Ok all I finally have the answer to the differences in watts between my quarq and the wahoo kickr so I will post my experience so everyone can see what happened with me and hopefully use it to achieve the result they want.

First off a big thank you to the guys at wahoo who worked this through with me.

So I calibrated the wahoo using the kit which wahoo sent which significantly changed the calibration number from 600+ to 433.

No joy numerous spin downs and still a difference of 20-25w. But this didn't tally to my HR readings so I had my quarq re calibrated. The result was the slop was off they estimated power increase of 5.7%. Loaded bike up on wahoo did a full 90 minute workout and bang at last avg power was within 8-10w thought thats better.

What I notice though as I stared at the garmin for the full workout was that the wahoo drifts upwards over time in terms of power readings and what started out with the quarq reading slightly higher ended with the quarq reading 12-14w lower than the wahoo. So I did a spindown at the end of the 90 minutes and that changed my number for the wahoo.

Did another ride tonight for 60 minutes and the same thing happened quarq started reading higher and then slowly the quarq reading showed a lower value but this time only a difference of 4-5w.

So i am happy with that now.

I hope this helps everyone else get a closer match as I think it's the best trainer I have had.

I have had my Kickr for about 1 week and really dislike it:

1) constant clicking in gears whatever the gear and none of the smooth feel I was expecting. I have Di2 that worked just perfectly with my Reynolds training wheel and Zipp disc race wheel.

2) Power compared to my SRM is way off: in the 15-25 watts range whatever I do. Spindown after 10 minutes, spindown after 20 minutes - it doesn't matter.

So what I will most likely do is return my $1,100 trainer.

I guess I will stick with my 10 year old Cyclops Fluid trainer and that will be that.

I was excited to try trainer road and get all high tech, but w/ my SRM head unit I guess that's good enough.

Still, I am bummed out. Not looking forward to boxing all that stuff up and shipping it out.

Am I the norm or are others experience this as well?

I was there when I fiorst got it to try and help you please read this thread.

Re the clicking adjust your DI2 when its on thew trainer I had to do mine as well slight difference I was coming from shimano to I think its a sram cassette. Then my clicking went away.

Raise a ticket and then send some files comparing your srm output to the wahoo they may recommend a calibration kit which I got and significantly changed my number. Don't assume your srm is bang on I did intiially with my quarq but it turned out to be reading low by nearly 6%. I then noticed that the wahoo drifted after about 40 minutes so did a spindown after a good 90 min session since then my power is within 4-5w. That whole p[rocess took me about 3 months so it depends if you want to invest the time and effort to slowly discount each component. Wahoo will work with you.

Mo data Mo problems
-Notorious B.I.G.

I ran a few tests last month with all three. Finally getting around to looking at the files. I have not been successful in graphing them.

Anyone have any experience with this? I have 3 files each from 2 rides in my google drive that I can share for anyone interested.

I too have wondered about this, given all the complaints about 'My Kickr is 20 watts off my SRM" etc. There have got to be people with CTs who have SRMs who can comment.

The CT is susceptible to all of the same sources of error as the KICKR plus what I would suspect would amount to more as the CT's reading is highly dependent on the press on force between your tire and the friction roller of the load generator. This means your type of tire, your inflation and the adjustable angle of the friction roller can all affect the press on force which determines the rolling drag and has a major effect on the accuracy of the unit. The KICKR may introduce some new sources of error on it's own but it certainly eliminates those specific to press on force.

Of course temperature also plays a major roll in the accuracy of the unit and the CT needs to be properly warmed up over a period of 10-15 minutes minimum then perform a spindown calibration each and every ride if you expect the unit to be accurate. KICKR has a similar spindown but I believe Wahoo's guidance says you only need to perform the calibration every few weeks rather than every ride. Perhaps that advice needs to be modified to be similar to that of the CT (warm up and calibrate every ride) to help increase accuracy.

In all of these threads I think people simply lack awareness that power is measured in fundamentally different ways between their trainers and their strain-gauge based power meters and why that matters. For that I will defer you to Dr. Coggan's response to one of the other similar threads on this topic:

Lastly, for my n=1, my CT regularly tracked 10-20 watts low relative to my Quarq. It would track closer after a proper warmup and calibration but it was never perfect. That was expected and presented no issue to it's usefulness to me as a trainer. My KICKR now tracks more closely to my Quarq with less regular calibration and no noticeable drift, however my indoor versus outdoor power numbers still differ significantly and I always perform an indoor test using my indoor power (trainer) to use as the basis for indoor training. I consider this more common sense than any great sacrifice.

It totally amazes me when people "are disappointed" when their trainer's power does not agree with SRM. First question that comes to mind is how much did they pay for their SRM? They want trainer with built in power meter for the price less then they bought their power meter for. Nice deal ;)

Good point..

Yeah, like SRMs are not sold at a 1200% markup anyway, right? It probably costs $300-$400 to manufacture that thing and they sell for 4k so not exactly the best example.
Power2Max can sell a PM for $700 that is just as good and they probably make a decent buck from it too. So if you add $700 + whatever a decent fluid / magnetic trainer costs you get to about $1100 which is what Kickrs sell for. So I believe people are justified in wanting to have at least some accuracy.

Also it's easier and cheaper to not be so constrained by the need to miniaturize, cut weight to an absolute minimum and perfectly waterproof the unit. At $1000+ one should expect pretty darn good level of precision and accuracy. My ancient Computrainer still delivers on both after nearly 20 years of heavy use.


Hugh

---

---

Genetics load the gun, lifestyle pulls the trigger.

Exactly! You have to do a roll-down calibration after the tire warms up. But after that, the Computrainer should be pretty consistent. If it is not, there might be something defective with the device and it needs to be looked at.

i have quarq meters on road and TT bike, a computrainer and (no longer) a kickr i wanted to switch to the kickr for ease of quickly putting bikes on and off and not having to use a trainer tire/wheel. immediately i felt that the readings on the kickr were too high. i did a bunch of comparison tests between 2 quarqs, kickr and the computrainer, always with the kickr 15-25 watts higher than the other 3 units. Wahoo was very responsive and tried twice to fix it, shipping it free back and forth, but eventually they just refunded me and took it back.

I am thinking mine is faulty. My spindowns both warm and cold give the same readings. 1235 and about 19 seconds. The tech support from Wahoo have suggested I tighten the belt to get the spindown to 15-16 seconds. Seems poor really given the price of the unit that it is not spot on when it leaves the factory.

yeah its a bummer because its really a slick unit and the ride feels awesome. i just couldn't get around it not being accurate.