Bike tire rolling resistance and speed
08-02-21, 04:58 AM
#51
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Ok you are thinking of effect on wind drag. If the temperature drops from 60F to 30F, the air is 6% more dense. Air drag varies linearly with density so 6% more wind drag at the same speed. In my case, winter riding is on frozen or saturated muddy trails. Lots of energy lost in deforming the trail surface, so speed and drag are less. Also I wonder if energy lost deforming rubber and casing at the colder temperature will start to increase more than linearly?
Otto
Otto
08-02-21, 08:39 AM
#52
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I think here lies the best answer
https://www.cyclingabout.com/touring...tance-testing/
And the data is here
https://www.bicyclerollingresistance.com/tour-reviews
https://www.cyclingabout.com/touring...tance-testing/
Comparing the Schwalbe Almotion and Schwalbe Mondial there is 19.2w of extra resistance overall (two tyres). This translates to about 1.49km/h (0.93mph) slower travelling speeds on the Mondials with all things being equal (150w, 85kg total weight, flat road). Knowing the speed difference, we can determine the time differences over the course of a typical touring day using Bike Calculator*.
On A Flat 100km Route (0% Gradient)
Over 100km, the 1.49km/h drop in speed from the Mondials will add 11 minutes and 49 seconds to your cycling time (5.4% slower). To put that into perspective, carrying 30kg (66lb) extra on your touring bike would add 7 minutes to your ride time (3.2% slower) over 100km.
On A Hilly 100km Route (10km up, 10km down x5 @ 2% Gradient)
Assuming it’s hilly, rolling resistance plays an even greater role because of the lower travelling speeds. The slower Mondials add 18 minutes to your cycling time (7.0% slower). To put that in perspective, carrying 20kg (44lb) extra on your touring bike would add 17 minutes to your ride time (6.8% slower) over 100km.
On A Flat 100km Route (0% Gradient)
Over 100km, the 1.49km/h drop in speed from the Mondials will add 11 minutes and 49 seconds to your cycling time (5.4% slower). To put that into perspective, carrying 30kg (66lb) extra on your touring bike would add 7 minutes to your ride time (3.2% slower) over 100km.
On A Hilly 100km Route (10km up, 10km down x5 @ 2% Gradient)
Assuming it’s hilly, rolling resistance plays an even greater role because of the lower travelling speeds. The slower Mondials add 18 minutes to your cycling time (7.0% slower). To put that in perspective, carrying 20kg (44lb) extra on your touring bike would add 17 minutes to your ride time (6.8% slower) over 100km.
https://www.bicyclerollingresistance.com/tour-reviews
08-02-21, 01:36 PM
#53
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Amazing but is actual controlled rolling test the tire with the least rolling resistance was a 16" tire with 1.75 width.
08-02-21, 03:04 PM
#54
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I have no idea how many. I will assume 99% of cyclist don't understand wheel hub bearings and how QR plays a factor in that.
It is of no surprise that many dont see the difference in roll resistance in tires. Their QR is too tight to ever see the difference in tire performance anyways.
My opinion. Then again roll resistance is pointless, once you add in shoddy bike maintenance. Dirty chains, dirty cog wheels, cross chaining, worn out cassettes, etc...
People either understand it or they don't. If you feel the difference in roll resistance on tires, congrats on having a maintained bicycle.
It is of no surprise that many dont see the difference in roll resistance in tires. Their QR is too tight to ever see the difference in tire performance anyways.
My opinion. Then again roll resistance is pointless, once you add in shoddy bike maintenance. Dirty chains, dirty cog wheels, cross chaining, worn out cassettes, etc...
People either understand it or they don't. If you feel the difference in roll resistance on tires, congrats on having a maintained bicycle.
Also, rolling resistance isnt pointless once you factor in a worn or dirty drivetrain. If you have a dirty/worn drivetrain and slow rolling tires, you will be slower than that same drivetrain with fast rolling tires. That shows there is a difference.
08-02-21, 07:59 PM
#55
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People's QR skewers are too tight for them to notice a reduction in rolling resistance due to different tires? Yeah, I guess I am part of the 99% who are unenlightened because I dont even understand how the two are connected. A QR skewer being loose or tight doesnt change a tire's rolling resistance so of course the difference in rolling resistance could be felt regardless of QR tightness.
Also, rolling resistance isnt pointless once you factor in a worn or dirty drivetrain. If you have a dirty/worn drivetrain and slow rolling tires, you will be slower than that same drivetrain with fast rolling tires. That shows there is a difference.
