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Main
Date: 06 May 2007 09:10:25
From: Dave
Subject: Kona bottom bracket and headset
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Hi All,
I've got a Kona Lava Dome MTB which is now about 10 years old. I'm
using it more frequently these days, but it's showing its age.
Firstly, I had suspected that the headset bearings were going when
the
steering became 'crunchy'. Secondly, there is considerable slack in
the bottom bracket to the point that on half the cycle, the chain
rubbed against the derailer.
Being an engineer by trade I have bravely decided to fix these
problems. First, I took the headset to bits. The top headset bearing
looked OK but the bottom one fell to pieces with ball bearings flying
around. It was also very rusty and clearly no oil or grease had
passed
that way for some time. Clearly this bearing is knackered, but where
can I get a replacement?. The young herbert from halfords suggested
that I should replace the headset which I thought was completely
unnecessary when a replacement bearing would do the job. So my first
questions is, how do I go about getting a replacement for this
bearing
and is it likely to be Kona-specific or am I likely to be able to get
this from another supplier?. There are various websites like:
http://www.bonthronebikes.co.uk/435-0
but there's nothing there that refers to particular bike makes or
models or that looks right anyhow.
The next problem (the bottom bracket) seems to require a number of
specific tools to 'crack' it open. Firstly, I used a crack remover to
get that out of the way. Next I am faced with a chrome ring 6 notches
around the edge. See picture:
http://www.moorenet.co.uk/IMG_0875.JPG
Now, I've seen a number of tools on the web for unscrewing these
types
of things, but they don't look appropriate for this particular
fitting. Next, the cartridge end seems to be 'turnable' only through
some holes in its end into which I suspect some exotic (and to doubt
expensive) tool should be inserted.
So what's my best approach?. Can I get the appropriate tools or are
they simply not available anymore?.
Ta in advance,
Dave
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Date: 06 May 2007 22:15:15
From: Steve Gravrock
Subject: Re: Kona bottom bracket and headset
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On 2007-05-06, Dave <dave_m_moore@post2me.freeserve.co.uk > wrote:
> Hi All,
> I've got a Kona Lava Dome MTB which is now about 10 years old. I'm
> using it more frequently these days, but it's showing its age.
> Firstly, I had suspected that the headset bearings were going when
> the
> steering became 'crunchy'. Secondly, there is considerable slack in
> the bottom bracket to the point that on half the cycle, the chain
> rubbed against the derailer.
>
> Being an engineer by trade I have bravely decided to fix these
> problems. First, I took the headset to bits. The top headset bearing
> looked OK but the bottom one fell to pieces with ball bearings flying
> around. It was also very rusty and clearly no oil or grease had
> passed
> that way for some time. Clearly this bearing is knackered, but where
> can I get a replacement?.
Clean the bearing races thoroughly and inspect them. Look for any rust
or pitting, and run a ball-point pen around each race to check for
roughness. From your description, I expect that you'll find significant
damage to at least the fork crown race.
If everything's in good shape, repack with new balls and waterproof
grease. If on the other hand there's damage, I agree that you're better
off having the headset replaced. Even if the headset isn't so badly
damaged as to be unusable, it'll be much harder to adjust properly.
Get it replaced, and then the next time it needs service you'll be
able to learn with undamaged parts.
> The young herbert from halfords suggested
> that I should replace the headset which I thought was completely
> unnecessary when a replacement bearing would do the job. So my first
> questions is, how do I go about getting a replacement for this
> bearing
> and is it likely to be Kona-specific or am I likely to be able to get
> this from another supplier?.
Any bike shop or bearing supplier should be able to sell you appropriate
balls if you bring the old ones in. Likewise, your local bike shop is
your best bet for a replacement headset. Headsets are cheap enough, but
replacing them requires some fairly expensive special tools that the bike
shop already has and you probably don't have.
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Date: 06 May 2007 19:13:03
From: Ryan Cousineau
Subject: Re: Kona bottom bracket and headset
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In article <1178467824.939692.283890@o5g2000hsb.googlegroups.com >,
Dave <dave_m_moore@post2me.freeserve.co.uk > wrote:
> Hi All,
> I've got a Kona Lava Dome MTB which is now about 10 years old. I'm
> using it more frequently these days, but it's showing its age.
> Firstly, I had suspected that the headset bearings were going when
> the
> steering became 'crunchy'. Secondly, there is considerable slack in
> the bottom bracket to the point that on half the cycle, the chain
> rubbed against the derailer.
