The other day I replaced my stock tires on my trek 2100 which were bontrager race lite 700x25c to Michelin Pro Race 700x23c and My first ride on the new tires on a 26 mile route that I ride regularly turned out to be my fastest time to date on that route here's the numbers on my old tires: Avg speed 15,max speed 35.3, time-1.44.11 then on my new tires first ride : Avg speed-16.8mph,max speed-36.5mph,time-1.33.49 shaving nearly 11 minutes off my avg time!!!! So I am in awe and refuse to believe that tires can make that big a difference so I go for a 26 mile ride today same route similar weather avg speed-16.5mph, max speed-36mph,time-1.35.33 nearly identical to my previous days ride it's gotta be the tires. I just thought that was interesting and figured I would share it.

PHX

The Pro Race 2 has one of the lowest coefficients of rolling resistance. If you go from a tire that has a poor Crr to a fast tire, the difference can be quantifiable.

The Pro Race 2 has one of the lowest coefficients of rolling resistance. If you go from a tire that has a poor Crr to a fast tire, the difference can be quantifiable.

Quantifiable and 1.5 mph are completely different things. I've never heard of credible data that suggests that tires (in the same performance category) can give even 0.1 mph.

i suppose on a technical course better tires could easily make a 1-1.5mph difference if they inspired more confidence and better cornering. But that would have to be an awfully technical course where you are constantly pushing the limits the whole time -- not really a typical training loop.

Did you update the speedometer from 25c to 23c?

That was my thought too. I don't think it will make a 1.5mph difference but it will give false readings...

Quantifiable and 1.5 mph are completely different things. I've never heard of credible data that suggests that tires (in the same performance category) can give even 0.1 mph.

It isn't likely that 1.5 mph is due to different tires... but it could be a *lot* more than 0.1 mph!

Here is some data from an Oct-2005 test done by Tour. The last number
is the difference in speed relative to the best tire. There is a 1 mph spread between the fastest and slowest tire.

Tire Crr Speed* Delta

Deda Tre Giro d'Italia 0.0038 23.08
Vittoria Open Corsa Evo CX 0.0039 23.05 0.03
Michelin Pro 2 Race 0.0042 22.96 0.12
Vittoria Diamante Pro Rain 0.0044 22.90 0.18
Michelin Megamium 2 0.0047 22.81 0.27
Pariba Revolution 0.0048 22.78 0.30
Michelin Carbon 0.0050 22.72 0.36
Panaracer Stradius Pro 0.0051 22.69 0.39
Schwalbe Stelvio Plus 0.0052 22.66 0.42
Schwalbe Stelvio Evolution Front 0.0056 22.54 0.54
Continental GP Force (rear) 0.0057 22.51 0.57
Hutchinson Fusion 0.0057 22.51 0.57
Schwalbe Stelvio Evolution Rear 0.0057 22.51 0.57
Continental Ultra GatorSkin 0.0058 22.48 0.60
Ritchey Pro Race Slick WCS 0.0058 22.48 0.60
Schwalbe Stelvio 0.0059 22.45 0.63
Specialized S-Works Mondo 0.0061 22.39 0.69
Continental GP 3000 0.0067 22.21 0.87
Hutchinson Top Speed 0.0069 22.15 0.93
Continental GP Attack (front) 0.0073 22.04 1.04

*
in MPH
185lb rider + bike
250W rider output
CdA = .32m^2 (racing crouch, normal road bike)
Transmission efficiency = 96%

I've had similar experience with the OP. the standard stock tyres on my bike was specialized mondo. after three punctures, all within one month, i decided to switch to kenda kaliente. there was a noticeable drop in my average speed. on one of my standard routes, my average speed dropped from 25.2km/h to 24.5km/h. in fact, the first day i had them on, i could actually feel that i had to exert more energy to maintain a respectable pace, which proved to be quite tiring after a while.

after a while, then i decided to switch to michelin pro2 race, primarily for longer rides, and there was a noticeable difference. the michelins rolled a lot better and felt more effortless.

recently, i upgraded my wheelset - campy protons with michelin pro2 race. the kenda went back on the stock wheelset alex AT400. on one of my longer training route, the AT400/kenda combo had an average speed of 24.8km/h. the protons/michelin on the same route was 25.7km/h. yes, i accept that the protons are a significant step up from the AT400 but i would maintain the view that tyres do make a difference in my experience. disagree if you like. we each have different experiences and this is just my experience.

boon

Did you update the speedometer from 25c to 23c?

