Back on my mountain bike :(

Just after my previous post about mysterious noises on my road bike and
all the wonderful plans I had for this weekend, I went to ride the road
bike to the Eastern suburbs as is my wont around this time of day.

I got it out and had not gone 3m and went change gears and the fscking
gear assembly just came off the bike I have an old Suntour gearing
system which bolts onto the bike frame and being a very very old bike, I
had not realised that over time, the threads had rusted on the "nut"
welded on the frame, so basically the bolt which holds the gear lever
assembly on the frame has stripped the threads of the "nut". Just can't
believe I was so stupid as to not think something as basic as rusting
could occur on this part of the bike and I could have done something

I discovered that if I can get a longer bolt (maybe 1/4" longer) I might
be able to hold the gear lever assembly to the frame as the threads
deeper down in the "nut" appear to be ok (if that makes sense).

Alternatively, I could cut the threads on the nut again to a different
pitch(?) and use a different bolt - pain in the posterior to get it right.

Or find some way to repair the threads on the nut - haven't got a clue
if this is possible.

Or grind away the nut on the frame and weld on a new nut - might have to
call in some favours and even then I might end up with a bogey job as
the frame wall is probably quite thin.

Or get a new gear assembly which is strapped onto the frame a la the old
Raleigh frame I found in a council cleanup (which I am loath to
cannablise because I was planning to restore that frame).

Well, whatever my options are, I am stuck with my 24-speed Repco
mountain bike for a while.

I would appreciate suggestions as to how I could fix the stripped
threads on the nut as I do prefer the road bike for my everyday
commuting as the Repco is not setup for commuting.

Hmm... maybe I should use the other old mountain bike instead of the
Repco, a 15-20 y.o.(?) Gemini 21-speed with twist gears. The Gemini is
setup for longer distance riding but with 26" wheels and dodgy gears
..... you know, you know ....

In aus.bicycle on Thu, 10 Jun 2010 01:11:25 +1000
Geoff Lock glock@home wrote:
Or find some way to repair the threads on the nut - haven't got a clue
if this is possible.

The usual method of repairing threads is a Helicoil or similar. You'd
have to measure the thread size and pitch and find if there's a thread
replacement that will fit.

There's also a thing called a rivnut which might replace the hole and
thread you have.

Zebee

Are they indexed or friction shifters?

If you can live with friction shifters I can check my used parts bin for a
pair of clamp-on shifters for you (I have an ample supply in both
bottom-tube and headstem sized varieties.)


BTH

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On 10/06/2010 9:39 AM, BT Humble wrote:
Are they indexed or friction shifters?

If you can live with friction shifters I can check my used parts bin for a
pair of clamp-on shifters for you (I have an ample supply in both
bottom-tube and headstem sized varieties.)

Friction shifters.

Whereabouts you be, matey?

On 10/06/2010 5:51 AM, Zebee Johnstone wrote:
In aus.bicycle on Thu, 10 Jun 2010 01:11:25 +1000
Geoff Lockglock@home wrote:
Or find some way to repair the threads on the nut - haven't got a clue
if this is possible.

The usual method of repairing threads is a Helicoil or similar. You'd
have to measure the thread size and pitch and find if there's a thread
replacement that will fit.

I vaguely recall the term Helicoil. Thanks for jogging my memory, Zeebee.

There's also a thing called a rivnut which might replace the hole and
thread you have.

Thanks again for this tip.

Geoff Lock wrote:

On 10/06/2010 9:39 AM, BT Humble wrote:
Are they indexed or friction shifters?

If you can live with friction shifters I can check my used parts bin for a
pair of clamp-on shifters for you (I have an ample supply in both
bottom-tube and headstem sized varieties.)

Friction shifters.

Whereabouts you be, matey?

Canberra, but Australia Post delivers just about anywhere.

