Bottom bracket warranty issue?

williambowland

My new bike (Whyte 19) has a really annoying habit of throwing the chain off the outside of the big chain ring when back pedalling. No big deal, you might think, but apparently I back pedal quite a bit to set my feet for cornering and so on. So - it happens quite a lot. It also happens when spinning the cranks backwards to lube the chain.

I checked the mechs, mech hanger and so on and everything seems OK. I did notice that the chain was thrown off at a specific point in each cycle, though.

I since noticed that the bottom bracket fit looks a bit uneven (it is a press fit BB30). I did a crude check and there is a definite "wobble" in the crankset as it rotates. It is only a mm or so but it is clearly out of alignment and I am assuming that it is this which causes the problem with the chain.

I want to know if this is unusual to the point where I should raise it as a warranty issue.

Any advice?

Churz...

MrChuck

Could be that the chainring is bent...?

supersonic

Bottom brackets do not cause them to wobble - the whole chainset would just revolve in a different plane, but in line. The cause is usually a slightly misaligned axle to spider on the crank. This causes the rings to oscillate back and forth.

bungalballs

I'd definitely take it back to your LBS where you bought it... it clearly has an issue and isn't working quite correctly, and an LBS worth its salt would be more than happy to help. If you start fettling you might get the blame!

I also have a Whyte and my experience of the warranty is that it's brilliant - the LBS did a whole load of stuff whilst it was in in addition to what I took it for and Whyte paid for the lot.

nicklouse

Or a bent ring.

LBS time.

williambowland

Cheers gents...

TBH I checked the rings again more carefully and there isn't as big a deflection as I thought originally - if anything.

Guess you're all right - back to the shop to investigate the chain issue.

Can't say I'm too impressed with the FSA BB30 bottom bracket in general, though...

mattv

Chainrings often have ripples in, usually not a problem at all. A good bike shop should be able to set the front mech up so you don't even notice except when crossing the gears.

Northwind

BB30 seems a backward step to me, but what specifically is it doing that you don't like? It can't cause the wobble you describe.

The solution to the backpedalling issue is to stop backpedalling- don't try and get a hardware fix for a software problem.

nicklouse

New chain do not like back pedalling FACT.

williambowland

Spent a bit more time looking at it... and I am pretty sure it is just a slight bend in the mech hanger despite my initial comments.

Probably a case of looking for a problem that doesn't exist and overlooking the obvious! Thanks for the comments, though... made me go back and reassess. Still getting used to 10 speed - the tolerances seem to be that much higher.

As for the BB30 - I just get the feeling that the sealing is below par. I need to look into re-greasing the bearings but I need some new tools to get the cranks off and adjust the preload.

And back pedalling - I only do it to switch my forward foot... half a turn of the cranks. I will try to do it with a forward spin from now on but it is a bit of a habit, I reckon.