Power Meters / Powermeters (SRM, Powertap, Quarq, Ergomo, Vector, Stages, power2max, P2M, 4iii, InPower, Cinch)

The trouble is that power meters tend not to recognise negative power figures and report these internally and externally as zero. So when you're slowing down, the power meter thinks that there's no power, and starts an autozero even though in fact there's load being applied, albeit reverse load. This skews the zero, and gives you inflated power figures.

Ah right, that makes sense. Thanks for explaining it.

In my experience a Garmin will take the slope value of perceived "zero torque" moment as a reference, leading to track power taps giving ever escalating power figures unless the auto-zero on the head unit is disabled. This may have been a "feature" of one particular combination of Garmin and PM however.

gives you inflated power figures.

Frankly I can't see the problem. A PM that does something other than report misery? Sign me up.

Easier ways of doing it. Just stick some tape across a head unit and write: "3S PWR: Twelvty bazillion megawatts". And then beeeliieeeeevee. Job done.

Recently serviced Powertap G3 with almost new 11S freehub. The wheels are Ardennes SL with CX-Ray spokes. The rims are a bit worn but otherwise they are good wheels.

That for €350 (£311) with no cassette and tyres is a good deal, right?

or

Pioneer SGY-PM910H Ultegra 6800 powermeter, 172.5mm cranks. This is the left & right version. Chainset has between 1000 & 1500km on it. Selling as I had to cut back on racing and can't justify holding onto it. Comes with magnet arms which mount on chainstays using zip ties or self-adhesive magnetic patches which also mount on chainstays and are a bit tidier. Also included are spare screws for the crankset cover and 2 spare CR2032 batteries. Claimed battery time is 180 hours. €650

(£580)

or

Pioneer SGY-PM910H Ultegra 6800 powermeter, 172.5mm cranks. This is the left & right version. Chainset has between 1000 & 1500km on it. Selling as I had to cut back on racing and can't justify holding onto it. Comes with magnet arms which mount on chainstays using zip ties or self-adhesive magnetic patches which also mount on chainstays and are a bit tidier. Also included are spare screws for the crankset cover and 2 spare CR2032 batteries. Claimed battery time is 180 hours. €650

(£580)

Difficult to say. There are pros and cons to both. The main benefit of having a crank-based powermeter is of course that you can use different wheels on that bike and still have a power meter. The advantage of a Powertap is that it's easy to switch from bike to bike. How many bikes and how many wheels? If the answer is one bike and one set of wheels then provided you're happy with Ardennes SL rims and the rims are genuinely 'a bit worn' rather than 'totally fucked' then the Powertap looks like a good deal.

Dont think I'll be doing much road racing for the next while (so probably wont be getting carbon race wheels) so think I might go for the powertap. Just wasnt sure of the going rate really. I suppose I'll also get a bit back from selling the wheels I've currently on my bike.

Thanks

I have a set of Powertap G3 wheels laced on Velocity deep V rims with Sapim spokes. 11s shimano. Free hub is slightly cut up, but I have swapped cassettes no problem.

I paid £295 on here 8 months ago and hardly used them. Looking for offers in that region if anyone is interested. Will start a sale thread at done point.

Unfortunately the powertap cleats are £20+ 😐

Use Wellgo R096 cleats for about £7, they're the exact same thing

Power2max with some BF discounts

https://www.power2max.de/europe/en/produkt-kategorie/power-meters-en/power2max-type-s-road/

CycleRepublic have DT Swiss RR460 rims on DT Competition spokes with
PowerTap G3 for a £500 with 2 year warranty. So £300 for second hand, part worn rims and no warranty probably isn't worth a punt

https://www.cyclerepublic.com/powertap-g3-dt-swiss-r460-alloy-wheelset-shimano.html

Think you can use BC discount for 10% off

Powertap US have 50% off their C1 chainring so about £260 + shipping etc.

Anyone using the NG eco? Am thinking of getting one for the Isen with the 4s interface to use shimano chainrings.

Anyone having issues finding their Quarq in the Qalvin iOS app?
Didn't have problems with iOS 10 on my iPhone 5S, but no luck with iOS 11 on iPhone 6...

Got the FSA Powerbox with the same internals. Works a charm - not had a single issue.

Would £500 be an acceptable, non-forum price to ask for a pair of used but well cared for powertap p1 pedals? One little scuff but otherwise perfect?

who has Vector 3?

I did 2 rides since getting them, the left/right balance is off and few other bits of data, NP looked ok. I tightened them on feel using a generic pedal wrench and have used the pedal washers that came with it. Garmin says 34nm max torque. Do I need to get a big torque wrench and this to get it correct?

I am guessing the numbers are off because both pedals are torqued differently?

Torque is pretty important for their installation.

I knew it was for previous versions didnt imagine it'd be the same case for the 3.

(because I am thick)

This looks good: https://www.aliexpress.com/item/MXITA-3-8-5-60N-Professional-Adjustable-Torque-Wrench-Bike-Repair-Tool-Torque-Spanner-Tool-hand/32791223581.html?spm=2114.search0104.3.82.446024feY1dkjd&ws_ab_test=searchweb0_0,searchweb201602_2_10152_10151_10065_10344_10130_10068_10324_10342_10547_10325_10343_10340_10548_10341_10192_10190_10084_10083_10615_10307_10301_10303_10059_10314_10184_10534_100031_10604_10103_10142,searchweb201603_2,ppcSwitch_5&algo_expid=13a8d2a2-a599-4afd-b50e-f07353230460-11&algo_pvid=13a8d2a2-a599-4afd-b50e-f07353230460&priceBeautifyAB=0

I thought with the 3's that they weren't installation torque sensitive?

That's exactly my understanding, via DC Rainmaker: https://www.dcrainmaker.com/2017/11/garmin-vector-3-power-meter-review.html

so y is dis happening guise?

http://tpks.ws/9LUcu