Go Back  Bike Forums > Bike Forums > Road Cycling
Reload this Page >

My power meter can give me torque information...what is that telling me?

Notices
Road Cycling “It is by riding a bicycle that you learn the contours of a country best, since you have to sweat up the hills and coast down them. Thus you remember them as they actually are, while in a motor car only a high hill impresses you, and you have no such accurate remembrance of country you have driven through as you gain by riding a bicycle.” -- Ernest Hemingway

My power meter can give me torque information...what is that telling me?

Old 05-14-18, 10:25 AM
  #1  
cthenn
Senior Member
Thread Starter
 
Join Date: Jan 2010
Location: Walnut Creek, CA
Posts: 2,473

Bikes: 2015 Trek Emonda SLR, 2002 Litespeed Classic, 2005 Bianchi Pista, 2016 Devinci Hatchet, Some BikesDirect MTB I never ride.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 65 Times in 37 Posts
My power meter can give me torque information...what is that telling me?

When I upgraded my computer to a Wahoo, one of the power metrics I could display is "torque". Does anyone know what one can learn from that value? There are several variations of the metric, the one I'm using is "last lap torque", but I really don't know what I'm looking at when I see the value. I think my plan is to learn through osmosis, as I try to correlate the value to how hard I pushed on a given lap, how I felt, etc. How is torque different or comparable to power numbers? Seems to be more or less correlated, the higher the wattage, the higher the torque, more or less, but I don't know how that metric might be useful in comparison to lap power. The values are usually in the low 2 digit numbers (20s-30s) for an effort in my Z4 range, but don't even know the units lol! 20 or 30 what, and is that a lap average number? I understand the definition of the word, and obviously the more power you put into the pedals, the higher the torque value will be, but I don't quite understand how or what to take from a given effort looking at that value vs just looking at power.
cthenn is offline  
Old 05-14-18, 11:11 AM
  #2  
tomato coupe
Senior Member
 
Join Date: Jul 2009
Posts: 963

Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 577 Post(s)
Liked 361 Times in 185 Posts
Simple, qualitative explanation: your power is your torque multiplied by your cadence.
tomato coupe is offline  
Old 05-14-18, 11:30 AM
  #3  
pesty
Master Sarcaster
 
pesty's Avatar
 
Join Date: Apr 2006
Location: DFW, Texas
Posts: 527

Bikes: 2018 Allez Sprint, 2016 Trek Crockett Canti

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 190 Post(s)
Likes: 0
Liked 0 Times in 0 Posts
Basically, it's how effective you're pedal stroke is at delivering power all the way arround. Higher is better, I want to say that 30% and higher is pretty good. If you want a really detailed write up, look here: https://www.cyclinganalytics.com/blo...dal-smoothness
pesty is offline  
Old 05-14-18, 11:41 AM
  #4  
tomato coupe
Senior Member
 
Join Date: Jul 2009
Posts: 963

Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 577 Post(s)
Liked 361 Times in 185 Posts
Originally Posted by pesty View Post
Basically, it's how effective you're pedal stroke is at delivering power all the way arround. Higher is better, I want to say that 30% and higher is pretty good. If you want a really detailed write up, look here: https://www.cyclinganalytics.com/blo...dal-smoothness
The OP is asking about torque -- what you referenced is completely different.
tomato coupe is offline  
Old 05-14-18, 12:03 PM
  #5  
gurk700
Senior Member
 
Join Date: Apr 2016
Posts: 256
Mentioned: 1 Post(s)
Tagged: 0 Thread(s)
Quoted: 151 Post(s)
Liked 8 Times in 5 Posts
Originally Posted by tomato coupe View Post
Simple, qualitative explanation: your power is your torque multiplied by your cadence.
/thread
gurk700 is offline  
Old 05-14-18, 12:33 PM
  #6  
RChung
Senior Member
 
Join Date: Sep 2009
Posts: 1,607
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 372 Post(s)
Liked 191 Times in 81 Posts
Originally Posted by tomato coupe View Post
Simple, qualitative explanation: your power is your torque multiplied by your cadence.
This is true for most power meters. For Power Tap hubs, power is measured at the rear hub so power is (hub) torque multiplied by the wheel's rotation speed.

Knowing the torque can be useful for 1) checking the accuracy of your power meter, or for diagnosing problems; or 2) examining "QA" (aka pedal force and pedal speed analysis). Most riders never look at QA analyses, nor do they ever check the accuracy of their PMs, so most riders can just ignore the torque data field.

