First venture into measuring power

space2ground1 · 14-11-2020 8:14pm #1

Hi all,
I’ve got to the stage where I think having access to power data would be very useful and for me, enjoyable in planning training. Before Covid I kept an eye on it using a wattbike in the gym from time to time but without that facility I think it’d be good to have my own power meter at home and outside on the bike.

Does anyone have any up to date recommendations for someone like me who’s not going to need ultra accurate data but something that’s enough to follow FTP/power based training sessions?

The price of Garmin vectors is out of reach so I’m wondering if I should wait or go for something simpler or less well known. Asking with Black Friday on the horizon too in case there’s deals worth watching out for.

Thanks for the advice!

dahat · 14-11-2020 8:30pm

4iii single sided crank, these are reasonably priced and will serve every purpose you need.

Daroxtar · 14-11-2020 8:40pm

This^
My next unnecessary purchase

Danville · 15-11-2020 2:30am

I too highly recommend the 4iiii single sided crank powermeter. €300 approx and well worth that.

Dual sided powermeter costing a minimum of €1,000 will tell you that your left leg is 2% stronger than your right one, so what?

In you’re not racing single sided is perfect for your needs.

Remember a powermeter is primarily a pacing tool, lots of YouTube videos about them.
Best of luck.

lennymc · 15-11-2020 11:13am

i'd also buy a copy of racing and training with a power meter by Hunter Allen - as a lot of the value in a power meter comes from understanding what the numbers are telling you. It's 20 quid, but is worth it's weight in gold.

lennymc · 15-11-2020 11:16am

Danville wrote: »

Remember a powermeter is primarily a pacing tool

I wouldn't agree - a power meter is a device that tells you what power you are putting out at a particular point in time, and transmits various data points - nothing more - nothing less. It's what you do with that data that allows you use it for the various training aspects of bike riding depending on your goals - be that a TT or a peak power, or V02 or whatever.

joey100 · 15-11-2020 11:45am

Danville wrote: »

Dual sided powermeter costing a minimum of €1,000 will tell you that your left leg is 2% stronger than your right one, so what?

.

Not entirely accurate. Dual sided can now be got for fair bit under 1000 euro, Favero assimo get great reviews, same as power2max and can get both closer to 600 euro.

Dual sided measures both sides, single side measures one side (usually left) and doubles. So your left leg might be 2% stronger at 80% effort, but 1% stronger at 100% effort and then 3% weaker at around 110% and that's all when your fresh. Will this track accurately when you start to fatigue? Will it still be the same % when your only starting to fatigue or will the gap widen as you get more and more tired, 3/4 hours into a spin? The big thing you need from a power meter is that it's consistent, single sided power meters just can't be as consistent as a dual sided.

But it's up to you what you want and how much you want to spend. I have both so I'm not saying you necessarily need dual sided but you do need to have an idea of why a dual sided is more consistent and accurate than a single side.

lennymc · 15-11-2020 11:54am

the assioma pedals are probably the best power meter I have had (been with power for 10+ yrs). Have had hub, crank and pedals from various manufacturers. The big plus with the Favero is that they are easily swapped between bikes - and are available in single sided for about 400 quid iirc.

Daroxtar · 15-11-2020 11:59am

joey100 wrote: »

Dual sided measures both sides, single side measures one side (usually left) and doubles. So your left leg might be 2% stronger at 80% effort, but 1% stronger at 100% effort and then 3% weaker at around 110% and that's all when your fresh. Will this track accurately when you start to fatigue? Will it still be the same % when your only starting to fatigue or will the gap widen as you get more and more tired, 3/4 hours into a spin? The big thing you need from a power meter is that it's consistent, single sided power meters just can't be as consistent as a dual sided.

Well you're not entirely right there. A single sided PM can be every bit as consistent as dual sided, it's your legs that can be inconsistent. Most studies tend to show very little variance between the two legs, especially at higher power. The biggest differences are usually at very low watts and slow cadence.
You are right though, consistency is paramount. No point having a PM that varies by 10% from one day to the next.

FWIW, Sky (amongst others) raced on single sided Stages PMs for years. If it's good enough for them then it's absolutely fine for 99% if the rest of us. That said, if someone wants dual sided then go ahead and get it.

and still ricky villa · 15-11-2020 12:05pm

+1 on pedal based meters.