Thanks everyone for raining on my parade and bringing me back to earth, and thankyou for reminding me to update the tire size on my computer. I am sure that that is part of it and when I am able to ride that route probably tomorrow with the updated info in my computer I will repost , I will also set my stopwatch as well so I can verify the data and see if there was in fact an improvement. I do see that the mileage was slightly off from the tire change without updating the computer, on the old tires the distance was 26.18 miles and after the tire change the distance was 26.33 miles, I will post an update after my next ride. And to those of you that could only reply that it was BS, well I did not, nor would I post, anything intentionally misleading or false. And thankyou to those of you who put some thought into what could have effected my computers readings.

thanks teddysaur,
PHX

Control: Are you in the same fitness now? Same wind? Weather?

BS. I know you didn't do it on purpose. Nobody would be able to tell a difference unless on a power meter in a lab environment. And then, I'd get a machine to turn the pedals instead of a human.

Did you update the speedometer from 25c to 23c?

my thoughts as well, but it doesn't explain the 11 minute improvement. :rolleyes:

Could someone please explain what rolling resistance is? In all my engineering classes, we only spoke of friction, both static and kinetic. Rolling resistance is a phrase that gets thrown around alot, but no one has given me a real definition of it. What is the "coefficient of rolling resistance" and how is it measured? Thanks

TB

Thanks everyone for raining on my parade and bringing me back to earth, and thankyou for reminding me to update the tire size on my computer.

I'm afraid that it is time to face facts, and just admit that it is you who have gotten stronger and faster, and not your tires. Yes, I know that you must be far to humble to claim credit for the speed improvement yourself, instead of heaping praise on an inanimate object, but I think the fact speak clearly by themselves.

So, I guess this begs the question - why are people so willing to credit their equipment purchases with performance improvements, rather than accepting that it is they themselves that have improved? Afterall, doesn't the rider provide most of the weight, most of the drag, most of the control, and all of the power? Large changes in performance are therefore likely due to the rider, not the equipment - so why do so many riders ascribe so much of their performance improvements to their equipment?

Could someone please explain what rolling resistance is? In all my engineering classes, we only spoke of friction, both static and kinetic. Rolling resistance is a phrase that gets thrown around alot, but no one has given me a real definition of it. What is the "coefficient of rolling resistance" and how is it measured? Thanks

TB

The coefficient of rolling resitance is a dimensionless parameter describing the retarding force of rolling divided by the weight of a rider.

Generally speaking, for a moving wheeled vechicle on flat ground, you can separate the forces causing it to slow into two catagories; aerodynamic drag which is proportional to v^2, and rolling resistance which generally varies linearly with velocity. On a bicycle, rolling resistance is dominated by parasitic losses within the tire itself (caused by the constant deformation of the tire). For this reason, rolling resistance is essentially treated as coulomb friction even though there is a small viscous fricitonal component to it.

- so why do so many riders ascribe so much of their performance improvements to their equipment?

Because it is easier to spend money on equipment than it is to commit to training. When the next performance plateau is reached, OP will look for new equipment as it is an easier fix than changing or improving training techniques.

Otherwise, in the relatively untrained who don't quantify fitness progression (regular testing) it seems to be the equipment making the difference.

Could someone please explain what rolling resistance is? In all my engineering classes, we only spoke of friction, both static and kinetic. Rolling resistance is a phrase that gets thrown around alot, but no one has given me a real definition of it. What is the "coefficient of rolling resistance" and how is it measured?

If you go back to your engineering text books, you'll probably find some information "hysteresis damping" or "hysteresis losses".

For a simple description, when a tire rolls, the tread and casing deform at the ground contact point, flattening out a bit at the ground. The flexing of the tread and casing is mostly elastic, but a small amount of the energy to deform it is absorbed as heat energy. This energy is not returned when the tread and casing leave the ground contact point, and is instead dissapated as heat. For bicycle tires, these losses are very small, but still very real.

The coefficient of rolling resistance corresponds similarly to the coefficient of friction, in that it describes the force/energy dissipated by the rolling of the tire over a distance, and is proportional to the normal force on the tire - the normal force is generally the weight supported by the tire:

Frr = Crr x Fn = Crr x M x g

Frr = Rolling resistance force
Crr = Coefficient of rolling reistance
M = Mass supported by the tire
g = Acceleration of gravity.

