Computrainer calibration drift?

Triathlon Forum
1

I’ve been wondering about this for a long time. I always calibrate my computrainer after the recommended 10" warmup. I’ll run it 3 times and start using the CT after all 3 runs are consistent. I’ve noticed, however, that if I check the calibration after using the CT for a period of time it often is different. For example today I did a 30" field test. I warmed up then calibrated for 10-15 minute, did the 30" field test and rechecked the CT. The cal # varied from 2.09 initially to 2.20. The room was quite cold-probably low 60’s so I don’t see how the machine could have over heated.

Does anyone know significant is the variation?

Thanks,

Pat

2

10 minutes might not be enough time to adequately warm up the LG, especially if you aren’t pushing a lot of watts (similar to your workout wattage).

You would be hard pressed to overheat the LG, it is more likely that it hadn’t warmed up all the way, especially if the room was cold.

4

Wow, thanks. Both of your answers really help. No I don’t push a ton of watts, I don’t think I have a ton of position change but it’s good to know about that.

Thanks,

Pat

5

Make sure the temperature change for you bike is not too great. Temp change on the wheel/tire can expand/contract the wheel, which will skew your cal #'s.

Eric

6

FWIW, my experience is similar to yours. My initial calibration # is highest, then drops after a 10 minute warmup, then creeps back up towards the initial # during the workout.

7

http://www.bases.org.uk/newsite/pdf/Abstract%20book%20etc.pdf

Abstract A9 might be of interest to Computrainer owners…

8

Doc,

I couldn’t find the abstract. I was able to get to the home but where should I look for articles?

Thanks,

Pat

10

Got it, thanks,

Pat
.

11

Oh my,

" Based on these data we would recommend
that investigators use repeated 2min bouts at
200W warm-up until the calibration value has
plateaued, which should occur in 2-6 minutes
depending on the external temperature. It is
vital that calibration occurs immediately after
the warm-up period without stopping as even
a small delay affects the calibration value. "

I’m not even sure I can hold 200W for 2-6 minutes. I guess I’ll have to settle for less precise calibration.

Thanks much, you’re right good info for all CT users.

Pat