Am I correct in thinking the Sram boost cranks are 'boosted' in the crank rather than the chainring...
...whereas Raceface cinch boost are 'boosted' by fitting a different ring, and the cranks themselves are 'boost-neutral', as it were?
I'm thinking of swapping a Sram boost chainset onto a non-boost bike, you see, and I have a feeling it's not really going to work in terms of chainlines.
Nope.... well maybe.
SRAM Direct mount cranks its all in the ring or spider. SRAM fixed arm cranks the crank is offset.
AFAIK until really recently RF doesnt/didn't actually do a boost crank. All their cranks are somewhere between the two, and some (Ride/Aeffect/older turbines) can be adjusted more in or out, but never to full boost until a short while ago (so recent you wouldnt have them).
You might find aftermarket rings that mean the situation is different of course.
EDIT: I don't know that SRAM ever made a fixed arm boost crank FWIW.
the Sram crank is a
- Sram X1 Carbon Eagle GXP Boost PF, QF 168 / 32T
with a direct mount x-sync 32t ring
The ring doesn't appear to have any offset/dishing at all.
if it can't be un-boosted then it's for sale (brand new)....
Sram chainrings come with two offsets, 3mm & 6mm. The 3mm is for use on boost frames while the 6mm is for use on non-boost frames. Depending on frame however you can use either chainring setup to get the chainline you prefer.
My Shan GT will only except the 3mm (boost) setup due to clearance issues. My old Rocketmax (boost) & Rocket (non-boost) frames didn't seem to care either way.
@benpinnick did not know that about Raceface cranks, seems to make more sense in a way.
Cheers, thanks
The X1 carbon is a good crank, shame to sell it. I would suggest getting a steel non boost ring for it. Yes its adding a bit of weight but the crank is pretty light, and you'd find with the right chainline and a steel ring its going to last forever.
Yep. Now it can be un-boosted then I'll swap it over and keep it. Ta.
Sram chainrings come with two offsets, 3mm & 6mm
They also do a zero offset.
They also do a zero offset.
Didn't know that. Is that for super boost or just to have more chainline options?
Not sure, i'm my case it was needed to clear the stupid chainstay design!
Didn’t know that. Is that for super boost or just to have more chainline options?
Its for super light short axle BB30 cranks.
It should be on the inside of the chain ring what the offset is. It is on all the SRAM ones we have.