A track specific or just a road one? Not sure about converting a quarq..the question is whether it can handle negative torque or not I would think.

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It would be a quarq riken AL. Haven't seen much discussion on doing this but I also thought the negative torque issue might be a problem.

My guess (just that though) is you'd fritz it the first time you put any backpressure on it.

Might contact quarq and see if its possible, or if it can be converted

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My Blog - http://leegoocrap.blogspot.com

Negative torque is not going to affect the strain gages in a Quarq (or any other power meter). The question is what does the software do with the invalid input, and to find that out you would need to either be privy to the software algorithm, ask Quarq, or try it and analyze the data.

It would be an interesting experiment, for sure.

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"...the street finds its own uses for things"

I've seen Rahsaan Bahati race a Red Hook Crit with a PowerTap. Another racer asked him something about how he handles negative values or something ( hey, they were riding and I was spectating) - didn't really hear the answer.
So, I've really got nothing to add other than I've seen someone do it with other equipment.

From Quarq:

Hi

Thank you for contacting me. You wouldn't get any useful information when the Riken is going in reverse, but it wouldn't hurt the power meter in any way if that is what you are asking. Physically you would be able to fit it on without any issues. Please let me know if you have any other questions.

Cool

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My Blog - http://leegoocrap.blogspot.com

May not be an issue with a quarq but... I have my old stages on a single speed mtb and going up steep stuff (low cadences say ~30rpm) it doesn't measure anything because the cadence is too low.

thanks. fixed gear different that ss. always in motion.

that's absolutely true but in my example it's more a function of cadence (low - what's the threshold?) than "movement". hope that makes sense :)

I use my quarq elsa on a track bike for occasional fixed gear crits and very frequent fixed gear training. And previously used a rival stages.

Both do give a value when back pedaling to break. The numbers are generally very low, but not zero and not negative. I've always assumed they were noise and that the system isn't really made to measure in that way -- but I don't have any evidence to back that up.

I've wondered how a pedal based power meter would behave because it would still see the pressure on the pedal and have an angular velocity to measure.


But, to get to your question, the main thing you'll notice is how disheartening your data is. TSS from a fixie ride can be pretty low even if you feel like you did a ton of work. Kind of like on the MTB -- the "rest" isn't really all that restful.


Semi - related: The best bike related purchase/expense I ever made was having Drew at cyclocarbon cut the dropouts out of my old madone and put track droputs in. It is my winter / bad weather bike. I actually like going out to ride in the rain because it is an excuse to dig out my fancy fixie. And it takes 5 minutes to clean to perfection. And I think it only cost like $250.


Have fun
Andy

I put an old Powertap wheel on my single-speed commuter (converted from a crappy old road bike using spacers, a chain tensioner and a Shimano Alfine crank). Love having power on my commute.

Thanks. I'm mostly using for some high-cadence drills and endurance. The goal was reviewing TSS and seeing how many calories are actually burned during these rides. Without a PM it is basically a guesstimate of the Garmin but with the PM it will give me a better idea of actual TSS and calories are burned. Wonder why the TSS is lower in what you say. The fixie does provide me with a better overall LSD workout than a road bike due to the constant spinning w/o coasting. Actually forces fitness.

I don't know exactly why, but the RPE:whatever power based training metric seems higher on the fixie than on the road bike. Peak power and high power intervals are about the same. But the cumulative effect feels harder than the data would show.

For me, living in Iowa, I suspect a lot of it is flat tailwind. Riding along "easy" at IF 0.4 but cadence 120 takes it out of you, but doesn't show up in the data.

Races are about the same. I end up with an IF about 0.95 for both hard crit and hard fixed gear crit

I ride with about 71 gear inches for training and 93 gear inches for racing. For perspective, I'm usually 60-70 gear inches for singlespeed cyclocross racing and 40-50 gear inches for SS MTB racing, depending on the course. I just did the pisgah MTB stage race on my SS and ran 41 gear inches there.


Again, this is fun. In my opinion, everyone should have a fixed gear training bike. I'm not sure that the training benefits are as good as some people make them out to be. But it is a good way to mix things up and helps you think about gearing for other stuff.


Andy

FWIW, I tried to install an old bottom bracket based powermeter (Ergomo) on a fixie and it didn't work. The readings were all wacky and I suspect it was because of all the "negative" torque the spindle experiences.

I've used a Quarq, and it worked fine.

SRM and Power2Max are both more robust in a fixed gear application (either track versions, or normal road versions) - but if you already have a Quarq, run it - it'll be fine.

I use a Riken al on my track bike without any issues.

I had one client use his Garmin Vectors on a fixed gear bike. The data was nonsense and worthless.

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I know two track racers who use Garmin Vectors, and the data is fine for both. One ran a Powertap at the same time for comparison. They correlated almost perfectly.

I've used a Stages, and it wasn't that great. Useless at very low cadences, like the first 10 seconds of a pursuit start.

How do they perform the Garmin "calibration" process, which requires freewheel backpedalling?

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Were you in Pisgah this past weekend doing that race?

If so, there is a very good chance you passed me as I was hiking up the Daniel Ridge Loop Trail. That is the part of the route that descended along the Davidson River just prior to aid station 1.

Looked like a great time.

Yep. Pisgah stage race. It was hard. I did on my singlespeed. My wife did on her full suspension. I think she had more fun than I did. Those trails are brutal. Daniel ridge was a fun descent. But Farlow seemed impossible. I almost can't believe it was in the race.

Andy

Tried the Quarq on the fixed gear and it works like a charm. No problems/concerns at all.