Talk to me about power meters

I’m trying to get back to decent bike fitness and been toying with getting a power meter for the road – gravel bike. I confess I love data and using the peanut left right analysis on my Wattbike has been super helpful sorting out a high imbalance between my legs.

i know next to nothing about power meters apart from you can get single or double sided and some are quite expensive!

I think I’d prefer the pedal models, but really don’t know if they’re effective etc

any pointers? Or deals at the mo.

I confess I love data

This is my downfall. I got so used to power data using the turbo trainer that I started to miss it when riding my bikes. I reckoned it was most relevant when using my road bike though, reasoning that MTB and gravel riding were both too variable to garner any meaningful analysis. That made the choice of crank or pedal-based metering much easier so I bought the Magene PES 505 Base cranks to replace the Ultegra cranks on my roadbike.

https://www.magene.com/en/power-meters/41-pes-p505-base-power-meter.html

My decision was influenced by the review on the Gplama YouTube channel.

I’ve had one powertap hub, and currently have two Power2Max, a Quarq and a pair of Favero Assioma pedals.

If the Assiomas had been available first I’d only have them.

I use 4iiii single sided on my bikes. Last time I looked they could be had for under £200 with discount. Generally reliable and helpful fuel my data addiction. No issues with reliability after 3 years.

I use 4iiii single sided on my bikes. Last time I looked they could be had for under £200 with discount. Generally reliable and helpful fuel my data addiction. No issues with reliability after 3 years.

I’ve got 4iii x2, FSA powerbox/power2max, Powertap x2, and a Stages.

The FSA/power2max is the only one I’d avoid as the app doesn’t work properly and battery drain is high. The rest are all fine

The rest were all well under 300 each. One Powertap was £40 including the wheel. Shop around

Thanks, the bike this is going on has sram rival group set. If that rules out the magene.

whats the deal with one vs two vs spider option ? Is more better, reviews seem to suggest one is enough

another strong recommendation here for Assioma pedals. I’m running a pair from 2019 that are still going strong

I’ve had the assioma duos for a while and they are good – very reliable reputation for power meters.

I had the single sided one initially and they can be a bit inaccurate if there’s a l/r imbalance – it will be doubled for the output. This doesn’t matter if it’s just for training as you just need consistency. It does matter if you’re in a comparative setting like zwift racing, switch between pms like turbo / watt bike / outside, or are just interested in tracking your power in the longer term over years.

I have a single sided 4iii that has been wareantied once – the first one was giving increasingly daft power readings where it said I was producing about 4W/kg in Z2 (I am not a pro tour rider) so they took it back and replaced the sensor and it’s been fine since then.

Favero have good Black Friday deals, single sided Assioma is all you need.

though I use them road only, still on mtb pedals and stiff mtb shoes for gravel

The favero ASSIOMA look good but no Sl pedal option, that I can see. Though there’s the Assioma DUO-Shi

half the price of the garmin rally though

I had the single sided one initially and they can be a bit inaccurate if there’s a l/r imbalance – it will be doubled for the output. This doesn’t matter if it’s just for training as you just need consistency. It does matter if you’re in a comparative setting like zwift racing

I’ve got a road bike with dual sided power meters which revealed I’ve got a consistent 52% L/48% R power imbalance.

I recently also got single sided Favero Assimo MX SPD pedals so emailed Favero about the power imbalance – they advised me to use the Favero app to apply a -3.8% power adjustment to correct the overall output. So, if you know the extent of your power imbalance, it can be corrected automatically…

Assioma Uno is £250 on Black Friday. This is a fabulous deal on a great product from a company that has superb customer service. I already have two Unos and am thinking of a third. Their MX SPD pedals use a different non-pod system in the axle and are more expensive. I imagine their next gen road pedals will follow the same.

I always think single sided are fine, mind I am balanced and ride fixed wheel. Even if you are not, what realistically do you think you can do about it?

I have 3 different power meters.

Power2 max has been the most reliable. That’s on my old TT bike which is on the turbo permanently now. Must be at least 5 years old very reliable and consistent.

