tire pressure upgrade on 08 touring edition

thats up to you fred but my tires are 42/40.

 

My 08 Touring #6 is at 42/40 psi. Has been for the last 5000+ miles.

 

It is not advisable to inflate tires above the maximum rating given on the sidewall. The 42/40 PSI front/rear commonly reported here applies to the non-touring Goodyear Integrity tires, which have a maximum rating of 45 PSI.

 

The Touring tires are sidewall rated for 50 PSI.

I've been running 50/48 for 4 weeks. I'm now trying 40/38 to see how handling improves and MPG deteriorates. I'm more concerned about traction and safety (and avoiding expensive collision repair bills) than a few pennies in my wallet today.

 

My 2008 Touring Package 6 has the 41 max tires. I inflated them to 41 all-around without a worry in the world.

 

I believe the better formulation would be to drop the rears by "2psi" from the fronts. Handling and weight distribution will benefit.

so 41/39 is a better way to go than 41 all.

 

Do you have fear any of using those fully inflated tires with a full load and/or on a hot day?

 

Just a reminder especially for those whose pressure is on the edge or over limits, pressure will vary greatly with outside temperature. If you live in a cold area and haven't checked / adjusted lately you should. If you have when / if it gets warm again make sure you check them and let out air if needed.

 

It's important to have the tire fully inflated for a full load. The lower the inflation pressure on a full load, the more likely the tire is to fail if I understand correctly. So in the case you named higher is better.

Tires generate heat while running. The more pressure, the less heat they tend to generate because the sidewalls flex less. This is somewhat self regulating as higher rubber/air temp results in higher pressure. Internally generated heat is the enemy of the tire. If you run pressure too low the tire will get too hot and although the pressure will rise as a result, it will probably not be enough to save the tire from failure.

Someone who did tire design work (or similar) posted about this a few months ago and if I remember correctly there is a lot of safety factor built into the sidewall maximum. I'm pretty certain the person stated that the operating temperature (versus cold inflation pressure) is factored into the design. This is probably done for the max speed rating as well (but I don't remember if that was addressed)...and that is well above where most of us operate our tires.

 

Recommended tire pressures are always when cold. A hot (driven 4+ miles) tire pressure can increase by as much as 4 psi. A tire thats set to 42 psi cold will rise to 46 psi when hot. If you set your tires to the maximum on the side walls cold, you are in danger of exceeding this when the tire heats up.

 

Hi All,

I think the best pressure to run tires at, for everyday driving, is the pressure that results in an even wear across the whole width of the tire. In a US Prius with 165 sized tires thats somewhere between 40 and 44 PSI front, and 2 psi lower in the rears.

For the touring guys, measure your tread depths with a caliper, write em down. Then run the car for 10K miles at one pressure. Then check the tread depths again. If its wearing more on the edges, a higher pressure is indicated. If more in the middle of the tread, a lower pressure should be set.

 

I think some of you are confusing the "do not inflate above 40psi to seat bead" with the "maximum side wall pressure". You never want to exceed 40psi when mounting new tires on the wheels(seating the bead). However max sidewall is where you want to be, wellin my case i'm a little over. For example, my integrities say do not exceed 40psi while seating bead, but, if you look on around the side it says max 44 sidewall psi when cold. This means when the car hasn't been driven anywhere 44psi is ok, they take heat expansion while driving into consideration so need to worry. Just set your tires your tires at max sidewall and have you no worrys. =) Hope this helps clear things up some and for what its worth i've been running 54/52 for the past 7k or so and still noticw more outside wear so they are now at 60/58. Having owned a lowered car before a little roughness from increased psi is nothing compared to a lowered car.

Happy motoring!

 

Sorry for the crappy grammer/spelling. There doesn't appear to be an "edit" button when your on PC mobile.

 

I have falken ziex 912 tires. They are a few months old. I recently inflated them to 44/42psi. They seem to be okay. They were 35/33 before & my mileage suffered.

 

Unfortunately I don't see any improved fuel mileage when I ran 42/40, no increase at all. I run the door jam pressure 35/33 The mileage stayed the same.

 

Surely the US touring version runs 195/55/16 tyres the same as UK/European Prius. The extra width allows slightly lower pressures without loosing MPG or stability. In fact going even wider to 205/55/16 shows even more benefit.

John (Britprius)