BB size Kona Kilauea/XTR M900

[Bergy]

Ok so I’m fitting M900/901 XTR to my Kona build, currently as a mock up I’ve fitted an older UN52 BB I had knocking about in my spares but looking at the axle length the cranks/rings have allot of clearance I’m wondering if I should be using a shorter axle (will have to check the exact size but think it’s a 73-113) should I be dropping it to 108?

 

[FluffyChicken]

107mm standard size for M900.

68mm shell for the Kona

 

[nstarmore]

BB spindle length for M900 is 107 - 113 according to Sheldon Brown so what you've got should give you a 50mm chainline but if you have plenty of clearance you could go narrower.

 

[Bergy]

Ok so 68mm shell opens up some nice options to reduce the weight,
Has anyone tried using a Token BB before?

Wondering if a 103mm axle will be to tight ?

Token Carbon Square Taper Shimano Bottom Bracket - English - 103mm

Token Carbon Square Taper Shimano Bottom Bracket 103mm and a Wide Range of Top Quality Cycle Parts And Accessories at Competitive Prices with Free UK Postage.

www.highonbikes.com

 

[nstarmore]

No idea if it'll be too tight but your chainline will be off. 107-113 is what you need.

 

[Frankenorange]

107mm XTR BB for the win. Bullet proof. No drama.

For weightweenie points the ultimate would probably be :-

107mm hollow titanium 17mm diameter axle (were available on ebay a few years ago - something to do with Klein)

The cups from one of those Token BB's (just need to be 31mm diameter internal bore and i think the Token is this)

Two 173110 2RS bearings

Guessing the WW version would be in the region of 130-140grams.

If you really need to run a 103mm and are repainting, or don't care about paint, then you can take a G-clamp to the chainstay and squash the tube a bit. Do it yourself, or get a builder to do it for you.

 

[FluffyChicken]

No idea if it'll be too tight but your chainline will be off. 107-113 is what you need.

Yeah but the 113 /50mm should be avoided unless it's a fat frame downtube.
The mech just works better.




No need for third part info from Sheldon Brown, all the info documents and specs are in the Archive on here.

 

[nstarmore]

No need for third part info from Sheldon Brown, all the info documents and specs are in the Archive on here.

I thought it might be but confess to not checking whereas I'd referred to Sheldon Brown historically for the same query

 

[d8mok]

I’ve got a 73 x 107 M900 BB on eBay. Happy to sell via here at £50 posted

Shimano UN91 M900 XTR retro Square Taper Bottom Bracket 73 X 107 | eBay

Find many great new & used options and get the best deals for Shimano UN91 M900 XTR retro Square Taper Bottom Bracket 73 X 107 at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

 

[minor_LEGEND]

I’ve got a 73 x 107 M900 BB on eBay. Happy to sell via here at £50 posted

Shimano UN91 M900 XTR retro Square Taper Bottom Bracket 73 X 107 | eBay

Find many great new & used options and get the best deals for Shimano UN91 M900 XTR retro Square Taper Bottom Bracket 73 X 107 at the best online prices at eBay! Free delivery for many products.

www.ebay.co.uk

Yeah but 68mm shell.
I'd try a 110mm - commonly found, the 107mm is an XTR only (UN91) iirc