Affordable power meters for SRAM MTB drivetrains?

I have been hoping to get a power meter on my XC bike with a SRAM Eagle drivetrain for a while now, but can’t seem to find many options. It seems like there are more and more affordable power meters available (i.e. Stages, 4iiii) but I can’t seem to find many for my SRAM drivetrain other than Quarq which is more expensive than I’d like. Any ideas or recommendations for MTB powermeters (left side only is fine) that are more affordable? Thanks everyone

I have a power2max NGeco on my MTB. I am not running SRAM cranks, but take a peek at their site. I see a SRAM option that may work for you.

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Perhaps this is not what you want to hear, but I’d just spend the money on the Quarq. I have one on my road bike, and its performance has been flawless. It is one of the benchmark power meters for @dcrainmaker and @GPLama for a reason: they just work, give reliable numbers and are based on very reliable, mature tech.

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I went through the same thought process as you. I couldn’t find anything suitable. No 4iiii option in stock seemingly for years and stages almost as expensive as some non-left side options.

I ended up going for a Power2Max NG-Eco as well, it’s been great so far.

One thing to bear in mind if you go Quarq - do you have 3 or 8 bolt chainring mount. If you have the standard 3, then you’d need a new crank as well.

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although the manufacturers say it is not possible, I changed my cranks and chainring from sram Eagle GX to Shimano XT 12 speeds with 4iiii power meter. It was cheaper than any other option. I already have 2 years using that configuration with no problem (sram eagle cassette with kmc 12 speed chain and the shimano cranks and chainring)

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I have a Sigeyi powermeter…
Works like a charm :grin:

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I looked at Sigeyi before settling on P2M a couple of months ago. They had zero stock in the UK seemingly, so it was pretty much a non-starter at that time. Checked again today and their UK website is offline.

Curious why you say you need a new crank. Am I missing something? Do you know if these work with lower level GX cranks?

From what I see this should bolt right on and go. The two issues I see is the 104 bolt pattern limits the Crainring size. I think one or two companies offer one that will work as small as 30T. Other is if you need 3mm offfset.

Thanks for any insight.

For Power2Max, should be good to go with a standard SRAM MTB crank (3 bolt pattern).

My comment above was regarding Quarq MTB PMs. They mount to a special ‘power ready’ version SRAM crank that uses 8 bolts to mount the spider rather than 3. Unless you already have the 8 bolt version then you’d need to also purchase that.

I run a 32T on mine. I think Garbaruk make a 30T that fits because the teeth are offset inwards slightly.

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The spider based options like Power2Max and Sigeyi look great, good reviews. I have the SRAM GX Eagle 148 Dub crank, which has direct mount chainrings. Do you all know if a spider based power meter would work on that?

Yeah, the PM spider mounts in place of the chainring. You’d then need a new chainring to mount on the PM (typically a 4 bolt 104 bcd depending on the PM).

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I had quarq and then got a Bike with 3 bolt sram and power2max fit and has worked as well as the quarq for the last 8 months.

Joe

second vote for 4iiii left crank. put one on my gravel bike and one on my CX bike. works great. Can find them for ~250-300$

They don’t make one for SRAM MTB cranks. Most companies don’t. I’ve looked at most of them. It’s really Power 2 Max, Sigiey or Quarq

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I did a 4iii factory install on my left side X01 eagle crank arm a few years ago and overall I haven’t had any issues, but if I could do it all over again I’d spend more to get spider and/or dual sided system.

Like most people I’m right leg dominant and while you can apply a scale factor to try and compensate the L only system just makes harder to compare efforts and track training stress* with my other bikes that I believe have more accurate power meters.

*Huge caveat to the above is that TSS on MTB is not very comparable to road for me regardless. L-only PM underestimation may be a part of that, but the efforts are physiologically different. 100 TSS on road is far easier to me than “100 TSS” on proper trails.

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This is a great option! Running XT cranks with a Wolftooth chainring and 4iiii PM in my Cutthroat with Eagle GX AXS

Probably a good spot for this…
TheProsCloset is selling 4iiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiiii XTR PMs for cheap right now
4iiii PRECISION Power Meter Shimano XTR FC-M9020 = $225

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Does anybody know if a M8100 crank works with a M9000 or M9020 crank arm?

I would do the left only given the lower cost, but the M9000 cranks cost $450+. An M8100 is like $150.

I went down this same rabbit hole as I’m putting this on a MT511 (OEM Deore with 4-bolt spider). The difference between x000 and x020 is 6mm of “q-factor” (x030 are +9mm), which is measured on the outside of the crankarm where the pedal spindle meets the arm. The difference is probably on the spindle length and the number of spacers you need to put at the bottom bracket, not the thickness of the arm or offset. Stages sells these as one part. I think 4iiii sells them as different parts because of the label on the donor part.

There are also 4-bolt chainring cranks and direct mount cranks. The 4-bolt spider adds 6mm of q-factor as well. Note: XTR M9100 / m9120 uses a different attachment method from all others.

Shimano lists the arm as the same part #

R2 has pics and wights of each part number. note the spacers on the x020 and x030 series.
m8000: https://r2-bike.com/SHIMANO-Deore-XT-Crank-Direct-Mount-1x12-speed-FC-M8100-1-without-Chainring
M8120: https://r2-bike.com/SHIMANO-Deore-XT-Crank-Direct-Mount-1x12-speed-FC-M8120-1-Boost-without-Chainring
M8130: https://r2-bike.com/SHIMANO-Deore-XT-Crank-Direct-Mount-1x12-speed-FC-M8130-1-without-Chainring

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I just found this info, which seems to indicate that you can’t mix and match Mx000 and Mx100 crank arms and cranksets between generations due to a change to the spine interface depth. Bah!