Michelin race pro 3 - PSI
Discussion
100 for both
Some info here too :
ervelo - Wheels and tyres: Fatter is the way to go
The team are using Zipp wheels again: 404s for regular racing and wider, shallower 303s for the cobbled classics. The tubular tyres of choice are Vittoria's Pavé and Corsa Evo CX models. The standard widths for these are 27mm and 23mm, but the team have been trying a 24mm Pavé and a 25mm Corsa Evo.
Vroomen explains: "The 24 is basically an narrow Pavé (I'm not really doing it justice if I describe it like that). And the 25 is the same tread pattern as a standard Evo CX 23mm but on a bigger casing. That allows us to run that tyre with a slightly lower pressure but still have very little rolling resistance and that fits very well on the new, wider Zipp rims.
"In general, I think everybody should be riding wider tyres all the time but especially on a race like this weekend or Flanders, a Pavé is really overkill. So I think the 25mm Evo CX is really the way to go."
Tyre pressures are vital to get right too, and during the team's recce of the 2.5km Lange Munt cobbled sector, they tested different combinations of tyres and pressures. "One thing we're testing is 8, 7, 6, 5 bar and then see what the results are," said Vroomen. "Every mechanic of every professional cycling team puts too much pressure in the tyres. We've weaned them off of that so at least there's not 12 bar in them any more.
"We don't run these crazy high pressures ever because it actually increases rolling resistance. But how low we can go? That's what we're trying to ascertain. In Paris-Roubaix, in some cases for some riders, we run less than 5 bar. But that's quite personal with body weight.
"There's sort of an optimum so you want to stay close to that. That depends on the surface as well. That's why the ideal pressure on the track is higher than on the road. In general a wider tyre has a lower rolling resistance than a narrow tyre. You can take a wider tyre with a little lower pressure and still have lower rolling resistance.
"There are tests that will show wider tyres are less aerodynamic. But a significant portion of that is because you have all these rims that are optimised for a 21mm tyre. You put a 27mm tyre on it and of course it's crap but that's not really fair to the tyre. Now you see with the Zipps for example, you have the wider Zipps.
"The difference will not be as big as when they measured it five years ago because the rim wasn't really designed for that width. That's why we combine the on-the-road feedback from the riders, which is qualitative, with what we measure in the lab and try to find an optimum. "
Some info here too :
ervelo - Wheels and tyres: Fatter is the way to go
The team are using Zipp wheels again: 404s for regular racing and wider, shallower 303s for the cobbled classics. The tubular tyres of choice are Vittoria's Pavé and Corsa Evo CX models. The standard widths for these are 27mm and 23mm, but the team have been trying a 24mm Pavé and a 25mm Corsa Evo.
Vroomen explains: "The 24 is basically an narrow Pavé (I'm not really doing it justice if I describe it like that). And the 25 is the same tread pattern as a standard Evo CX 23mm but on a bigger casing. That allows us to run that tyre with a slightly lower pressure but still have very little rolling resistance and that fits very well on the new, wider Zipp rims.
"In general, I think everybody should be riding wider tyres all the time but especially on a race like this weekend or Flanders, a Pavé is really overkill. So I think the 25mm Evo CX is really the way to go."
Tyre pressures are vital to get right too, and during the team's recce of the 2.5km Lange Munt cobbled sector, they tested different combinations of tyres and pressures. "One thing we're testing is 8, 7, 6, 5 bar and then see what the results are," said Vroomen. "Every mechanic of every professional cycling team puts too much pressure in the tyres. We've weaned them off of that so at least there's not 12 bar in them any more.
"We don't run these crazy high pressures ever because it actually increases rolling resistance. But how low we can go? That's what we're trying to ascertain. In Paris-Roubaix, in some cases for some riders, we run less than 5 bar. But that's quite personal with body weight.
"There's sort of an optimum so you want to stay close to that. That depends on the surface as well. That's why the ideal pressure on the track is higher than on the road. In general a wider tyre has a lower rolling resistance than a narrow tyre. You can take a wider tyre with a little lower pressure and still have lower rolling resistance.