Also, rolling resistance isnt pointless once you factor in a worn or dirty drivetrain. If you have a dirty/worn drivetrain and slow rolling tires, you will be slower than that same drivetrain with fast rolling tires. That shows there is a difference.
Do you span your own hubs? Maybe you run sealed bearings. Regardless, the point I am trying to make becomes more obvious with loose ball. Yet it still plays a factor with sealed bearings. There is a sweet spot for QR skewer tightness.
In my opinion drag is drag. Most people have so much mechanical drag they will write off just how huge tire rolling resistance difference can be.
Even on a roll out testing. Guys are measuring roll out in a difference of limited amounts. it could be so much more of a difference, if their hubs was in tip top shape. Even hub grease choice makes a difference.
Its not that it isn't there, its just that poor bike maintenance (knowledge) subtracts from your roll resistance gains.
Even I didn't care about cheap tires, to a degree) on my singlespeed becauseI I lost all the drag of a rear derailleur and jockey wheels with its delete.
To a degree, was impacted by riding in A group or B group.
To a degree was impacted by was it a 100 mile ride, or a 30 mile ride.
Again my point being most people wont experience the full benefit of lowering roll resistance, to fully appreciating the difference it can make.
I'd drop the "roll resistance" topic right in there with a light bike vs heavy bike. One rider says the difference is huge, while another rider says it is not so different.
08-03-21, 03:29 AM
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A typical high-performance road bicycle tire has a smooth center section devoid of any tread. When a cyclist is riding in a straight line, the lack of tread in the center section of the tire reduces rolling resistance.
Rolling resistance is measured in Watts, which is the energy the cyclist has to expend to make the tires go around and move the bicycle forward. A bicycle tire with an aggressive tread takes more energy to rotate.
This tire is Schwalbe G-One Allround Super Ground SpeedGrip. The rolling resistance of this tire is 34 watts. Two tires, front and back, have a total rolling resistance of 68 watts.
Is 68 watts good or bad rolling resistance? Depends on what you want out of a tire. If you live where there is a mixture of dirt and paved roads, this tire may be just what you need.
This is not a cheap tire and costs about $80.
I live in an area where the roads are fairly well maintained, and there is an abundance of concrete bike paths.
his is typical of a low-rolling-resistance road bike tire. These are the tires that came on my road bike. This is a Specialized S-Works Turbo RapidAir 2Bliss Ready tire in 700x32c. This tire has 9.7 watts of rolling resistance. Two tires have 19.4 watts of rolling resistance. Up to a certain point, the wider versions of any tire have less rolling resistance, than the narrow versions.
This Specialized tire is light, strong, puncture-resistant, and costs $80.
You may notice that there are some small treads on the tire sidewalls. Bicycles don’t go in straight lines. During cornering the sidewall tread improves traction, particularly if the road surface is wet.
A bicycle tire is not just a rubber band on your wheels, but complex and sophisticated technology.
The WTB Thickslick costs $33 and is intended for rough urban roads. The soft rubber compound conforms to road imperfections. My guess would be that this tire has high rolling resistance. Durability is what this tire offers, not speed.
Tire rolling resistance is not the most important factor in overall bicycling performance.
Rolling resistance is measured in Watts, which is the energy the cyclist has to expend to make the tires go around and move the bicycle forward. A bicycle tire with an aggressive tread takes more energy to rotate.
This tire is Schwalbe G-One Allround Super Ground SpeedGrip. The rolling resistance of this tire is 34 watts. Two tires, front and back, have a total rolling resistance of 68 watts.
Is 68 watts good or bad rolling resistance? Depends on what you want out of a tire. If you live where there is a mixture of dirt and paved roads, this tire may be just what you need.
This is not a cheap tire and costs about $80.
I live in an area where the roads are fairly well maintained, and there is an abundance of concrete bike paths.
his is typical of a low-rolling-resistance road bike tire. These are the tires that came on my road bike. This is a Specialized S-Works Turbo RapidAir 2Bliss Ready tire in 700x32c. This tire has 9.7 watts of rolling resistance. Two tires have 19.4 watts of rolling resistance. Up to a certain point, the wider versions of any tire have less rolling resistance, than the narrow versions.
This Specialized tire is light, strong, puncture-resistant, and costs $80.
You may notice that there are some small treads on the tire sidewalls. Bicycles don’t go in straight lines. During cornering the sidewall tread improves traction, particularly if the road surface is wet.
A bicycle tire is not just a rubber band on your wheels, but complex and sophisticated technology.
