Pirelli p7 225 45 17xl. Max psi 51. My car: corolla. Toyota recommends 30. I was thinking 35. Does anyone use similar sized tires and what psi do you run and why? Ride is too soft at 30 psi but i wanted to find out optimal for best mpg, grip and even wear.
You are using an out of date browser. It may not display this or other websites correctly.
You should upgrade or use an alternative browser.
You should upgrade or use an alternative browser.
Optimal PSI on 225 45 17XL??
- Thread starter Rolla07
- Start date
- Status
- Not open for further replies.
35 sounds good. Maybe a hair more.
If grip is what your after read up. http://mgaguru.com/mgtech/tires/sp101.htm
Originally Posted By: Rolla07
Pirelli p7 225 45 17xl. Max psi 51. My car: corolla. Toyota recommends 30. I was thinking 35. Does anyone use similar sized tires and what psi do you run and why? Ride is too soft at 30 psi but i wanted to find out optimal for best mpg, grip and even wear.
First, you have to realize that this is all about the compromise. You can't get max grip, max mpg, and even wear using the same pressure. You are going to have to chose a compromise that works for you.
For max mpg's you'll want to use the largest amount of inflation pressure you can. But this sacrifices grip and tire wear - for safety's sake this is something you definitely shouldn't do.
For max grip, you'll want as much footprint on the ground as you can - which means low pressures. The problem here is that max grip on the tire doesn't translate into max grip of the vehicle - because the vehicle's steering and suspension was set up with a certain relationship between the tire's slip angle and its cornering speed - a thing called akerman - and this is affected by inflation pressure. Plus, the speed that a tire reacts to steering input is also affected by inflation pressure - and higher is more responsive.
So getting maximum grip is a matter of selecting a compromise pressure that makes for a responsive car and matches the steering and suspension geometry of your vehicle - and the only way to know is testing.
Default posted a link to a procedure - and the problem with the procedure is that the guy is only looking at the outside of the tire - and not timing anything. His procedure may or may not get to the optimum. He may over shoot it. He may under-shoot it. It depends on the car's suspension. When I was racing, I used that procedure, but I also looked at lap times.
And even wear? Most tire wear occurs in the cornering mode. In some respects, geip and wear are going in the same direction. But where they depart is a matter of degree - and the way the vehicle's steering and suspension is set up - that pesky old akerman thing again.
But let's do some math to see where you are.
You didn't tell us the year of your Corolla, but everything I looked at said that these vehicles use tires with about an 88 load index. Your 225/45R17's have a load index of 94 (or so). This means they are oversized compared to the stock tires. That also means the inflation pressure published by Toyota is too high for the tires you have.
So I would recommend using 30 psi as it is in the right direction. You could inch the pressure up, but I wouldn't go any more than 33 psi - and, of course, this depends on what compromise you are looking for.
Pirelli p7 225 45 17xl. Max psi 51. My car: corolla. Toyota recommends 30. I was thinking 35. Does anyone use similar sized tires and what psi do you run and why? Ride is too soft at 30 psi but i wanted to find out optimal for best mpg, grip and even wear.
First, you have to realize that this is all about the compromise. You can't get max grip, max mpg, and even wear using the same pressure. You are going to have to chose a compromise that works for you.
For max mpg's you'll want to use the largest amount of inflation pressure you can. But this sacrifices grip and tire wear - for safety's sake this is something you definitely shouldn't do.
For max grip, you'll want as much footprint on the ground as you can - which means low pressures. The problem here is that max grip on the tire doesn't translate into max grip of the vehicle - because the vehicle's steering and suspension was set up with a certain relationship between the tire's slip angle and its cornering speed - a thing called akerman - and this is affected by inflation pressure. Plus, the speed that a tire reacts to steering input is also affected by inflation pressure - and higher is more responsive.
So getting maximum grip is a matter of selecting a compromise pressure that makes for a responsive car and matches the steering and suspension geometry of your vehicle - and the only way to know is testing.
Default posted a link to a procedure - and the problem with the procedure is that the guy is only looking at the outside of the tire - and not timing anything. His procedure may or may not get to the optimum. He may over shoot it. He may under-shoot it. It depends on the car's suspension. When I was racing, I used that procedure, but I also looked at lap times.
And even wear? Most tire wear occurs in the cornering mode. In some respects, geip and wear are going in the same direction. But where they depart is a matter of degree - and the way the vehicle's steering and suspension is set up - that pesky old akerman thing again.
But let's do some math to see where you are.
You didn't tell us the year of your Corolla, but everything I looked at said that these vehicles use tires with about an 88 load index. Your 225/45R17's have a load index of 94 (or so). This means they are oversized compared to the stock tires. That also means the inflation pressure published by Toyota is too high for the tires you have.
