Wobbly chainring

[Chris S]

The top of my chainring moves laterally by up to 5mm during a single rotation. Is this usual on a 1990 Raleigh Chiltern?

If I tighten up the bottom bracket to reduce the movement then it binds in some places.
(I'm currently waiting for a crank puller to remove it and inspect it properly)

 

[mrandmrspoves]

Rotate chainset until cranks are vertical and then hold the crank arms near the padals and try rocking them towards and away from you. If there is lateral movement it is a bottom bracket issue. If no lateral movement, check chainring bolts. If chainring bolts are tight and there's no lateral play in the bottom bracket, the chainring is warped slightly. You can gently straighten it with a large adjustable spanner.

 

[Ajax Bay]

@Tail End Charlie
https://www.cyclechat.net/threads/raleigh-chiltern.203330/
As above ref checking chainring bolts.

 

[Ming the Merciless]

Are the chain ring bolts all present and tight?

 

[Cycleops]

Sounds like the BB is badly worn allowing vertical and probably horizontal movement which you should be able to feel by holding the cranks.

Are the cranks cottered?

 

[Chris S]

No - they're square tapered cranks and there aren't any chain ring bolts (it's a cheap one piece unit).

It's definitely a bottom bracket issue and I don't think a 5mm wobble is acceptable, it could damage the chain. I'll have to wait until the crank puller arrives and then look at this properly.

 

[Sharky]

Not sure that it is a BB problem. If out by5mm on the chain ring, then it would be even more noticeable with the pedals and you would feel it when you ride.

 

[CXRAndy]

You can feel if its the bottom bracket and should be able to see the axle move whilst moving by hand.

 

[12boy]

Lets hope a 25 buck Shimano BB will make you well. Frequently one piece crank/chain ring setups aren't the stoutest and it's possible the tapered areas inside the crank arm are worn or deformed. If you have some other crank/ chain ring parts you can see if the problem persists with them, once you get your puller.