Need some help from the computrainer experts out there. I did a CP30 test last night, but realized at the end that I didn’t push the set button when I recalibrated before the start. So, the press on force was set to 3.8 when it really should have been around 2.9. What effect does this have on my results? Will the average watts reading for the ride be too high or too low? Any idea on how high or low? Thanks in advance for the help!
I’m using a high press on force based on the recommendation of Richard Wharton’s book. He says in the book that press on force should be at least 2.7. So I usually set it higher than that before warming up, and then recalibrate it afterwards. I just messed up the second part. Oh well, I figured my results would end up way off.
rmur is pretty in line with what CT say in their manual (p15 basic manual).
They suggest that 0.01lb equates to load of 1/2 watt at 25mph. So assuming that you were at around that pace that would mean that you were out by 45 watts.
according to recent posts made by the folks at computrainer (over on the racermate forum), the press on force should a, be as little as possible with no slippage b, more for hill workouts and other high wattage efforts and less for easier or recovery rides. this is very roughly paraphrased to you might want to head on over to racermate to verify.
yes, that is what I thought, too. In fact, I thought it should always be at least under 2.00.
(I take that back. I took a look at the manual last night and realized I was wrong. It has to be below 5.00, otherwise something is wrong with the application force.)
Just to be clear, I am going by Richard Wharton’s book on training with Computrainer. This isn’t based on Racermate’s recommendations. According to the book, there was a study that showed that press on force of under 2.7 could results in recording lower watts then what is actually being produced due to slippage. He also pointed out that this is going to eat up you tires faster. I only use 2.7 when I’m testing and want to be as accurate as possible. For a regular ol’ training ride I go with the 2.0 setting. Close is good enough during those rides.
And this is why I had a powertap years before I had a CT. And I don’t for a second regret either purchase.
whoa! under 2.70! So when I was doing the regular calibration method (the one they advise you to do in the manual) and getting mubers between 1.07 to 1.23 I was not getting the right numbers? I did this before all my tests in the last few years and these weren’t accurate?..Well they may be accurate for comparison purposes I guess. But how do you get to 2.7? Just press the tire on the roller even more I would guess.
Thanks for the info!
According to the research mentioned, I guess the answer is… Yeah, it’s not accurate… Now, I don’t know to what degree it’s not accurate. Personally, I’m not too anal about it. If I’m a few watts here or there, then it’s not big deal. Other people want to be exact. My guess is that you’re not really that far off, but if you are one of those who want it exact, then maybe you should crank it up to 2.7. To get to 2.7 I just really crank it on there at the start and then make adjustments after warming up.
they keys are, 1. no tire slippage and 2. your methods for calibrating are the same each time. who cares if it’s off as long as it’s off by the same amount each time.
What is the book by Wharton you are talking about
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