I don't think you'll see a measurable difference on the road. They're both good tires. But you will be wearing out a nice expensive tire on the trainer. Buy a cheap wire bead tire for the trainer.

don't worry.....the ones I use are really knackered now.....but I did test a new pair of each to check on the noise issue....I was just wondering.

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Stephen Perera
Gibraltar, Europe
graphics@gibraltar.gi

Hmm. I think some Continentals use a silica-additive in their rubber according to their sales literature. I wonder if that has something to do with it.

Either way, I agree the two tire brands feel a lot different on the road.

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Tom Demerly
The Tri Shop.com

I've ridden a lot of miles on both tires, and noted the same noise issue. I personally feel faster on the Pro Race, and the GP3000 has a ridiculously harsh ride in comparison. I don't know that the difference between them is likely to be significant in rolling resistance, most modern race tires are overall very similar. Unfortunately there is very little printed, nonbiased data on this. Sort of like the argument against 700x20c tires because they supposedly have more rolling resistance than 700x25c.

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Do you have a race wheelset? If yes and that's your training wheels you are talking about don't make a big deal of it... the more friction in training the better :P

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http://twitter.com/krepster || http://www.pedro-gomes.com || follow all the action on facebook

I had a really noisy Conti on my CT and it drove me nuts. I was advised to buy some Belt Lube from a hardware store. Fixed the problem instantly. Guess I go faster now as I'm all lubed up. :-)

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Graham Wilson
USAT Level III Elite Coach
http://www.thewilsongroup.biz

sperera,

The short answer, yes. Energy/power is consumed to generate the additional noise. This is power that would have been available for moving forward if it were not consumed making louder noise.

However, it is probably only a watt or two. It is probably not noticible realistically, other than the noise.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

thanks for all your replies....yes, neither feel faster than the other on the road of course...

but if like me the noise drives you nuts when training indoors the best tyre is definately the Michelin Pro Race......really quiet tyre.

There you are....there is a conclusion to this after all.

How about this for an ad:

"For indoor trainers....choose Michelin Pro Race tyres....they're miles quieter!"

hahahahahhahaa

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Stephen Perera
Gibraltar, Europe
graphics@gibraltar.gi

Though sound does require energy to generate it, there is no way of knowing whether both tires are losing the same energy and vibrate in different ways, thus are audible as sound or might be non-audible vibration. There also might be other variations that would account for equally performing tires. For example, one might be a little stiffer (the conti) and so vibrates less, but may have lateral compression. The mich is suppler and so vibrates at an audible wavelength but doesn't have the side compression. I would bet the rent, that the power loss in both tires is negligible. Thinking that it might be a few watts, or that the energy consumed to create sound might be "1 or 2 watts" is preposterous. That amount of energy dedicated solely to producing sound would likely be more than you could handle.

Softride has an interesting method of testing rolling resistance on their website. It is something of a rolldown taking you bike from 15mph to 1mph and measuring distance. Maybe try it with your tires.

Quote: "Thinking that it might be a few watts, or that the energy consumed to create sound might be "1 or 2 watts" is preposterous. That amount of energy dedicated solely to producing sound would likely be more than you could handle."




BenDavis,

Thank you for your contention, but I will respectfully disagree.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

Quote: "Thinking that it might be a few watts, or that the energy consumed to create sound might be "1 or 2 watts" is preposterous. That amount of energy dedicated solely to producing sound would likely be more than you could handle."

Reply: Thank you for your contention, but I will respectfully disagree.

***

I don't mean to contend, but simply clarify the potential of energy. The concept of a few watts generating the sound of a squeaking tire is very questionable. I will wholeheartedly agree that there are many many watts lost to rolling resistance. Lots of forces act to provide this resistance, but the energy wasted in vibration translated to audible sound is so miniscule. Here's an example.

Go to RadioShack and buy a device that converts energy to sound. Make sure it at least similar in frequency to the squaeky tire. Check it's power rating. It will look something like this. "Buzzer operates on 7-14VDC, carrying 150mA current maximum. Buzzer tone rated at 2,400-3,700Hz."
The sound range is pretty comparable, so do the math. Even at maximum output, and maximum voltage (which the buzzer doesn't operate on), you are looking at 150mA or .15A running @14V. 0.15 x 14 = 2.1 watts. That's 2.1 watts to generate a 110 decibel sound. That's like riding your bike with a beeping smoke detector hooked up to it.

Sure, there is a sound producing efficiency discrepancy between a tire and a speaker, but as my original post stated "energy dedicated solely to producing sound", ie, as efficient as the speaker, "would likely be more than you could handle". Feel free to disagree. I hope your bike isn't this loud.

Quote: "Sure, there is a sound producing efficiency discrepancy between a tire and a speaker, but as my original post stated "energy dedicated solely to producing sound", ie, as efficient as the speaker, "would likely be more than you could handle".




BenDavis,

You can go to Radio Shack. I will go for a bike ride.

As you indicated, the scenario you described to electrically generate sound is much more efficient than a tire on a roller.

For sperera's real world example, we cannot discount the inefficiencies of producing sound in this manner simply because it is convenient or because the inefficiencies are difficult to quantitatively measure. They exist, nonetheless, in the real world

For these reasons and others, I still believe my estimate to be reasonably accurate in the real world.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

I agree, inefficiencies are difficult to quantitatively measure. But there are better ways than using generated sound. I think that is what I am getting at. My biggest problem with 'sound only' is this. If I ride outside and put my bike on my trainer, it is relatively quiet. If I take off my wheel, clean it with a rag, and then put it back on the trainer, it squaeks like a field mouse in a vice. I can't imagine that this difference in sound is increased rolling resistance due to a cleaner wheel. It is probably mostly due to compressed rubber against a flawless metal surface not being able to easily uncompress, and under friction screeching as it uncompresses. If this is the case then the compression problem would manifest itself on flawless surfaces only, like trainers, velodromes, etc. So where you might loose efficiency ie, energy as sound) on a trainer (whether it is 3 watts or .3 watts), you woldn't on a normal road. Exactly why your bike doesn't make noise on the road like that.