I was lucky enough to win a set of Power Tap P1s and use them across 3 bikes.
Swapping around is a doddle if you don't let them seize.
I've dual sided but never used it after the first few months

lennymc · 15-11-2020 12:06pm

Daroxtar wrote: »

FWIW, Sky (amongst others) raced on single sided Stages PMs for years. If it's good enough for them then it's absolutely fine for 99% if the rest of us. That said, if someone wants dual sided then go ahead and get it.

Just on that, im sure there was a big wad of cash in there as well

Personally - I very rarely use the power meter during a race to look at power data - as there is so much not in my control in terms of required power to not be dropped. I might occasionally look at it when climbing as i question my life choices that have led to that point, normally just before I go boom!
TT is different tho, as you can use it to help stay at or about your planned power for the tt.

Paul_Mc1988 · 15-11-2020 12:09pm

If you're going for single sided and cheap I'd go stages gen 3 or 4iii.

4Wii is +/- 1%
Stages is +/-1.5% but has ATC (active temperature control)

If you're brave enough go for one of these

https://youtu.be/y38dwJ4h-TY

Plastik · 15-11-2020 12:11pm

https://www.adverts.ie/other-bike-parts-accessories/powertap-pedals/21699016 Seems like a great deal for dual sided.

gn3dr · 15-11-2020 5:37pm

I'm toying with getting a power meter also. I do really like the idea of dual sided pedals especially with some of the data that the Garmin measures. What turn me off a little bit though is the Look only cleats. All my stuff is SPD SL. Also the reliability stories of the Garmin pedals when they were first out is a little concerning. Then there is the price...I just bought a Kicker Core so man maths for power meter isn't quite working out at the moment.

Then the problem with the single sided ones is swapping from bike to bike is a pain. My stuff is relatively old but in mint condition from when I previously cycled so my winter bike has a pre Hollowtech Dura Ace crankset (7700) - to get the single sided I'd need to buy a full crankset - which is further unnecessary cost. The Summer bike would be OK I think because that has Dura Ace 7800.

Decisions decisions. It's a pity there are no SPD SL power meter pedals.

space2ground1 · 15-11-2020 11:36pm

Thanks for all the info. I’d be hoping to do some FTP tests and base my training plans on that for triathlon in 2021. I’m never going to be competitive but I enjoy the data side of things and I think it’d be useful to make sure the training sessions I do are worthwhile. It would also help make good use of a training programme with power as an option.

I’ll be using the same bike on the road and with a non smart tacx. If it went well I’d consider spending more money the year after possibly but I don’t want to fork out loads and realise that I didn’t really get much benefit from it.

Loads of food for thought so far. Cheers!

this.lad · 16-11-2020 12:10am

Very interesting thread. I have a Giant TCR with the power meter built in to the pedals, only got it recently and had no ide this was on the bike when I bought it until I picked it up and the guy handed me a charging cable for it ðŸ™ˆ

Deadly bike and I'm knocking out some decent speeds on ot so I was thinking that if I had CF a bit of solid data it would be a shame not to use it to try to improve my progress.

I use strava and all that but this seems to be the next step, I cycle alone almost all the time and am prone to sauntering rather than pushing myself, I think this might give me a bit more motivation, I dont even have a speedometer at the minute.

Any advice on the best head unit to use along with it? Anyone use the NeosTrack ?

Not trying to hijack OPs thread, might fit in nicely here.

Paul_Mc1988 · 16-11-2020 11:49am

this.lad wrote: »

Very interesting thread. I have a Giant TCR with the power meter built in to the pedals, only got it recently and had no ide this was on the bike when I bought it until I picked it up and the guy handed me a charging cable for it ðŸ™ˆ

Deadly bike and I'm knocking out some decent speeds on ot so I was thinking that if I had CF a bit of solid data it would be a shame not to use it to try to improve my progress.

I use strava and all that but this seems to be the next step, I cycle alone almost all the time and am prone to sauntering rather than pushing myself, I think this might give me a bit more motivation, I dont even have a speedometer at the minute.

Any advice on the best head unit to use along with it? Anyone use the NeosTrack ?

Not trying to hijack OPs thread, might fit in nicely here.

Wahoo element bolt is a great head unit.

