Still got a problem with my chain or derailler set-up...

[Maz]

Hi

I was riding to work this morning. Gears changing OK.

However, when I push the pedal around in the reverse direction (e.g. foot clipped in and getting foot at the top of the stroke ready for starting from stopped at lights or in stationary traffic) the chain goes really, really slack and the jockey wheels moves forward a lot. Makes an unhealthy noise, too.

In the end, I turned around and went home, in case I was damaging the chain and/or mech.

Does anyone know what's going wrong? I'm getting really pssed off - I thought the bike was A-OK what with sorting the 'ratchety' chain problem (posted in another thread).

Will try and post a video later to show you what's happening.

 

[monkeypony]

Possibly the chain trying to hop down the cassette. Its quite usual when the chain is running at an angle. If you're stopped at lights and change down to the big ring at the back to pull away but leave it in the big ring at the front the angle of the chain will cause it to hop down the cassette when back pedalling. This may be your problem.

 

[Moodyman]

No idea Maz.

But you'll be pleased to know you're not alone with bike trouble.

For the last two weeks, I’ve been commuting with a strong brake rub on my front wheel and only yesterday discovered the cause.

I serviced my front hub a couple of weeks ago and when I put it back together the hub axle moved a fraction of a mm to one side causing the disc brake rotor to rub on the pads.

I re-tuned the hub cones last night after the homeward commute and all works well. But as I spent half an hour in the cold garage with sweaty clothes, I’ve now got a sniffle and a headache.

Should have kept pedalling with the brake rub…me thinks.

Hope this makes you feel better about your problem.

 

[potsy]

I'd try tweaking the barrel adjuster on the rear mech Maz, 1/4 turn at a time only though. After each turn spin the pedals backwards slowly and watch for any juddering.
Mine was doing this and it was sorted quite quickly.

 

[dodgy]

Hi

I was riding to work this morning. Gears changing OK.

However, when I push the pedal around in the reverse direction (e.g. foot clipped in and getting foot at the top of the stroke ready for starting from stopped at lights or in stationary traffic) the chain goes really, really slack and the jockey wheels moves forward a lot. Makes an unhealthy noise, too.

In the end, I turned around and went home, in case I was damaging the chain and/or mech.

Does anyone know what's going wrong? I'm getting really pssed off - I thought the bike was A-OK what with sorting the 'ratchety' chain problem (posted in another thread).

Will try and post a video later to show you what's happening.

Sounds like your freehub is freezing up, probably oil/grease has thickened up. Normal service will be resumed when we get the thaw.

 

[I like Skol]

Sounds like your freehub is freezing up, probably oil/grease has thickened up. Normal service will be resumed when we get the thaw.

I was going to suggest the above also. If you can't wait for a thaw (how long?) or it doesn't improve then you will have to resort to a hub stripdown and either try to lube the freewheel or replace with a shiny new one (they are probably considered consumeables by the manufacturer?)

 

[Maz]

I'd try tweaking the barrel adjuster on the rear mech Maz, 1/4 turn at a time only though. After each turn spin the pedals backwards slowly and watch for any juddering.
Mine was doing this and it was sorted quite quickly.

Thanks for the suggestion. I'll give this a try.
Presumablly clockwise turns of the barrel adjuster to tighten up?

 

[Smokin Joe]

Thanks for the suggestion. I'll give this a try.
Presumablly clockwise turns of the barrel adjuster to tighten up?

Anti clockwise to take up cable slack.

 

[Maz]

Anti clockwise to take up cable slack.

Thank you.

 

[dodgy]

If your chain goes slack when reverse peddaling, it really is a sympton of stuck freehub. If you start meddling with cable adjustments you'll just introduce more hassle

 

[Gerry Attrick]

Also check that the jockey wheels are running freely.

 

[02GF74]

For the last two weeks, I’ve been commuting with a strong brake rub on my front wheel and only yesterday discovered the cause.

I serviced my front hub a couple of weeks ago and when I put it back together the hub axle moved a fraction of a mm to one side causing the disc brake rotor to rub on the pads.

I re-tuned the hub cones last night after the homeward commute and all works well. But as I spent half an hour in the cold garage with sweaty clothes, I’ve now got a sniffle and a headache.

How is that possible? The position of the hub on the axle is determined by where the cones are and the lock nut which holds in place the cones butts up agasint the drop outs; in other words you can change the position of the hub on the axle - but the hub, and thus the brake disc, remains in the same place relative to the drop outs and brake caliper.

here's a picture showing the locknut that I refer to.

 

[screenman]

Think about it with a bit of logic. You back pedal this moves top of the chain towards the freewheel or sprockets, these will not turn because they are seized/stuck whatever so the chain has nowhere to go except slack. Now the chain at the bottom is now being made shorter so it must pull the mech forwards to compensate for this.

Take the wheel out, try and spin the free wheel bit stiff, now take it in the warm, lay it on its side with sprockets facing upwards and place a small amount of thin oil around where it looks like it would get inside the free wheel, spin it every so often to help the flow.

Do not meddle with the adjusters if you do not know what you are doing, may sound harsh but I would suggest it is good advice.

 

[screenman]

I would have thought the disc one was more a case of the wheel not being pushed home into the dropouts properly or moving slightly when you tightened it.

 

[Maz]

Sounds like your freehub is freezing up, probably oil/grease has thickened up. Normal service will be resumed when we get the thaw.

Spot on.

I brought the bike in, intending to tweek the barrel adjuster.
By the time I was ready to start, the freehub had thawed out (was near a radiator, too) and the problem had gone.

[media]http://tinypic.com/r/30nj52r/7[/media]

Thanks to all for your help!