Crr: real world rolling resistance?
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Crr: real world rolling resistance?
My new wheels with GP5000 TR S tubeless setup seemed a little slow. I have a road that I have measured my rolling resistance Crr using VE chung method. With GP5000 and latex tubes, two years ago I measured 0.0042 and 0.005 with butyl tubes. The pavement was new just under three years ago. Off I went and measured a whopping 0.0066 on my tubeless setup. Same 25 mm width on both and I used the same 89 psi. Temperatures were 73F vs upper 70's two years ago.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
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I vote #4.
Conti 5000 = the gatorskins of high-end supple tires. IMO, compared w/ Vittoria and Veloflex and Specialized.
Personally, I could care less about rolling resistance comparisons among similar type tires.
I need to lose 10lbs, get stronger, ride more aerodynamically and improve my spin.
Conti 5000 = the gatorskins of high-end supple tires. IMO, compared w/ Vittoria and Veloflex and Specialized.
Personally, I could care less about rolling resistance comparisons among similar type tires.
I need to lose 10lbs, get stronger, ride more aerodynamically and improve my spin.
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My new wheels with GP5000 TR S tubeless setup seemed a little slow. I have a road that I have measured my rolling resistance Crr using VE chung method. With GP5000 and latex tubes, two years ago I measured 0.0042 and 0.005 with butyl tubes. The pavement was new just under three years ago. Off I went and measured a whopping 0.0066 on my tubeless setup. Same 25 mm width on both and I used the same 89 psi. Temperatures were 73F vs upper 70's two years ago.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
More importantly, I'll ask the obvious question: are you racing? If no, then worrying about crr seems a bit silly. If yes, then you should consider how much slower you'd be with a puncture that might've sealed up with a tubeless setup. (And you might work on item #1 on your list.)
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How can you change 5 variables and expect to have anywhere a meaningful result?
Wow, talk about marginal gains! Are you preparing for the Olympics or World Hour Record?
Wow, talk about marginal gains! Are you preparing for the Olympics or World Hour Record?
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30 lbs is a massive difference. Imagine carrying 3 10 lb babies around full time and then placing them in a trailer with zero friction behind your bike. Now think of the additional pressure placed on your tires and the impact on rolling resistance if you were holding those babies in your arms when you ride. Am not an engineer and it shows.
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Trying to compare results with all the variables you have is ridiculous.
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Rolling
I too am interested in rolling resistance, but would never try to measure it on the road.
I use a Mouse to determine rolling resistance (click here)
Barry
I use a Mouse to determine rolling resistance (click here)
Barry
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My new wheels with GP5000 TR S tubeless setup seemed a little slow. I have a road that I have measured my rolling resistance Crr using VE chung method. With GP5000 and latex tubes, two years ago I measured 0.0042 and 0.005 with butyl tubes. The pavement was new just under three years ago. Off I went and measured a whopping 0.0066 on my tubeless setup. Same 25 mm width on both and I used the same 89 psi. Temperatures were 73F vs upper 70's two years ago.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
I can think of five explanations.
1. I am 30 pounds heavier (Crr is not constant, it is load and speed dependent)
2. The road surface got really bad in 2 years
3. Powertap G3 vs the crank based PM now used
4. These tires are slow
5. 45 ml of sealant is too much?
Is a Crr 0.0066 out of the ordinary for real world, worn pavement? Anyone ever measure? Anyone know of real world tests having been done quantitatively? The only ones I have seen are on velomobiles and 0.0066 is a good number for them and 0.01 is not out of the realm for mediocre tires or misaligned suspension. If this is normal on a road bike on 3 year old worn pavement, I won't chase my tail so to speak.
What was the drive train loss you assumed for the crank PM?
30 pounds shouldn't matter -- the calc accounts for changes in mass.
Can you describe the course and your protocol a little more? Were you wearing the same clothes (considering the 30 lb change in mass)? What was the change in CdA? An error in estimated CdA (for example, because of an error in wind estimation) of .01 m^2 is *roughly* equivalent to an error in Crr of .001, so if your estimate of CdA were .02 m^2 too low, it would make the estimated Crr in the ballpark of about .002 too high. You're kinda tall and heavy, aren't you? If so, an error in CdA of .01 m^2 might cause a slightly larger error in Crr.