Macy0161 · 16-11-2020 3:09pm

I have two 4iii's. But if I was buying now I'd most likely go for Assioma Duo's. When I got the first 4iii, there were still on BePro iirc, which were a bit more faff to swap iirc.

Similarly, I have a bolt, but if I was buying now I'd go Garmin 530 or 830.

paddydriver · 16-11-2020 4:13pm

Another recommendation for the 4iii non-drive side. Got mine from ProBikeKit - Ultegra. Was very reasonably priced and works well. Be careful on frame clearance - I have a Canyon Endurace and is literally half mm between the actual little power unit and my rear stay. Have seen people talk of having to install a shim to get the mm needed to clear the frame.

I too would go Assioma or Garmin Vector if they were SPD-SL - I just prefer not changing cleat system. Have read of a patent issue and possibly it opening up soon so that they will be able to go SPD-SL on next iterations, and also possible Shimano coming out with their own pedal based PM's soon when new Dura Ace/Ultegra group sets arrive.

Power data is interesting.. I don't study it very much, but that said it has been that kind of year. Hooks in well with the Garmin head units and gives lots of figures.

G1032 · 16-11-2020 9:16pm

Macy0161 wrote: »

Similarly, I have a bolt, but if I was buying now I'd go Garmin 530 or 830.

Why?

Taxuser1 · 16-11-2020 9:56pm

Assiomas all the way every day. Best by DC Rainmaker. Price, measurement, ease of use and swappAble between bikes. Works with look pedals. And if you crash, the pedal itself isn’t expensive to replace as the powermeter and shaft are separate. Can change the bearings every few years for small money

Macy0161 · 16-11-2020 11:27pm

G1032 wrote: »

Why?

Better navigation. Turn by turn on the bolt is dependent on what software you map on. Using strava, you don't get turn by turn.

A few other things.. Availability of cheap accessories/ mounts, and with no power meter the bolts calorie algorithm is off the wall (this is important to me, may not matter to others/ most).

RedB · 22-11-2020 9:36pm

I just took delivery of a my first power meter (Stages) and I’m out of depth already. I can’t seem to connect with it properly.

Do I need a fancy head unit or can it connect via a mobile phone as the website suggests? The Stages app is only able to calibrate it and doesn’t facilitate any data upload.

I just tried using the Wahoo Phone app on a 400m test ride and that seems to capture data but how does that connect to the Stages-Link website?

The Stages Sync app doesn’t seem to work as my laptop hasn’t been able to connect with the meter directly. Should I continue trying this approach or should I be trying to get the data to Stages-Link via a phone app or a head unit?

07Lapierre · 22-11-2020 9:43pm

Yes you need a head unit. Garmin or wahoo. The stages app can display power in real time, but if you want to record the data, you need a head unit. The app is also used for updating the firmware.

nilhg · 23-11-2020 8:27pm

4iii 105 PM for €229 and Ultegra for €269 in Mantel's Black Friday sale,

https://www.mantel.com/ie/power-meters

space2ground1 · 23-11-2020 10:55pm

nilhg wrote: »

4iii 105 PM for €229 and Ultegra for €269 in Mantel's Black Friday sale,

https://www.mantel.com/ie/power-meters

Thank you! I need a 170mm for 105 and that's out of stock. I've set up a notification. Hopefully I might find similar on Friday.

Yermander · 26-11-2020 11:01am

space2ground1 wrote: »

Thank you! I need a 170mm for 105 and that's out of stock. I've set up a notification. Hopefully I might find similar on Friday.

I was browsing the link above, and seen that the 170mm crank is in stock, if you haven't found it elsewhere.

Diarmuid · 26-11-2020 12:42pm

I have a Power2Max and a 4iii left sided. If I was buying one tomorrow, I'd go with the 4iii. Price is unbelievably competitive. I got one for 250.
The readings are very consistent but as others have mentioned may not give the full picture. So if you are just using it on its own, you won't have to worry but if you have a mix of power meters on bikes you will have to calibrate the 4iii one.
I had to add 10% to adjust for the difference in my left/right balance. Fortunately the 4iii itself can be programmed using a phone to do the adjustment on the unit. After that it's transparent

Taxuser1 · 26-11-2020 4:16pm

earlier this week I did a 20 minute test and to be absolutely sure i recorded the ride with my Assioma pedals using the Garmin and the wahoo as the main power source - 3% difference between power sources. absolutely great pedals now 4 years old. one bearing change.

