Power Meter Questions

g0g

Thinking of buying a Power Meter if I can get something accurate enough fairly cheaply and looking for advice. I don't race but like training and love stats/gadgets. Seems like the cheaper options are Stages non-drive, 4iiii non-drive, Assioma Uno and Garmin Rally RS100 all around €300-450 single sided? From what I can tell all 4 seem to be reliable enough? My bike has Ultegra Di2 with 8100 172.5 Cranks, and I use SPD-SL pedals/cleats. I do have a second commuter bike on SPD-SL so ideally don't wanna change cleats.

Some questions:

1. Should I be fussed matching Groupset? If I go with non-drive crank power meter can I as easily pick a 105 as an Ultegra? I assume the difference between the two is gonna just be weight? Would having Ultegra on the drive side and 105 as the power meter cause any issues at all or purely cosmetic? Seem like that could be € 100 difference
2. Have I missed anything brand from my cheap options list?
3. Stupid question but is a crank easy to swap? I've never removed mine and wondering how you make sure it goes back on straight - is there only one position (straight) that it actually fits back on?
4. Stating the obvious but if I spot a second hand 175 or 170 crank that's an absolute no no? i.e. mixing different crank lengths on a bike

Has anyone spotted an great deals on them? From what I can see

RS100 - cheapest seems around € 450

Stages/4iii - seem € 400ish for latest gen Ultegra or € 300ish for 105

Assioma - € 400ish but would force me to use their cleats instead

Thanks in advance for any advice!

G1032

Magene PES P505 Base Power Meter

Swapping cranks very easy. Should be no issues really.

Different length cranks on either side an absolute no no

boredatwork82

I have the Assioma duo-shi and also a 4i 105. Both dual sided. No difference. The ease of switching the pedals is a great benefit of the Assioma but you don't want to be doing it to often. The metal on the pedals is much harder than the cranks.

The Assioma is available as just a Shimano axis if you use Shimano pedals.

Overall I find them handy for following my wahoo program from the turbo out on the road. Its a nice option.

beggars_bush

Assioma

G1032

https://www.boards.ie/discussion/2058352504/power-meter-questions

Assioma don't use a proprietary cleat. You can choose Look or Shimano

CramCycle

From what I can tell all 4 seem to be reliable enough? Yes they are, I have 4iiii, I know loads with Assioma without issues.

1. Should I be fussed matching Groupset? If I go with non-drive crank power meter can I as easily pick a 105 as an Ultegra? I assume the difference between the two is gonna just be weight? Would having Ultegra on the drive side and 105 as the power meter cause any issues at all or purely cosmetic? Seem like that could be € 100 difference. Not really, will it annoy you after a few years, maybe. I would match but unless there is a different Q factor, then they should be fine, but do check that.
2. Stupid question but is a crank easy to swap? I've never removed mine and wondering how you make sure it goes back on straight - is there only one position (straight) that it actually fits back on? Really easy, you need an allen key, a pre tension tool (I have loads of them if you are around Dublin or Wexford but they cost a fiver in your LBS at most)
3. Stating the obvious but if I spot a second hand 175 or 170 crank that's an absolute no no? i.e. mixing different crank lengths on a bike. Unless you have a proper bike fit where they identify that you have a leg length difference and you get it fitted appropriately, then no, don't do it. You will get used to it but just don't

Assioma - € 400ish but would force me to use their cleats instead As others have said Assioma can run Shimano now, just have to buy that model, so do Garmin but then your budget goes up a bit.

68 lost souls

I have a 105 4iiii Left-Side Podiiiium Powermeter that I picked up new for €200 and it drops out quiet a bit I am not super happy with it. I am using it on with a Tiagra groupset so you can mix and match. I use it on my gravel bike as I wanted power there but am running mountain bike cleats. I use an assioma duo on my road bikes and its great very happy with those. I am using the assioma/welgo cleats but you can also use Look keo cleats. I have a set of look keo carbon pedals on another bike and use my assioma cleats with those no issue.

joey100

I'd stay away from stages seen as they had laid off their entire workforce and seem to be very close to going under. I've had single sided 4iiii, dual sided 4iiii, dual sided garmin and dual sided Favero's, shimano version. Dual sided 4iii and garmin seem to be most consistent for me. The single sided read very high, and had some issues. Favero's seemed good but for the shimano it widens the Q factor by a good bit on either side of the bike and I couldn't get on with it. I'd probably go the favero's and go for a cheap set of look pedals on your other bike. I'd go Favero over Garmin only cos the Favero are rechargable battery, Garmin use a strange battery (Cr1/3N) that I've found hard enough to source.

Macy0161

I've two left side only 4iii's going - one a 105 (currently on my gravel bike with a grx crankset), and ultegra one my road bike. Haven't had any issues with either, and when I tested they matched each other and my turbo within respective margin of error.

That said, I don't think there was any realistic SPD-SL pedal options when I got them, or SPD ones when I wanted power on the gravel bike. If I was going knew now, I'd go Favero, notwithstanding I expect a new road model minus the pods now they've nailed the spd pedal.

casion3

I have a left sided only stages ultegra.

Got 2nd hand. If your on a budget keep an eye on the adverts section here and done deal.

172.5 crank length is pretty popular so they come up from time to. Only thing is they go fast.

g0g

Thank you all for the really useful replies. By complete coincidence I found a 172.5 Stages 105 second hand on Adverts yesterday after posting this and am gonna take a chance on it. Fraction of the new price and I can always sell on and upgrade if the non-matching components drive me mad after a while!

Whatwicklow

I have used a 4iiii for the past 5 years and swap it between a road, mtb and cx bike. No issues and v reliable.

07Lapierre

https://www.boards.ie/discussion/comment/122167730#Comment_122167730

I have campag Chorus I Chainset and a Campag Chorus II Powermeter. NOBODY has ever commented on the different cranks, as lets face it…you cant look at both sides of the bike at the same time! ;)

JMcL

I've a 4iiii single sided 105. I was going to spring for the Ultegra version when I got the new bike a few years ago but then developed sense, swallowed notions of it looking cheap and put it on. It's worked really well in the 2-1/2 years since as it had done for the 3 years before that. Only problems have been the coin cell battery running out, but they last months (obviously dependent on how many hours a week you're doing)