Last edited by RChung; 05-08-22 at 03:58 PM.
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How much less could you care? I you could care a LOT less then this must be a very important issue for you. If you could care only a little bit less then maybe not so much. Of course if you meant to say you COULDN'T care less then we might better understand that you don't care at all. Inquiring minds want to know.
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I have the solution, but it works only in the case of spherical cows in a vacuum.
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How much less could you care? I you could care a LOT less then this must be a very important issue for you. If you could care only a little bit less then maybe not so much. Of course if you meant to say you COULDN'T care less then we might better understand that you don't care at all. Inquiring minds want to know.
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Reduce the variables and create a repeatable protocol. ABAB, or ABBA style. Same power meter, surface, bike, wheels, etc….Then try again.
Love all the BF Freds rolling into a topic like this to express their ignorance with a bunch of “couldn’t care less” and “flying cows” BS.
Contribute or GTFO.
Love all the BF Freds rolling into a topic like this to express their ignorance with a bunch of “couldn’t care less” and “flying cows” BS.
Contribute or GTFO.
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1. Only the pros need to worry about that. Are you a pro?
2. The best riders are the best because of what they do so just imitate them.
3. Things I can't see, can't measure, or don't care about aren't important.
4. Things I can see or measure are important, so you should care about them.
5. If I don't know how to do something, it's too complicated for anyone to know how to do.
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1. rolling resistance of your tires (within a given category) is an order of magnitude less important than moving the air resistance at speed
1a. Not comparing road race 25mm to hybrid 35s... etc
2. Measuring rolling resistance with uncalibrated devices, years apart and with other variables - to judge a tire is an exercise in useless statistics.
3. You don't always get the answer you want
3a. See post #3. Lose weight (10# for me), get stronger, ride aerodynamically and spin better.
4. Buy tires that you think make your ride more enjoyable
5. If you race, ride what your sponsor tells you
6. If you race and don't have a sponsor - you have bigger problems than tire rolling resistance
7. If you sell expensive tires, worry about RR, esp Forum gossip, totally unfounded.
Don't call me Fred, my name is 'Mr. Wildwood'. Read everyone's posts completely before 'burning' contributors or suggesting someone GTFO.
YRRMV (Your rolling resistance may vary)
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And Shimano equipment is 5 X better because they are represented in the pro peloton 5 X more than other companies (individually).
and I should apologize..., my Conti 5000s are an early version, before tubeless ready was out. With latex tubes, I have to run 80-85psi in the 5000s to have the same 'supple' feel of Vittoria & VeloFlex at 100-105. If all are 25mm = the one with the lower pressure by ~20psi will absolutely have the highest rolling resistance, tubeless ready or not.
and I should apologize..., my Conti 5000s are an early version, before tubeless ready was out. With latex tubes, I have to run 80-85psi in the 5000s to have the same 'supple' feel of Vittoria & VeloFlex at 100-105. If all are 25mm = the one with the lower pressure by ~20psi will absolutely have the highest rolling resistance, tubeless ready or not.
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0.0066 is a lot for those tires. How much has the road surface changed? Sometimes I take a photo of the road surface with my phone cam so I can keep track of the surface.
What was the drive train loss you assumed for the crank PM?
30 pounds shouldn't matter -- the calc accounts for changes in mass.
Can you describe the course and your protocol a little more? Were you wearing the same clothes (considering the 30 lb change in mass)? What was the change in CdA? An error in estimated CdA (for example, because of an error in wind estimation) of .01 m^2 is *roughly* equivalent to an error in Crr of .001, so if your estimate of CdA were .02 m^2 too low, it would make the estimated Crr in the ballpark of about .002 too high. You're kinda tall and heavy, aren't you? If so, an error in CdA of .01 m^2 might cause a slightly larger error in Crr.
What was the drive train loss you assumed for the crank PM?
30 pounds shouldn't matter -- the calc accounts for changes in mass.
