Cycling and bicycle racing discussion forums.   View New Forum Topics
Today's Forum Topics

Set as homepage


Go Back   Cycling Forums > Tech Corner > Power Training
User Name
Password
Register FAQ Members List Calendar Search Today's Posts Mark Forums Read


Welcome to CyclingForums.com

You are currently viewing our website as a guest which gives you limited access to view most discussions. You will have to register before you can post to this thread.

By joining our free online community you will have access to post new topics, communicate privately with other cyclingforums.com members (PM), respond to polls, upload photos and access other special features like product reviews and classifieds.


Powertap Pro test

Reply
 
Thread Tools Search this Thread Display Modes
Old 25-03.-2005, 06:44 AM   #1
vitiris
Registered User
 
Join Date: Jul 2003
Location: Devon
Posts: 70
Default Powertap Pro test

My Powertap Pro misreads Watts (by about a factor of 2x) but is fine on everything else. I have zeroed the Torque with no joy. I also ran the test and got the following reading for the Torque information of 497 on the bottom line and 497 on the middle line with 0 at the top. When I rotate the cranks the bottom line minus the middle equals the top as it is meant to do. Totally flummoxed , any ideas gratefully received

Thanks

Sean
__________________
there's no gain without pain
vitiris is offline  
Reply With Quote
Old 25-03.-2005, 08:11 AM   #2
jws
Registered User
 
Join Date: Jan 2004
Location: Pittsburgh, USA
Posts: 189
Default Re: Powertap Pro test

Quote:
Originally Posted by vitiris
My Powertap Pro misreads Watts (by about a factor of 2x) but is fine on everything else. I have zeroed the Torque with no joy. I also ran the test and got the following reading for the Torque information of 497 on the bottom line and 497 on the middle line with 0 at the top. When I rotate the cranks the bottom line minus the middle equals the top as it is meant to do. Totally flummoxed , any ideas gratefully received

Thanks

Sean



Hi Sean, I replied to you over at Wattage already, but it sounds exactly like my problem last year with a new Pro. I had to send it back for a new torque tube. Do a stomp test and if it's off, it'll probably need to go back. Jimmy
jws is offline  
Reply With Quote
Old 25-03.-2005, 09:15 AM   #3
vitiris
Registered User
 
Join Date: Jul 2003
Location: Devon
Posts: 70
Default Re: Powertap Pro test

Quote:
Originally Posted by jws
Hi Sean, I replied to you over at Wattage already, but it sounds exactly like my problem last year with a new Pro. I had to send it back for a new torque tube. Do a stomp test and if it's off, it'll probably need to go back. Jimmy


Jimmy, thanks a lot. I have heard about a stomp test but how do you actually do it? An url to a webpage explaining would be great

Cheers

Sean
__________________
there's no gain without pain
vitiris is offline  
Reply With Quote
Old 25-03.-2005, 03:26 PM   #4
jws
Registered User
 
Join Date: Jan 2004
Location: Pittsburgh, USA
Posts: 189
Default Re: Powertap Pro test

Quote:
Originally Posted by vitiris
Jimmy, thanks a lot. I have heard about a stomp test but how do you actually do it? An url to a webpage explaining would be great

Cheers

Sean



Sean,

Check out this link(Q #23):

http://www.midweekclub.ca/powerFAQ.htm#Q23


Jimmy
jws is offline  
Reply With Quote
Old 26-03.-2005, 12:28 AM   #5
vitiris
Registered User
 
Join Date: Jul 2003
Location: Devon
Posts: 70
Default Re: Powertap Pro test

Quote:
Originally Posted by jws
Sean,

Check out this link(Q #23):

http://www.midweekclub.ca/powerFAQ.htm#Q23


Jimmy



Once again thanks Jimmy . I carried out the stomp test, hopefully correctly, I tried two different cogs and got figures of -67.5% and -71.2%. Does this sound correct and what does it mean except I guess it is meant to be zero

Sean
__________________
there's no gain without pain
vitiris is offline  
Reply With Quote
Old 26-03.-2005, 03:09 AM   #6
jws
Registered User
 
Join Date: Jan 2004
Location: Pittsburgh, USA
Posts: 189
Default Re: Powertap Pro test

Quote:
Originally Posted by vitiris
Once again thanks Jimmy . I carried out the stomp test, hopefully correctly, I tried two different cogs and got figures of -67.5% and -71.2%. Does this sound correct and what does it mean except I guess it is meant to be zero

Sean



Oh yes, Sean....if the error's that high, you've got a bad torque tube. Call Graber and let them know.

The error should be close to zero, probably no more than a couple percent.

The good news is that I think they have parts for the Pro, as opposed to the SL.

Ciao, Jimmy
jws is offline  
Reply With Quote
Old 30-03.-2005, 09:06 AM   #7
PowerPunk
Registered User
 
Join Date: Jan 2005
Posts: 24
Default Re: Powertap Pro test

Quote:
Originally Posted by jws
Oh yes, Sean....if the error's that high, you've got a bad torque tube. Call Graber and let them know.

The error should be close to zero, probably no more than a couple percent.

The good news is that I think they have parts for the Pro, as opposed to the SL.

Ciao, Jimmy

Just plan for significant down time. I just had my torque tube replaced and Graber had my wheel for a month.
PowerPunk is offline  
Reply With Quote
Old 01-06.-2005, 06:47 AM   #8
vitiris
Registered User
 
Join Date: Jul 2003
Location: Devon
Posts: 70
Default Re: Powertap Pro test

Quote:
Originally Posted by jws
Oh yes, Sean....if the error's that high, you've got a bad torque tube. Call Graber and let them know.

The error should be close to zero, probably no more than a couple percent.

The good news is that I think they have parts for the Pro, as opposed to the SL.

Ciao, Jimmy


Jimmy, it's back and I've had the wheel rebuilt and I have now tested it. Wow, it works, it reads power and I haven't been so happy in ages (yes I live a seriously sad life). I shall give it it's first outing on the club TT tomorrow night and can hardly wait It has already made me feel better because I now have a more realistic reading on the turbo (Taxc Excel), I always thought it under read but couldn't know by how much but after a quick spin I'm guessing 300W Powertap is about 250W Taxc.

Thanks for all your help

Sean
__________________
there's no gain without pain
vitiris is offline  
Reply With Quote

Reply


Thread Tools Search this Thread
Search this Thread:

Advanced Search
Display Modes

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

vB code is On
Smilies are On
[IMG] code is On
HTML code is Off
Forum Jump



All times are GMT +10. The time now is 03:43 PM.


Powered by: vBulletin Copyright © 2000 - 2008, Jelsoft Enterprises Ltd.
Copyright © 2001 - 2006 cyclingforums.com

Links to websites we like:
Pezcyclingnews | Cyclingnews.com | Wine Zone | iinet