[Closed] Tiagra bottom bracket

I thought the bearings were a different width on road BB's so the Axle on an MTB crankset wouldn't fit?

I know the road cups do not use the plastic spacers like mtb one so might not leave enough thread in the frame if you added your old ones.

Guess the inner tube would be shorter too on the road one
But you could prob use the old one or none at all

But I have not tried it myself

My Tiagra BB in my road bike lasted 260 mud free miles, wouldnt bother with it.

Fair do's, thanks.

Back to Deore.

tiagra BB in my Croix de Fer has done almost 2000 miles (a lot of those on muddy/dusty bridleway). It does need replacing but there is still life in it yet! Would be v happy to get another 2k miles for only a fiver! Might get something more bling though 😀

and for balance, the sora BB on my commuter has done around 1000km/600miles in filhy, salty, muddy conditions.

and it's fine.

I got about 3000 winter road miles out of my Tiagra BB until it really was so trashed I had to replace it. I was happy with that.

But for the reasons mentioned above with lack of thread engagement on an MTB I'd not be keen.

I stripped mine and found next to no grease in it, which was why it was trashed, I packed with grease but the damage was done. I fitted a much better BB with less resistance and much smoother. i find Shimano BB's very stiff turning even in XT form.

Road and MTB cups are different widths, your cranks probably wouldn't fit properly.

Tiagra fitted on my mtb fine
Road doesn't use the plastic spacers, mtb uses 3 (68mm width) that's all surely?
If your concerned about central tube reuse one of your old BB!
And as for road bearings on an mtb, the only bb that will fit my Meta AM without modification is a road Dura-Ace one, the bearings look identically sealed to an xt level bb92 press fit one and it's lasting fine so far

Shimano road BBs are wider than MTB ones, 3mm overall if memory serves me correctly, your call as to whether that's suitable.