to
> spending money for changing your bike, borrow one with the front end
> geometry you're thinking and give it a try. 45 mm fork offset with 74
> degree head angle and 700 x 23s is a bit unusual but not beyond the
> pale. After all, lots of perfectly ridable bikes have trail numbers
> down into the 35 mm range (and up to 60 mm or so).
That's kind of the thing, the last bike I won a crit on (and felt more
comfortable cornering on) was my 2004 Cannondale team bike, which had a bit
more trail at 73.5 w/45mm rake. It's only in the last year or so I've been
able to choose my own bike, I always had a team bike before this.
> How does if feel in fast corners? Do you feel like the front end is
> going to wash out? Does if feel like the rear wheel is going to come
> around and slide out?
The latter, I feel like any line adjustment I have to make I'm going to put
too much weight on the front wheel and wash the rear. Last tough descent I
raced was a couple weeks ago (points as steep as 17%, with switchbacks),
and I literally did slide the rear around a couple of the corners, which
didn't help my confidence. To be fair, the guy dropping me is an ex-euro
pro, but other local nobodies like me are able to hang better than I.
This is what got me thinking about the front center distance. But the weight
distribution tells me that's not so much the issue.
> Are you faster around left hand bends than right
> hand bends (or voce versa)?
Not really.
> Have you tried different tires (e.g., 700 x 25 slicks)? Have you played
> with tore pressure (100 psi vs 110 psi vs 120) to see if that
> beneficially changes the feel of the bike?
Yes on all accounts, and no not really any difference.
> Are your shoulders tense? Death grip on the bars? Craning your neck to
> see the line through the corner? All of those can slow you down. Some
> fine tuning of your position might benefit.
My front end is already pretty high for a racer (drop to bars is 10cm, has
been as much as 13 at points in my life), and the position is great for
everything else. I should mention I do professional bike fits myself.
Relaxing in corners...yeah I practice that, and I know that staying loose on
the bike is key. Sliding the rear wheel doesn't help with that (although I
caught the slides and stayed up), there just seems to be some feedback
coming from the bike, the "too far forward" sensation that's making me less
comfortable in high speed corners.
I should add, I'm fine on straight descents...get up over 50mph no problem,
feel comfortable, typically can move up in groups in these situations. Same
for low speed (<25mph) corners in crits. It's just when we go fast (and
selections are made), I'm closing gaps after every corner.
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Date: 18 May 2007 19:42:44
From: John Forrest Tomlinson
Subject: Re: Increase trail or longer front center
|
On Fri, 18 May 2007 09:27:48 -0600, "John Verheul"
<vjohn1020@qwest.net > wrote:
>. It's only in the last year or so I've been
>able to choose my own bike, I always had a team bike before this.
Cry me a river ;-)
--
JT
****************************
Remove "remove" to reply
Visit http://www.jt10000.com
****************************
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Date: 18 May 2007 16:03:27
From: Tim McNamara
Subject: Re: Increase trail or longer front center
|
In article <464dc720$0$511$815e3792@news.qwest.net >,
"John Verheul" <vjohn1020@qwest.net > wrote:
> "Tim McNamara" <timmcn@bitstream.net> wrote in message
> news:timmcn-30DA12.23222617052007@news.iphouse.com...
> > I think the issue may be other than trail. Before you commit to
> > spending money for changing your bike, borrow one with the front
> > end geometry you're thinking and give it a try. 45 mm fork offset
> > with 74 degree head angle and 700 x 23s is a bit unusual but not
> > beyond the pale. After all, lots of perfectly ridable bikes have
> > trail numbers down into the 35 mm range (and up to 60 mm or so).
>
> That's kind of the thing, the last bike I won a crit on (and felt
> more comfortable cornering on) was my 2004 Cannondale team bike,
> which had a bit more trail at 73.5 w/45mm rake. It's only in the last
> year or so I've been able to choose my own bike, I always had a team
> bike before this.
>
> > How does if feel in fast corners? Do you feel like the front end
> > is going to wash out? Does if feel like the rear wheel is going to
> > come around and slide out?
>
> The latter, I feel like any line adjustment I have to make I'm going
> to put too much weight on the front wheel and wash the rear. Last
> tough descent I raced was a couple weeks ago (points as steep as
> 17%, with switchbacks), and I literally did slide the rear around a
> couple of the corners, which didn't help my confidence.
I imagine not.
> To be fair, the guy dropping me is an ex-euro pro, but other local
> nobodies like me are able to hang better than I.