Let me know the diameter of the down tube on your bike and I'll have a
look (assuming that I can't interest you in a headstem-mounted set?) :-)


BTH

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On 10/06/2010 6:50 PM, BT Humble wrote:
Geoff Lock wrote:

On 10/06/2010 9:39 AM, BT Humble wrote:

Whereabouts you be, matey?

Canberra, but Australia Post delivers just about anywhere.

Let me know the diameter of the down tube on your bike and I'll have a
look (assuming that I can't interest you in a headstem-mounted set?) :-)

I just walked in (it's 0430 in Sydney now) after riding 14kms in the
freezing cold - well, it seemed cold given my rather fragile
constituition so lemme warm up a bit, have something to eat, etc etc
and I'll go look for my verniers. They are somewhere around.

I may have to consider a headstem mounted set (something I never thought
of) but somehow I think that the path the cables run to the derailleurs
could be a problem. I'll have to think it through first before troubling
you but thank you for the very kind offer.

Geoff Lock wrote:
I may have to consider a headstem mounted set (something I never thought
of) but somehow I think that the path the cables run to the derailleurs
could be a problem. I'll have to think it through first before troubling
you but thank you for the very kind offer.

There are some special fittings to make it work, I'll find a picture of an
example of how it's done if you like.


BTH

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On 11/06/2010 5:12 PM, BT Humble wrote:
Geoff Lock wrote:
I may have to consider a headstem mounted set (something I never thought
of) but somehow I think that the path the cables run to the derailleurs
could be a problem. I'll have to think it through first before troubling
you but thank you for the very kind offer.

There are some special fittings to make it work, I'll find a picture of an
example of how it's done if you like.

BT, I am very grateful for the help you have so kindly offered over the
last coupla days and it makes me feel like I should be trying harder at
my own end as well to lessen the burden I am to others.

So here is an update of the state of the "nation", so to speak.

I went to see John Abeni at Europa Bikes in Kensington, NSW and
explained my problem to him. He found a head stem gear lever assembly
and gave me some tips as to how to set up the cables. The gear assembly
had been apparently sitting in the cupboard for nearly 30 years and
coincidentally is also a Suntour - brand new never used! He also had a
Campagnolo which I could not afford - very lightweight, compact, great
action and very snazzy. I now have a backup plan in the head stem set
because I was also talking to another friend about my problem.

Mick has a friend who owns a workshop which works only on high
performance Subarus - street and race. In exchange for a couple of hours
of muscle power in moving some furniture around the place, Mick will
have a look at my bike : helicoil as per Zeebee's suggestion, grind and
replace, re-tap, make a new bolt and nut or remanufacture a new gear
lever system if he felt like it, whatever (although remanufacturing is
an unlikely option as he may not be inclined to turn on the various
machines required in the process.)

So, please do take it easy for the time being, put up your feet and
relax whilst I see what comes out of Mick's efforts and/or my backup
plan with the headtem set I picked up from Johnno.

I have still not found my verniers but if you saw my "workshop" you will
not be too surprised either

On another note, the Gemini MTB actually feels quite good to ride on
despite me not having ridden it for nearly 12mths. The twist gear for
the rear derailleur is a bit stiff and edgy but all the gear changes are
good, so I am getting some good speeds on it. Just gotta do something
about the front brakes though - very very dodgy.

Thanks for all your help and advice so far

Geoff Lock wrote:
On another note, the Gemini MTB actually feels quite good to ride on
despite me not having ridden it for nearly 12mths. The twist gear for
the rear derailleur is a bit stiff and edgy

That's pretty much standard for a grip shifter. If you can dismantle and
lube the cable it'll help a bit.

...but all the gear changes are
good, so I am getting some good speeds on it. Just gotta do something
about the front brakes though - very very dodgy.

V-brake or cantilever? If they're calipers then you have my pity! :-)

Thanks for all your help and advice so far

No problemo, I'm doing my cycling vicariously through you at the moment
(operational requirements are only leaving me averaging 2 bicycle commutes
per week).


BTH

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