Chain Slipping

[jm031689]

Hi everyone,

I recently bought a Gazelle Champion in fairly good condition but I have noticed that under heavy load the chain occasionally slips.

I am completely new to gears having been a single speeder for a long time, and this bike has friction downtube shifters which take a bit of getting used to. When I experience the slipping I think that tweaking the shifter a little bit generally gets rid of the problem, or am I fooling myself? I've only had the bike a few days so don't have a lot of evidence to go on.

My questions is, could lining the chain up not quite right result in it slipping? The chainring and sprockets look OK although I'm no expert, and the chain doesn't feel slack.

Thanks for any help!

 

[Midlife]

Chain slipping is usually due to a mismatched "chain and block", usually a new chain on an old worn block, the chain gradually rides up over the sprocket and jumps back down into the block again. Usually worse on the smaller sprocket because of the physical number of cogs (small number)

Could be other things though..........

Shaun

 

[jm031689]

Thanks for your reply midlife. I think I will take it to my local evans tomorrow and get them to give it a quick look. Definitely not something caused by poor gear changing technique then?

 

[Midlife]

Friction levers are pretty easy to use and less hassle that indexed gears which need adjustment..........all you do is simply move the lever so the noises stop and the job's a good one

Just don't ride into a parked car as it's easy to get transfixed staring down at the rear mech.

If the jockey cage of the rear mech is twisted or bent then it may be impossible to get actually get a straight chain line....

What sort of drivetrain ? pic?

Cheers

Shaun

 

[jm031689]

I have discovered the (beautiful) simplicity of friction gears as I had to set them up. When I picked the bike up I couldn't reach the highest gear on the rear sprocket and I kept throwing the chain into the spokes when going to the lowest gear!

There are some pictures here:

http://www.flickr.com/photos/57844052@N ... 864466285/

The rear mech looks to be parallel with the wheel so I think a straight chainline should be possible. Took it out for another test and gave it a bit of a hammering and the slipping problem didn't rear it's head. Hopefully it was my initial lack of skill in shifting. The rear sprocket's teeth are still all flat so I think it should be OK. Will still pop into Evans tomorrow for a second opinion.

 

[Dead Rats]

ask them to check the chain for stretch?

 

[Midlife]

Looks like Shimano 600 Shimano is often said to be on the quieter side of shifting............unlike Campag stuff which bumps and clangs LOL

Shaun

 

[Old Ned]

Will Evans know what friction shifting is?

 

[jm031689]

Yes the chainset and derailleurs are Shimano 600. I took the bike to Halfords in the end (only because I passed it on route) and they agreed the chain and cassette looked to be in good condition as far as they could tell.

But they had a look at the chainring and it was very wobbly! The chainring was pretty loosely attached to the cranks embarrassingly and they suspected this might be the cause. So it's been tightened and we will see what the outcome is. No slipping as yet.

And yes, the mechanic in Halfords knew what friction shifting is!

 

[Dead Rats]

Yes the chainset and derailleurs are Shimano 600. I took the bike to Halfords in the end (only because I passed it on route) and they agreed the chain and cassette looked to be in good condition as far as they could tell.

But they had a look at the chainring and it was very wobbly! The chainring was pretty loosely attached to the cranks embarrassingly and they suspected this might be the cause. So it's been tightened and we will see what the outcome is. No slipping as yet.

And yes, the mechanic in Halfords knew what friction shifting is!

he's probably got it on his new BSO sorry