The coefficient of rolling resistances of narrow high pressure bicycle tires is typically in the range of 0.003 - 0.007. The coefficient can seem very small, but it can add up to significant losses at racing speeds. For example if a bicycle/rider with a mass of 80 kg (176.4 lb) rolls at 11 m/s (24.6 mph) on tires with a Crr of 0.005, the power losses due to the rolling resistance is:

Prr = Frr x V = Crr x M x g x V = (0.005) x (80 kg) x (9.806 m/s) x (11 m/s^2) = 43 Watts

The other day I replaced my stock tires on my trek 2100 which were bontrager race lite 700x25c to Michelin Pro Race 700x23c and My first ride on the new tires on a 26 mile route that I ride regularly turned out to be my fastest time to date on that route here's the numbers on my old tires: Avg speed 15,max speed 35.3, time-1.44.11 then on my new tires first ride : Avg speed-16.8mph,max speed-36.5mph,time-1.33.49 shaving nearly 11 minutes off my avg time!!!! So I am in awe and refuse to believe that tires can make that big a difference so I go for a 26 mile ride today same route similar weather avg speed-16.5mph, max speed-36mph,time-1.35.33 nearly identical to my previous days ride it's gotta be the tires. I just thought that was interesting and figured I would share it.

PHX


Did you reset your cycle computer for the newer (smaller diameter tires)?

What about tire pressure?

I'm afraid that it is time to face facts, and just admit that it is you who have gotten stronger and faster, and not your tires. Yes, I know that you must be far to humble to claim credit for the speed improvement yourself, instead of heaping praise on an inanimate object, but I think the fact speak clearly by themselves.

So, I guess this begs the question - why are people so willing to credit their equipment purchases with performance improvements, rather than accepting that it is they themselves that have improved? Afterall, doesn't the rider provide most of the weight, most of the drag, most of the control, and all of the power? Large changes in performance are therefore likely due to the rider, not the equipment - so why do so many riders ascribe so much of their performance improvements to their equipment?

Yeah, whatever. Then how come when I made the upgrade below to my bike, my average speeds went WAY up?

If you go back to your engineering text books, you'll probably find some information "hysteresis damping" or "hysteresis losses".

For a simple description, when a tire rolls, the tread and casing deform at the ground contact point, flattening out a bit at the ground. The flexing of the tread and casing is mostly elastic, but a small amount of the energy to deform it is absorbed as heat energy. This energy is not returned when the tread and casing leave the ground contact point, and is instead dissapated as heat. For bicycle tires, these losses are very small, but still very real.

The coefficient of rolling resistance corresponds similarly to the coefficient of friction, in that it describes the force/energy dissipated by the rolling of the tire over a distance, and is proportional to the normal force on the tire - the normal force is generally the weight supported by the tire:

Frr = Crr x Fn = Crr x M x g

Frr = Rolling resistance force
Crr = Coefficient of rolling reistance
M = Mass supported by the tire
g = Acceleration of gravity.

The coefficient of rolling resistances of narrow high pressure bicycle tires is typically in the range of 0.003 - 0.007. The coefficient can seem very small, but it can add up to significant losses at racing speeds. For example if a bicycle/rider with a mass of 80 kg (176.4 lb) rolls at 11 m/s (24.6 mph) on tires with a Crr of 0.005, the power losses due to the rolling resistance is:

Prr = Frr x V = Crr x M x g x V = (0.005) x (80 kg) x (9.806 m/s) x (11 m/s^2) = 43 Watts


Thank you for a great explanation.

-Eric

Thank you for a great explanation.

-Eric
of course it was, but damn you math guys. next time there's a throw down on rbr, i'm bustin out the coleridge and pope. stupid useless literature. i should have listened to mom and dad on that one...

but seriously, i love when you guys equation up. it feels like i'm back in school (which is a good thing)

.....

So, I guess this begs the question - why are people so willing to credit their equipment purchases with performance improvements, rather than accepting that it is they themselves that have improved? .....

But isn't this all about the placebo effect? This is a REAL human issue and I'd venture to say (without any study to back me up, just a strong hunch) the real reason that the theoretical gain of new tires (or any bolt on enhahcement) is minsicule yet the practical result is significant. If machines pedalled the tests then things would be differnet of course. But most of us are not machines and we are EASILY pychologically effected by cool looking carbon, stiff looking bottom brackets, cleanliness and so on. If it looks fast it invokes all the right chemical responses to provide a quantifiable performance enhancement.

Correction, I have been part of a study back in college. My cricket team participated in a psych department study on positive reinforcement. At the time we did not know the intent of teh study, we were just interviewed after games and videoed practice sessions. Some were given extremely positive feedback (we would examine video footage with the interviewers) while others were given the opposite. Over time they examined our performance in the field and it was amazing how the positive group would attack the ball, throw down the stumps, make better decisions etc etc... as opposed to the other group.

