Need a new BB for the CX bike 68mm English thread with ultegra cranks. So is any hollowtech compatible (105/Ultegra Dura Ace) it just comes down to how much I wanna spend ?
Cheers
I think so (Certainly my experience) but you can run in to trouble using none Shimano parts. I knackered a Deore bb trying to fit Race Face cranks.
Yes, CRC were knocking out cheap XTR ones a while back.
Yes, and the only difference with the MTB ones is the centre spacer tube so if there's a particularly good deal on those, you can just reuse the one from your existing bb.
Was thinking of getting a hope but price difference is quite a lot so gonna stick to Shimano.
XTR = £23.99 @ CRC
I think so (Certainly my experience) but you can run in to trouble using none Shimano parts. I knackered a Deore bb trying to fit Race Face cranks.
Different spacing / tensioning system. You need a RF compatible BB for RF axles, GXP with GXP, etc.
Bollox, guess who has an un used XTR BB that came with some cranks but binned the spacer tube from removed BB !
My XTR BB works fine on my RF Evolve cranks, should it not? Different method to preload bearings, but all else equal, no?
I stand corrected. I was pretty sure there was a small difference in axle length so that one wouldn't tension the bearings properly, but RF themselves say it's OK (bit over half way down)
GXP not, I'll stand by that, they have a stepped axle or something.
It's not a "spacer" as such, is it? Just reduced shite and water ingress from seattube I think.
It's not a "spacer" as such, is it? Just reduced shite and water ingress from seattube I think.
Yep, that's what it's for - if you've got a carbon bike with a completely sealed BB shell you don't need them - otherwise you do - the back side of the bearings will be sitting in a pool of mud/water otherwise.
I'm not sure if there's a difference with the Shimano stuff but Chris King's road BB cup is slightly wider than the MTB version.
Edit : It might be the other way - MTB wider than road but there's certainly a difference in the King stuff.
Just got an Ultegra one at wiggle £11.00. Must keep plastic tube thingy 🙂
carbonfiend, I've got an XT centre tube that should fit the XTR shells no issue if you want it for the cost of postage, or I could buy your XTR BB off you? 😉
You can have the XTR of me if u want as the only other hollowtech bike I have has a Hope in it which I just replace bearings when needed. Let me dig it out & send u a mail.
shimano and other similarly priced BB's will be fine, though as above, the sleeve may need binned. as long as you have one spacer non drive side and two drive side for a 68mm bB you'll be fine.
oh and the BB isn't hollowtech, the crankarms are. the original Shimano hollowtech cranks ran on octalink BB's. Hollowtech II cranks have an integrated axle and run with external type BB's (for threaded BB shells).
paule - Member
Yes, and the only difference with the MTB ones is the centre spacer tube so if there's a particularly good deal on those, you can just reuse the one from your existing bb.
Nope, cups are slightly wider on the road ones 2.5mm wider iirc) so you could run into spacing issues
The actual visible cup should be the same width but the threaded part is longer on a MTB BB.
Shouldnt cause any problems tho
Nope, the visible cup is wider also. Trust me, caused me all kind of confusion when I first shoved an MTB one into the road bike
Regardless of longevity is the xtr much better than xt?
Shimano Road BB cups are 1mm wider than MTB, normally on 68mm road frame they are used without spacers, you can use MTB cups but I'd put 1mm either side. Note MTB BB also comes with a wider tube between cups which you can't use on a road frame without deforming it (or using all the spacers) they are generally meant for 73mm BBs.
The XT BB has a bigger bearing than the Deore BB, and seem better sealed. I went through a pile of Deore BBs before I started using XT. An XT BB is only £10 on CRC (cheaper than the Deore!) so I haven't tried the XTR as XT works for me.
The thread on a Mountain BB is longer on the drive side in case you are using a BB mounted derailleur. The Saint BB has an even longer thread for BB mounted chain device. The Saint BB looks otherwise idential to the XT.
GXP uses a stepped crank (24mm/22mm) I've tried using shims on a Shimano BB (24mm) but had problems with chainring offset and eventually binned the GXP crank. GXP BBs don't seem to last either, and are limited in choice, which was the main reason I changed to Shimano.