Can you describe the course and your protocol a little more? Were you wearing the same clothes (considering the 30 lb change in mass)? What was the change in CdA? An error in estimated CdA (for example, because of an error in wind estimation) of .01 m^2 is *roughly* equivalent to an error in Crr of .001, so if your estimate of CdA were .02 m^2 too low, it would make the estimated Crr in the ballpark of about .002 too high. You're kinda tall and heavy, aren't you? If so, an error in CdA of .01 m^2 might cause a slightly larger error in Crr.
The road in question is a little used but scenic (Rt 29 in NJ between Frenchtown and Stockton) state highway with a wide shoulder. They use a lot of salt in winter. It looks like the tar portion of the mix suffers. Visually, it is not as smooth but it also does not have any potholes. 2 years ago, it was smooth as a baby's bottom. I wish I took photos.
I actually have the exact wheels that I tested with last time and they still have the same tires and tubes. I am going to do an ABBA test to compare. Maybe the road. But I also did a 200K where my power output should have given me faster speeds.
For those who think I am misguided, I do sometimes race and a few years ago I had my eyes on a 24 hour record. At this time, I just want to be as efficient as possible with randonneuring so that I can sleep. Randonneurs do distances of 200, 300, 400, 600, and 1200km. I am trying to qualify for Paris Brest Paris next year. Saving a couple hours would be used for sleeping.
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#22
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1a. Not comparing road race 25mm to hybrid 35s... etc
3a. See post #3. Lose weight (10# for me), get stronger, ride aerodynamically and spin better.
Last edited by HTupolev; 05-09-22 at 05:30 PM.
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In the real world -
1. rolling resistance of your tires (within a given category) is an order of magnitude less important than moving the air resistance at speed
1a. Not comparing road race 25mm to hybrid 35s... etc
2. Measuring rolling resistance with uncalibrated devices, years apart and with other variables - to judge a tire is an exercise in useless statistics.
3. You don't always get the answer you want
3a. See post #3. Lose weight (10# for me), get stronger, ride aerodynamically and spin better.
4. Buy tires that you think make your ride more enjoyable
5. If you race, ride what your sponsor tells you
6. If you race and don't have a sponsor - you have bigger problems than tire rolling resistance
7. If you sell expensive tires, worry about RR, esp Forum gossip, totally unfounded.
Don't call me Fred, my name is 'Mr. Wildwood'. Read everyone's posts completely before 'burning' contributors or suggesting someone GTFO.
YRRMV (Your rolling resistance may vary)
1. rolling resistance of your tires (within a given category) is an order of magnitude less important than moving the air resistance at speed
1a. Not comparing road race 25mm to hybrid 35s... etc
2. Measuring rolling resistance with uncalibrated devices, years apart and with other variables - to judge a tire is an exercise in useless statistics.
3. You don't always get the answer you want
3a. See post #3. Lose weight (10# for me), get stronger, ride aerodynamically and spin better.
4. Buy tires that you think make your ride more enjoyable
5. If you race, ride what your sponsor tells you
6. If you race and don't have a sponsor - you have bigger problems than tire rolling resistance
7. If you sell expensive tires, worry about RR, esp Forum gossip, totally unfounded.
Don't call me Fred, my name is 'Mr. Wildwood'. Read everyone's posts completely before 'burning' contributors or suggesting someone GTFO.
YRRMV (Your rolling resistance may vary)
The reason was I did not want to chase my tail. If it isn't the tires, it is bearings but very doubtful, probably the road. Doubtful the tires. Possibly too much sealant inside. In any case, I am quite confident I can make improvements.
I know how to run experiments. I spent a good part of my career running or reviewing experimental results. I accept large error bars around my Crr 0.0066 point estimate (N =2). I had been suspecting friction somewhere on my bike was excessive. Yes, I have much bigger problems. You all know that. I also accept that. I just want to use as little energy as possible to go long distances. Why do you have a problem with that? I also enjoy optimisation. Why do you have a problem with that? Going as fast as I can on as little energy as possible over many hours is appealing to me. I do not know why but it appeals to me.
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BTW.....weight should not matter. Crr is generally thought to be load and speed independant, although I somewhat disagree with that. I am fat because I have had a lot of injuries. I promise to lose the weight. Weight is taken into consideration and really cannot be much of a factor in the Crr estimation that I provided.