chain problems on single speed cruiser



Hi

I am having intermittent drive train problems on a Schwinn SSX Single
Speed cruiser that I recently bought new. I ride the bike about 3
miles to the station and along the way the chain is prone to jumping
especially under load or when going along a bumpy road. The chain
often drops off the cogs completely once or twice along the way. It
also tends to jam the pedals from moving forward and if I pedal
backwards very slightly and forwards again it seems to avert the chain
from falling off.

The bike shop said it might be a chain tension issue and they
installed a new chain and apparently set the tension.

Any ideas as this has lost my confidence in the reliability of the
bike. I am wondering if it is more of an alignment problem but all
looks ok to me....

Thanks
 
in message <[email protected]>,
[email protected] (' [email protected]') wrote:

> I am having intermittent drive train problems on a Schwinn SSX Single
> Speed cruiser that I recently bought new. I ride the bike about 3
> miles to the station and along the way the chain is prone to jumping
> especially under load or when going along a bumpy road. The chain
> often drops off the cogs completely once or twice along the way. It
> also tends to jam the pedals from moving forward and if I pedal
> backwards very slightly and forwards again it seems to avert the chain
> from falling off.
>
> The bike shop said it might be a chain tension issue and they
> installed a new chain and apparently set the tension.


This really should not happen.

On a single speed it's pretty important that the chainline is straight - in
other words that the sprocket on the rear hub is in the same plane as the
chainwheel. You can check this by sighting along the chain - does it look
straight? If it isn't, take it back to the shop where you bought it and
tell them to fix it.

Next, the chain should not be bar taut, but you should not be able to lift
the chain in the middle of its run by more than about half an inch. If you
can then it is not tight enough.

At the end of the rear forks there should be a slot on each side which is
more or less horizontal (or else there should be an eccentric bottom
bracket, but this is more unusual and usually only on expensive bikes).
The ends of the axle sit in this slot, and are (on single speeds) held in
place by two large nuts. To adjust the chain tension, slacken the nuts and
move the axle back until the chain is taut enough (test as stated above),
then tighten the nuts firmly. What I suspect is happening is either that
the bike shop didn't tighten the nuts enough, or else they aren't gripping
well enough; in either case the axle is slipping forward under load.

If this continues to happen after you have adjusted the chain and tightened
the nuts firmly, you could fit 'chain tugs', which prevent the axle being
pulled forward.

http://www.wiggle.co.uk/ProductDetail.aspx?ProdID=5300005220

--
[email protected] (Simon Brooke) http://www.jasmine.org.uk/~simon/

;; may contain traces of nuts, bolts or washers.
 
In article <[email protected]>,
[email protected] says...
> Hi
>
> I am having intermittent drive train problems on a Schwinn SSX Single
> Speed cruiser that I recently bought new. I ride the bike about 3
> miles to the station and along the way the chain is prone to jumping
> especially under load or when going along a bumpy road. The chain
> often drops off the cogs completely once or twice along the way. It
> also tends to jam the pedals from moving forward and if I pedal
> backwards very slightly and forwards again it seems to avert the chain
> from falling off.
>
> The bike shop said it might be a chain tension issue and they
> installed a new chain and apparently set the tension.


They've probably fixed it - it's possible they know there's an issue
with poor quality chains on these bikes[1] and they routinely replace
them with better ones if they cause a problem.
>
> Any ideas as this has lost my confidence in the reliability of the
> bike. I am wondering if it is more of an alignment problem but all
> looks ok to me....
>

It could be a number of things. Here's how to check for some of them:
Take the chainguard and chain off and turn the cranks while looking
closely at the teeth on the chainring from above - if a tooth is bent or
if the chainring is warped it should be fairly obvious.
Repeat with the rear sprocket, although excessive float and bent teeth
are pretty unlikely there.
From the front, sight along the inside of the chainring to the inside of
the rear sprocket - they should appear pretty much in line.
Refit the chain, make sure the rear wheel is centred in the frame and
pulled back as far as it will go to tension the chain.
Turn the cranks backwards - there shouldn't be any tight spots in chain
tension. If there is a tight spot reset the chain tension at that point
and check again. Check for loose spots - finger pressure on the middle
of the chain run shouldn't move the chain vertically by more than half
an inch or so. If you can't eliminate tight spots without creating
excessively loose spots the chainring might be off-centre and need
replacement.
Turning the crank backwards, watch the chain as it comes off the bottom
of the rear sprocket - any stiff links should be fairly obvious, you
might be able to free them off by hand by bending the chain from side to
side a few times, otherwise you'll need a chain rivet tool.


[1] I'm only guessing, but I've seen this sort of thing before.
 
On 1 Jul, 12:46, Rob Morley <[email protected]> wrote:
> In article <[email protected]>,
> [email protected] says...
>
> > Hi

>
> > I am having intermittent drive train problems on a Schwinn SSX Single
> > Speed cruiser that I recently bought new. I ride the bike about 3
> > miles to the station and along the way the chain is prone to jumping
> > especially under load or when going along a bumpy road. The chain
> > often drops off the cogs completely once or twice along the way. It
> > also tends to jam the pedals from moving forward and if I pedal
> > backwards very slightly and forwards again it seems to avert the chain
> > from falling off.

>
> > The bike shop said it might be a chain tension issue and they
> > installed a new chain and apparently set the tension.