>
> Being an engineer by trade I have bravely decided to fix these
> problems. First, I took the headset to bits. The top headset bearing
> looked OK but the bottom one fell to pieces with ball bearings flying
> around. It was also very rusty and clearly no oil or grease had
> passed
> that way for some time. Clearly this bearing is knackered, but where
> can I get a replacement?. The young herbert from halfords suggested
> that I should replace the headset which I thought was completely
> unnecessary when a replacement bearing would do the job. So my first
> questions is, how do I go about getting a replacement for this
> bearing
> and is it likely to be Kona-specific or am I likely to be able to get
> this from another supplier?. There are various websites like:
Replace the headset. It's cheap, quick, and quite likely that if the
balls are bad, the races are bad too. Check them for pitting and
discolouration.
> http://www.bonthronebikes.co.uk/435-0
> but there's nothing there that refers to particular bike makes or
> models or that looks right anyhow.
The headset for your bike will be one of four types: 1" or 1-1/8", and
threaded or threadless. The most likely combos for that bike are 1"
threaded or 1-1/8" threadless, but the other two are not impossible.
Those first two should be stocked by any bike shop worth the name, 1"
threadless are a common road standard, and 1-1/8" threaded is rare,
If the top cap of the headset unscrews from the top of the fork's
steerer tube, that's threaded. If there are no threads on the top of the
fork's steer tube, you have a threadless headset.
The inch-measure diameter refers to the ID of the head where the headset
cups press in. The easiest way to check the size is to measure the steer
tube, which is commensurately smaller: 7/8" OD for a 1" headset, and 1"
OD for a 1-1/8" headset
> The next problem (the bottom bracket) seems to require a number of
> specific tools to 'crack' it open. Firstly, I used a crack remover to
> get that out of the way. Next I am faced with a chrome ring 6 notches
> around the edge. See picture:
> http://www.moorenet.co.uk/IMG_0875.JPG
> Now, I've seen a number of tools on the web for unscrewing these
> types
> of things, but they don't look appropriate for this particular
> fitting. Next, the cartridge end seems to be 'turnable' only through
> some holes in its end into which I suspect some exotic (and to doubt
> expensive) tool should be inserted.
> So what's my best approach?. Can I get the appropriate tools or are
> they simply not available anymore?.
First, you're going to need to take the opposite crankarm off to finish
this job, and the best time is now, before you loosen off the BB cups.
The tools you're seeing are for the newer Shimano splined bottom
brackets ("BB"), which you do not have. The tools to take your BB out
are widely available, though while virtually any shop will have a set in
their shop, many will not stock them for sale.
The outer ring (shiny in your picture) is a lockring, and can be easily
bodged off with a hammer and punch on one of those notches. The inner
cup will then be removable, but you'll still need a pin spanner, a
somewhat specialized tool (it's not strictly a bike-specific tool, but
few home mechanics would have one). You can order one. There is no easy
bodge I know of.
Here's a nice reference to the BB tools:
http://parktool.com/products/category.asp?cat=25
An HCW-5 would be the proper (but not vital) lockring tool. An HCW-4 or
one of their two round-pin spanner tools (differing in their pin
diameters) will do.
With the cup removed, you'll find a bunch of bearings, probably caged,
and you can pull the spindle free, which will give you access to the
other set of bearings too. You don't have to remove the other (the
"fixed") cup at this point.
Check and clean the bearing balls. These are readily available at good
bike shops and wherever fine bearings are sold.
Check the bearing races on the cups and the spindle. If worn or pitted,
replace. If you have to replace either of these items, it may be easier
to just buy a new cartridge BB, since price for good ones start at $20,
and life is short.
There's more.
--
Ryan Cousineau rcousine@sfu.ca http://www.wiredcola.com/
"I don't want kids who are thinking about going into mathematics
to think that they have to take drugs to succeed." -Paul Erdos
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Date: 06 May 2007 22:46:24
From: Steve Gravrock
Subject: Re: Kona bottom bracket and headset
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On 2007-05-06, Ryan Cousineau <rcousine@sfu.ca > wrote:
> The headset for your bike will be one of four types: 1" or 1-1/8", and
> threaded or threadless. The most likely combos for that bike are 1"
> threaded or 1-1/8" threadless, but the other two are not impossible.
> Those first two should be stocked by any bike shop worth the name, 1"
> threadless are a common road standard, and 1-1/8" threaded is rare,
1-1/8 is relatively uncommon, but if the OP is right about his bike's
age I wouldn't be at all surprised to learn that that's what he has.
Fortunately they're still available, although the selection is a bit
limited. QBP still carries a couple, so most bike shops should be able
to order one even if they don't have any languishing in a drawer
somewhere.
<http://preview.tinyurl.com/3bpu8f >
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