ergo trainer / sram

[nath1]

Hi all, i have a Taxc basic ergotrainer that i use for powertraining, i have wonderd often as to how accurate these figures are, over the last year they have gone up and io race alot faster so i have been happy thus far. Yesterday i was able to set my friends bike up and use who is lucky enought to have the SRAM power meter. I used his turbo which is a cable braked version of mine and was bemused to see that in every zone i was kicking out about thirty more watts than usual, which i realise is a good thing but it has left me wondering how accuratte my ergo is? For me, i would love a SRAM for its accuracy but the pocket will not stretch that far yet so is there an ergo that is more precise in wattage measurements that anyone knows of. Cheers nath1

 

[ric_stern/RST]

Hi all, i have a Taxc basic ergotrainer that i use for powertraining, i have wonderd often as to how accurate these figures are, over the last year they have gone up and io race alot faster so i have been happy thus far. Yesterday i was able to set my friends bike up and use who is lucky enought to have the SRAM power meter. I used his turbo which is a cable braked version of mine and was bemused to see that in every zone i was kicking out about thirty more watts than usual, which i realise is a good thing but it has left me wondering how accuratte my ergo is? For me, i would love a SRAM for its accuracy but the pocket will not stretch that far yet so is there an ergo that is more precise in wattage measurements that anyone knows of. Cheers nath1

I have a Tacx Basic or Excel (can't recall). It's a nice trainer, but isn't at all accurate. I've used other people's Tacx trainers and theirs have also been inaccurate but off by differing amounts to mine...

I've done comparisons between various trainers and power meters. And, as seen in the 2004 Gardner et al paper the SRM (not SRAM) and the Power Tap are accurate to each other when the SRMs have been calibrated (many come from the factory poorly calibrated).

If your friend's SRM hasn't been accurately calibrated with (e.g.) known certified masses it may not be accurate, and it's highly likely your Tacx isn't accurate either. The SRM can be made accurate by calibration, the Tacx can't.

If you want to check the accuracy of your Tacx and don't want to calibrate anything, then your best bet is to compare it with a Power Tap (just make sure the torque is zeroed). This is the easiest option.

Ric

 

[nath1]

Hi thanks for the reply, in your knowledge are the taxc turbos generally under accuratte or over or do they differ with no reall general accuracy. It is a shame that SRM is so expensive hopefully one day they may produce a slightly cheaper option. Thanks

 

[ric_stern/RST]

Hi thanks for the reply, in your knowledge are the taxc turbos generally under accuratte or over or do they differ with no reall general accuracy. It is a shame that SRM is so expensive hopefully one day they may produce a slightly cheaper option. Thanks

The Tacx trainers i've used (as have other trainers) have been all over the place, so you can't say that they are either under or over estimating. Additional note: the accuracy alters at different absolute powers...

There's also the Power Tap to consider which is at least as accurate as the SRM Pros.

Ric