As for "the innefficiencies being difficult to quantitatively measure". They are not. My original post was about sound only, and it's correlation to rolling resistance. It is entirely possible, with a decibal meter, to find out the amount of energy that a squeaking bike is producing as sound only, and then mathematically derive the amount of wattage required to produce said sound. The problem with correlating sound only, WITHOUT all of the other non-audible vibration, compression, and frictions, as it affects rolling resistance is that the original poster wondered if sound and rolling resistance were directly proportional. There is too much to the equation being left out. The only way to have a better idea, would be to test the sound in both tires, and then perform some other tested/reliable rolling resistance test. (ie, rolldown on a trainer after finding the bearing, and momentum equivalency of the two wheels, or a real world rolldown test.) That, coupled with the fact that sound itself (not including other factors: compression, inflection, friction, etc.) does not comsume that much energy in comparison to the other factors that are drastically affecting rolling resistance.

BUT...

I really don't want to argue, I am fine if we disagree. I am just trying to provide some limited science to figure out an answer to a problem. I am not trying to battle, but instead enlighten. So I think in response to your original question, that trainer squeak has zero correlation with real world rolling resistance. I have tried to explain why not. I would be interested in scientific terms why you beleive the opposite. Though, since a reputable bike manufacturer claims to have found an accurate way of measuring rolling resistance, I would probably try their method, and not use sound as a rolling resistance gauge.

That was too long. Here it is short.

Quote: "does this mean the Michelin is a faster tyre cos less noise means less friction i.e. it rolls better?"

No. Just 'cos' there is less noise that doesn't mean there is less friction. Sure, less noise means less energy lost as noise, but that doesn't directly mean less overall energy lost becuase you have to account for all the other things that rubber on a 'tyre' does. All these other things can't be easily measured. Your time would be better spent finding another method of measuring rolling resistance or using one already used by an existing bike manufacturer.

Quote: "So I think in response to your original question,that trainer squeak has zero correlation with real world rolling resistance. I have tried to explain why not. I would be interested in scientific terms why you beleive the opposite."





BenDavis,

Scientifically, all other things being equal, a noisy tire is consuming more energy than a quiet tire.

Now, I will agree that there is probably no way to equalize all other factors between two different tires.

An interesting test, however, would be a roll down test on a computrainer. One would have to set the press on force exaclty the same on both tires. This may require a little effort, but it is not impossible. Then one would peddle to generate a specfic number of watts of power. The higher the number of watts, the more accurate the test would be. One would then time the roll down to a stop. The tire with the lower rolling resistance would take the longer time to stop. With each tire, one would repeat the test and average the times to increase accuracy.

However, this would only determine the tire with the lower rolling resistance, not necessarily the quieter tire. In fact, the louder tire may turn out to have a lower rolling resistance. You indicated possible factors that could contribute to this possiblity.

Your example regarding the cleaning of the tire and presuming that this reduces friction is more than likely an incorrect presumption. Rather than reduce friction, cleaning the tire actually increases friction. By cleaning the wheel, you are increasing the coefficient of friction while at the same time reduced the likelihood of slipping between the tire and the roller by removing the dust and other foreign matter that can contribute to tire slip.

In summary, the short answer is the noisy tire consumes more energy than the quiet tire, all other things being equal. I will agree, as I indicated previously, that the energy consumed in generating the noise is relatively small and could approach a point of insignificance in terms of measuring its effect on rolling resistance.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.

Does anyone have a computrainer and a few hours to spare. I'd love to find out which has better rolling resistance, between the conti and the michelin. I think they are probably the most common tri tires, and I'm surprised that the manufacturers don't try to outdo one another with stats like this.

I've ridden both tires. The conti is faster, harder, and harsher. The Michelin is softer, slower, but better in corners. That's my impression for what it's worth.

-Robert

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"How wonderful it is that nobody need wait a single moment before starting to improve the world." ~Anne Frank

BenDavis,

I have a Computrainer and both Continental Grand Prix 3000 tires and Michelin Axial Pro tires. But I do not have any Axial Pro Race or Pro Race tires and am not presently interested in investing $50 each for two tires to run the test. The "test" would not take a couple of hours. Probably less than 30 minutes if that, oh, I forgaot about changing tires. Okay, maybe an hour max.

Now you might think that one only needs one tire, for the rear wheel to do the test, but if the results indicate this is the tire to ride, then one needs a second tire for the front! So, the short of it is, my "charge" for performing such a test would be two new Michelin Pro Race or Axial Pro Race tires.

I have never ridden Michelin Pro Race or Axial Pro Race tires. I have raced on Continental Supersonics so I am mildly curious if Michelin's are any better (faster) or worse. The Continentals have a much higher pressure rating than the Michelins so there is also the lower pressure softer tire deforms to imperfection is road issue versus higher pressure tire deforms less and bounces more losing contact with the road. This could be more of an issue on a technical course. If someone wants to "donate" a pair of new Michelins, I'll do a roll down test and let you know the results as well as the test protocol.

FWIW.

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Ben Cline


Better to aspire to Greatness and fail, than to not challenge one's self at all, and succeed.