Bottom Bracket Standards...386Evo

I have a normal Shimano Hollotech Ultegra BB, with some hybrid DA/SRAM cranks on the TT bike.
They are a little big at 55/42 for my needs and desires next year.

I have a 52/36 Ultegra on my summer roadie and some 50/34 105s on my winter bike…

…but they are both 11sp and my TT bike is 10sp.

  1. Is there any issues with an 11sp chainset and 10sp chain?

I’ve looked at new rings (oo-er!) and it seems like I can get a snazzy new chainset for a similar price.
But, the one I’ve seen is a 386Evo, yes, yet another standard!

After some Googling, looks like I can get an adapter and everything is sweet:

Is it that easy?
Just whack in that new BB and away you go?

I’ve got a similar set-up with a 30mm Rotor crankset.
I tried some cheap chinese bearings first to see if it would work OK, and it did but they didn’t last 5 mins.
I’ve got RaceFace ones now and they’ve been fine. Rotor so their own but they are pretty dear.

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Shouldn’t be. 11sp chains are slightly narrower, but whilst Shimano would have you believe you need specific chainrings, I moved the praxis works rings from 10sp SRAM Red to 11sp Ultegra di2 without issue. Praxis do quote the rings as being 10/11sp however.

But ultimately, something that can accept the marginally narrower 11sp chain should be fine accepting a 10sp chain. I can put my 10sp road bike on my smart turbo with an 11sp cassette and not have any real problems. That’s using ERG mode to negate the need for any shifting.

The Scott Plasma 3 I moved to had BB86, compared to the BB30 on the S-Works Transition I moved from. My power meter was a P2M on a Rotor 3D30 crankset. I had to get adapters (link) to make it work. It’s workable, but not perfect. Cramming a 30mm spindle into a BB36 opening requires very small bearings from what I’ve read. Brand new, or after a service when they’re fully greased up, you’d struggle to get 1 full spin of the cranks when no chain is installed. After riding for a while, they loosen up a bit. I probably now get 2-3 rotations. That’s still a lot less than ideal though.

Unless you are in my situation of trying to make an expensive power meter work on a frameset, I’d say try and find a crank with a 24mm spindle to avoid those issues.

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I’ll be using the Bottom Bracket above - as that just screws straight into the current frame I have.
The spindle looks like it goes straight through…

…what you two say, is that it does work.
Looks like a nice way to get a smaller ring piece on.

My understanding is that 10 & 11 speed chains are the same dimensions internally, all the width savings are on the outside. E.g. Rivets not protruding beyond the plates (hence why they break more often but you’ll get me on my Luddite soap box)
As such I don’t think chain rings should be an issue.
Ps. I’m in a similar situation to Stenard in that I was trying to use a Powermeter. Can’t comment on the efficiency of the thinner bearings just that I got everything to work.

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Mine’s an English threaded BB so same situation as you.

OK, so I can spend money and get the TT specific crankset and BB…

…or just switch out the road bike 11sp ones, for free, which is a few minutes job.

CHEERS :heart:

But if you’re just buying a new crankset, then can you not just do a bit more searching to find a good deal on a 24mm spindle unit. As I say, yes it’ll work, but it’s somewhat the case of trying to ram a square peg into a round hole, and you do compromise to get it to work.

I would guess there’s a few watts lost if I got really technical, in terms of the cranks not spinning optimally freely. So part of my (limited!) power going into the crank is lost in friction at the BB. But that was a compromise I was willing to make in order to utilise my expensive P2M. If I was on some kind of other power meter setup (i.e. pedals), I definitely would not be making that compromise.

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Sorry, I thought you already had a BB386 crankset (must read things properly)
Yes it will work, but if you’re buying new and starting from scratch get a 24mm one.
Bigger bearings will be smoother and last longer (and cheaper to replace)

In my experience, 10 and 11 speed chains and chain rings are pretty much interchangeable. The shift quality using a 10 speed chainset on an 11 speed setup is marginally worse.

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Cheers…looks like I will try this route first.

Obvs will need a second chain with a few less links in there, to prevent the slap!

No. I run an 11 speed 105 chainset with a 10 speed chain and it works just fine

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If you’re using an external BB (threaded) you should be fine with a 30mm axle. If however it was internal, you’d be replacing it at least every year as the bearings are small and last no time; that’s the set-up I have in my TT bike unfortunately.

I had a BSA30 Rotor threaded adaptor on my old TT frame; it was good quality, and lasted much better than the press fit equivalent.

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Gonna try out the 11sp option first.

I cannot believe just how expensive individual rings are :scream:
Just totally normal 52/53T ones.

So…when moving down from a 55/42 to a 53/39, should one take three links out of the chain?
If moving down to a 52/36, then would you remove up to six links?

I’ve always used the Sheldon Brown method for chain length. Put the chain on the biggest ring and biggest sprocket but not through the derailleur and add 2 links. Never had any issues like that.


Dan from GCN just told me the exact same thing on the tube.
If Sheldon says it, there is nothing else worth trying.


Thanks for that. Sounds a simple protocol. Half the time I end up being prudent, and then removing one link at a time for fear of over-shortening!

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Dan on the tube here:

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Yes timely for me too. Going to slap some bigger rings on the tt bike :+1:t2: