Pls Help with Sram Force BB30 bottom bracket spindle removal

Cochin_biker

Hi:
I bought a new (old stock) Sram Force (20-speed) Powerglide crank set with a BB30 (I think it is compact - spindle is about 95 mm) bottom bracket with 52/36 chaining (I think it is a 2012 model carbon crank). My Specialized Tarmac has a BSA bottom bracket, which has a smaller diameter shell width to accept the BB30 spindle and bearing. So I bought an adapter from Wheels Manufacturing which allows me to use the BB30 in the BSA BB-shell (essentially they moved the bearing outside the shell instead of the standard inside as is seen in BB30). The Wheels Manufacturing BSA to BB30 adapter requires use of a longer spindle (>106 mm).

MY PROBLEM IS THAT I HAVE NO IDEA HOW TO REMOVE THE SPINDLE FROM THE DRIVE SIDE CRANK (SPIDER). I wrote to Sramusa, but got no reply. Checked all forums for many hours, but found no answer. Is there a way to remove the Sram force spider/crank from the spindle? If so, I can replace with a longer spindle and my problem will be solved. Otherwise, I have to chuck my crank and the adapter etc (a $400 loss)

Thanks folks

sungod

afaik there's no option for longer spindle with sram bb30 cranksets, they are designed for true bb30 use only

there are bb30 compatible cranksets (i.e. rotor) that have longer spindles allowing them to be used in non-bb30 frames, but not sram

Cochin_biker

sungod wrote:

afaik there's no option for longer spindle with sram bb30 cranksets, they are designed for true bb30 use only

there are bb30 compatible cranksets (i.e. rotor) that have longer spindles allowing them to be used in non-bb30 frames, but not sram

Thanks for the advice. Since after much search I found no info on how to remove the drive-side crank from the spindle, I suppose Sram designed it as a permanently fixed crank-spindle joint although I can still see some sort of a locking devise where the spindle meets the crank/spider that is filled with grease.

trailflow

I don't think the spindles are available to buy.

But Sram Force 22 PF30/BB30 chainsets have a longer spindle. They are designed to work across BB30/BB30a/BB386 EVO/BBright bb's.

Return it for a refund or sell it on. Why do you need to chuck it ?

gloomyandy

There is also the Sram S series cranks these offer a wider BB30 variant that is compatible with BBRight (I use a s-951 crank set on my Cervelo R5).

Cochin_biker

Thanks Sungod, Trailflow, Gloomyandy for the advice. I don't want to invest any more since I spent on the crank set (which came with the groupur set) and an adapter from Wheels Manufacturing to convert BSA BB to BB30 (but it needs a longer spindle). I can't return the item also because it was a final sale.
A good machinist that I know told me that he can make the BB shell bore larger of the BSA BB of my Specialized Tarmac (the frame is carbon, but the BB shell is metal) so as to fit the in-board BB-30 bearings (I need to widen the 36mm hole to 42mm to take the in-board bearings). It's risky, but I live on the edge anyway and seems like an exciting project. Besides, I now I am obsessed with making it work.
What do you all think?
I heard from Sram folks, who said that in this particular version of the Force crank set the drive-side spindle is bonded to the crank arm and can't be removed (I assume not easily)
Thanks

gloomyandy

Sounds risky to me, but it probably depends very much on how good your friend is and the equipment he has available. You will need a pretty good fit for the BB30 bearing otherwise you will be joining the many other members of the "my BB30 BB is clicking" club. Good luck! Personally I'd be selling both the crank and the adapter and getting a GXP crank and bottom bracket.

trailflow

I very much doubt the bb shell has that much extra material to play with. Even if it does. It will make the walls of the shell very thin and could have a much higher chance of failure. Just seems like a bad idea. Do you know of any other examples of this being done ? i dont. Google isn't finding anything.

sungod

Cochin_biker wrote:

...
What do you all think? [/b]
...

imho that's a really bad idea...

if the mechanic is saying he can take the frame and ream out the existing bsa threaded bb shell to 42mm he'll be removing 3mm of shell thickness

he'll need to meet the stringent bb30 tolerances for size and concentricity (for which best practice is through bore, then cut deeper grooves to fit the clips)

the remaining thin bit of alloy - which was designed to take the crank load, but has now lost 3mm wall thickness, even more if clips are used - is going to have to retain it's shape under load

tbh i'd think you'll end up with a trashed frame

AK_jnr

Sounds like a sh1t idea.