"There are tests that will show wider tyres are less aerodynamic. But a significant portion of that is because you have all these rims that are optimised for a 21mm tyre. You put a 27mm tyre on it and of course it's crap but that's not really fair to the tyre. Now you see with the Zipps for example, you have the wider Zipps.
"The difference will not be as big as when they measured it five years ago because the rim wasn't really designed for that width. That's why we combine the on-the-road feedback from the riders, which is qualitative, with what we measure in the lab and try to find an optimum. "
Hang on a minute, can some explain how a fatter tyre has less rolling resistance. It makes no sense. Ceteris paribus the bigger contact patch the greater friction, so the rolling resistance is greater.
I could understand it they are claiming less fatigue due to a less harsh ride, but they're not.
I could understand it they are claiming less fatigue due to a less harsh ride, but they're not.
So, after a bit of googling it seems it's down to side wall flex. Narrower tyres flex more as a percentage of their cross-section. The more flex, the more heat generated by the flexing sidewall, so of the available potential energy (the rider) the less is converted to kinetic energy (forward motion)
That said, fatter tyres have more aero drag and obviously weigh more.
Wonder where the cross-over point is though?
Interesting stuff, and of course wider tyres offer a better ride and thus reduce rider fatigue . That's it I'm fitting 265 section tyres on my road bike
That said, fatter tyres have more aero drag and obviously weigh more.
Wonder where the cross-over point is though?
Interesting stuff, and of course wider tyres offer a better ride and thus reduce rider fatigue . That's it I'm fitting 265 section tyres on my road bike
Having read a bit more - I wondered why you can't just up the pressure on on the narrow tyre to reduce wall flex - it seems that narrow tyres are still better for most of the time...
http://www.schwalbetires.com/tech_info/rolling_res...
Reading this article it does suggest that it is down to rider fatigue. If you need to have some compliance in the tyre for poor surfaces, a wider tyre will perform better at the same pressure as a narrow tyre, but a narrow tyre at a higher pressure will out-perform a wider one at a lower pressure, but offer a harsh ride.
http://www.schwalbetires.com/tech_info/rolling_res...
Reading this article it does suggest that it is down to rider fatigue. If you need to have some compliance in the tyre for poor surfaces, a wider tyre will perform better at the same pressure as a narrow tyre, but a narrow tyre at a higher pressure will out-perform a wider one at a lower pressure, but offer a harsh ride.
rhinochopig said:
Having read a bit more - I wondered why you can't just up the pressure on on the narrow tyre to reduce wall flex
My understanding is that the tyre wall has to flex enough to be able to deform to the road surface. If the pressure is too high then the tyre skips across between the imperfections in the road surface and this not only causes a harsh ride, it will increase rolling resistance as well. It's worth noting that many rolling resistance tests seem to be done on a cylinder roller which is perfectly smooth, this is obviously not the same as real world tarmac which is rougher than a badgers arse
itsnotarace said:
If the pressure is too high then the tyre skips across between the imperfections in the road surface and this not only causes a harsh ride, it will increase rolling resistance as well.
I reckon this is spot on, i used to race cars on track so have a good *feel* for tire grip, running these Pro 3 last night @ 120 psi , when the road surface was poor they would skip very badly, fine on the smooth stuff, will try the 105/110 recommend above.Regards harsh ride, man-up
itsnotarace said:
My understanding is that the tyre wall has to flex enough to be able to deform to the road surface. If the pressure is too high then the tyre skips across between the imperfections in the road surface and this not only causes a harsh ride, it will increase rolling resistance as well.
It's worth noting that many rolling resistance tests seem to be done on a cylinder roller which is perfectly smooth, this is obviously not the same as real world tarmac which is rougher than a badgers arse
If it's not in contact with road then it has zero rolling resistance It's worth noting that many rolling resistance tests seem to be done on a cylinder roller which is perfectly smooth, this is obviously not the same as real world tarmac which is rougher than a badgers arse
I guess the increase comes from the landing - wall flex = heat.
This could be the next plane + conveyor thread
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