The WTB Thickslick costs $33 and is intended for rough urban roads. The soft rubber compound conforms to road imperfections. My guess would be that this tire has high rolling resistance. Durability is what this tire offers, not speed.
Tire rolling resistance is not the most important factor in overall bicycling performance.
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08-03-21, 05:34 AM
#58
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A typical high-performance road bicycle tire has a smooth center section devoid of any tread. When a cyclist is riding in a straight line, the lack of tread in the center section of the tire reduces rolling resistance.
Rolling resistance is measured in Watts, which is the energy the cyclist has to expend to make the tires go around and move the bicycle forward. A bicycle tire with an aggressive tread takes more energy to rotate.
This tire is Schwalbe G-One Allround Super Ground SpeedGrip. The rolling resistance of this tire is 34 watts. Two tires, front and back, have a total rolling resistance of 68 watts.
Is 68 watts good or bad rolling resistance? Depends on what you want out of a tire. If you live where there is a mixture of dirt and paved roads, this tire may be just what you need.
This is not a cheap tire and costs about $80.
I live in an area where the roads are fairly well maintained, and there is an abundance of concrete bike paths.
his is typical of a low-rolling-resistance road bike tire. These are the tires that came on my road bike. This is a Specialized S-Works Turbo RapidAir 2Bliss Ready tire in 700x32c. This tire has 9.7 watts of rolling resistance. Two tires have 19.4 watts of rolling resistance. Up to a certain point, the wider versions of any tire have less rolling resistance, than the narrow versions.
This Specialized tire is light, strong, puncture-resistant, and costs $80.
You may notice that there are some small treads on the tire sidewalls. Bicycles don’t go in straight lines. During cornering the sidewall tread improves traction, particularly if the road surface is wet.
A bicycle tire is not just a rubber band on your wheels, but complex and sophisticated technology.
The WTB Thickslick costs $33 and is intended for rough urban roads. The soft rubber compound conforms to road imperfections. My guess would be that this tire has high rolling resistance. Durability is what this tire offers, not speed.
Tire rolling resistance is not the most important factor in overall bicycling performance.
Rolling resistance is measured in Watts, which is the energy the cyclist has to expend to make the tires go around and move the bicycle forward. A bicycle tire with an aggressive tread takes more energy to rotate.
This tire is Schwalbe G-One Allround Super Ground SpeedGrip. The rolling resistance of this tire is 34 watts. Two tires, front and back, have a total rolling resistance of 68 watts.
Is 68 watts good or bad rolling resistance? Depends on what you want out of a tire. If you live where there is a mixture of dirt and paved roads, this tire may be just what you need.
This is not a cheap tire and costs about $80.
I live in an area where the roads are fairly well maintained, and there is an abundance of concrete bike paths.
his is typical of a low-rolling-resistance road bike tire. These are the tires that came on my road bike. This is a Specialized S-Works Turbo RapidAir 2Bliss Ready tire in 700x32c. This tire has 9.7 watts of rolling resistance. Two tires have 19.4 watts of rolling resistance. Up to a certain point, the wider versions of any tire have less rolling resistance, than the narrow versions.
This Specialized tire is light, strong, puncture-resistant, and costs $80.
You may notice that there are some small treads on the tire sidewalls. Bicycles don’t go in straight lines. During cornering the sidewall tread improves traction, particularly if the road surface is wet.
A bicycle tire is not just a rubber band on your wheels, but complex and sophisticated technology.
The WTB Thickslick costs $33 and is intended for rough urban roads. The soft rubber compound conforms to road imperfections. My guess would be that this tire has high rolling resistance. Durability is what this tire offers, not speed.
Tire rolling resistance is not the most important factor in overall bicycling performance.
If you can get one point, rolling resistance is not a fixed quantity in watts. The total resistance and the actual coefficient varies by speed, temperature, rider weight, road condition, temperature, the type of tube used, pressure, how worn the tire is, rubber compound, casing construction and many other factors, some in your control.
The OP posed a naive question. 20 watts of rolling resistance for slow tire would come at about 7 mph and 10 watts would come at about 3.5 mph (Crr of 0.008) whereas for a fast tire like GP5000 with latex tubes (Crr of 0.004 on good roads), the speeds would be more like 7 mph and 13 mph.
Put another way, it would take around 50 watts to travel at 10 mph on slow tires. If you put the GP5000 with latex tubes on, the same 50 watts will get you nearly 12 mph. There is not a single other improvement one can make to a bike, other than e-assist, to get you from 10 to 12 MPH with the same power....unless one's chain is filthy