Do not underestimate the power of the best (legal) performance enhancer available to us all - the mind.

Did you reset your cycle computer for the newer (smaller diameter tires)?

I recalibrated my cateye computer for the new tires and checked and adjusted tire pressure to 110psi which is the same tire pressure I always run. Here are the numbers from todays ride same route similar weather conditions with the exception of a slight headwind. Avg. Speed:17mph VS Avg. Speed:15mph
Max Speed: 38.7mph Max Speed:35.3mph
Elapsed Time:1.32.10 Elapsed Time:1.44.11
Stopwatch: 1.31.39 Distance: 26.18miles
Distance: 26.18miles
I am not saying that the michelin tires are the only reason for the improvement I also would attribute some improvement to clothing,form,effort,pedals there are a multitude of factors that are involved, however the most quantifiable improvement I saw was immediately following the tire replacement. Believe it or not!!!

PHX

I recalibrated my cateye computer for the new tires and checked and adjusted tire pressure to 110psi which is the same tire pressure I always run. Here are the numbers from todays ride same route similar weather conditions with the exception of a slight headwind. Avg. Speed:17mph VS Avg. Speed:15mph
Max Speed: 38.7mph Max Speed:35.3mph
Elapsed Time:1.32.10 Elapsed Time:1.44.11
Stopwatch: 1.31.39 Distance: 26.18miles
Distance: 26.18miles
I am not saying that the michelin tires are the only reason for the improvement I also would attribute some improvement to clothing,form,effort,pedals there are a multitude of factors that are involved, however the most quantifiable improvement I saw was immediately following the tire replacement. Believe it or not!!!

PHX

Were the weather conditions, i.e., humidity, wind vel., wind dir., temperature, etc., exactly the same along the route? Was your physical state exactly the same on the rides in question? Was the bike in the same state, i.e. did you lube the chain before the ride? Did you wear the same clothes or was one set tighter or looser than the other? Does your computer start and stop automatically? If so, are you certain that it does so in exactly the same fashion every time, or is there some variance?

You can't rule out tainting of your results, too, from psychological effects. You obviously knew you were on new tires.

I think the wise choice would be to not believe your results.

Were the weather conditions, i.e., humidity, wind vel., wind dir., temperature, etc., exactly the same along the route? Was your physical state exactly the same on the rides in question? Was the bike in the same state, i.e. did you lube the chain before the ride? Did you wear the same clothes or was one set tighter or looser than the other? Does your computer start and stop automatically? If so, are you certain that it does so in exactly the same fashion every time, or is there some variance?

You can't rule out tainting of your results, too, from psychological effects. You obviously knew you were on new tires.

I think the wise choice would be to not believe your results.

If you read through my previous posts you will see that this is the third ride same route since changing the tires and each ride produced nearly identical results and All other conditions clothing bike set-up etc. were identical other than the tire replacement.

phx

I think you forgot to mention that you had the michelins filled with air, not water like on your previous tires. Michelin's are great tires, but I think the other posters are right -- please take credit for your better form.

If you read through my previous posts you will see that this is the third ride same route since changing the tires and each ride produced nearly identical results and All other conditions clothing bike set-up etc. were identical other than the tire replacement.

phx

If you read my post you'll find that I'm saying there's no way you could have held every one of those factors constant over your 3 rides. In fact, there's no way you can with any proof claim that the tires were the reason for your "increased speed."

How do you know that you just didn't pedal faster because you were psyched to have new tires? How do you know that you faster speed couldn't be attributed to you just feeling better? How do you know that the weather conditions were exactly the same? In all three cases, you don't.

You want to believe the tires were the reason for your increased speed, but there's no emprical reason to believe that was the case, nor is there any empirical proof. Your "experiment" doesn't hold up as an experiment, in terms of scientific method.

I believe the best way to address the skeptical response would be to try the old tires on your current setup to rule out the other equipment changes/variables. It would also rule out whether or not it's just better fitness.

Although, I believe his experiences with the tires. For me the differences were noticeable when I used Tufos vs Veloflex Pave's and Michelin Pro Races. The latter two were noticeably more comfortable, smoother riding and faster rolling. This is with me going into the new tires with a skeptical/doubtful attitude....aka I didn't believe the tires would be any faster. Now I am a believer and using the tire rolling resistance charts for the buildup on my track bike (where rolling resistance changes are very noticeable and less attributable to road slope changes).

