BB/cranks cricking - facing!?

MrGeebs

I have a Diamondback hardtail with an aluminium frame with an external GXP type bottom bracket that I bought from Pauls over the web in June 2011. From the very first time I rode it the cranks creaked a little, I took it for a service a month later at a LBS and mentioned it, they said that they tightened the cranks and the noise did go away for a time. Lately it's been getting worse & now it's sort of a cricking that happens when the left hand pedal is going over the top, worse when under pressure, up a hill for eg, it's been driving me insane every time I ride.
I took it back to the LBS yesterday and he wiggled the pedals and recommended a new bottom bracket (minimum £25 quid) - he also said that it would definately improve with a 'facing' - using a special lathe type turning tool that makes both edges of the frame shell where the BB sits parallel with each other, meaning the force is applied preciselly in order with the frame of the bike. Sounds ok to me, but he wants to charge £25 for the pleasure and then 25 for the BB makes £50 . . . . to get rid of a cricking!?! gahhhhh.

I'd like to pull apart the cranks and try greaseing things up again myself before forking out that sort of cash but looking at the instructions it says I need a torque wrench and the cheapest they go for is £27 quid.

Any thoughts anyone?
Is facing really required, wouldn't that have been done as standard?
would you expect a BB to last only 5/6 months or so? ( I ride about 60 miles a week, most weeks)
Any other thoughts anyone?

1mancity2

Facing may need doing depending on how the frame was done at the factory, how long a BB will last depends on the quality of it and the type of riding it's gone through.

You can try greasing it up, but if the BB is on its way out it won't solve the problem.

cooldad

You don't need a torque wrench.

baznav73

The frame should be faced if using external cups and you only need a new bb if yours has play, nine times out of ten just removing the bb cleaning and regreasing the threads and refitting solves creaking.

nicklouse

MrGeebs wrote:

I have a Diamondback hardtail with an aluminium frame with an external GXP type bottom bracket that I bought from Pauls over the web in June 2011. From the very first time I rode it the cranks creaked a little, I took it for a service a month later at a LBS and mentioned it, they said that they tightened the cranks and the noise did go away for a time. Lately it's been getting worse & now it's sort of a cricking that happens when the left hand pedal is going over the top, worse when under pressure, up a hill for eg, it's been driving me insane every time I ride.
I took it back to the LBS yesterday and he wiggled the pedals and recommended a new bottom bracket (minimum £25 quid) - he also said that it would definitely improve with a 'facing' - using a special lathe type turning tool that makes both edges of the frame shell where the BB sits parallel with each other, meaning the force is applied preciselly in order with the frame of the bike. Sounds ok to me, but he wants to charge £25 for the pleasure and then 25 for the BB makes £50 . . . . to get rid of a cricking!?! gahhhhh.

I'd like to pull apart the cranks and try greaseing things up again myself before forking out that sort of cash but looking at the instructions it says I need a torque wrench and the cheapest they go for is £27 quid.

Any thoughts anyone?
Is facing really required, wouldn't that have been done as standard?
would you expect a BB to last only 5/6 months or so? ( I ride about 60 miles a week, most weeks)
Any other thoughts anyone?

if it has not been done it should be. the tools are £600. what does it involve? see the FAQs.

Anonymous

GXP cranks do need a fair bit of force on the 8mm nut (don't touch the 10mm nut by the way!). With a torque wrench I find it's surprising how far you have to go (45Nm at least I think) and keep worrying that I'm over tightening. With that much torque I end up using a breaker bar to undo the things!

But no, you don't need a torque wrench. Would help if a shop could show you first time just how much you should apply, but that assumes they know what they're doing with those cranks.

And plenty of grease helps reduce play.

if it has not been done it should be

A debatable topic that many a thread has discussed . All depends how well it was manufactured and if you can tell if it needs it or not (of course almost all LBS will say it will). To some part the kind of BB is a factor also. From what I understand the GXP stuff is designed with different loading to reduce bearing wear. It fixes the left side bearing between spindle and crankarm, leaving drive side to "float axially on the spindle" (as they say), and making the two BB faces parallel shouldn't make a difference so facing is questionable in my opinion. And as I just noticed recently the newer GXP BBs seem to leave a 2mm gap between bearing face and crank face on the drive side, which I thought was odd but turns out is as designed.

Chasing I have even more issues with that a wire brush and suitable copper grease on the threads should solve. Again, unless it's really badly manufactured.

nicklouse

deadkenny wrote:

and making the two BB faces parallel shouldn't make a difference

err makes a big difference as the bearings are not self aligning.