Creaky crank question...

[eddiec]

My turn to interrogate those with mechanical know-how...

Finally dusted off the duallie (2002 XT-specced Marin) for a weekend spin and have noticed some awful creaking noises coming from the crank/bb...

Performed a little test at the lights and discovered that when stopped with both brakes locked on, there appears to be some rotational play as the cranks can be rocked back and forth (ie. as if pedalling) a small amount accompanied by an awful lot of creaking.... Any idea what this is? Loose cranks? Stuffed bb? Loose chainrings? Some kind of gypsy curse?

Eddie(hoping this won't be expensive)C

 

[Peter McCallum]

eddiec <[email protected]> wrote:

> My turn to interrogate those with mechanical know-how...
>
> Finally dusted off the duallie (2002 XT-specced Marin) for a weekend
> spin and have noticed some awful creaking noises coming from the
> crank/bb...
>
> Performed a little test at the lights and discovered that when stopped
> with both brakes locked on, there appears to be some rotational play as
> the cranks can be rocked back and forth (ie. as if pedalling) a small
> amount accompanied by an awful lot of creaking.... Any idea what this
> is? Loose cranks? Stuffed bb? Loose chainrings? Some kind of gypsy
> curse?
>
> Eddie(hoping this won't be expensive)C

If the play is forward/backward then it seems you need to tighten the
cranks, if you haven't wrecked them already. Can you move the cranks
independently of each other?

Peter
--
Peter McCallum
Mackay Qld AUSTRALIA

 

[eddiec]

If the play is forward/backward then it seems you need to tighten the
cranks, if you haven't wrecked them already. Can you move the cranks
independently of each other?

Peter
--
Peter McCallum
Mackay Qld AUSTRALIA

Cranks was probably what I suspected, but as they're somewhat of a mystery to me, wasn't sure...

I don't think they're moving independently... But I'll check. I'm hoping they're not stuffed, as the creaking has only just started (and only really kicks in when you're pushing hard)... I'll have a tighten and see what that does, and tighten up the chainring bolts while I'm at it...

Thanks.

 

[jazmo]

Cranks was probably what I suspected, but as they're somewhat of a mystery to me, wasn't sure...

I don't think they're moving independently... But I'll check. I'm hoping they're not stuffed, as the creaking has only just started (and only really kicks in when you're pushing hard)... I'll have a tighten and see what that does, and tighten up the chainring bolts while I'm at it...

Thanks.

I just had a chainring problem myself!

http://www.cyclingforums.com/t233874-check-your-chainring-bolts.html

Check those chainring bolts! I was getting terrible creaking while under load on my small chainring. It was a reasonating creaking sound that wasn't exactly in time with my pedalling strokes.

 

[ritcho]

My turn to interrogate those with mechanical know-how...

Finally dusted off the duallie (2002 XT-specced Marin) for a weekend spin and have noticed some awful creaking noises coming from the crank/bb...

Performed a little test at the lights and discovered that when stopped with both brakes locked on, there appears to be some rotational play as the cranks can be rocked back and forth (ie. as if pedalling) a small amount accompanied by an awful lot of creaking.... Any idea what this is? Loose cranks? Stuffed bb? Loose chainrings? Some kind of gypsy curse?

Eddie(hoping this won't be expensive)C

It doesn't look good, but a cheap scenario is that the bottom bracket bearings need adjustment. This is if you are using old-school cup and cone bearings. Many BBs these days use cartridge bearings and aren't adjustable http://sheldonbrown.com/tooltips/bbadj.html. If you have the latter type, then crank movement is _bad_ news. Either the BB cartridge bearing has failed or the crank has loosened (in which case its shape has irreversibly changed to something that won't ever fit properly on the spindle again.

If it was just a bit of creaking, but no discernible play, then you'd probably be ok...

Ritch