My pedals are Favero Assioma Pro MX-2
Excellent work and result! Shows how important it is to have a well-running drivetrain, I definitively can’t afford to lose 25W!
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Interesting issue and even more interesting solution
Wild to see that just swapping and/or cleaning drivetrain parts netted 25W, would never have thought the loss would be that high.
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Power match, IDK. I haven’t tried it awhile, but when I last did, the ERG response was laggy and regulation not as good. With power match, the app gets in the regulation loop whereas using the trainer for power, it’s all done in the trainer. TR might have since done things to improve how well power match works.
I keep my old road bike permanently on the trainer. PM pedals are on the current bike and the mtb has a PM. A couple of years ago they were all within a few Watts. I probably should check again, putting the mtb on the trainer and the PM pedals on the mtb and recording all three. It’ll be a fun thing to do next time I’m snowed in. I could try power match at that time too. I expect it’ll be much better than the last time I tried it.
for sure - the theory I ascribe to is the further down the chain you measure power the less accurate it tends to be. The trainer has more influencing factors like clean drivetrain, chain wear, temperature at calibration etc whereas the pedal power or crank power is closer to where the power is being applied (at the pedal) and thus reads it at the source. The trainer is infering power based on the chain etc. For many I am sure trainer power works great. I have seen better consistency with pedal and crank
Your BB looked pretty bad. I get more revolutions than that on my MTB when I spin the pedals backwards with chain on.
Someone should build up a bike with pedal, crank, spline, spindle and hub power meters and then put it on a smart trainer just for fun
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Cross posting from another thread.
Interesting experience for me.
I bought a TacX Neo3M, upgrading from my Neo 2T and immediately threw my MTB on it to do some testing against a Quarq and Favero Assioma (3 Power Meters Simultaneously - The Trainer, Quarq Spider, and Pedals). I was immediately seeing it reading about 5% low against the Quarq and Assiomas and was starting to get a little pissed because my 2T had always been dead on.
Swapped my old road bike on, and wouldn’t you know it - it’s now pretty much dead on which is telling me my MTB needs some damn work…
MTB: Transmission 10-52, SRAM Flat Top, Waxed Chain. But, my guess is that everything needs a cleaning and I definitely need a re-wax.
Road Bike: Old SRAM 11 Speed, but only used on the trainer. Silca Synergetic Wet Lube.
Eye opening for me - but losing 15 watts on the MTB due to the drivetrain is something I need to do a little testing on. May need to re-evaluate which wax I’m using and even look at one of the new KMC Chains, clean everything up and then test again.
I’ve been wanting to do a similar test but wasn’t sure what method to use to record power from two different sources. Out of curiosity, what did you use ? The pedals recording on the head unit and the trainer on the trainerroad app ?
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Multiple ways to do this. Your way is the easiest I think.
I have a head unit connected to pedals or my quarq usually, and then TR to the Trainer. But then I’ve also dual-run Zwift and had Zwift be connected to the trainer, head unit to pedals, and trainerroad to quarq for three power signals in the same ride.
I use the DC Rainmaker Analyzer tool for comparisons.
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I used power pedals connected to head unit and trainer connected through zwift
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Does your bottom bracket need servicing?
If that was directed at me - no, definitely not. I have an aftermarket one that I can service in about 10 minutes so it gets done and checked reasonably frequently, and I spin it every time the chain comes off. Even if I want to flush the bearings and re-pack, that probably only adds 20 minutes.
Guessing this one is all the (lack of?) efficiency of the T-Type Chain, the condition mine is in, Maybe cleaning / servicing jockey wheels.
Not sure when I’ll get it done, but I’ll post results when I re-test.
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In my experience, those SRAM jockey wheels tend to pull in fine grass/weeds and require frequent service if riding anywhere with vegetation. It just takes a minute to pull the jockey wheels and remove the little bearing covers, clean out the stuff wrapped around under them, and reassemble. And I’ve had those little bearings get totally crunchy with grit also. You can pry the dust seals off the bearings and try to clean them out, but I’ll usually just replace the jockey wheels once the bearings get infected.
My trainer has an old road frame slave with a waxed chain. So it’s probably pretty consistent over time.
I probably should know the difference between my Garmin pedals on my MTB and the trainer watts. I don’t do much structured workouts on the MTB, but I suppose there are a few extra watts at the pedals I get credit for at races. That data is messy anyways.
I will echo this. When I went through this process myself up above, I found that my Jockey wheels were quite dirty and had gunk under the dust covers. Cleaning and oiling them helped a lot.
I found a very quick and dirty way to do this I think.
Just connect both pedals/cranks and the home trainer to the trainer road app and go to the devices tab, it will show instant power readings from.
I would advise against instant, too variable and too many spikes.
You want to compare average power from multiple sources over a steady state interval, and there are times overlaying the graphs is helpful.
Yes indeed, I was doing that in erg mode so it helps a bit with the spikes but the power readings are out of sync so it’s hard to see a trend.