Can i run a road ht2 chainset with an MTB HT2 bb?
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Can i run a road chainset with an MTB bb?
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Posted 4 months ago #
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Yep.
Posted 4 months ago # -
no issues?
Posted 4 months ago # -
I think it's fine if you take out the spacers, and use the old sleeve. The mtb one is wider.
Posted 4 months ago # -
Don't quote me on this but I thought shimano road and mtb are a different diameter axles. Why would chris king and hope do road versions of their BB unless the was a difference.
Edit
Actually I think the axel length is slightly different but I think you can make it work.
Posted 4 months ago # -
mountain bike frame BB shells are 72mm and road ones are 68mm so as long as you use the right sleeve then jobs a good un
as bikewhisperer said
Posted 4 months ago # -
No. The cups of a road HT2 BB are 1mm narrower each so if you put in an MTB BB it'll be too tight. Axle diameter is the same.
Posted 4 months ago # -
seem to remember I had "issues" with mixing the two but the detail eludes me I'm afraid. I think it involved a bodge of sorts with the spacers used in an unconventional way.
alsomountain bike frame BB shells are 72mm
think you mean 73mm and even then there are some with 68.
i don't even think you need to use a central sleeve so can't see that as an issue either.Posted 4 months ago # -
I fixed a Specialized Secteur where they'd bodged it from the factory.. They put in a MTB BB without the spacers and mashed up the sleeve which stopped it turning freely. I did wonder how many other bikes were out there from that day's production run with the same problems.
The axle length between road and MTB is different, but I was under the impression that the cups are the same outside thickness.. I've never measured them though. If they've got to accommodate italian BBs then that version would have to be 1mm narrower per cup, so it would make sense that the BSA one is 1mm wider.Posted 4 months ago # -
The cups of a road HT2 BB are 1mm narrower each so if you put in an MTB BB it'll be too tight
Not according to my calipers
Posted 4 months ago # -
well that's my theory out the window then!
Posted 4 months ago # -
Last time I measured some road cups they were a different width to MTB (1mm each side i think )and as mentioned axle length is different too. haven't got the brainpower to work out why !
Posted 4 months ago # -
I know my new SRAM BB has instructions for fitting it to either an MTB or a road bike, the only difference appears to be the external spaces as mentioned above.
Posted 4 months ago # -
My cx bike has some XTR cups with a tiagra chainset, just changed the tube over and no spacers, few 1000 miles in an no probs. I think the difference between road and mtb BB is mainly the seals on them. I was stuck years ago with a RF X-type BB that died very quickly i.e. 300miles and put in a 105 one cause that's all I could get in a hurry it lasted 3yrs hard MTBing
Posted 4 months ago # -
anyone know definitively
Posted 4 months ago # -
right i have been and done this, all 6 of my shimano road cups are indeed 1mm shorter, now the after market bb's such as superstar knc etc all seem to be the same and the road version is identical to the mtb version except it has 2x 1mm spacers, its the same with hope, same cups, shorter inner tube and 2x1mm spacers
Posted 4 months ago #
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