JimmiesRustled · 26-11-2020 5:37pm

Just to play Devils advocate here. I know a lot of people are happy out with single sided power and that's great. If it works for you and is consistent that's all that matters.

For me anyway the issue was the inconsistency of one sided power. Due to a couple of bad injuries when I was younger I have a non-linear imbalance between left and right legs. I say non-linear as it might be 49/51 between Zone 1-2, 46/54 between zones 2-3, 44/56 between zones 3-4 and so on.

The issue I had wasn't the accuracy, it was the inconsistency in training between zones.

So take for example a threshold of 300 watts, so zone 4, which in the above example had a 12% difference between left/right leg. That would mean you're no longer training in zone 4. If the power meter is on your stronger leg you're at 336watts and if its on your weaker leg its 264 watts. But that 12% discrepancy only occurs in zone 4. If it was 12% across all zones it could be accounted for no issues.

I think in comparison to when Stages first came out, the power meter market is now filled with decent competition. 4iiii on sale at the moment in the above link for €225 I believe. I think these generally retail for €270. An FSA powerbox which gives total power is €500 or you can pick up a pedal based system for anywhere between €640 - €700. The other issue to consider is if going to power, do you have more than one bike? Changing a crank arm and moving it across can be a right pain.

Power meters are great tools but I see so many riders inflating numbers and inflating FTPs for bragging points. A 20 minute test where no 5 minute effort to deplete W' has been used and then the rider takes 100% of the 20 minute figure and uses it as their basis to train. Which in turn lead to workouts that you can't complete because your FTP is too high. The same with Ramp tests. These can suit certain athlete types but even over on the Trainerroad forum there are a tonne of people complaining about being unable to complete 3x20 sweet spot work which is generally down to the fact that they're doing 3x20 at threshold. I would encourage anyone looking at moving across to power based training to have a read of the book that Lenny linked to earlier.

I digress but I just wanted to put forward the counter point to single sided power.

space2ground1 · 26-11-2020 6:19pm

Yermander wrote: »

I was browsing the link above, and seen that the 170mm crank is in stock, if you haven't found it elsewhere.

I missed the boat again it seems!

So much great advice here, thanks again. I have just one bike and a basic enough turbo. Finances wouldn't really let me stretch to a two side setup at the moment so this will just be a bit of a luxury. What I'm hoping to do with it is just use it to have a better sense that my training is worthwhile. I'll do the ftp and then get figures to base a few weeks on and then the ftp again. Really I just want to see that I'm training properly so that theres some tangible improvement.

I'm not, nor will I ever be competitive but I think I'd enjoy and be motivated by knowing that the 6 weeks work I did based on ftp has led to an increase and I know I'm better for it etc.

I'm fairly sure my numbers won't be anything worth bragging about to anyone else so it'll just be nice to confirm that the training I'll do is working.

I'm going to need a better Garmin for the bike too (the triathlon black hole for money.. exhibit A) as my Edge 25 hasn't got a power option. I could put my 735xt on a bracket but where's the fun in that?

With the budget tight, I think the Garmin Edge 130 Plus will be the weapon of choice.

space2ground1 · 08-12-2020 11:33pm

To put a lid on the thread for now, I just wanted to say thanks again for all the advice.

I'm a proud owner of a 4iii left side meter and took my first spin over the weekend. It seems fine and we'll see how I go on an FTP during the week.

Next I need to find a bog standard version of TrainerRoad or something like that to talk to my HR, Cadence, Power and Speed. All I want is to see the graph and data on a screen in front of me but $20 a month for the most basic functions within TrainerRoad seems beyond what I need.

My Garmin tri HRM is Ant+ only so I'd need a new one of those and a 130 Plus to see the data on the road.

I'll also need to get some sort of second job at nights and weekends to pay for it all.

Thanks again!

lennymc · 08-12-2020 11:43pm

see if you can get a second hand head unit, (maybe 100 euro?) that allows you to load workouts (Garmin head unit & software gives ability to create free workouts and download them to the head unit from your pc, and you can do the workouts indoors or out doors), that will show you all of the ant+ data you can shake a stick at during the ride, and then use the likes of strava & intervals.icu for tracking the data over time - free versions of both, so no monthly fee.

ftp - there are a few protocols, the gold standard is the 20 minute test, which is horrible. do a warm up, do 5 minutes full gas, take a good recovery cycling easy, then 20 minutes as hard as you can. FTP will be 95% of your power for the 20 minutes. 8 minute test is less horrible, but slight less accurate apparently.

enjoy (if you enjoy it you are doing it wrong!)

