I'm looking to build a 10-speed...no front der. with a single-speed crank and a 10-speed rear der. This will basically be a flat-bar road bike. I ride a lot of bike paths with the wife and I really don't need the extra gears that a double or triple crank provides (plus I already have a bike or two like that).

My question...who makes a nice lightweight single-speed crankset? The bike has a standard english bottom-bracket with a Dura Ace 7900 BB installed. I'd like to preserve that if I can.

I'm not really looking to cheap out on a crankset. I have a really nice frame this would be going on and I'd like to keep that theme. Plus, I have a feeling I'll be riding this build quite a bit.

Thanks.

Your Shimano bottom bracket requires a Hollow-Tech II crank or equivalent with the spindle built into the drive side crank arm. I'm unaware of any single ring crank that fits it. Shimano does offer a Dura Ace Track single chainring crank (FC-7710) but it uses an Octalink splined bottom bracket (BB-7700) and your current 7900 won't work.

So, you will probably have to change the bottom bracket to match whatever crank you choose unless you just remove one chainring from your existing crank. If you do that, consider fitting a "flat" chainring in place of the Dura Ace rings as the lack of shifting enhancements will make it less likely to spill. Surly offers appropriate stainless steel flat chainrings in 130 mm BCD from 38T to 50T.

the catch-22 is, the chainline with your current crank and a single ring will be suboptimal by a few mm. it will work OK

true, But you can always adjust it slighty, chosing the side of the crank to mount the ring, and use spacers as well if needed. I pulled old spacers off a mtb crank and they have saved my life running a single speed front ring.

Would something like this work with a normal Dura-Ace/Ultegra BB?

https://bike.shimano.com/publish/cont...0.-type-..html
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https://www.missoulabikesource.com/Pr...px?item=430008


The BB it is calling for is a Tiagra BB. Not sure if that's the same design as the DA BB though. It is a 2-piece HollowtechII crank, though.

shimano recommends sm-fc4500 BB. saw one on ebay for 10. buy it now. whether or not this is a ****ional match for a "normal Dura-Ace/Ultegra BB" or not IDK. good luck. i didn't know about the alfine SS crank. thanks.

Shimano - "2-Piece crankset with integrated bottom bracket"
Missoula - "With Bottom Bracket"
Why don't you just use the one it comes with?

The OP asked for a light crank. I don't think either of these comes close.