I have a built in power sensors on my Shimano Ultegra cranks on my Giant TCR. These have been really good the past four years. I just need to remember to carry out re calibrations to eliminate temperature differences causing power readings to be off. Especially when you start a ride at 2 degrees and it warms up by 10 degrees or so during the ride.

I have the Favero Assiomo dual sided road pedals. They were pretty reliable and you can replace the bearings and pedal body. However the left sensor on my set recently went a bit crazy giving me huge power reading of 2000watt averages on rides. I got in touch with Favero and they said it needed replaced. Since it was out of warranty they offered me a new left pedal at a slightly reduced price. I didn’t take them up on the offer and I’m glad I didn’t as the BF offer is way cheaper.

I was thinking of getting the Favero mountain bike pedals but I’m unsure as if they go faulty outwith the warranty you need to replace them. It’s not cheap. So currently I’m not sure what the best option is. One thing to note though is that power meters are quite useful on road but the power readings off road have huge variations. When the going is technical you won’t have much time to look at the power readings. It is quite useful after the event to see how much energy you have used.

Thanks

Even if you are not, what realistically do you think you can do about it?

This – i have a plan from the physio, been months & months now – not just cycling, but weights, exercises etc etc, as it’s quite an imbalance and the extra effort the rest of me puts in to compensate for keeps resulting in a constant stream of harsh injuries that keep me from making sustained progress, as I keep having to stop and recover from the injury.

And the query here arises from monitoring the peanut L-R chart on the wattbike as I train and it’s been really useful. My data love aside, it has been useful to see.

what I’m not so sure on is how do you see the data ? Does it come through on your garmin ride stats, Strava, or is there another app you need to use?

I see the peanut graph when training with my Neo on Tacx and I can see left/right balance on my Garmin Edge when riding outdoors. I also get a summary L:R balance in my Connect stats after the ride.

Thanks @scotroutes that’s brilliant, I was nearly going for the garmin rally just so I’d have all the data in one place, but I’d have to go without coffee and cake for a month or two to offset the outlay.

Having owned both Garmin Rally and Favero Assimio SPD, the Assimio’s are miles better. Nicer clip in action, lighter, lower stack, more reliable so far (Garmins had to be warranteed).

Also have a 4iii left crank 105, can’t beat that for the price.

I had some garmin rally, had quite a lot of problems with them needing batteries every 2 or 3 weeks, first they sent me some new battery compartment caps, then replaced them under warranty. Then after the warranty had expeired started having the same problems again, and was offered cheap replacements, which I then sold unused.

I have had stages and 3iii one sided in the past and they were ok, but didn’t have the same level of data.

The sram/quarq are my favourite, and I would take a fair bit of persuading to use anything else, and are compatible with the current sram cranks, unfortunately they are not compatible with the cranks from 2 or 3 years ago.

I had some garmin rally, had quite a lot of problems with them needing batteries every 2 or 3 weeks, first they sent me some new battery compartment caps, then replaced them under warranty.

that sounds rubbish, I’m sure I read the blurb stating the batteries lasted a year.

The sram/quarq are my favourite, and I would take a fair bit of persuading to use anything else, and are compatible with the current sram cranks, unfortunately they are not compatible with the cranks from 2 or 3 years ago.

I need a 2x so this starts to look as expensive as the garmin rally option.

theres a lot of options.

Yeah, there are lots of online complaints about the issue with batteries, and garmin trying to gaslight the users suffering the problem claiming cleaning contacts or replacing battery covers is the fix, but it is clearly a deeper issue.

One thing to note, IMO heart rate is a better metric for gaining or regaining cycling fitness from a low point, I think power is a better tool to start using when you are 90% there.

that sounds rubbish, I’m sure I read the blurb stating the batteries lasted a year.

Ive been using one Rally spd on the road bike for about 6 months and it’s been no problem at all. Even taken it on the MTB a few times for interest.

Op, I have a SRAM carbon single sided stages MTB PM you can have second hand.  It’s fully working, I can find out the model number if you’re interested.

Thanks @kryton57

Op, I have a SRAM carbon single sided stages MTB PM you can have second hand.  It’s fully working, I can find out the model number if you’re interested.

Im after this for road use, I may be wrong, but don’t think the mtb arm will be what I need for the road bike.

