2009 Carerra Kraken BB problem?

muran

Looking for a little help with my 2009 Carerra Kraken.

http://www.thebikelist.co.uk/carrera/kraken-2009

Out on a ride yesterday I noticed a loud clunk and a vibration through the crank on the down stroke of the pedals (same both sides). Only noticeable when under load and pushing hard in a high gear or when pushing down hard on the pedals when at the bottom. I'm not noticing anything particularly rough in the rotation of the crank though.

Firstly, is this likely to be the bottom bracket that needs replacing? Prior to the ride the bike had been stood for around a year.

If this is the case I'm happy to replace. For the Truvativ Iso Flow crank set can anyone confirm which BB I need for my model? I've narrowed it down to these and I am thinking the first one buyt could do with confirmation:

http://www.halfords.com/webapp/wcs/stores/servlet/SearchCmd?srch=truvativ+bottom+bracket&action=search&storeId=10001&catalogId=10151&langId=-1

Thanks in advance ...

EDIT: Just realised the chainset spec from my first link: Truvativ Isoflow with Power Spline BB - so the middle option of the two, right?

The Rookie

Only one is powerspline (in the bikelist link you'll see it says powerspline), only powerspline will fit your cranks.....the GXP won't fit at all (I would have thought it obvious from the pics that they couldn't all fit, two are hollow and one has an axle sticking out both sides!)

CRC will be cheaper than Halfords I would think.

muran

yes, hence my edit (which was made before your reply)

I obviously didn't see that at first.

Does the fault described sound like a BB fault or am I on the wrong lines?

Can anyone point me in the right direction for the correct tool as I'd like to get them ordered up all at the same time if this is the problem?

cooldad

Parktools has all the info.

muran

No matter, found this http://www.chainreactioncycles.com/x-to ... -prod14914

Still though, from the fault described, people would recommend changing the BB?

The Rookie

muran wrote:

yes, hence my edit (which was made before your reply)

Not before I started typing it though!

cooldad

muran wrote:

No matter, found this http://www.chainreactioncycles.com/x-to ... -prod14914

Still though, from the fault described, people would recommend changing the BB?

Sounds more like the cranks are loose, but...

muran

Made some progress, noise obviously caused by bottom bracket moving. Made a quick vid to show but need good eyesight! Can just be seen at about 13 secs.

Hoping getting the tool and nipping it up should resolve.

http://www.youtube.com/embed/NHXt6CbZWFU

The Rookie

Bottom bracket isn't moving at all as far as I can see, arm looks loose on the axle, just tighten the Allen bolt.

oxocube1

A bb swap should sort it. Looks and sounds like play has developed between the axle and sealed bearings in the BB. I've worked on many with a similar issue in the shop. Fairly straightforward swap with the correct tools, just don't forget that the driveside cup is a left-hand thread (it unscrews clockwise), and you will need a crank extractor/puller if you don't already have one.