I do periodically check the accuracy of my PM, so I do like being able to get the torque value. Once I diagnosed a problem with a power meter by noticing that the product of torque and cadence (and a conversion constant) didn't quite equal the power; it turns out the cadence measurement was off.
RChung is offline  
Old 05-14-18, 01:50 PM
  #7  
tomato coupe
Senior Member
 
Join Date: Jul 2009
Posts: 963

Bikes: Colnago, Van Dessel, Factor, Cervelo, Ritchey

Mentioned: 2 Post(s)
Tagged: 0 Thread(s)
Quoted: 577 Post(s)
Liked 361 Times in 185 Posts
Originally Posted by RChung View Post
This is true for most power meters. For Power Tap hubs, power is measured at the rear hub so power is (hub) torque multiplied by the wheel's rotation speed.
​​​​​​​That's why I emphasized qualitative -- my purpose was to give the OP a sense of how torque and power are related, without going into details.
tomato coupe is offline  
Old 05-14-18, 02:08 PM
  #8  
Racing Dan
Senior Member
 
Racing Dan's Avatar
 
Join Date: Aug 2015
Posts: 1,554
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 891 Post(s)
Liked 65 Times in 53 Posts
Originally Posted by cthenn View Post
When I upgraded my computer to a Wahoo, one of the power metrics I could display is "torque". Does anyone know what one can learn from that value? There are several variations of the metric, the one I'm using is "last lap torque", but I really don't know what I'm looking at when I see the value. I think my plan is to learn through osmosis, as I try to correlate the value to how hard I pushed on a given lap, how I felt, etc. How is torque different or comparable to power numbers? Seems to be more or less correlated, the higher the wattage, the higher the torque, more or less, but I don't know how that metric might be useful in comparison to lap power. The values are usually in the low 2 digit numbers (20s-30s) for an effort in my Z4 range, but don't even know the units lol! 20 or 30 what, and is that a lap average number? I understand the definition of the word, and obviously the more power you put into the pedals, the higher the torque value will be, but I don't quite understand how or what to take from a given effort looking at that value vs just looking at power.
You can develop a given power, say 200w, at any RPM you like. Just "mash" the gears more or less, dependig on what gear you have chosen. The touque value is a measure of how much you mash the gears. For the same power, RPM will go up and torque go down if you choose a light geat and RPM will go down and torque up if you choose a heavy gear.
Racing Dan is offline  
Old 05-15-18, 09:38 AM
  #9  
cthenn
Senior Member
Thread Starter
 
Join Date: Jan 2010
Location: Walnut Creek, CA
Posts: 2,473

Bikes: 2015 Trek Emonda SLR, 2002 Litespeed Classic, 2005 Bianchi Pista, 2016 Devinci Hatchet, Some BikesDirect MTB I never ride.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 65 Times in 37 Posts
Originally Posted by Racing Dan View Post
You can develop a given power, say 200w, at any RPM you like. Just "mash" the gears more or less, dependig on what gear you have chosen. The touque value is a measure of how much you mash the gears. For the same power, RPM will go up and torque go down if you choose a light geat and RPM will go down and torque up if you choose a heavy gear.
OK, this dumbs it down enough to my level . On a short steep hill I did 300w at over 40 "torque units" while out of the saddle mashing at probably 65-70rpm whereas on other 300w efforts it can be closer to 30 if I try to spin it more. I'll probably keep the metric for a while see if it ends up having any usefulness for me.

So, what are the "torque units" shown?
cthenn is offline  
Old 05-15-18, 09:57 AM
  #10  
redlude97
Senior Member
 
Join Date: Sep 2011
Posts: 4,656
Mentioned: 28 Post(s)
Tagged: 0 Thread(s)
Quoted: 1924 Post(s)
Liked 177 Times in 129 Posts
Originally Posted by cthenn View Post
OK, this dumbs it down enough to my level . On a short steep hill I did 300w at over 40 "torque units" while out of the saddle mashing at probably 65-70rpm whereas on other 300w efforts it can be closer to 30 if I try to spin it more. I'll probably keep the metric for a while see if it ends up having any usefulness for me.

So, what are the "torque units" shown?
Are you measuring HR as well? If not you should be for it to be useful. See how your HR varies with the torque/cadence difference for the same avg power.
redlude97 is offline  
Old 05-15-18, 10:56 AM
  #11  
chaadster
Thread Killer
 
Join Date: Aug 2008
Location: Ann Arbor, MI
Posts: 9,356

Bikes: '15 Kinesis Racelight 4S, '76 Motebecane Gran Jubilée, '17 Dedacciai Gladiatore2, '12 Breezer Venturi, '09 Dahon Mariner, '05 Novara Big Buzz, '12 Mercier Nano, '95 DeKerf Team SL, '19 Tern Rally

Mentioned: 19 Post(s)
Tagged: 0 Thread(s)
Quoted: 1046 Post(s)
Liked 28 Times in 15 Posts
Originally Posted by cthenn View Post
OK, this dumbs it down enough to my level . On a short steep hill I did 300w at over 40 "torque units" while out of the saddle mashing at probably 65-70rpm whereas on other 300w efforts it can be closer to 30 if I try to spin it more. I'll probably keep the metric for a while see if it ends up having any usefulness for me.

So, what are the "torque units" shown?
Torque units displayed is Nm, or Newton meters.

