Race Face crank issue

[Mr Panda]

Evenin

Today I swapped rings from a 5 bolt Suntour crank arm to a Race Face Turbine. Unfortunately, whilst the outer and middle rings are fine, the granny sits too close to the middle ring due to profile of the crank, where the chainring bolts fit.
The Suntour crank has a flange profile which places the granny ring closer to BB, but the Race Face crank is different, although the bolt hole diameters are identical. Do I need some spacers or do I need different rings?

 

[poweredbypies]

Sure i have heard mention of spacers being used on rf cranks.

 

[FMJ]

16mm bolts + 9mm spacers on Turbine LPs. IIRC the standard Turbines are the same.

 

[FluffyChicken]

Steel Granny ?

You need 1mm longer spacers for steel granny rings (might not be for all sizes) compared to the alu rings the Tubines will be designed for.

or you need to turn the granny around.
Original design was spacers into the holes (probably the suntor), later it switched around to recess the bolt (probably the turbines).

P.S. IB or LP ?

 

[Mr Panda]

It's a stainless steel Specialized granny - came with the original Suntour stuff on my 1992 Cinder Cone and everything worked fine.

FMJ - yes it looks as if spacers and longer bolts of approx those dimensions would do the trick. I'm just not sure if there is a part missing on the RF's, or if I need to use a specific granny with them :|

I'll try get a photo up to explain better.

 

[FluffyChicken]

Photo's will help. I actually think the spacers are 8.30mm
I didn't think you didn't have any spacers at all

I'm assuming it's it's a 110/74.

 

[Mr Panda]

Piccys:

the cranks in question (sorry not sure which version of turbines)


outer and middle rings look ok, but granny is squashed up against inner face of middle ring




granny bolts straight onto inner face of spider - I think this is where there should be spacer(s) or similar.......


Suntour on the right has raised flanges on arms into which granny ring bolts go. RF doesn't.




Suntour.....All my other cranks appear to be similar in design to this


Advice appreciated

 

[FMJ]

You need the longer 16mm bolts and the 8.3mm spacers (the 9mm I originally posted was measured w verniers on an assembled crank, and was approximate). On Shmoo/ST cranks the granny is already spaced out correctly via the raised mounting bosses.

 

[FluffyChicken]

8.30mm is from their early instructions.
M900 XTR also used the loose spacer setup as did a few others.
No idea why Shimano used it for some, guess it saved on cold forging (they would add extra width ?)
For others it was do to the spider setup.

 

[Mr Panda]

Excellent guys, thanks - as I suspected

Now, where to buy spacers and long bolts?

:xmas-big-grin: