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Rolling resistance of tires - a thread

Old 03-29-11, 04:16 PM
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I_like_cereal
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Rolling resistance of tires - a thread

I run 23c Armadillos on my roadie. I have been reading that they have a high rolling resistance. I emailed Specialized and asked them if they had white papers on their testing data for rolling resistance or at least something to give me a benchmark to compare 'dillos to other tires.

This is the response:
I'm not sure what you are looking for exactly, sorry. We do not have a quantitative rolling resistance value for the tire if that is what you are looking for... sorry. If you would like to compare it with other models, I can give you an educated guess as to which tire will have more or less rolling resistance in comparison.... if you have any further questions, feel free to write back or call.

No quantitative data and an educated guess.

I read somewhere that there is an independent company in Sweden or Norway that is testing tires for rolling resistance.

Does anyone have any analysis of rolling resistance of certain tires? Does anyone know if any manufacturer has this information or if they just say this model rolls faster than this model.

Thanks in advance.
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Old 03-29-11, 04:34 PM
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Go look at the Continental website, they used to have a comparsion of high performance clinchers....but suffice to say low rolling resistance requires a very supple sidewall and tread....and GP4000s were the winner
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Old 03-29-11, 04:34 PM
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While rolling resistance is a quantity exhibited by a tire it is not necessarily inherent to the tire. In addition to tire construction, the rolling resistance exhibited by any particular tire is also influenced by:
-road surface
-tire pressure
-rider weight
-temperature
-the tube used
-the rim used
...among other things

I would not be at all surprised if (for most tires) tire A was measured to have lower rolling resistance than tire B under certain conditions, but higher rolling resistance under a different set of conditions. The world is stranger than you can ever imagine.
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Old 03-29-11, 04:35 PM
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It's true that is a measure of rolling resistance in all tires as well as anything else that rolls or moves. That said, rolling resistance can also be affected by how much air PSI is run in any tire. Soft tires take A LOT more energy to move than proper inflated or hard pumped tires.

It has to do with tire flex.

http://en.wikipedia.org/wiki/Rolling_resistance

"A characteristic of a deformable material such that the energy of deformation is greater than the energy of recovery. The rubber compound in a tire exhibits hysteresis. As the tire rotates under the weight of the vehicle, it experiences repeated cycles of deformation and recovery, and it dissipates the hysteresis energy loss as heat. Hysteresis is the main cause of energy loss associated with rolling resistance and is attributed to the viscoelastic characteristics of the rubber."


http://www.terrymorse.com/bike/rolres.html

http://www.sheldonbrown.com/tires.html

http://www.bicycletires.com/a_49/tire_width/article.htm

In general, I always run my tires pumped up really hard to cut Rolling resistance by cutting down on tire flex. This makes for a really hard butt busting ride (all my bikes have sprung saddles) by it also makes the bike and me much easier to move.
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Old 03-29-11, 05:38 PM
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The more that I learn about bicycle tire rolling resistance, the more interesting it becomes. A LOT of the ideas that we have intuitively aren't true.

1. As you weight a tire and ride down the road the tire flattens in a front-to-back direction. Now take a bare tire and try to flatten it with your fingers. The resistance that you feel with your fingers is energy that has to come from somewhere and is lost as you ride. That's rolling resistance. The obvious way to reduce rolling resistance is to produce a tire that has super suple sidewalls and requires less energy to deform.

Specialized Armadillos may be the poster child for super stiff sidewalls so they're going to have a lot of rolling resistance. Depending on where you ride however and if you count the time that you spend fixing flats, Armadillos may still get you to your destination sooner because Armadillos are VERY flat resistant. Tire selection is an exercise of trades and balances.

2. Intuitively, many folks think that skinny tires will necessarily have lower rolling resistance than fatter tires. If everything else is equal, that's not true. A skinny tire AT THE SAME AIR PRESSURE will deform more front-to-back than a wider tire. Since this deformation is what causes rolling resistance, a skinny tire will have higher rolling resistance.

Of course, it's never that simple. Skinny tires have fewer square inches of sidewall so they can safely handle more air pressure. As a general rule, bike riders use more air pressure with skinny tires which negates the rolling resistance advantage of wider tires. I think that most riders are looking at the wrong side of the equation. If everything else is equal, a wider tire will yield EQUAL rolling resistance at a LOWER air pressure. The lower air pressure will also yield a more pleasant ride.

3. So it looks like rock hard air pressure will win the rolling resistance war. That's true so far as rolling resistance goes, but it's not necessarily going to be faster. A rock hard tire is going to bounce upward more over every tiny little bump. The energy that's required to lift the bike upward over each bump has to come from somewhere. On a bicycle, that's ultimately always comes from the rider. Too much air pressure for the road condition slows you down.

4. As I was watching the Tour de France a few years ago, Phil Ligget commented the riders use about 115 psi tire air pressure. Assuming that's true, that's good enough for me. I use wider tires, however, so I use a little less air pressure than that.
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Old 03-29-11, 05:44 PM
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Actually, Specialized is a client of Wheel Energy Laboratories, so they do have qualitative data, although perhaps none that they're willing to share, or for that particular variant of Armadillo.

See stories here, http://www.bikeradar.com/gear/articl...e-myths-29245/ and here, http://www.cyclingnews.com/features/...f-wheel-energy. Also on page 62 of the February 2011 issue of Peloton Magazine.
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Old 03-29-11, 07:14 PM
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Originally Posted by Retro Grouch View Post
2. Intuitively, many folks think that skinny tires will necessarily have lower rolling resistance than fatter tires. If everything else is equal, that's not true. A skinny tire AT THE SAME AIR PRESSURE will deform more front-to-back than a wider tire. Since this deformation is what causes rolling resistance, a skinny tire will have higher rolling resistance.

Of course, it's never that simple. Skinny tires have fewer square inches of sidewall so they can safely handle more air pressure. As a general rule, bike riders use more air pressure with skinny tires which negates the rolling resistance advantage of wider tires. I think that most riders are looking at the wrong side of the equation. If everything else is equal, a wider tire will yield EQUAL rolling resistance at a LOWER air pressure. The lower air pressure will also yield a more pleasant ride.
The fatter tyre will also have more braking and turning grip, all things being equal. That's why the tyre lab referred to advised running wider rubber for crits than for TTs.

It's also important to note that

1. As roads get rougher wider lower pressure tyres reduce energy lost to vibration: this is why quite a few European racing teams use cyclocross bikes or special models of road bike that can take 28s for the rougher stages of road races. (This is close to RGs #3)

2. Most of the work a rider does at max speed on the flat is against air resistance. The faster you go, the more this applies.

In practice, if you can run them, the best tyre for an activity like commuting or touring is something like a Marathon Supreme in 35-40mm. Lots of grip, good puncture resistance, low RR at a sensible pressure.

Last edited by meanwhile; 03-29-11 at 07:23 PM.
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Old 03-29-11, 07:19 PM
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Originally Posted by tsl View Post
Actually, Specialized is a client of Wheel Energy Laboratories, so they do have qualitative data, although perhaps none that they're willing to share, or for that particular variant of Armadillo.

See stories here, http://www.bikeradar.com/gear/articl...e-myths-29245/ and here, http://www.cyclingnews.com/features/...f-wheel-energy. Also on page 62 of the February 2011 issue of Peloton Magazine.

The Dillo maybe the slowest tyre in existence; I'm not surprised Spesh won't share.

Tour Magazine (a German publication) occasionally does very... German tyre tests. RR, grip, etc. There's an example here:

http://www.conti-online.com/generato...gp4000s_en.pdf
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Old 03-29-11, 07:26 PM
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Originally Posted by Nightshade View Post
In general, I always run my tires pumped up really hard to cut Rolling resistance by cutting down on tire flex. This makes for a really hard butt busting ride (all my bikes have sprung saddles) by it also makes the bike and me much easier to move.
This is probably a losing strategy. If the ride is such that you need a sprung saddle than RG's point 3 is coming into play and you're talking energy losses from vibration.
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Old 03-30-11, 07:41 AM
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I've got *****s on one of my bikes left over from when I was riding in CA where with other tires I'd sometimes flat multiple times on a single ride due to thorns. I've found the rolling resistance of properly inflated *****s to be much less than other tires that were flat. Since relocating to wild and wooly New England, pinch flats from post winter potholes and bad pavement have supplanted thorns.
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Old 03-30-11, 08:56 AM
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Originally Posted by meanwhile View Post
In practice, if you can run them, the best tyre for an activity like commuting or touring is something like a Marathon Supreme in 35-40mm. Lots of grip, good puncture resistance, low RR at a sensible pressure.
i think it's foolish to claim that there is a "best" way to do anything in the cycling world because so much of it comes down to individual riding situations and good old fashioned personal preference. you may indeed find that a 35-40mm tire with lots of grip, good puncture resistance, and low RR at a sensible pressure, is the "best" for your commuting purposes, but i have found just the opposite to be true for me. i used to run big apples at 70psi on my old commuter, and that worked for awhile, but then i got a true road bike and started commuting on it with my rubino pro 23s inflated to 135psi, and it was like a cycling reawakening. there is no way in hell i would ever want to go back to some soft, spongy tire for my daily commute if i don't have to*. i love the feeling of riding on a steel rail. it may be uncomfortable at times, but comfort is for old people; i'm not there yet. also, a HUGE chunk of my daily commute is a smooth as silk MUP where i don't even have to touch the brake levers for 8 miles, so, yeah.



* in winter i do switch back to a much softer, studded snow tire that i run on my winter bike, but that's because i'm forced to because rubino pro 23s at 135psi simply don't work on snow and ice (also, the road bike won't take fenders)

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Old 03-30-11, 09:43 AM
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Originally Posted by tsl View Post
Actually, Specialized is a client of Wheel Energy Laboratories, so they do have qualitative data, although perhaps none that they're willing to share, or for that particular variant of Armadillo.

See stories here, http://www.bikeradar.com/gear/articl...e-myths-29245/ and here, http://www.cyclingnews.com/features/...f-wheel-energy. Also on page 62 of the February 2011 issue of Peloton Magazine.
Now if they would only publish the data we as cyclists would have a better idea about our tire selection and it would force companies to improve the design not just reinvent and slap a new name on it.
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Old 03-30-11, 10:03 AM
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I have three bikes, road, mountain & hybrid. The road has 23s at 100 psi, the hybrid has 28s at 100 psi, and the mountain bike is using off-road tires inflated to 60 psi. The road bike is the fastest, but when I am in areas of bad pavement, I have to slow down & be more careful. The MTB is compromised, but road hazards are no concern. The hybrid works on all road surfaces decently.

Horses for courses. What road surfaces are you trying to make time on? Based on another post you made I believe you are trying to speed up your commute. My personal choice for a high speed commuter would be 28s on a cyclocross bike. One flat tire will slow you down more than anything.
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Old 03-30-11, 10:36 AM
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Not really trying to speed anything up. I am just a knowledge junkie. I like to make informed decisions on the stuff I buy. I figure if I am going to drop $60 -$70 per tire I want to know what I am getting for that money.

You would't buy a car just because someone said it was this or that without any proof to back the claim up. I bought the 'dillos cause I wanted something rock solid to commute on because changing flats in the rain sucks and I grew tired of it after the third puncture flat in two days. I understood the trade offs, but if I want to replace them I would like to do so for a similar tire that has a little less rolling resistance. Yes I will be going back to 25s.
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Old 03-30-11, 11:35 AM
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I've decided that tires are an art, not a science. I'm looking for an off-road capable tire that works in the street. And doesn't cost too much.
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Old 03-30-11, 11:41 AM
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The higher the thread count on a tire,the better it rolls.The hump in front of the tire contact patch is smaller.Works the same on automotive tires also.
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Old 03-30-11, 11:46 AM
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Originally Posted by Flying Merkel View Post
I'm looking for an off-road capable tire that works in the street. And doesn't cost too much.
"Off road capable" is another interesting concept.

I wonder how much the tread that you see on even mountain bike tires really matters. I know that it matters on big rocks and in the mud. On hard packed dirt or on a crushed limestone trail, I'd just as soon use a slick.
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Old 03-30-11, 02:27 PM
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Bicycle Quarterly Magazine tested a number of tires for rolling resistance a couple of years ago. The old issues are not on the web for free so you have to dig up an old hard copy. The surprising result was that width is not the only determinent for rolling resistence. Some wider tires were faster than narrow tires in roll down tests. On their web site you can find some interesting observations by Jan Heine on tire width; www.bicyclequaterly.com.

Whether wide tires are faster or not, they are more comfortable. Right now I have Panaracer Col de la Vie 650B (684x38) on a Univega conversion, and find that they absorb road shocks great. New England roads are not much smoother than dirt now.
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Old 03-30-11, 03:22 PM
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Originally Posted by Retro Grouch View Post
"Off road capable" is another interesting concept.

I wonder how much the tread that you see on even mountain bike tires really matters. I know that it matters on big rocks and in the mud. On hard packed dirt or on a crushed limestone trail, I'd just as soon use a slick.
Trust me, tread matters.

A couple years ago, I ran Intense Micro Knobby 2.25's on my MTB; they were awesome on smooth surfaces, horrid under any other conditions. GRAVEL would defeat them. Last year and again this spring, I'm running Michelin Country Dry 2.15's. Not a real aggressive tread, but worlds better in varied conditions, and almost as good as the Micro's on pavement. Both roll best at about 60psi.

Hard-packed dirt is essentially the same as pavement, in my experience; hit some mud, though, even just moist dirt, and the Micro will spin out in unpredictable ways. Grass, too. The Michelin will handle both.
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Old 03-30-11, 05:16 PM
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I'm looking for an off-road capable tire that works in the street.
Trekking type Continental Travel Contact 622-35, or 559 47

Cheaper: WTB Allterainasaurus , not the lowest rolling resistance , given all tread blocks move .

a slick tire or one with a continuous slick center band helps ..
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Old 03-30-11, 07:12 PM
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Originally Posted by fietsbob View Post
Trekking type Continental Travel Contact 622-35, or 559 47

Cheaper: WTB Allterainasaurus , not the lowest rolling resistance , given all tread blocks move .

a slick tire or one with a continuous slick center band helps ..

