FRM CU3-M20 Cranks

Cranksets can be one of the last things we think about for a bike, often we choose to just run what your bike came with! This works just fine, until you want to customize your bike, or actually start building up something from a frame.

Versatility is something that we want our bikes to give us, but we need to expect this from our components too. Forks with travel adjustments, on-the-fly changes to compression damping, dropper posts… we are getting what we are asking for, all in the name of a better ride.

So why not have cranks that can adapt as well? It’s easy enough for some models, such as a Shimano XT crank. The triple can be made a double, or a single with the right ring and a guide. But they’re not that light, and the range of chain ring sizes might be hard to tune for whether you’re on a 26” 27.5” or 29” wheeled bike. Wheel size makes a difference to gearing, don’t forget that.

FRM have offered light, strong cranks for a while. The CU3-M20, although lacking in imagination for the name, is light (585-610g depending on length and configuration), stiff, and you can change the whole spider setup.

Because you can change the spider, via a press fit attachment and lockring, you can fit a spider with 104 BCD for double or singles, or an XX1 spider, or FRM’s own integrated spider double ring setups, which are superlight, and offer ratios not always found elsewhere, like 25/39, 24/38, and 22/36. If you’re a gear nerd – you’ll love that choice!

The cranks themselves are made in Italy, CNC machined from Scandium, with Ti bolts. They are anodized black, so they’re not an item to colour match to your socks and gloves, but they will go with anything. The cranks use a 25mm axle, so FRM make their own BSA (standard thread in) bottom bracket to suit. PF30 and BB30 models are also available. The bearings are well sealed, so we should expect a long service life.

We are setting these cranks up with the 24/38 integrated spider setup first. It was pretty easy to install, sitting the rings on the back of the crank and using a piece of PVC pipe to tap them on (with grease). The lockring is then tightened down to keep it all in place.

Next up, we will get them fitted to the Whyte M109 C long term frame as we get started on the build.

Down the line, we will probably play with the gearing options, and see how the setup goes with FRM’s own wide-narrow rings for both the XX1 spider and the 104BCD setup.

From: Carbuta Australia (allan@carbuta.com.au)

Price: $750 depending on the build