>
> This is what got me thinking about the front center distance. But the
> weight distribution tells me that's not so much the issue.
I still am not thinking that trail is the issue, although I could
certainly be wrong due to bias (I like bikes with about 55 mm trail
best, but I am also riding on wider tires which makes a difference).
Usually low trail gives the steering a light feel that some people don't
like. However, low trail bikes also tend to be less responsive to
leaning the bike to turn- requiring more handlebar input- and maybe
that's what's making the difference for you.
This sort of thing is a real puzzle to figure out.
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Date: 18 May 2007 17:20:53
From: John Verheul
Subject: Re: Increase trail or longer front center
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> Usually low trail gives the steering a light feel that some people don't
> like. However, low trail bikes also tend to be less responsive to
> leaning the bike to turn- requiring more handlebar input- and maybe
> that's what's making the difference for you.
That sort of strikes a chord with me...maybe this low trail bike (all my
previous bikes have been 51 or more) just requires more hb input than I'm
used to and/or comfortable with.
Maybe I just need to grow a pair, dive into a couple fast corners and steer
the damn bike. It's not like I don't have health insurance...or scars
already.
> This sort of thing is a real puzzle to figure out.
Indeed.
Thanks everyone for the thoughts so far.
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Date: 17 May 2007 20:57:36
From: Ron Ruff
Subject: Re: Increase trail or longer front center
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John Verheul wrote:
> The bike is also
> fine when at training speeds, it's just in relatively high speed
> descending/cornering situations I cannot get around the turns as quickly as
> I'd like.
I'm sure you could dust me on a technical descent as well... but you
are racing against pros so the competition is pretty tough. I doubt
that your frame, steering geometry, or weight distribution is an issue
here. A steep geometry with little trail is *easier* to turn... if
anything it would feel twitchy and sensitive when you want to relax. I
used to have a steep and stiff frame and I liked it better for turns
than what I have now. But hey... it's a bicycle... it takes very
little muscle to get any of them to turn.
What is actually slowing you down? You must be getting some sensation
that causes you to back off. Is there noticeable flex in the bars,
stem, or fork? Those things can contribute, but I don't think they are
very important if you have good technique. After the turn is initiated
there shouldn't be significant twisting or lateral forces on the bike.
Maybe you tend to tense up in the turns... have you had a crash
recently? Being "loose" and balanced with a light touch is important,
I think.
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Date: 18 May 2007 12:42:17
From: Dan Connelly
Subject: Re: Increase trail or longer front center
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Ron Ruff wrote:
> I'm sure you could dust me on a technical descent as well... but you
> are racing against pros so the competition is pretty tough. I doubt
> that your frame, steering geometry, or weight distribution is an issue
> here. A steep geometry with little trail is *easier* to turn... if
> anything it would feel twitchy and sensitive when you want to relax. I
> used to have a steep and stiff frame and I liked it better for turns
> than what I have now. But hey... it's a bicycle... it takes very
> little muscle to get any of them to turn.
>
The amount of muscle isn't the issue. It's how comfortable you feel. I feel more comfortable in turns with more stability. The bike feels like it's will track better. Twitchy and quick isn't what you want, here.
I don't know why you doubt geometry is a factor. It doesn't take much to improve a sense of control. I could easily tell the difference with 2 cm off my stem. 1-2 cm of handlebar width also makes a difference. I've not experimented with trail.
Dan
P.S. I'm a slow descender, myself, so take this for what it's worth.
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Date: 18 May 2007 09:31:47
From: John Verheul
Subject: Re: Increase trail or longer front center
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"Ron Ruff" <rruffrruff@yahoo.com > wrote in message
news:1179460656.080325.220080@e65g2000hsc.googlegroups.com...
> What is actually slowing you down? You must be getting some sensation
> that causes you to back off.
That's what I'm trying to identify, and thus solve.
> Is there noticeable flex in the bars,
> stem, or fork? Those things can contribute, but I don't think they are
> very important if you have good technique. After the turn is initiated
> there shouldn't be significant twisting or lateral forces on the bike.
Same bar/stem as prior year's bikes, fork is Reynolds Ouzo Pro, have used
various front wheels, tires, tire pressures.
> Maybe you tend to tense up in the turns... have you had a crash
> recently? Being "loose" and balanced with a light touch is important,
> I think.
Yeah, no crashes recently...although maybe I'm just getting even more
conservative as I get older. Knock on wood, I can't even remember my last
road crash (in 'cross I crash often enough though).