G1032 · 09-12-2020 9:05am

How much of a lag, if any, do you guys see in power data being transmitted to the head unit? I have somewhere in the region of a 2 to 3 second delay with a ramp up in power being displayed on the head unit. Longer than that waiting for power to drop to zero after I stop pedalling (don't really mind that). The delay in ramp up is more of a pita.

lennymc · 09-12-2020 9:57am

could be smoothing - live power data is. very jumpy, and to get around that, the data can be smoothed over a period of time. Check in the settings for your device to see if smoothing is enabled.

some info about it here - https://powermetercity.com/2016/10/02/power-meter-tips-and-tricks/

Paul_Mc1988 · 09-12-2020 10:27am

G1032 wrote: »

How much of a lag, if any, do you guys see in power data being transmitted to the head unit? I have somewhere in the region of a 2 to 3 second delay with a ramp up in power being displayed on the head unit. Longer than that waiting for power to drop to zero after I stop pedalling (don't really mind that). The delay in ramp up is more of a pita.

You may have the device set to display 3 or 5 second power. I much prefer this as it doesn't bounce around as much.

Diarmuid · 09-12-2020 11:28am

space2ground1 wrote: »

Next I need to find a bog standard version of TrainerRoad or something like that to talk to my HR, Cadence, Power and Speed. All I want is to see the graph and data on a screen in front of me but $20 a month for the most basic functions within TrainerRoad seems beyond what I need.

GoldenCheetah has a train function, just pair it with a cheap ANT+ usb key

space2ground1 wrote: »

My Garmin tri HRM is Ant+ only so I'd need a new one of those and a 130 Plus to see the data on the road.

Why would you need a new HRM? You will need an ANT+ bike computer if you want it on the road.

Macy0161 · 09-12-2020 1:20pm

I've spare TrainerRoad referrals if you want to try it anyway. PM your name and email address if you want the free month.

fwiw it's much more than just HR/ Cadence/ Power, but only you can decide if the plans/ plan builder, calendar and analysis are value for money for you. Local terrain doesn't really work for me (I'd rather the turbo than outside hill repeats), but they have outdoor workouts with Garmin and Wahoo head units too.

G1032 · 09-12-2020 5:22pm

Paul_Mc1988 wrote: »

You may have the device set to display 3 or 5 second power. I much prefer this as it doesn't bounce around as much.

I have that setting, (3s) but I'm specifically on about actual power and the lag in actual power

comete · 09-12-2020 7:39pm

I have a dual sided 4iiii pm, 170mm 50/34 r7000, I’m thinking of selling in the very near future if anyone is still looking.

It’s in pretty good nick aside from a scuff on the bottom of one of the crank arms where it rubbed a cerb.

Bought in March of this year purely to ride Zwift on a dumb trainer, probably done about 2000-3000km max, mix of turbo and road.

Not sure what to ask, and need to find a replacement chainset first.

space2ground1 · 10-12-2020 12:46am

Diarmuid wrote: »

GoldenCheetah has a train function, just pair it with a cheap ANT+ usb key

Why would you need a new HRM? You will need an ANT+ bike computer if you want it on the road.

I thought if I'm to see the HR data on a laptop screen when I'm using the turbo, it'll need to come from bluetooth. No bluetooth on the Garmin tri HR. I didnt realise I could get an adapter. Thanks for the tip!

I have an old Ant+ head unit but it doesn't do power.

Just finished my first ftp test this evening. Did the 20 minute one.. (10 easy, 5 hard, 5 easy, 20 hard) and nearly puked. At least its a benchmark anyway to start from!

CramCycle · 15-03-2021 1:27pm

paddydriver wrote: »

I too would go Assioma or Garmin Vector if they were SPD-SL - I just prefer not changing cleat system. Have read of a patent issue and possibly it opening up soon so that they will be able to go SPD-SL on next iterations, and also possible Shimano coming out with their own pedal based PM's soon when new Dura Ace/Ultegra group sets arrive.