So I would recommend using 30 psi as it is in the right direction. You could inch the pressure up, but I wouldn't go any more than 33 psi - and, of course, this depends on what compromise you are looking for.
Originally Posted By: CapriRacer
Originally Posted By: Rolla07
Pirelli p7 225 45 17xl. Max psi 51. My car: corolla. Toyota recommends 30. I was thinking 35. Does anyone use similar sized tires and what psi do you run and why? Ride is too soft at 30 psi but i wanted to find out optimal for best mpg, grip and even wear.
First, you have to realize that this is all about the compromise. You can't get max grip, max mpg, and even wear using the same pressure. You are going to have to chose a compromise that works for you.
For max mpg's you'll want to use the largest amount of inflation pressure you can. But this sacrifices grip and tire wear - for safety's sake this is something you definitely shouldn't do.
For max grip, you'll want as much footprint on the ground as you can - which means low pressures. The problem here is that max grip on the tire doesn't translate into max grip of the vehicle - because the vehicle's steering and suspension was set up with a certain relationship between the tire's slip angle and its cornering speed - a thing called akerman - and this is affected by inflation pressure. Plus, the speed that a tire reacts to steering input is also affected by inflation pressure - and higher is more responsive.
So getting maximum grip is a matter of selecting a compromise pressure that makes for a responsive car and matches the steering and suspension geometry of your vehicle - and the only way to know is testing.
Default posted a link to a procedure - and the problem with the procedure is that the guy is only looking at the outside of the tire - and not timing anything. His procedure may or may not get to the optimum. He may over shoot it. He may under-shoot it. It depends on the car's suspension. When I was racing, I used that procedure, but I also looked at lap times.
And even wear? Most tire wear occurs in the cornering mode. In some respects, geip and wear are going in the same direction. But where they depart is a matter of degree - and the way the vehicle's steering and suspension is set up - that pesky old akerman thing again.
But let's do some math to see where you are.
You didn't tell us the year of your Corolla, but everything I looked at said that these vehicles use tires with about an 88 load index. Your 225/45R17's have a load index of 94 (or so). This means they are oversized compared to the stock tires. That also means the inflation pressure published by Toyota is too high for the tires you have.
So I would recommend using 30 psi as it is in the right direction. You could inch the pressure up, but I wouldn't go any more than 33 psi - and, of course, this depends on what compromise you are looking for.
+1 I think there is another thread on this.
Originally Posted By: Rolla07
Pirelli p7 225 45 17xl. Max psi 51. My car: corolla. Toyota recommends 30. I was thinking 35. Does anyone use similar sized tires and what psi do you run and why? Ride is too soft at 30 psi but i wanted to find out optimal for best mpg, grip and even wear.
First, you have to realize that this is all about the compromise. You can't get max grip, max mpg, and even wear using the same pressure. You are going to have to chose a compromise that works for you.
For max mpg's you'll want to use the largest amount of inflation pressure you can. But this sacrifices grip and tire wear - for safety's sake this is something you definitely shouldn't do.
For max grip, you'll want as much footprint on the ground as you can - which means low pressures. The problem here is that max grip on the tire doesn't translate into max grip of the vehicle - because the vehicle's steering and suspension was set up with a certain relationship between the tire's slip angle and its cornering speed - a thing called akerman - and this is affected by inflation pressure. Plus, the speed that a tire reacts to steering input is also affected by inflation pressure - and higher is more responsive.
So getting maximum grip is a matter of selecting a compromise pressure that makes for a responsive car and matches the steering and suspension geometry of your vehicle - and the only way to know is testing.
Default posted a link to a procedure - and the problem with the procedure is that the guy is only looking at the outside of the tire - and not timing anything. His procedure may or may not get to the optimum. He may over shoot it. He may under-shoot it. It depends on the car's suspension. When I was racing, I used that procedure, but I also looked at lap times.
And even wear? Most tire wear occurs in the cornering mode. In some respects, geip and wear are going in the same direction. But where they depart is a matter of degree - and the way the vehicle's steering and suspension is set up - that pesky old akerman thing again.
But let's do some math to see where you are.
You didn't tell us the year of your Corolla, but everything I looked at said that these vehicles use tires with about an 88 load index. Your 225/45R17's have a load index of 94 (or so). This means they are oversized compared to the stock tires. That also means the inflation pressure published by Toyota is too high for the tires you have.
So I would recommend using 30 psi as it is in the right direction. You could inch the pressure up, but I wouldn't go any more than 33 psi - and, of course, this depends on what compromise you are looking for.
+1 I think there is another thread on this.
- Status
- Not open for further replies.
Similar threads
- Replies
- 5
- Views
- 6K
