Power meter tech/ compatibility question for new bike

I am wondering what is the cheapest and lightest weight option to have two sided power on a bike I just ordered. I currently use garmin xc100 (one sided) pedals and I love them except for the 1 sided thing. (Its especially nice to have them for traveling and renting on bike trips). I would love to have 2 sided on the new bike but I can’t seem to understand what would be compatible, light weight, and reasonably priced for the Fezzari Signal Peak I am getting. It comes with XO transmission and I don’t really understand much about it. I do know that I will change out the chainring to either 34 or 36T from the 32 it comes with, not sure how relevant that is though?
Basically, should I get double sided pm pedals or something that stays on the bike?

It probably depends how many bikes you have or how likely you are to be swapping them often. Or how often you’ll be swapping cranks. My previous gen (and single sided) pedal based Favero Be Pro S is still working but if I was ever to replace it, it would be with the dual sided Favero Assioma. Theyve got a rep for be reliable and vfm. I’ve also got a crank based 4iii its been very reliable and wasn’t badly priced but I’ve not had power outdoors for a few weeks as I’ve been using another bike in grotty weather and for the bike I do have it on I’ve not been able (without expense) to experiment with crank lengths.

Yes, so I have a road bike and dual sided Favero Assioma for that one. I go on a mtb bike trip once or twice a year and rent a bike, its great to bring the garmin pedals and still get to track power in that situation.
I was planning on selling my other mtb so I think I won’t be needing to move power measuring around bikes unless I am traveling but I could definitely see a single speed mtb in my future so :person_shrugging:

Your best bet is probably to buy the right side upgrade pedal for your Rally. Unless there is a spider that fits those cranks.

T type aftermarket stuff is pretty thin right now but supposedly Wolf Tooth Drop Stop B works with Transmission, and they make a 104 BCD ring that fits Quarq and Sigey 104 BCD spiders. Whether those spiders will fit your cranks and have the correct offset and chainline I have no idea.

You could also see if 4iii would do a factory install on your crank arms, but I can’t see any of the above being cheaper than an upgrade pedal.


Might be a good idea to sell the XC pedal and get the SRAM Rival spindle power meter. I agree on the single sided power not being as good as the dual or central power, as my 4iiiii is slower to pick up power changes compared to my P2M.

Another thought, but a dual PM set now and sell sell the single side in the spring. Or do the upgrade.

It looks like the SRAM T-Type powermeter is left-side only (even though it’s housed in the spindle). That’s the easy button, but sounds like you want dual-sided readings?

Not sure why the Rival was recommended above - that’s a road crankset and one-sided, so fails on two requirements.

Your other option is an aftermarket crankset, but then you have to figure out which aftermarket chainrings are T-Type compatible (probably not many yet).

Honestly, I’d probably stick to the T-Type spindle OR use your pedal system (add the other side if you really need dual-sided readings).

The right-side torque goes directly to the chainring from the crank-arm, so the spindle has no source of resistance because it’s sitting in bearings.

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Yeah, this explains why I’m struggling to figure this out. Not only am I not that informed about crankset terminology but also it seems genuinely confusing.
I agree that the sram one seems one sided and I definitely want a dual sided option. Maybe the second Garmin pedal is the way to go in the end.
Should I do weight math to compare regular pedals and crank based power meter to Garmin pedals and regular crank? Or am I stepping towards weight weenie anxiety?

If you want true dual-sided, you have three “simple” options without getting wacky with some outside brands(magene, etc)…
-Add a right side Garmin Rally Pedal Power Meter- by far the easiest, ~$500
-XX SL Transmission Power Meter. They offer the spindle based version, which as discussed above is only left side, but they also offer a spider type version, that uses a proprietary thread on chainrings. You can buy the entire setup; crank arms, spider, chainring for ~$950. You could also source just the spider and chainring and mount it to your existing XO Eagle Transmission crank arms, ~$600
-Quarq 104BCD Spider, attached to either your existing XO Eagle arms, or buy some carbon ones from any generation(don’t need to be Transmission) and add a third party chainring from Stone, Garbaruk, WolfTooth, etc. ~$600 for spider and chainring to add to current crank arms.

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On nice, I hadn’t seen the XX SL spider-based meter. That’s probably the “cleanest” options here, but also the most costly. It does have a 34t ring, which might not be ideal, depending on your fitness and expected speeds. You can buy a 32t ring, but that’s another chunk of money.

Honestly, if the 1-sided pedal system has worked so far, I think I’d just add the other side and call it done.


XTR pedals are 310g. Rally XC200 are 450g. 140g addition.

XO-T crank is 720g. XX SL spider PM is 555. You SAVE 170g? Maybe I’m reading the specs wrong, but that’s a pretty massive savings for the $500 delta between adding the pedal and replacing the crank.

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Almost anything will be lighter than the Rally XC. Mine also squeak annoyingly with most shoes. I kind of wish I never got them and have for the past year and a half been tempted to sell them and get a Quarq for the bike they’re on. On the plus side, I have had no issues with power measurement or dropouts, so for that reason I have put up with the porkiness and squeaks.

Oh wow, I thought it was only my rallys that squeaked! I assumed it was something with my shoe interfacing with the pedal. God I hate the noise so much I often ride with my feet putting active pressure at an angle to get it to quiet down.
I think I will go for the xx spider crankset, save the weight and get rid of the squeak.
I will say that the rally pedals have been super reliable, get good battery life, and I have absolutely smashed them against rocks without any issues.

I suppose its also worth mentioning that Favero is doing a true SPD pedal, not requiring the hack, and as such, gets rid of the large “pod”… 380g, so somewhere between XTR and Rally…

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Some of my Shimano SPDs squeak as well (mix of XTR and XT XC models). I think that just happens with some shoe/pedal combos as the plasitc/rubber sole of the shoe is providing much of the side-to-side support in that system.

Yes, I was able to largely fix it on one pair of shoes with some cleat shims and changing from the supplied Garmin cleats to shimano. But, at the same time, the M540 pedals and Bontrager pedals I previously used had fewer noise issues. I am not a fan of these pedal bodies at all.

Man… my Shimano XTR trail pedals squeak like crazy. Constantly cleaning and having to use silicon based spray to keep them quiet. Been like that out of the box. Should’ve taken them back. Other XC pedals, including the Garmin Rally… nothing.

Maybe reach out to Garmin… see if maybe they can send you the “kit” to replace the externals?

So now I’m wondering if I get new pedals which ones to get that will be lightweight and quiet!

I’m a Shimano fan for pedals. They aren’t the lightest, but they’re bullet-proof, ubiquitous (if you need cleats or replacement pedals quickly), and reasonably priced.

I use XTR on race bikes and XT on my other bikes.

Xpeedo weight less (as do some other SPD-like designs). But, the Xpeedo I tried didn’t work perfect with Shimano cleats (and I didn’t want to swap 6 pairs of pedals), so they’re in my parts-bin for now.

Eggbeater w/ ti spindle are super light, but I managed to destroy 3 pair in 3 seasons, so sold the rest and went back to Shimano. It’s a shit design, IMO - the outboard bearing was just a cheap bushing, prone to catastrophic failure (taking out the end of the spindle). Annual rebuilds mitigate the problem but I didn’t want to risk getting stranded in the backcountry 4 hours walk from my car and out of cell range.

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