Potential good news for you this year, albeit rumour land: https://cyclingtips.com/2021/02/leaked-favero-assioma-shimano-compatible-power-meter-pedal/

Macy0161 · 15-03-2021 2:45pm

Really hope that's true, and includes spd pedals. I'd probably risk a warranty exclusion for pod strikes if I kept the rest of the warranty.

CramCycle · 16-03-2021 12:51pm

Macy0161 wrote: »

Really hope that's true, and includes spd pedals. I'd probably risk a warranty exclusion for pod strikes if I kept the rest of the warranty.

I get the impression it won't as Shimano seem reluctant to deal with others. I imagine it will be a spindle that you can use with certain Shimano pedals. Either way, I'd be happy with that. Have a 4iiii dual sided on back order but it could be months. Picked as 4iiii allow you to split them as one is not a slave to the other so you can have two single sided PMs if you want to quickly add one to another bike for a short while. I do like my SPD SL pedals though, so if this comes out in time, I might cancel that order and go for these.

Macy0161 · 16-03-2021 1:11pm

CramCycle wrote: »

I get the impression it won't as Shimano seem reluctant to deal with others. I imagine it will be a spindle that you can use with certain Shimano pedals.

Yes, I meant that it if it was a common spindle across SPD and SPD-SL. So if it will fit certain SPD-SL pedals it'll fit certain SPD pedals? I don't know whether there's common spindles in shimano road and mtb pedals though.

I've been tempted a few times for the current hack to get them working on MTB pedals - if they're selling with the intent of fitting you're own body, it removes a barrier to me.

CramCycle · 16-03-2021 1:21pm

Macy0161 wrote: »

Yes, I meant that it if it was a common spindle across SPD and SPD-SL. So if it will fit certain SPD-SL pedals it'll fit certain SPD pedals? I don't know whether there's common spindles in shimano road and mtb pedals though.

I've been tempted a few times for the current hack to get them working on MTB pedals - if they're selling with the intent of fitting you're own body, it removes a barrier to me.

I think there are different bodies, I know it was possible to remove the old ultegra spindle and put the Vector pedal spindle in but the Xpeedo hack indicates to me that there are enough differences between pedals that it might not be that simple. My Shimano SPDs internal part of the spindle is a good cm shorter than the Ultegra ones on my other bike, although total spindle length seems to be very similar. To me, based on those pics, they would need to be selling a sheath for the SPD only on top of the actual spindle but it is certainly feasible they will do Shimano SPD only as the threaded part of their spindle is long enough, maybe you can fit a nut to hold it more outboard?

Like this

Weepsie · 17-03-2021 1:06am

Anyone who uses speedplay, wahoo are apparently launches a speedplay powermeter. Details on DC rainmakers site

CramCycle · 22-03-2021 4:19pm

Trainer road had pics up of Garmin pedal power meter (not Vectors) and Cyclingtips have run with it. TR has since deleted and the lack of info anywhere makes me doubt it is anymore than a stunt as the boxes don't look as polished as most Garmin stuff. Probably an early April Fools but here are the photos: https://cyclingtips.com/2021/03/new-garmin-rally-power-meter-pedal-family-to-include-spd-sl-and-spd-models/

Macy0161 · 22-03-2021 4:50pm

Not so sure, I was listening to the Zwiftcast over the weekend, and during the close GPllama said he was in the thick of testing stuff that would be big news to all cyclists... Also, he and Rainmaker are active on the TR forum, and didn't dismiss it from what I saw (they were tagged pretty early).

Macy0161 · 24-03-2021 12:41pm

They're real anyway. Game changer in that you can swap pedal bodies. i.e. you can use the one power meter for Spd-SL and SPD.

https://www.dcrainmaker.com/2021/03/garmin-rally-power-meter-review-spd-spd-sl-look-keo.html

Will await to see what Favero do, after them hinting shimano compatibility.

Macy0161 · 24-03-2021 1:10pm

Single sided €666, except for the SPD which is €717. Plus 205 for the conversion kits.

If first time buying a power meter, and multiple bikes, this still seems ideal*. But I think I'll be waiting for Shimano to start stocking cranksets to swap my existing 4iiii to my gravel bike!

*even for consistency

First venture into measuring power

Comments