Crank arm always coming loose.

skate2create

How do! First Post so please be gentle!

Firstly, my bike..

I have a 2010 Scott Aspect 45, which I absolutely love.. but has a big niggle which bugs the absolute hell out of me!

Considering the rest of the 'kit' fitted as standard is of pretty decent spec (well, in my opinion anyway!), the bottom bracket/ crank arms are a bit of a let down.

I don't know if it's just me being quite heavy (16 stone, 6'3"), but the last two bikes that have used a square taper / UN (26) cartridge type bottom bracket (my Scott and my previous Giant) have both had the left crank arm come loose on a regular basis and bearings become far from smooth in a short space of time. I don't particularly abuse my bike and use it primarily for commuting with a little play in the rough stuff when I can.

Can I change my bottom bracket set up for something different to square taper, how difficult would this be and what would I need to change? (I assume just the crank arms to one that are compatible with the BB?
Suggestions of what to do/ go for would be greatly appreciated

Dan

supersonic

The crank arm will be buggered now, and will always come loose.

You can try a different system, but as you say, the BB and crank have to match. This is decent unit with external BB:

http://www.tweekscycles.com/Product.do? ... 2%A0Cranks

nicklouse

Once an arm starts coming lose it will continue to do so as the arm ( if ridden on) will now be deformed.

Yes you can fit any crankset.

See Parktools ( link below) for his to fit any crankset. I would look at a new HT2 Deore crankset. The BB shell will need facing ( LBS job).

skate2create

Excellent, many thanks to the both of you.

I'm usually OK with a set of spanners etc from a few years of playing with various cars, if I get the facing done by a local shop as suggested, would fitting the bottom bracket be pretty straight forward?
I have had a read through the parktools bits, it seems relatively straight forward but that might not be the case for someone that's never swapped a to a different BB setup (I have changed the BB like for like before).
Thanks again for the help so far!

Dan

cooldad

Easy 5 minute job. Screw the cups in. Poke the axle through, fit the crankarm, tension the bearings, tighten the bolts holding the crankarm on, job done.
That's Shimano HT11 anyway. Just need a BB tool and crank install tool. Less than a tenner.

skate2create

Excellent, thanks for the reply.
Last question (for now!)

Will I be able to use the existing front mech with the new set up? As I imagine the rings will be slightly further out from the frame than they are now. Will it just be a case of adjusting to suit?
Cheers again.

Dan

cooldad

Will be fine. The chainline should be about the same.

skate2create

Excellent, many thanks