Similar thread to Ergomo mafia make yourselves known ! but different enough to merit a new one…
I’ve used a Computrainer extensively for about 6 years and naturally have a higher % of the WTS on the RIGHT.
Just go an ergomo - anyone know if there’s a way to factor this non-50/50 distribution into the ergomo?.. or should I just live with the knowledge that the ergomo readings will be untrue relative to CT.
You could perform a step test at 4 or 5 different power outputs (e.g. 200, 225, 250, 275, 300) with 5 min at each step and compare the ave power over each step. Then adjust the k factor on the Ergomo so it matches the CT.
Thanks.
Ergomo is totally new to me so not sure how K Factor works. Are you suggesting trial and error adjustment of K Factor between each 5 minute step in intensity until they corelate?
No, I would do one contiguous trial running through the powers, then analyze the file after ward averaging the power over the five minue segments and using that for adjustment. Adjust prior to next test/workout and repeat. Instantaneous variability would preclued adjusting the k factor between steps.
Can you do this? Does the k-factor and power readings have a linear relationship?
Dave
I thought the R:L distribution wasn’t that accurate on the CT. I’d ask AC to see if he thought this would work.
Are your indoor and outdoor watts for CP60/intervals the same? Why do you want your ergomo to match your CT? How accurate is the CT? How consistent are CT watts from ride to ride?
Dave
On the units my clients and I have, yes. This would need to be determined empirically though. If the response were not proportionally linear on a particular unit compared to the CT, it might be that the CT were off. If that were the case, then I would pick a power close to FTP and make sure that was the power that matched most closely.
Does your power reading go up if you adjust your k-factor up? Can you give me an idea of how much each changes? If I wanted my ergomo to read about 15 watts lower at 200 watts - how would I change my k-factor?
Thanks
Dave
Does your power reading go up if you adjust your k-factor up? Can you give me an idea of how much each changes? If I wanted my ergomo to read about 15 watts lower at 200 watts - how would I change my k-factor?
Yes, increasing the k-factor increases the power reading. I’ve been told each k-factor unit will change the power reading by 3-5 watts. So if you want to lower by 15 watts I’d start out by lowering k-factor 3 units, then compare again, and repeat as necessary.
I’m not sure how the CT works, but if it measures power at the wheel, then the Ergomo should have a higher power reading than the CT for the same workload, since you need to account for drivetrain losses. Probably on the order of 1-2%. I wouldn’t adjust it so that they read the same.
I would take the l/r values from the CT with a BIG grain of salt.
don’t get me wrong, I live on my CT, but the assumptions and calculations for the l/r and spinscan are pretty significant (for starters, it only measures candence 1x per rev)
the CT does not know the l/r components of power generation and short of the kister force pedals (and something new coming soon) no other power meter does either.
Now, you could install a SRM onto the ergomo and compare the ergomo measurement vs the srm to get the l/r but short of that… the rest is a guess.
hth,
g
Thanks fot all the input. I think I’ll take the lazy option by doing enough training with my ergomo fitted P3 on the Computrainer so that the realtionship between the two becomes intuitive.
I don’t want to have my race bike on CT all winter so once I work out the corelation in my head I’ll switch to another bike on the CT and keep the ergomo P3 for riding outdoors from Spring onwards.
Just need to get that second ergomo BB for my indoor turbo bike… and my hack training bike… and my road bike… someone has to come up with a new power meter concept for the multi-bike owners of the world.
Fudging the K Factor is fine… so long as the difference is consistent as you fatigue. In my case, the spread between right and left becomes much greater over time, and thus, the Ergomo measures me progressively weaker relative to any other powermeter over the duration of a ride. No single fudge factor works in that case.