If you're using analysis software that displays Torque Effectiveness, you might find the TE percentage useful in improving your pedaling technique. For example, a 75% TE would indicate that 75% of applied torque is going towards moving the bike, while the remaining 25% is you working against yourself by keeping pedal pressure on the upstroke. Obviously, you'd want to see as high a TE percentage as possible.
chaadster is offline  
Old 05-15-18, 11:28 AM
  #12  
Racing Dan
Senior Member
 
Racing Dan's Avatar
 
Join Date: Aug 2015
Posts: 1,554
Mentioned: 9 Post(s)
Tagged: 0 Thread(s)
Quoted: 891 Post(s)
Liked 65 Times in 53 Posts
Originally Posted by cthenn View Post
OK, this dumbs it down enough to my level . On a short steep hill I did 300w at over 40 "torque units" while out of the saddle mashing at probably 65-70rpm whereas on other 300w efforts it can be closer to 30 if I try to spin it more. I'll probably keep the metric for a while see if it ends up having any usefulness for me.

So, what are the "torque units" shown?
There are several different ways to express torque. Pound foot, lbs ft, is common in the US, but if you set it to metric then Im betting it will display SI units. That is Newton metre, Nm. If you can make it show power, torque and RPM all at once, Im betting you quickly learn how they relate.
Racing Dan is offline  
Old 05-15-18, 02:01 PM
  #13  
RChung
Senior Member
 
Join Date: Sep 2009
Posts: 1,607
Mentioned: 23 Post(s)
Tagged: 0 Thread(s)
Quoted: 372 Post(s)
Liked 191 Times in 81 Posts
Originally Posted by cthenn View Post
So, what are the "torque units" shown?

It depends on your power meter, and whether your head unit is set to display in SI (metric) or Imperial units. The metric unit is Nm, the Imperial unit is foot-lbs.

Originally Posted by redlude97 View Post
Are you measuring HR as well? If not you should be for it to be useful. See how your HR varies with the torque/cadence difference for the same avg power.
You don't need HR for torque information to be useful.

Here's a plot that shows cadence and crank torque for the same guy in three different types of races. The plot is from here.




RChung is offline  
Old 05-15-18, 02:58 PM
  #14  
Abe_Froman
Senior Member
 
Abe_Froman's Avatar
 
Join Date: Aug 2016
Location: Chicago
Posts: 2,566

Bikes: Marin Four Corners, 1960's Schwinn Racer in middle of restoration, mid 70s Motobecane Grand Touring, various other heaps.

Mentioned: 76 Post(s)
Tagged: 0 Thread(s)
Quoted: 9346 Post(s)
Liked 53 Times in 47 Posts
Originally Posted by cthenn View Post
OK, this dumbs it down enough to my level . On a short steep hill I did 300w at over 40 "torque units" while out of the saddle mashing at probably 65-70rpm whereas on other 300w efforts it can be closer to 30 if I try to spin it more. I'll probably keep the metric for a while see if it ends up having any usefulness for me.

So, what are the "torque units" shown?
Probably foot-pounds, which is a pretty simple unit. It's the amount of force exerted on a bolt by a 1 foot long wrench with a pound of weight sitting on the end of it.
Abe_Froman is offline  
Old 05-16-18, 05:19 PM
  #15  
cthenn
Senior Member
Thread Starter
 
Join Date: Jan 2010
Location: Walnut Creek, CA
Posts: 2,473

Bikes: 2015 Trek Emonda SLR, 2002 Litespeed Classic, 2005 Bianchi Pista, 2016 Devinci Hatchet, Some BikesDirect MTB I never ride.

Mentioned: 10 Post(s)
Tagged: 0 Thread(s)
Quoted: 569 Post(s)
Liked 65 Times in 37 Posts
Cool, brilliant info in here, thanks! I'm gonna look more into torque effectiveness, does that require a L/R PM, because mine is left-only. I think I've experimented with that and pedal smoothness on the Wahoo data fields, and nothing shows up...
cthenn is offline  
Old 05-16-18, 06:31 PM
  #16  
Dean V
Senior Member
 
Join Date: Oct 2009
Posts: 2,572
Mentioned: 3 Post(s)
Tagged: 0 Thread(s)
Quoted: 902 Post(s)
Likes: 0
Liked 96 Times in 64 Posts
I don't recall anyone using Horsepower as a unit for power measurement for cycling, so why would there be a readout of ft/lb?
It would be like your car speedo reading out your speed in mph and distance in kms at the same time.
Dean V is offline  
Related Topics
Thread
Thread Starter
Forum
Replies
Last Post
Racing Dan
Electric Bikes
14
09-11-18 01:11 PM
Damien09
Road Cycling
5
03-23-16 01:41 PM
torque cyclist
Road Cycling
111
08-14-14 05:22 PM
mcafiero
Road Cycling
8
09-28-11 05:35 PM

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

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off


Thread Tools
Search this Thread

Contact Us - Archive - Advertising - Cookie Policy - Privacy Statement - Terms of Service - Do Not Sell My Personal Information

Copyright © 2018 MH Sub I, LLC dba Internet Brands. All rights reserved. Use of this site indicates your consent to the Terms of Use.