If you could get access to a 400m running track when it was empty, would it be possible to conduct good aero-testing on it?
Having never been on one, I’m wondering if the surface might make things difficult (increased Crr(?) making aerodynamic changes harder to spot), or perhaps it would be to spongy to ride on. I’d be interested to hear your thoughts, going to a proper velodrome isn’t really an option and it’s difficult to find a suitable loop nearby.
Cheers
You’re not allowed to ride bikes on most tracks, assuming it’s on the property of a school. Don’t be that guy (girl).
Obviously I’m not just going to rock up, but I’d rather check if it would be worthwhile before asking for permission. If given the go ahead we could make sure we were the only ones using it too.
Excellent. In that case, maybe you could find an older track (that’s not torn up with tree roots)? Older tracks are significantly more firm. It seems like that could help reduce the sponge factor. Also, as long as you can ride fast on the sponge, it should be pretty consistent, allowing you to get reasonably good qualitative data, even if it’s not great quantitative data. But that’s just a guess/assumption.
Main consideration is always that you want minimal wind.
After that a consistent road surface and no need to use the brakes.
Can you go ~20 to ~25mph around the turns?
Some elevation change can actually be useful too.
I assume you are talking about using the out-n-back equivalent of the Chung method to estimate CdA (I can’t remember who proposed this).
I am not as familiar with this approach, but I believe it work on the same general idea that CdA vs speed is a quadratic function wheel whereas Crr versus speed is linear, so you can separate them. Your Crr might be really high on a running track, but I don’t see why it wouldn’t work to get estimates of CdA. They may be biased if you don’t have a good guess at Crr, but a lower CdA is what you are looking for.
This is why its not worth it - https://www.youtube.com/watch?v=n4OzPrskdqU
Actually the way I remembered it was that he just lost it on a corner - not overlapped wheels - but anyhoo - could you get round those corners on your tribars without slowing ?
This is why its not worth it - https://www.youtube.com/watch?v=n4OzPrskdqU
Actually the way I remembered it was that he just lost it on a corner - not overlapped wheels - but anyhoo - could you get round those corners on your tribars without slowing ?
This. You really can’t keep speed through those corners without slowing… or maybe you can, but I sure can’t.
The sloped track on the velodrome looked scary, and then I realized that even at a slow speed, it was easier to make the corners on the track than on the flat apron.
This is why its not worth it - https://www.youtube.com/watch?v=n4OzPrskdqU
Actually the way I remembered it was that he just lost it on a corner - not overlapped wheels - but anyhoo - could you get round those corners on your tribars without slowing ?
Kevin Keegan!
what did they think was going to happen? lol
If you could get access to a 400m running track when it was empty, would it be possible to conduct good aero-testing on it?
Having never been on one, I’m wondering if the surface might make things difficult (increased Crr(?) making aerodynamic changes harder to spot), or perhaps it would be to spongy to ride on. I’d be interested to hear your thoughts, going to a proper velodrome isn’t really an option and it’s difficult to find a suitable loop nearby.
Cheers
Ah, yes. Jim Papadopoulos (co-author with DG Wilson on Bicycling Science) suggested this method years ago. He proposed having one power meter and two speedometers, one set to display current speed and the other to display average speed, and to ride so current and average speed were equal for each trial. Record the average speed and average power. Try again at a different speed. Lather, rinse, repeat. He thought that if you rode at average speed and the track was nearly circular that wind would cancel out. He didn’t think my method would work, both because I vary the speed and also because I don’t need to keep the elevation constant, but he didn’t have a power meter or two speedometers so he couldn’t do either his method or mine to be sure.
Anyway, people who have tried school tracks report it can work if it’s very calm and you can get permission to use it. Helps if the track is firm but it’s not completely necessary. Since Jim wasn’t able to try his method or mine, I thought I’d try his. However, the one time I tried Jim’s method wasn’t so happy. I tried at an elementary school track but a teacher came out to yell at me. That wasn’t the bad part – the bad part was that she was the exact doppelganger of my third grade teacher, Mrs. Bowman. I was in France at the time, about 8000 miles and four decades away from where I’d grown up but one can never be too sure with Mrs. Bowman so I cut short my runs and took a wide berth around that school for a long long time afterward. She wasn’t anyone to trifle with. Be sure to get permission.
Thanks for the replies.
Overall it sounds quite promising, if we can get access I’ll update here to give some feedback.
You’re not allowed to ride bikes on most tracks, assuming it’s on the property of a school. Don’t be that guy (girl).
I think thsoe narrow tires will overload the adhesion of most rubberized granule type tracks and tear them up in the corners if you corner hard at all.
I’ve never tried, but the corners are probably shallow enough to hold 20mph if you confident cornering, but again, I’m not sure I’d trust that surface. Maybe an old school soft asphalt track with those rubber strips in them.
Having caught hell from an AD for running on a track, I can’t see getting permission for this. Around here, a track is that thing you walk across to get to the football field.
Keep us posted on the method that you use here.
I have access to an older asphalt track. I’ve even seen the local tri club use it for kids brick work outs in the spring / summer. So, I shouldn’t catch grief for using it.
If you could get access to a 400m running track when it was empty, would it be possible to conduct good aero-testing on it?
Having never been on one, I’m wondering if the surface might make things difficult (increased Crr(?) making aerodynamic changes harder to spot), or perhaps it would be to spongy to ride on. I’d be interested to hear your thoughts, going to a proper velodrome isn’t really an option and it’s difficult to find a suitable loop nearby.
Cheers
Depending on where you live, you might be able to find a disused parking lot or something similar that could provide a circuit.
Depending on where you live, you might be able to find a disused parking lot or something similar that could provide a circuit.
I’ve used an industrial park on a weekend. I’ve used residential streets, both in loops and out-and-back laps. I’ve used up-and-backs on shallow hills. I’ve used multi-use paths at dawn (to avoid joggers and parents pushing prams. I know guys who’ve gone out near airport frontage roads at midnight – that requires more commitment than I possess. One of the virtues of my approach is that you can use far more types of terrain than the “classic” approach, which is done on flat (or constant slope) roads.