Help with new Crank purchase!!!

[BlackSwan83]

Hi,

So ive decided its time to get myself a new crank but i'm a fairly novice bike machanic and in need of some advice.

I recently fitting a new square tapered BB and pedals so familiar with taking that part of my bike apart but wondering the following:

A : Crank Length (what would a larger crank offer compared to a smaller one?) The one i'm looking at comes in 170 &175mm

B : Number of teeth, again i can select 44.23t or 48.36?
This is the crank im looking at getting http://www.chainreactioncycles.com/shimano-deore-m590-9-speed-triple-chainset/rp-prod40496

C : Would this be suitable to work with my current BB (Shimano BBUN55 Square Taper Bottom Bracket)

And the last question is, would it be recommended to replace my cassette and chain also?

Thank you for your time, lots of questions i know.

Samuel

 

[BlackSwan83]

Sorry,
I've just realised the crank about isnt for a square BB, would this crank be ok? http://www.chainreactioncycles.com/shimano-acera-m361-triple-chainset-square-taper/rp-prod106885 to be used with listed BB above?

 

[LimeBurn]

Might be wrong but I think they're hollowtech cranks so you would need a suitable bottom bracket to match. The crank arm length is purely personal to you if you are on the shorter side then you may prefer shorter crank length or if you get mild toe overlap and you want a little more clearance. Longer crank arms will give you a little more torque but won't spin as fast as shorter. Personally I've rode on 172.5 and 175mm and cannot tell the difference.

 

[BlackSwan83]

Thanks LimeBurn,
Would this little shopping list be enough tools/parts needed to change out the crank etc.

 

[BlackSwan83]

p.s Im not sure what hollowtech cranks are but i have taken the crank off before and it looks just like the one above, i cant seem to locate hollowtech cranks online!!

 

[stevede]

If the BB spindle is square, then indeed a square taper chainset is needed. To switch to Hollowtech, you would need to change the BB as well.

With the crankset you have chosen, I would save money on the cassette and go with this one http://www.chainreactioncycles.com/shimano-deore-hg50-9-speed-mtb-cassette/rp-prod443 Seems odd to spend more on a cassette than the crank.

The PC971 chain has done me good service and also a lower cost alternative. http://www.chainreactioncycles.com/sram-pc971-9-speed-chain/rp-prod9873

Tools wise: Will also need a chainset removal tool unless for the square taper, but then if I have understood your original post that you have changed the BB, you may already have this. Oh, also need a cassette lock ring removal tool.

Hope this helps

Regards

Steve

 

[LimeBurn]

As Steve said you'd need the cassette removal tool with the chainwhip that you already had on your list to be able to replace the cassette.

 

[the snail]

You need to check that the BB spindle length is correct for that crankset too. Regarding the chainring sizes, what size rings do you have on your current crankset?