Chain slip problem

rflynnr

I'm stuck here. I recently converted an old racer to single speed (not fixed gear). This meant a brand new drivetrain all round: new crank, big ring, an adaptor kit to allow me to use my old Shimano 10 speed hubbed wheel as a single speed, a new chain and a chain tensioner (as the dropouts are pretty much vertical).

The final result? Chainline is good, and chain tension seems fine. However, whenever I start off (i.e. apply a significant bit of torque) the chain almost invariably slips - just once. Thereafter it's generally fine until I have to stop and start again.

Given that everything is brand new I think I can rule out wear (even if the chain is a no-name brand and was not desperately expensive) as a cause. Which leaves me thinking chain tension is insufficent. I could remove two links and buy one of those half links which would improve things a little.

However before I do this, is there another possibility I'm not seeing?
The chain tensioner could be a little tighter:

kona

Your definatley not just spinning the tyre?

Have you replaced the freehub?

rflynnr

No, it's definitely chain slip and I had the hub serviced as recently as a month ago and it was pronounced fine. (It hasn't seen that much use anyway - can't be much over 2,000km.)

victorcarrera

A few possibilities here.

1. Can you increase tension on the tensioner. Possibly get a stronger spring for it.

2. Are parts compatible.
More to Buying A Chain Than The Width:
Note that although there is a standard bicycle chain tooth size, both in width and pitch, that is not true in the actual shape of the gear teeth. Each manufacturer designs the tooth shape on their sprockets slightly differently so finding compatible bicycle chain-gear-derailleur combinations is an important consideration before you buy a new chain.
From http://mywheelsandmore.com/bicycleChains/bicycleChainSizes.htm

3.8. Frame flex. Your one-speed mountain bike or cross bike has probably been designed to be at least reasonably light… even Surly folk don't enjoy riding 30 lb. bikes up hills. That means you have a light frame that has thin, light chain and seat stays that are anywhere from 16-20" long. Every time you push ‘n pull on the pedals, the bottom bracket swings back and forth and the long and skinny stays get pulled toward the drive side of the bike. The whole machine is gettin' twisted by your upper and lower body, especially so on the tough climbs. To a certain degree this flex is desirable and produces a comfortable ride, but any flex at all in a drivetrain system creates deviations that cause skippage, premature wear and, depending on your girth, chain launching. This is not a factor to be ignored! The best way to deal with drivetrain deviations from flex is to make sure all other factors are in order. Certainly a 3.5 lb. cro-moly frame is not the best choice for a one-speed, and if you're in this boat, I hope you weigh under 150lbs. Otherwise, by making sure your chainline is perfect, your rear cog is big, you're geared low enough, your drivetrain is in good shape and all components are wearing together, and your chain is tensioned and lubed properly, you can minimize any potential problems frame flexing will have on drivetrain skipping, chain launching and premature wear.
From: http://www.surlybikes.com/blog/spew/3_-_single-speed_drivetrains/

blorg

If you are using a chain tensioner I don't think you should have to remove any more links out of the chain, the tensioner should look after that for you. As to different chains meshing with different sprockets I really have never found that; I have used a wide variety of chains from Shimano, SRAM, KMC and Wipperman and they all work the same.

kona

rflynnr wrote: »

No, it's definitely chain slip and I had the hub serviced as recently as a month ago and it was pronounced fine. (It hasn't seen that much use anyway - can't be much over 2,000km.)

Ive seen new ones failing after a week:o Some are just bogey, but if it was serviced and okay then it should be fine.

It can only be a few things,as a outside the box... have you measured the pitch of the chain and the Freewheel?


I see Mr.Carrera has mentioned it

chakattack

Thanks for this thread rflynn

I have a similar problem with a new 10 speed chain on a 10 speed cassette with about 6,000k on it.

It skips everynow and then if I'm standing when climbing or taking off from lights. I'm guessing that either the cassette needs to be replaced or I didn't cut the chain short enough.

Anyone have any experience of it?

rflynnr

The chain and cassette will tend to wear at about the same rate. If both your chain and cassette had done 6,000k then I'd replace both at the same time.