26lb FatBike w. 1×11 set up

It took a couple of months of waiting for fairly ‘rare’ parts to roll in but pictured above is a happy customer (and not coincidentally the webguy’s wife) with her new Salsa aluminum Beargrease FatBike with SRAM’s XX1 1×11 drivetrain.

Well, out of necessity it’s not entirely XX1. Though SRAM is indeed coming out with a full XX1 set up for FatBikes that will, with a little luck, start shipping this winter with the also yet to be released top end carbon Beargrease, a 1×11 FatBike component group does not yet officially exist.

In order to achieve a 1×11 set up for this bike we had to use a Hope Fatsno 170mm rear hub with a conversion freehub body compatible with the XX1 cassette. The cassette in question uses a 10 tooth smallest cog and places it where the lock ring sits on a 10 speed cassette, and as a result the XX1 cassette interface with the freehub is quite different.

With that issue resolved by using the conversion body we also had to do some customizing up front with the crankset because the XX1 set up requires a unique chainring that employs a repeating fat/thin tooth pattern that, along with a high tension clutch type rear derailleur, keeps the chain from jumping off the front without the need for a front derailleur or chain guide.

We used an e13 crankset with a 100mm width to fit the oversized bottom bracket shell common on FatBikes and mated it with a Wolftooth chainring that is machined with the aforementioned fat/thin tooth pattern. Eventually a stock FatBike width XX1 crankset with the same tooth pattern will be available.

We could have at least used the XX1 chain ring with the e13 crank if it weren’t for the fact that the XX1 ring has a proprietary bolt hole diameter which necessitated us using the 3rd party Wolftooth ring that uses a standard diameter common with the e13.

The chain, rear derailleur, cassette, and GripShift are authentic XX1, and to our knowledge there are currently no substitutes for these components if you’re going for an 11 speed mountain bike setup, FatBike or otherwise.

We wanted this bike to be relatively light but didn’t want to compromise ridability so we used Rolling Darryl 80mm rims and Surly Nate tires. We could have gone for the lighter Marge Lite 65mm wide rims and Escalator tires but in our experience the Escalators aren’t a great ‘all around’ tire for local conditions (though they’re awesome in some conditions) and the Marge’s aren’t quite wide enough for some winter floatation requirements.

The Carbon Beargease that is supposed to make its debut this winter uses Marge’s and Escalator’s but to be blunt we think that as a spec wheelset that’s kinda cheating just to be able to report a light weight. To be clear we think that set up works well in some situations, but not in everything a Winnipeg winter (or even some summer trails) throws at us and we wanted this bike to be as usable as possible in as many situations as possible.

To that end we also sacrificed a bit of lightness and used Avid BB7 cable disc brakes. We just like the superb reliability and trail side adjustability of the BB7’s.

We finished the bike with a Thomson Masterpiece post, Elite stem, and carbon bar, a Chromag Moon saddle, and an old set of triple Ti Egg Beater pedals (we also have some Blackspire platform pedals with titanium spindles for winter riding).

All in the bike weighs 26lbs, 10oz in its current form. We hope to get it below 26lbs with a few more modifications, but we’re pretty happy with where it’s at now. With a 10-42 tooth rear cassette and a 42 tooth chainring up front (Editor’s correction: And by 42 we mean 32) we think we have pretty much the full range of gear ratios we use 99% of the time on a conventional FatBike drivetrain and we have the same or more rim and tire width and traction that you find on a stock Pugsley and Mukluk at about a 12 lb weight savings over those bikes.

Cost? If you have to ask… 🙂

Special thanks to Al for the blue anodized cable ends that finish things perfectly and Liam for all the help when mid-build frustration got the better of us.