Low gears feel very rough

[Jimmy Doug]

Hi,

Hoping someone can help me out here. For the past few weeks I've noticed that low gears feel rough, and they seem to be getting gradually worse. I've changed the cassette and the chain, but to no avail. Also (but perhaps this isn't related), very occasionally the transmission clunks once, and only once - this usually happens when quite a lot of effort is put into the chain: when starting or when there has been a recent shift change, for example. I'm wondering if it's the bb, but there is no play in the cranks and I would have thought that a worn bb would feel bad across all gears, not just the lower ones. Any ideas?

 

[Cycleops]

Could be your chainring is worn and/or warped. The only other thing is maybe the derailleur is twisted. Seems like you've covered everything else.

 

[Jimmy Doug]

Thanks for the reply. I've noticed that one of the jockey wheels is a little loose (but the nut is damaged and so I can't tighten it). I wonder if that has anything to do with it?

 

[accountantpete]

Give the cassette a good wobble to see if the freehub is loose.

 

[Jimmy Doug]

I wobbled the cassette as you suggested and noticed a tiny amount of play - probably no more than 1mm. When I fitted this cassette I didn't use too much force (although I did tighten it quite hard) because I reckoned it would tighten itself like a freewheel would.

 

[Peteaud]

Rear mech, what one is it?

If it is damaged i would just replace it for good measure.

 

[Jimmy Doug]

The cassette is brand new, as is the back wheel.

 

[Peteaud]

Thanks for the reply. I've noticed that one of the jockey wheels is a little loose (but the nut is damaged and so I can't tighten it). I wonder if that has anything to do with it?

Rear mech, what one is it?

If it is damaged i would just replace it for good measure.

Rear mech = rear deraileur.

I dont like the sound of anything loose, in case it locks up.

Depending on what one it is, they can be a reasonable price, so i would replace it.

 

[Jimmy Doug]

Ah, OK, got you now! The rear derailleur is as old as the bike, and has done 13 000 kms now. Do the symptoms sound consistent with a loose jockey wheel? Wouldn't I have problems in all gears?

 

[Peteaud]

Ah, OK, got you now! The rear derailleur is as old as the bike, and has done 13 000 kms now. Do the symptoms sound consistent with a loose jockey wheel? Wouldn't I have problems in all gears?

{ am thinking that maybe as the angle of the rear mech changes so the problem, gets worse. As you have replaced the cassette and chain i cant really rhink of anything else.

 

[Jimmy Doug]

Hmm - sounds logical. Perhaps I have more problems in lower gears because of the extra leverage created by the bigger sprokets. I was debating with myself whether or not to change the rear derailleur. I'll give it a shot and tell you what happens - but it won't be til after Christmas: I've already had to spend loads of dosh on broken parts recently! Why is it everything goes wrong at once? 13 000 kms without a problem, and now it's just one thing after the other. Oh well, it's still cheaper travelling by bike than by car.

 

[fossyant]

How often do you lube the chain?

 

[potsy]

Did you change the cassette like-for-like?
ie-same ratio 12-25, 13-26 etc?

 

[Jimmy Doug]

How often do you lube the chain?

I 'Mickle' my chain about once a week - maybe every two weeks if the weather's been dry. I cycle about 200 to 300 kms a week.

 

[Jimmy Doug]

Did you change the cassette like-for-like?
ie-same ratio 12-25, 13-26 etc?

Yes, I did. I used the exact same cassette - a bog-standard Shimano, HG-31, 11-32t, 8 Speed cassette. I'm thinking of switching to SRAM for better longetivity, though.