Duderdas

Hey all!

My bike has the BB

FSA BB386 CRANK TO BSA FRAME THREAD STEEL BEARINGS

^google it if needed, I'm not allowed to post links yet

I'm trying to figure out how to replace the crankset with something that 2x, reliable and easy to swap chainrings on.

Do I need to replace this bottom bracket to put a new crankset in? Or can I use any crankset that has a spindle width and diameter that matches the BB?

If I do need to replace the BB. Any suggestions on which to replace with a 2x, reliable and easy to swap chainrings on setup in mind?

Thank you!

holytrousers

Hi duderdas.
If you find a compatible crankset, with similar dimensions, of course you can use it. If your new crankset is not compatible, of course you will need to change the bottom bracket.
What are worried about, exactly ?

Duderdas

what do you mean? I’m worried i’ll buy a crankset that does not fit and be unable to get a compatible bb that fits the shell and crankset.

cpach

Bottom brackets aren't massively expensive so you can replace whatever bottom bracket to match whatever crank you want, but you can also install another FSA crank, which they make with doubles. You can use any crankset with an 30mm spindle that is adequately long--so really anything designed for 386EVO.

What's on there right now, and are we talking about a MTB or a road bike? On a number of FSA's modular cranksets you can install an alternate spider to run 2x on a crank sold as 1x.

Duderdas

This is for a 2016 Specialized AWOL Comp and it has a FSA crankset with a very limiting bolt pattern and minimum chaingring size.

So my next question is, any crankset with 30mm spindle diameter should be good, but what about matching up spindle width?

fietsbob

Tube spindles fixed to a crank arm dont have alternate lengths , unlike square taper..

Duderdas

What do you mean don't have alternate lengths? I can see different cranksets are different widths but all have 30mm spindles.

cpach

This is actually wrong. Some cranksets are designed for a relatively narrow bearing stance, as in BB30 which presses the bearings directly into the frame for a 68mm width, vs something like 386 EVO which uses the same spindle diameter but with the width of a outboard bearing crankset in a 68mm shell, which is 86.5mm wide.

For the OP's bike, they need a crank designed around an 86.5mm bearing stance, which would preclude cranks designed exlusively around BB/PF/30/30A, which have a narrower bearing stance.

cpach

Also, looking up that crankset, I'm like 80% sure you can replace the chainrings with these: https://shop.fullspeedahead.com/en/c...-abs-chainring . If you need smaller than 32t small ring, I'd probably recommend getting a FSA Energy Modular crankset if you want to run 46/30 chainrings and don't want to replace the BB. Otherwise you'll probably need to replace the BB.

Duderdas

Yes I am already with the smallest chainring this crankset supports (34 tooth) and would like to go down to a 28 ish.

Open to 2x or 1x.

Open to replacing BB.

Honestly just want to get off this BS proprietary FSA sizing/spacing.

Any suggestions for setup with new BB and crankset?

Bike Gremlin

If I understand correctly, the bike has threaded, British standard BB shell.
In that case, the simple(st) solution would be either square taper BB and matching cranks, or, more modern, Shimano Hollowtech II BB, with Shimano Hollowtech II cranks of your choice.

Product examples (do support your local bike shop and buy locally ):
Deore HT II BB
Shimano Deore cranks (4 bolt mounted chainrings with 104 / 64 mm BCD - smaller chainrings)
Shimano Sora cranks (4 bolt mounted chainrings with 110 BCD)
Shimano FC-RS400 cranks (5 bolt mounted chainrings with 110 BCD)

Final choice depends on your (desired) gearing, number of sprockets at the rear, as well as what kind of chainrings are available in your area.

Duderdas

Not bad examples!

What about:

SRAM GX 1000 2X11 CRANKSET

Found something at an ok price, in stock and the chainrings do 24-36 teeth which is perfect.

This should work correct?

cpach

That would work OK, but it is a wider 49mm MTB chainline, vs 45.5 that the rest of the Rival 1 rear derailleur is designed for. Also, you cannot use your existing rear derailleur and cassette with a 2x system--it does not have enough takeup capacity. The rear derailleur has no officially supported 2x configurations, but is rated for 32t of chain takeup--with the 12t difference in chainrings, you could theoretically use a maximum of a 10-30 cassette (and probably exceed that, probably a 10-34 would work), and smaller 11 speed XD compatible cassettes are not really a thing. Probably the easiest way to go about getting lower gearing is to run 1x. If you need more range, consider this article: https://bikepacking.com/gear/guide-t...t-drivetrains/ . They report success with a e13 9-46 cassette for increased range.

Duderdas

Yah I already got a 34 tooth on the chainring and modified cassette to 46-10 teeth on the back and it's still not low enough sigh.

So it sounds like I need a new drivetrain?

Lol what's going to be the cheapest way to hit around 18 ish gear inches on this bike?

Duderdas

I'm leaning towards Easton ea90 cranks and a small cinch 1x chainring. I might seriously sacrifice the top end speed, but I'm ok with that. I just want to be able to haul up crazy steep hills with my loaded bike.