Doubtful. Q-factor and crank length are different.
Hi Steve maybe showing my lack of knowledge but you can get the power meter in various crank lengths.
What is q- factor ?
Q-factor is the width between the pedals essentially (I don’t know the exact calculation of where it is measured).
Ultegra Q-factor is 146mm
XT is 176mm
many thanks back to the drawing board will have to carry on saving up 
So a brief follow-up here. The Quarq measures L/R and the Cinch is L only. According to several rides worth of data, when I am going hard off-road, I have a power imbalance around 48/52 (occasionally reaching 47/53). On the road it’s right around 50/50 with about 0.5% in either direction. So, if I’m doing 300 watts on the Quarq at a 48/52 split, you can say that 144 is coming from left side. If that is the case, the Cinch would only read 288. At a 47/53 split, it’s 282. Anyway, add in even a slight discrepancy between the two devices, it easily explains the difference between the Quarq and the Cinch in terms of readings. In general, my RPE puts the Cinch at about 335 and the Quarq at 360 or thereabouts. None of this really matters so long as the numbers are consistent. Having already run the Cinch for a season, I probably should have stuck with L-only measurement. The Quarq has been very reliable and it gives my heels a bit more clearance from the crank arm which was the goal to begin with (slightly lower profile than the Next SL crank). Now the Cinch/Next SL cranks live on my Tallboy so no more switching between bikes which was the even bigger goal.
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I’m using my 4iiii on a xt left crank arm. I have been switching it from my hard tail to my duely. I’m getting lazy so i bought an IQ2 so I can just grab my bike and go. For a marathon race I will look at my 3s power to pace. XCO race , I don’t pay attention to it at all. By the way, what’s the big deal with boost on xc bikes? I get it for enduro races but is it overkill for the average Joe xc racer?
Boost originated with XC and trail bikes, mainly because DH were still using 26" and 27.5" when 29ers became more common for XC.
As mountain bike geometries evolved over the years, they became longer and slacker. The geometry tweaks resulted in longer wheelbases that were much more accommodating to 29″ wheels without some of the drawbacks they would have previously had with the old school geometries. When these new larger wheel sizes became the norm on XC and Trail bikes, this discussion of widening the hub and it’s flanges took place. Since the bigger wheels lacked the steering precision that smaller wheels had, engineers were looking at a way to mitigate this. The result is the current 148×12/110×15 boost standard that comes on almost every bike produced after 2016.
More recently the talk of a 29″ DH and Enduro bikes were back on the table, and several manufacturers began to shift their focus to production level 29er gravity bikes. This is where the new hub standard comes in. A 29″ wheel is much more prone to lateral flex than a 27.5″ or 26″ wheel. By increasing the flange distance on the new 110×20 boost hub, you achieve more wheel stiffness.
Creating a stiffer hub was also a way of increasing the reliability of the wheel bearing system. Being limited on the spacing of the flanges by the cassette on the drive side and the disc brake on the non-drive side. The Boost range of hubs addressed the flange spacing issue by giving 6 more mm of room to space the spokes out (on the rear). This increases the triangulation of the spokes overall creating a stiffer wheel. The design allowed manufacturers to move the drive side wheel bearing substantially further out. Aside for wheel stiffness improvements in chain line were achieved.
The advantage of the now wider axle standard is obvious: given the wider hub flange, and the stronger spoke-bracing angle, the stiffness and stability of the wheel is massively enhanced. According to stats from the manufacturers, a 29″ rear wheel with a 148mm hub has the same stiffness as a 27.5″ wheel with a 142mm hub. Other claimed Boost advantages are:
- The increased stiffness results in more effective and more precise bike handling.
- Given the wider rear wheel, a shorter chain stay can be used.
- Suspension pivots can be placed wider apart and therefore stiffer.
- The wider rear hub offers you a bigger choice when it comes to chainrings.
- Boost improves clearance on the forks and the rear.
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Thanks for the comprehensive response. Well…I can’t afford the upgrade.
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Using a inpower, and I love it. Has been rock solid (like actually) and it finally needed a new battery yesterday after 1300miles, stopped at a market and got a AA.
I like non-groupset specific cranks (using shimano right now but would fancy eagle-lizing my bike in the future)
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I’m putting a set of Next R w/ Cinch power on my bike today. Not my first choice but they should be OK. I’ve been using Easton Cinch power for over a year on the road bike so I like the idea of one system on two bikes. The left power only is an issue for me indoors, but I don’t notice it outside as much.
I’m just looking forward to being able to train with power on trails again. Track TSS properly. Pace on those longer gravel climbs that link the single track…
The shorter stays is something that is bigger impact to me than the stiffer wheels. All of a sudden 29er bikes have that flickable feel that you used to only get on a 26 inch bike. My SS is still QR, but at least the rear bolts on to the axle and I don’t really notice much wheel flex… Fork flex yes, but then again the wheels on that one are laced with 32 single butted spoke so they are slightly heavier than some of the newer wheels around but make up for it not having to use a cassette.
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I have a Stages LSide PM on my MTBs…and on wild descents I will get a “1-off” power spike close to 1700w. How can I eliminate these spikes in overall ride data?
Stages suggested the following, but I can’t seem to figure out how to do it in either Garmin Connect or TrainingPeaks.
“Depending on the platform you use for analyzing your ride files, you may be able to set limits for your power data. For example, setting the upper limit to 1,300 watts, which would then ignore any power spike above 1,300.”
If you use WKO4 or Golden Cheetah you can remove the spikes manually.
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Guys, do you know if it possible to use PowerTap P1 pedals with a MTB (and get accurate power numbers)? Aside from having to use road bike shoes, and the risk of hitting the power meter, it should work, right? I was thinking of doing this as a temporary solution until the budget allows me to buy something more suitable.
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Yes, the P1/P2 pedals will install and function fine. Just a scary combo if you have to unclip and step off.
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I ride with my Assioma’s on the MTB but on the road or gravel only nothing technical. I don’t think they handle pedal strikes well.
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Thanks, glad to know I am not the only one planning this! Do you need to change any settings for the wheel size? On the MTB I have 29" wheels instead of 28" on the road bike. I know that I need to input the correct crank length, but I am not sure if the wheel size is relevant for the power calculation.
Crank size is the only setup you need to do aside from the zero offset, that should be done daily.
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I strongly suggest selling an organ and getting the Quarq XX1 power meter. I’m loving mine! Bonus, it’s miraculously very close (1-2%) compared to my 2017 Kickr Snap. On Taylor -2 today the NP difference was 1 watt between the two.
Having power outside is amazing both during and post ride (and soon, race) analysis. I didn’t know what I was missing.
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I bit the bullet and ordered the Quarq XX1 Eagle and am upgrading my BB to DUB from GXP. I will let you know how it goes.
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