Chainset and Bottom Bracket for Shimano 9 speed

[pfm401]

I'm looking to replace the chainset and bottom bracket for my 9 speed mountain bike (Saracen Mantra 2015). Current chainset is Shimano FCM391 (Altus I think) and bottom bracket CH-52.

I've had Hollowtech on my road bike and prefer that to the set up above, but am confused as to the range of 9 speed Shimano products! Not sure if I'm allowed to post sites but on bikester there's a range of 9 speed chainwheels e.g. FC-MT300, FC T4060 (Alivio), FC M4050 which Shimano describes as "compatible with an outboard, 24mm bb interface" (is this Hollowtech?)

Any views as to which is best, or if indeed I should stick to square taper or use Octalink? Or another brand?

Finally there's chainrings with 2 rings rather than the 3 on the above (my current one is 3), again I shifted from a triple to compact on my road bike and much prefer it (simpler and has plenty of gears for my use), any views on whether this is also worth it for MTB (I realise I'd also need a new front shifter and derailleur).

Thanks, Paul.

 

[iluvmybike]

Don't bother with Octalink bbs - either stay square taper or move to Hollowtech/outboard cups. Make sure yuor new chainset matches your choice! 24mm is the standard width of a Shimano Hollowtech crank spindle

 

[Cycleops]

I used a Shimano Deore crankset on my gravel bike. This is Hollowtech and came with a the BB bearing but was not described as being included so check with the seller.
Steer well clear of Octalink which has now been discontinued.

 

[si_c]

If you are familiar and happy with Hollowtech II then get the FC-M4050 and the SM-BB52 bottom bracket to go with it.

 

[pfm401]

If you are familiar and happy with Hollowtech II then get the FC-M4050 and the SM-BB52 bottom bracket to go with it.

Cheers, do you know why that one is hollow on the right hand (chain ring) side, as opposed to FC T4060 which looks like the Tiagra on my road bike? Us it cosmetic or different fitting?

 

[si_c]

Cheers, do you know why that one is hollow on the right hand (chain ring) side, as opposed to FC T4060 which looks like the Tiagra on my road bike? Us it cosmetic or different fitting?

Cosmetic.

 

[pfm401]

Cosmetic.

Cheers, what about the FC-MT300 then, is that same fitting / quality, just it's cheaper

 

[si_c]

Cheers, what about the FC-MT300 then, is that same fitting / quality, just it's cheaper

It's part of the Acera groupset rather than Alivio - think Claris to Sora in road bike groupsets. It'll work fine, it'll just be a bit heavier and I believe the tooth profiles are less advanced so shifting might be a little less smooth. Depends what the price difference is which one I'd go for.

 

[pfm401]

It's part of the Acera groupset rather than Alivio - think Claris to Sora in road bike groupsets. It'll work fine, it'll just be a bit heavier and I believe the tooth profiles are less advanced so shifting might be a little less smooth. Depends what the price difference is which one I'd go for.

Thanks, Alivio is £48 ish and Acera £32 ish so I'll probably go with the Alivio, not much to pay for the better shifting.

Any views on the Deore 1 X 12 setup, obviously that's a jump in price as I'd need new shifter and rear mech (I probably need a new cassette anyway so not too fussed about that)