A 2x Power Meter on a Salsa Cutthroat G1

 The G1 Salsa Cutthroat is an amazing bike, but it's got some old standards that make upgrades a bit tricky.

In particular, it has a non-Boost mountain bike spacing for the crankset, and a max chainring clearance size of 42/28. This gearing ratio is very old school. SRAM adopted it for a while before dropping 2x systems for 1x entirely, and Shimano's gearing has put 10 teeth between the two front rings for a while now.

The BB92 standard has a reputation for shitty bottom brackets with 30mm spindle diameter, so we'll want to stick with the 24mm spindle or SRAM GXP. You may choose to go with a higher maintenance option, but since I want to ride this thing on the Tour Divide, I'm going for reliability.

To further complicate matters, you may want a power meter!

So, here's the cranksets I've considered, the set I went with, and what I eliminated from consideration.

Winner - Shimano XT 8100

  • Shimano FC-M8100 crank arms, 165mm
  • Wheels Mfg Thread-Together BB
  • power2max NGeco Shimano DM spider power meter
I'm a bit of a Shimano fanboy. Their stuff Just Works, reliably, and is easy to do maintenance on. Plus, the rest of my kit is Shimano XT, so it'll match. It has a 24mm spindle and comes in a variety of sizes, including the 165mm that I'm excited to try out with my stubby little femurs.

The XT 8100 features a direct mount system, and power2max makes a power meter spider for it. Their 2x adapter will make an ordinarily-Boost chainline into a standard chainline, fitting the Cutthroat's spacing. The spider accepts two rings, with 104/64 BCD spacing. It's easy to find the 28 rings, but 42t rings are still difficult to find. I've been running the stock 10 speed rings with no issues, so I've ordered several 10 speed 42t 104 BCD rings to have as backups in case they become completely unavailable.

This setup should drop my crank weight by about a pound from stock, be more reliable, and have a power meter. I'm stoked.

The other options in this range should work, too. I was a bit concerned with the Q factor on the XTR 9100 crankset being too narrow. I couldn't find a measurement for the depth of the crank arm to see if it would actually fit, and $450 is a bit much to drop on an experiment.

Runner-Up - Race Face Aeffect R

The Race Face Aeffect R crankset is extremely similar to the Shimano XT M8100 set. It's a few grams heavier, about $30 cheaper, and comes in just as many lengths as the XT. I went with the XT because the Aeffect wasn't in stock in 165mm, and because the Aeffect's installation process is a tiny bit more annoying than the Shimano crank installation.

The Aeffect R uses a 24mm Cinch spindle, and I could have used the same spider, ring, and BB situation as the XT.

The Rejects

I rejected a lot of options, for a few reasons.

Race Face 30mm Cinch

Race Face Turbine and Next SL cranks were appealing, but the 30mm Cinch spindle was an unfortunate requirement - those BBs have a bad reputation, and the Cinch installation is a bit more finicky than I'd like for a bikepacking/touring bike.

The Next SL was really appealing from a weight perspective, but the reliability problems with the pedal inserts makes them less appealing.

XTR M9000

The XTR M9000 crankset comes in a 38/28 gearing, and since it's old, it has lots of availability at a pretty good price. Then you can get a Stages power meter on the left, and you're set. This is a great option if you don't mind the 38 top gearing, but, well, I do. The Cutthroat is my "do it all" bike, and that includes spinning out while going down mountain roads.

If I didn't want the top-end power, I'd just run a 1x. A 34t ring and a 50t cog has the same low end as my 28t ring and 42t cog. That dramatically simplifies things and lightens the bike. I'd rather invest in my Cutthroat than get a road bike, though.

XTR M985

So, these did come with a 42/28 gearing. However, they're out of production for two generations now, and they're hard to come by. They're expensive. But! They would be a great choice if they were more available.

It's also difficult to find these in shorter crank lengths - 165mm was either not an option or not en vogue.

SRAM XO GXP 42/28 Double

This is the most straightforward upgrade. Wouldn't even require a new bottom bracket! But it has the same issues as the XTR M985 - hasn't been in production for years, not easy to source, etc. It's also not clear to me how to run a power meter on it. And, lastly, it's carbon - and carbon cranks have reliability issues with the pedal inserts.

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