I’m liking my recently bought Favero Assioma MX pedals. I used them whilst being tested for threshold and VO2 max at the MIHP… They were really accurate when compared to the professional equipment.

These pedals show that I have a significant imbalance (40-60) owing to past injuries. Also, my platform centre offset varies massively.

I also have a Quarq power meter spider… But that doesn’t give “true” dual sided measurement. (It reports  47-53).

Think I’d be suggesting you get a pair of Favero pedals.

I would take warranty into account when buying power meters. Most have 2 year manufacturers warranty. The only kne I spotted with longer was the Power2max NG meters which have a 5 year warranty. There may be others with a 5 year warranty. I would want 5 years warranty if I was buying an expensive power meter. I’d probably be ok with a 2 year warranty on a cheap single sided meter.

I think the Garmins are vulnerable to water ingress but having said that mine were power washed (not by me) which is definitely unadvisable for any power meter with a replaceable battery

Unless you’re racing at a fairly high level, I just don’t see the point in them; expensive for what they are. And as this is a MTB forum, I’m surprised why anybody would care – just get out and ride the trails and keep the skills up to scratch.

Too many of us are influenced by the cycling media obsessed by performance and fitness, and not enjoyment…….

We have been through the mill with these. Not me, I am a punter. But Mrs Yak races and uses these. Over the years, we have been through/ still using:

Avio – cheap. didn’t work in the cold. failed quickly

SRM – not at all cheap new, but bought used. Worked well until an unexpected submersion then failed. Long drawn out returns to Europe and faffy customs stuff return. Now fixed and still working and on a bike that doesn’t get submerged. Rechargeable.

Quark – spider version on sram dub. This worked well and still is, although isn’t really on a training bike now. Eats little button batteries though. Only issue was short lifespan of dub bbs, but that’s not a power meter issue, more a bb shell alignment issue on the bike it was on. Also the non-drive carbon crank arm failed, so it’s running a bodge alu crank one side and carbon on the other. Like trigger’s broom.

Quark – axle version. Better battery life as it uses a AAA battery. Nothing wrong with this one.

In general, from a maintenance point of view, they are mostly all a cause of faff and bother that I would avoid unless you are training/coached/racing etc. If yes to all that then I can’t see much wrong with the current axle based quark/sram ones with alu crank arms.

I have Favero Assimo MX SPD dual sided and a 4iii one – the 4iii one is good, but used to have another one that conked out after 3 years or so. The MX ones have been good so far, can’t comment on longevity as i’ve not had them long. It is very handy being able to swap between bikes (I run mtb SPDs on my road bikes, just with stiffer (/more roady) shoes).

I’ve got Garmin rally XC pedals (dual) adn flip them between bikes (apart from my trail/enduro bike).
I like the data.. it’s a useful indicator of fitness, overtraining, underperforming etc…
For the road it’s prob MOST useful, but an XC/marathon race can give useful data too

DrP

Worth being aware that different power meters use different assumptions when estimating* your power so you might end up with noticable discrepancies between whatever meter you get and a wattbike. I’m not sure if this will affect the L-R data you’re targeting but it’s worth being aware of in case you get surprising results with a new meter.

*I think this is the right term to use here, and I’m not implying that PMs are bad, just that they have to do a bit of processing to their actual measurements to give you the reading you see.

Unless you’re racing at a fairly high level, I just don’t see the point in them; expensive for what they are. And as this is a MTB forum, I’m surprised why anybody would care – just get out and ride the trails and keep the skills up to scratch.

Disagree with that. Obviously they are completely unnecessary if your goal from cycling is mucking about with your mates and having fun. But if you plan to do any training, want to race (road, gravel or xc), And many on here do, then there is no better tool for the job imo.

Thanks all

I was about to buy the Favero Assioma DUO-Shi in the sales, but quick google suggests the battery is in no way replaceable on these, it’s a full replacement which after two years will likely be at a cost to me. And as someone pointed out earlier ideally a longer warranty would be ideal. I do get why it’s 2 years on these.

Agree with earlier posts, I am leaning towards the pedal options. They sure aren’t budget options though.