It isn't likely that 1.5 mph is due to different tires... but it could be a *lot* more than 0.1 mph!

Here is some data from an Oct-2005 test done by Tour. The last number
is the difference in speed relative to the best tire. There is a 1 mph spread between the fastest and slowest tire.

Tire Crr Speed* Delta

Deda Tre Giro d'Italia 0.0038 23.08
Vittoria Open Corsa Evo CX 0.0039 23.05 0.03
Michelin Pro 2 Race 0.0042 22.96 0.12
Vittoria Diamante Pro Rain 0.0044 22.90 0.18
Michelin Megamium 2 0.0047 22.81 0.27
Pariba Revolution 0.0048 22.78 0.30
Michelin Carbon 0.0050 22.72 0.36
Panaracer Stradius Pro 0.0051 22.69 0.39
Schwalbe Stelvio Plus 0.0052 22.66 0.42
Schwalbe Stelvio Evolution Front 0.0056 22.54 0.54
Continental GP Force (rear) 0.0057 22.51 0.57
Hutchinson Fusion 0.0057 22.51 0.57
Schwalbe Stelvio Evolution Rear 0.0057 22.51 0.57
Continental Ultra GatorSkin 0.0058 22.48 0.60
Ritchey Pro Race Slick WCS 0.0058 22.48 0.60
Schwalbe Stelvio 0.0059 22.45 0.63
Specialized S-Works Mondo 0.0061 22.39 0.69
Continental GP 3000 0.0067 22.21 0.87
Hutchinson Top Speed 0.0069 22.15 0.93
Continental GP Attack (front) 0.0073 22.04 1.04

*
in MPH
185lb rider + bike
250W rider output
CdA = .32m^2 (racing crouch, normal road bike)
Transmission efficiency = 96%



Here we go again...:rolleyes: Are we there yet?

I'll echo many of the others - there are just too many variables to attribute it to tires alone. There is no way I could expect to ride the same route 2 consecutive days at the same speed. Perfect example: Monday I rode my favorite 30 mile very hilly route at an average speed of 20.0. Wednesday I rode it at 21.3. Same equipment, same everything. This happens to me all the time. But if I had made an equipment change on Wednesday I could be prone to attributing it to that. It is also pertinent to note that both of those speeds are significantly shy of my personal best for that ride of 22.9, which was done with heavier wheels than I am using now. The difference? Form, and luck. Sometimes you just have a good day.

however the most quantifiable improvement I saw was immediately following the tire replacement. Believe it or not!!!

PHX

My wife would agree with you in a heartbeat. I replaced her Bontrager Race Lites with Michelin Pro Race and she was ecstatic. She told anyone who would listen to her how much faster she was on the new tires. I also ride the Pro Race and tried to tell her that there could not be all that much improvement in speed but she kept on bragging about her new tires. We never tried to quantify the difference and I would expect no more than a fraction of an MPH. But for whatever reason she was impressed to say the least.

Al

Gotta love component purchases, the placebo effect and a creative imagination. LOL

See it constantly in this sport.

I ride rollers daily in the winter. Typically I'll ride steady in my 48/12 or 48/13 (cross bike) for an hour and call it a day. Not easy to pedal, but not ball-busting either. Just boring, steady 70% riding.


Ive been doing this for a couple months now...getting old!

Anyways, few weeks ago I switched from some worn-thin Conti Ultra 2000 tires to Mich. Pro2 Race (not the ultralight version) and I discovered a problem.

I was not getting a workout with the Pro2 races on! Seriously... I was rolling along 48/12 and it felt too easy. I wasnt working enough (its cold in the garage!) I first thought it was my new chain lube experiment (synthetic motor oil), then it dawned on me that it must be the tires I had just put on.

Promptly put the Ultra 2000's back on and it was immediately harder to pedal.

I thought I was loosing my mind until I read this thread. I figured new tires would be harder to pedal since the tread is thicker. Guess not.

Now, Im no michelin tire dealer either....in fact their tires seem to cut too easily I have found... but daggone, I really do thnk the rolling resistance thing might be something worth considering.

Here is a link to data from a project I've been doing for the last 4 months. The data is what it is - I can't prove the validity on a real road and vice versa. There are further discussions in the BTR Performance forum if you might be interested.

http://www.biketechreview.com/tires/AFM_tire_crr.htm

Al

Dayum, if I spent 1/4 of the time I spend reading these forums actually training I could significantly lower my times on my regular routes. Then I'd have even more time to read these forums... lmao