I'm using a Kenda cross tire in front. Not good at anything other than straight line pavement. Scary in the mud conditions we have now, scarier leaning over too far on pavement. Will check out the others though; thanks.
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Old 03-30-11, 07:25 PM
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Originally Posted by Steely Dan View Post
i think it's foolish to claim that there is a "best" way to do anything in the cycling world because so much of it comes down to individual riding situations and good old fashioned personal preference. you may indeed find that a 35-40mm tire with lots of grip, good puncture resistance, and low RR at a sensible pressure, is the "best" for your commuting purposes, but i have found just the opposite to be true for me. i used to run big apples at 70psi on my old commuter, and that worked for awhile, but then i got a true road bike and started commuting on it with my rubino pro 23s inflated to 135psi, and it was like a cycling reawakening.
Yes, you prefer 23s - but so what?

I'm talking about a reasonable OBJECTIVE best, not what fits your emotional needs. The 23s you're running have appalling grip compared to a larger tyre and aren't actually bringing you any benefits. It should tell you something that the tyre testing lab articles say that they're too narrow even to be a good choice for crit racing...

If a crosser with 40mm Supremes will run as fast as your road bike with 23s at the wattage you use for commuting, brake and turn faster, handle pot holes better and puncture less (and all of these things are true) then, for that purpose, the 40 is a better tyre. You might not like it as much, but these are different things. Lesson in basic logic and English: Don't confuse "Best" with "What I like most." Objectively, a 23mm tyre is inferior to a 40mm tyre made of race grade rubber like the Supreme.

Last edited by meanwhile; 03-30-11 at 08:03 PM.
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Old 03-30-11, 08:06 PM
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Originally Posted by Flying Merkel View Post
I've decided that tires are an art, not a science. I'm looking for an off-road capable tire that works in the street. And doesn't cost too much.
There's no such thing as just "off-road." Tyres for heavy mud are very different to tyres for gravel or hard pack. Any tyre that was really good in mud would be dangerous on the road - the teeth at the side needed for cornering in mud cause "walking" while cornering on hard stuff. Not good...
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Old 03-30-11, 08:53 PM
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Originally Posted by meanwhile View Post
If a crosser with 40mm Supremes will run as fast as your road bike with 23s at the wattage you use for commuting, brake and turn faster, handle pot holes better and puncture less (and all of these things are true) then, for that purpose, the 40 is a better tyre. You might not like it as much, but these are different things. Lesson in basic logic and English: Don't confuse "Best" with "What I like most." Objectively, a 23mm tyre is inferior to a 40mm tyre made of race grade rubber like the Supreme.
You're leaving out the weights though. There are a lot of things which could be made better on a bike if you're willing to deal with a substantial increase in weight...but the end result would be a bike that weighs 40 pounds.

So you have to cut corners somewhere: spoked wheels instead of solid wheels, skinny tires instead of wide ones, a frame that can only hold 300 pounds instead of 600 pounds, nonenclosed drivetrains, etc, etc. Given all the stop and go accelerations encountered by a commuter, I'm of the opinion that commuting bikes benefit from lightness more than any other; So if there is a place where the skinny tire compromise would be worthwhile I think it would be in the context of commuting.

BTW, extra weight results in lost energy for the same reason that hard tires bouncing/vibrating results in lost energy. While in theory the energy is returned after a little round trip, in reality it encounters inefficiencies along that path which result in net losses. It's the "bird in the hand is worth two in the bush" principle.

An unfortunate fact of science is that often the things which are objectively measured are merely the things which are easy to measure as opposed to the things which should be measured.

Originally Posted by tsl View Post
Actually, Specialized is a client of Wheel Energy Laboratories, so they do have qualitative data, although perhaps none that they're willing to share, or for that particular variant of Armadillo.
Or maybe they don't think the experiments are very informative? This particular technique for measuring rolling resistance has been harshly criticized:

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Old 03-30-11, 09:55 PM
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At some point there has to be some practical decisions made about rolling resistance. Once an optimal tire construction has been realized, rolling resistance will be pretty much determined by the that expendable rubber compound used on the outside of the tire. And there things are not much different than rollerblade wheels, motorcycle tires or car tires. A harder rubber compound will last longer and have less rolling resistance. It`ll also have increasingly poor braking and cornering performance as the hardness index increases.

Personally I`ll take better braking performance and cornering ability over a bit of reduced rolling resistance any day. As has been pointed out - at some point rider aerodynamics has more of an impact than tire rolling resistance anyway. At practical speeds - driving control over a variety of conditions and circumstances is a lot more important to me.

And those Schwalbe Marathon Supremes look really good - weight wise, protection wise and performance wise.
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