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Date: 17 May 2007 17:19:01
From: datakoll@yahoo.com
Subject: Re: Increase trail or longer front center
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is it possible to assemble the pieces both + and - then try each setup
out in real time?
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Date: 17 May 2007 15:54:09
From: Scott
Subject: Re: Increase trail or longer front center
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On May 17, 4:31 pm, "John Verheul" <vjohn1...@qwest.net > wrote:
> Since moving out west (US) a couple years ago, practice as I might I just
> can't quite descend with riders who are otherwise of my ability. Recently,
> I've also been having a hard time cornering in criteriums at high speeds
> (over 30mph). Lower speed laps I'm fine, but I'm closing gaps on fast laps,
> and getting caught when I attack because I'm just not carrying as much speed
> as my competition.
>
> I practice plenty (have a 14 mile climb behind my house with switchbacks,
> and a local training crit), and it's my 21st season of racing, so I'm going
> to assume I've maximized the skills area as much as I can. The bike is also
> fine when at training speeds, it's just in relatively high speed
> descending/cornering situations I cannot get around the turns as quickly as
> I'd like.
>
> I'm slightly taller than average at 6'1", and don't use a lot of setback on
> my road bike (7-8cm), so I suspected I might have too much weight on the
> front wheel. Bathroom scale measurements indicate I don't. It's right around
> 43/57 front/rear.
>
> So now I'm looking at frame geometry. I'm using a frame that has a steep
> 74' head angle, and a 45mm raked fork. With a 23c tire that's only about
> 4.9cm of trail, very low by most standards. Bike also has a pretty short
> front-center of 60cm (on a 60cm frame).
>
> My options to improve handling as I see it are:
>
> 1) Get a 40 or 43mm raked fork, which would increase trail to 5.1 or 5.4
> respectively, more in what most people seem to feel is a more average range
> for a racing bike.
>
> 2) Get a frame with a longer front center to move cg even further back in
> the wheelbase, thus keeping more weight off the front wheel in steep
> descending corners (but perhaps leading to front wheel washout in flat crit
> corners?).
>
> Any opinions? If I pick option 1, would you get a 40 or 43 rake fork, and
> why?
John,
My impression is that there's nothing about your bike's geometry
that's causing the problem. Most bikes within a reasonable range will
corner just fine, so long as the 'driver' is willing to. Unless your
bike loses traction at the speeds your talking about, or bursts into
flames, or whatever, it's the rider and not the bike that's causing
the problem.
Having said that, it's also quite possible that your bike IS
contributing to the problem in ways that the geometry doesn't have
anything to do with. For example, I find that I'm much more willing
to descend or corner faster on a bike with a stiffer fork and front
end. I've found that a 'loose' feeling in the front end is a bit
unnerving and the flexiness I feel is misinterpreted as the tires
about to lose traction. With a stiffer frame, I'm more confident and
thus descend/corner faster.
For example, last year I switched from a reasonably stiff titanium
frame to a Madone SL frame. Much stiffer headtube. I found that on a
certain route near my home with some moderately tight, but not
switchback tight, curves, I could take the descent at full speed and
never feel the need to back off or to brake even a little bit. On the
ti frame I always stopped pedalling and often felt compelled to scrub
a little speed before entering the turns. Just wasn't sure enough
that everything was okay. Considering that the wheels and tires were
switched from one frame to another, the big difference was the
frameset.
Of course, if you're going to switch frames to something that's
stiffer, you may as well try to maximize your position/fit on the new
one while you're at it.
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Date: 17 May 2007 16:30:45
From: Dan Connelly
Subject: Re: Increase trail or longer front center
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Scott wrote:
> My impression is that there's nothing about your bike's geometry
> that's causing the problem. Most bikes within a reasonable range will
> corner just fine, so long as the 'driver' is willing to.
I'm sure even John could dust me on a technical descent, but I find my descending is position-dependent. Going to a shorter stem seemed to help a lot. John's measurement of front wheel and rear wheel normal load, given preference to a reduced front wheel load, is consistent with this.
I rode San Francisco - > Palo Alto this morning (41 miles), for Bike to Work Day, with a group including a guy on one of these:
http://www.electrabike.com/04/images/townie_section/home_page/01.jpg
He appeared to have a very low front wheel load, with his COM almost over his rear axle. It would be interesting to see how well that would handle a twisting descent. Unfortunately, we had none on our route.
Dan
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