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torque question

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torque question

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03-05.-2007, 07:51 AM	#1
whoawhoa Registered User Join Date: Oct 2004 Posts: 1,019	torque question When you run the torque test on a powertap, it's ok for it to be slightly off, right, as long as it stays zero? When I did it today the top line read "0" and both the middle and bottom line read "517."

04-05.-2007, 03:33 AM	#2
woodgab Registered User Join Date: Jun 2004 Posts: 50	Re: torque question Not sure what you mean by slightly off, but having just gone through this with Saris: 500-525 are acceptable numbers for the middle and bottom line. I asked to confirm what the manual says about the bottom minus the middle being the adjustment factor and was told that, so long as torque is zeroed properly, being the same is fine. FWIW, I'm 507 / 507 right now. The wheel should be stopped, with you off the bike for test mode. A couple more things about zeroing I didn't know about. My race file from a new SL was trashed over the weekend, showing 35-40 watts while coasting. I was told one should NOT zero torque while coasting on the bike, but rather with the rear wheel spinning freely, holding the right hand button down for 10 seconds, not just until the top screen clears (usually ~2 seconds). I hate the idea of having to re-zero every ride in order to avoid trashy files. On a sidebar, I've had 3 PowerTap pro's work to a transponder mounted 3.5 inches up the stay. The SL, in my case, needs it closer to 2 inches. YMMV.

10-05.-2007, 02:02 AM

jetnjeff

Registered User

Join Date: Mar 2006

Location: Budd Lake NJ

Posts: 187

Re: torque question

Told by who? Not everyone at Saris is fullly up to speed on this product.

Others on the forum have stated zeroing while coasting is fine.

I have done it and followed it up with wheel spinning freely test and had no difference. It would be fairly inconvenient to have to stop during a alpine stage to zero due to the temp change.

Quote:

Originally Posted by woodgab

Not sure what you mean by slightly off, but having just gone through this with Saris:

500-525 are acceptable numbers for the middle and bottom line. I asked to confirm what the manual says about the bottom minus the middle being the adjustment factor and was told that, so long as torque is zeroed properly, being the same is fine. FWIW, I'm 507 / 507 right now. The wheel should be stopped, with you off the bike for test mode.

A couple more things about zeroing I didn't know about. My race file from a new SL was trashed over the weekend, showing 35-40 watts while coasting. I was told one should NOT zero torque while coasting on the bike, but rather with the rear wheel spinning freely, holding the right hand button down for 10 seconds, not just until the top screen clears (usually ~2 seconds).

I hate the idea of having to re-zero every ride in order to avoid trashy files. On a sidebar, I've had 3 PowerTap pro's work to a transponder mounted 3.5 inches up the stay. The SL, in my case, needs it closer to 2 inches. YMMV.

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