I have a computrainer and ride it several times per week. Sometimes when climbing the back wheel slips, is that normal? Also, on the trainer I average 3-5 mph slower than on the road. I have never done the “calibration”. Will doing this make the speed more accurate? I just hate the idea of getting started, then hopping off to get the thing calibrated…
If it slips you need to increase the roller pressure. While holding the flywheel grab the wheel and try to pull it against the roller, if you can make it slip that way increase the roller pressure until you can’t (unless you are a powerlifter).
You have to do the calibration for it be accurate at all. With the roller pressure high enough to avoid slipping on steep hills there is a lot of rolling resistance. Even using the same brand tire and the same pressure the drift over the life of the tire can be substantial.
"I just hate the idea of getting started, then hopping off to get the thing calibrated… "
Andy…I think you haven’t read the directions, have you? The answer to both of your questions is right in the first few pages.
You don’t get off the bike to calibrate a Computrainer. You push two buttons on the handlebar unit, pedal to 25mph and let it coast down. If you’re warming up with the computer screen on, simply stop pedalling, unplug the serial cable from the handlebar unit, do your calibration and plug the cable back in. After a 5-minute warmup, the unit is ready for calibration. Calibration takes all of about 10 seconds to do, and you certainly don’t need to get off the bike. If you don’t calibrate, none of your workouts and power measurements will be consistent, and you’re defeating the whole purpose of a Computrainer. You might as well have a fluid trainer.
If your tire slips, clean it with alcohol first, and then give the knob an extra bit of a turn. And, of course, calibrate again.
Oh – and read the entire manual.
{Also, on the trainer I average 3-5 mph slower than on the road. } reply
Me too. On my long aerobic rides, I average 15-16 mph on the CT but at a recent hilly half IM, I averaged 19.9. Since getting my CT in January, I have ridden almost exclusively indoors. My times are getting faster and I feel like I’m getting a better workout.
The CT is harder, no doubt, so when you ride outside you’ll be faster too.
"On my long aerobic rides, I average 15-16 mph on the CT but at a recent hilly half IM, I averaged 19.9. "
I’ve had that effect too, but I think much of it has to do with race day. We should all get a big bump of power output on race day if we’ve peaked and tapered properly. I had never gone over 21 mph for even 40 minutes on the Ctrainer, yet went out and averaged 22.1 in a half ironman.
After some very careful checking of HR, RPE, power output, pace, etc. between the Ctrainer and on the road with a Powertap, my Ctrainer paces turn out to be pretty accurate. I think that I’m “slower” on the Ctrainer because riding a trainer is just mentally tough, and going faster on a real road surrounded by other people is mentally easier to do.
The speed is off for several reasons, but the biggest that comes to mind is wind resistance. C-trainer is obviously using some generic number for wind resistance and most triathletes are probably much more aero than the standard roadie. Think about it, I go the same speed on the c-trainer whether I sit up very tall or get on the aerobars.
Andy: Do the calibration before every ride. Your tire pressure will be different. Temperature and humidity will be different. You might weigh more or less or have on something heavy or just left your keys to the vault in your jersey. :), Yes, it’s a pain. But you do want valuable data, right?
Have you checked out the demo of the new cycling peaks software at www.cyclingpeakssoftware.com ? Download it and import your CT data. Fun, fun, fun.
-Robert
The big thing I notice on the CT is the descents are WAAAY harder than real life, so if there is much time spent at negative grades the difference will add up quickly. Uphills are also slightly harder because the flywheel effects don’t quite emulate the forward momentum of your body and bike in the real world. Still it’s a harder workout that way and the Velotron alternative that would largely correct the momentum problems is $5000 and even a bicycling money pit like me can’t justify that.
If you’re using the computer screen with a course and the small spinscan window, you don’t have to unplug the cable. Just scroll through the views until you get to the one that probably has 2.00 on it. Then pause the program using F1 and hit the ‘set’ button (F3 maybe). That will then go into the calibration mode. Hit the set button again, un pause the program and keep riding.
Aah…you’ve got the newer software than I do. Nice feature.