>
> They've probably fixed it - it's possible they know there's an issue
> with poor quality chains on these bikes[1] and they routinely replace
> them with better ones if they cause a problem.
>
> > Any ideas as this has lost my confidence in the reliability of the
> > bike. I am wondering if it is more of an alignment problem but all
> > looks ok to me....

>
> It could be a number of things. Here's how to check for some of them:
> Take the chainguard and chain off and turn the cranks while looking
> closely at the teeth on the chainring from above - if a tooth is bent or
> if the chainring is warped it should be fairly obvious.
> Repeat with the rear sprocket, although excessive float and bent teeth
> are pretty unlikely there.
> From the front, sight along the inside of the chainring to the inside of
> the rear sprocket - they should appear pretty much in line.
> Refit the chain, make sure the rear wheel is centred in the frame and
> pulled back as far as it will go to tension the chain.
> Turn the cranks backwards - there shouldn't be any tight spots in chain
> tension. If there is a tight spot reset the chain tension at that point
> and check again. Check for loose spots - finger pressure on the middle
> of the chain run shouldn't move the chain vertically by more than half
> an inch or so. If you can't eliminate tight spots without creating
> excessively loose spots the chainring might be off-centre and need
> replacement.
> Turning the crank backwards, watch the chain as it comes off the bottom
> of the rear sprocket - any stiff links should be fairly obvious, you
> might be able to free them off by hand by bending the chain from side to
> side a few times, otherwise you'll need a chain rivet tool.
>
> [1] I'm only guessing, but I've seen this sort of thing before.


Thanks for the great advice, will do some more investigation! - Steve
 
On 1 Jul, 20:27, [email protected] wrote:
> On 1 Jul, 12:46, Rob Morley <[email protected]> wrote:
>
>
>
>
>
> > In article <[email protected]>,
> > [email protected] says...

>
> > > Hi

>
> > > I am having intermittent drive train problems on aSchwinnSSXSingle
> > > Speed cruiser that I recently bought new. I ride the bike about 3
> > > miles to the station and along the way the chain is prone to jumping
> > > especially under load or when going along a bumpy road. The chain
> > > often drops off the cogs completely once or twice along the way. It
> > > also tends to jam the pedals from moving forward and if I pedal
> > > backwards very slightly and forwards again it seems to avert the chain
> > > from falling off.

>
> > > The bike shop said it might be a chain tension issue and they
> > > installed a new chain and apparently set the tension.

>
> > They've probably fixed it - it's possible they know there's an issue
> > with poor quality chains on these bikes[1] and they routinely replace
> > them with better ones if they cause a problem.

>
> > > Any ideas as this has lost my confidence in the reliability of the
> > > bike. I am wondering if it is more of an alignment problem but all
> > > looks ok to me....

>
> > It could be a number of things. Here's how to check for some of them:
> > Take the chainguard and chain off and turn the cranks while looking
> > closely at the teeth on the chainring from above - if a tooth is bent or
> > if the chainring is warped it should be fairly obvious.
> > Repeat with the rear sprocket, although excessive float and bent teeth
> > are pretty unlikely there.
> > From the front, sight along the inside of the chainring to the inside of
> > the rear sprocket - they should appear pretty much in line.
> > Refit the chain, make sure the rear wheel is centred in the frame and
> > pulled back as far as it will go to tension the chain.
> > Turn the cranks backwards - there shouldn't be any tight spots in chain
> > tension. If there is a tight spot reset the chain tension at that point
> > and check again. Check for loose spots - finger pressure on the middle
> > of the chain run shouldn't move the chain vertically by more than half
> > an inch or so. If you can't eliminate tight spots without creating
> > excessively loose spots the chainring might be off-centre and need
> > replacement.
> > Turning the crank backwards, watch the chain as it comes off the bottom
> > of the rear sprocket - any stiff links should be fairly obvious, you
> > might be able to free them off by hand by bending the chain from side to
> > side a few times, otherwise you'll need a chain rivet tool.

>
> > [1] I'm only guessing, but I've seen this sort of thing before.

>
> Thanks for the great advice, will do some more investigation! - Steve- Hide quoted text -
>
> - Show quoted text -


FYI - Took my bike back to the bike shop and this time they noticed
two things:

- The front chain ring was slightly bent if the rotation is viewed
from above. This could have caused the back wheel to be slowly forced
out of alignment and eventually lead to the problems I am seeing...

- Also, while chain tension throughout one revolution of the chain
ring can be slightly different my chain ring when rotated display
large differences in chain tension. Making it difficult to maintain
proper tension throughout the revolution.

All in all I will probably replace the chain ring and all should be
OK.

Thanks
S
 
In article <[email protected]>,
[email protected] says...

> FYI - Took my bike back to the bike shop and this time they noticed
> two things:
>
> - The front chain ring was slightly bent if the rotation is viewed
> from above. This could have caused the back wheel to be slowly forced
> out of alignment and eventually lead to the problems I am seeing...


If that's what they said then I reckon they're either clueless or trying
to baffle you with ********.
>
> - Also, while chain tension throughout one revolution of the chain
> ring can be slightly different my chain ring when rotated display
> large differences in chain tension. Making it difficult to maintain
> proper tension throughout the revolution.


They should have spotted that when they fitted the new chain.
>
> All in all I will probably replace the chain ring and all should be
> OK.
>

I wonder if maybe you should find a bike shop where the staff don't wear
Stetsons. Was this the same shop that sold you the bike?