Frm Cu2 Integral came in but houston we have a problem

Discuss light weight issues concerning mountain bikes & parts.

Moderator: Moderator Team

Post Reply
Posts: 253
Joined: Thu Oct 05, 2006 8:10 pm
Location: Chicago, Istanbul, Madrid

by EddieChi

I got a second hand frm last week (minus the chainrings)
it's not the 2x9 but the triple.

Looks very interesting, definitely different than the Raceface since it doesn't have a real crankbolt that tightens the crank together.
The way the raceface works is Left arm has the spindle and then it rightens to the right arm (with chainrings) with a supplied crank bolt.

The FRM spindle is on the right arm and attaches to the left arm with 2 bolts that just pinch tighten it to the spindle.

Crank Arm + spindle = 336g
Other Arm = 174g
Bottom Bracket = 88g for cups and 12g for plastic middle
End Cap = 7g

Total minus chainrings and chainrings bolts is 605g or 617g if you use that plastic bb piece.

For total weight sake (add in extralite 44t (61g) 32t (28g) 22t (14g) + 16g chainring bolts)
= 724g total weight

HERE is where the problem comes into play.

First, there is not enough clearance for the extralite 44t ring. It does not fit on there and more than likely I will have to sand down each piece on the extralite for it to fit snug (shave a few grams off in the meantime :)

The worst part is that I can't use the token bb with the skf bearings. The FRM spindle, after trying to fit it in the token bb, is larger than the raceface spindle. You can see that the hole on the FRM cups are bigger than the token cups.
The token cups will not go through the spindle. So does that mean if the FRM bb is broken that I am SOL?
Clearly the companies that make aftermarket bearings for these bb have the same uniform bearings to just pop in and pop out.

That was kind of one of the reason why I prefered integrated systems because of bb interchangeability(if thats a word :)
The skf bearings were so smooth, it was like butter in the way they turn, the frm is not as good.

So On one hand I am very happy in the frm crank in the fact that it's very lightweight and has a very simple design. On the other hand the bb really bothers me.

Posts: 151
Joined: Wed Jan 03, 2007 8:11 pm

by sjors

nice and lite. But nothing specials
cycling is a passion

by Weenie

Visit Online Retailer for HighEnd cycling components
Great Prices ✓    Broad Selection ✓    Worldwide Delivery ✓

User avatar
Posts: 181
Joined: Sat Feb 18, 2006 2:58 pm
Location: Newcastle, UK


I may be wrong but i think the bearing you show on the left (in last pic) has a plastic reducer/cover fitted much like shimano, if you remove this im pretty sure you will find the bb internal dimension is the same as the one on the right. You might want to modify the spacer so you can use the cover bit of it still as this might be important for spacings/sealing of those cups (never seen one of those ceramic ones before).

Posts: 253
Joined: Thu Oct 05, 2006 8:10 pm
Location: Chicago, Istanbul, Madrid

by EddieChi

You are correct, thanks! :D
I pushed it into the spindle and the plastic piece just popped right off.

The token SKF without the plastic middle weighs a measily 82g!

Post Reply