On the TCH side panel, it says the tire inflation pressure for a fully loaded car should be 32 or 33 PSI. I'm just wondering why many ppl on these forums are jacking up their PSi to hi 30's if not 40s.

I've read that too hi a pressure can promote uneven tire wear.

Any input? Thx.

 

I picked up my car on June 9 and just checked the pressure for the first time the other day and they all read about 36 psi. It's been pretty hot here lately so I wouldn't be surprised if they were about 32 or 33 when it was a bit cooler. Anyhow, after my next fill up I plan on adding about 5 psi and compare my mileage over a few tanks.

BTW, does your screen name indicate problems with a TCH or purchasing a TCH?

 

Default Re: PSI

It's a whole PANDORAS BOX of issues my friend...

Some people who are REALLY KNOWLEDGABLE hypermilers have put thousands and thousands of miles on "overinflated" tires and had no problems at all.

Me personally, I put 28,000 miles on my 2004 HCH with the tires in the high 40s, then in the mid 50s, then ending at 58 PSI when I traded it in for my TCH.

I'm running my TCH at 46 PSI right now, and I will increase that when the heat dies down a little.

I have seen no uneven tire wear at all. Tires actually "last longer" if less rubber is taking a pounding from the road.

DISCLAIMER: These are MY OPINIONS, based on research and personal OPINION, and are not meant as a guide or enticement to other drivers to emulate my PSI habits.

 

Check the tire sidewall. It will indicate a maximum pressure when cold. It is generally safe to go up to this PSI. Lower pressures will tend to wear edges: I have found that I get better (even) treadware (as well as better MPG) near maximum PSI with modern tires.

Toyota's specified PSI is a compromise between performance and ride comfort, my priorities differ.

JeffD

 

Also note that just driving to the gas station to put air in the tires warms up the tire enough where the psi is no longer considered cold psi. So what you put in will be less than the recomended psi.

Make sure to take the psi in the morning before the sun starts to warm up the tires and deffinately before you drive on them. that will give you a more accurate messurement of the cold psi pressure.

 

Why I usually do is take the pressure when they're cold. I then take it again at the gas station. If they've gone up by 3 psi, I just add 3 psi to my desired pressure.

 

I wonder where people come up with this. Talk to a tire engineer, he will tell you that the numbe ron the tire is the MAX pressure when the tire is used under MAX LOAD. The car manufacturer uses data to determine the proper pressure, less contact patch on the ground (over inflated tires) is not necessarily the best either. Sure most cars the pressure is determined for best trad off of ride and comfort, but 50 PSI in a tire sounds a bit extreme. I read an article from a Michelin engineer who said that a "few" pounds over was better than under. Michelin's own site says to not over inflate the tires, to use the car makers numbers. At 50 PSI the ride has to be as bad as solid tires, hell I only go 3-5PSI over and you can feel the harder ride.

 

This would be my first post on this very, very interesting board that helped me pass the time faster until I picked up my TCH last week. Thanks a lot, guys. Sorry, but I got to say something about the higher tire pressures as suggested here in the low 40s or even 50s. While a higher tire pressure will save thread and gas, it will also reduce significantly the adherence of the tire to the road. This can be very dangerous, especially on wet roads. From past experience, I think you can safely increase the recommended tire pressure by 5-7 psi but not much more without becoming unsafe. During summer cold pressure may be about 37-38, while fall, winter and spring one may increase that safely to 39-40 (up north). The max tire pressure would be about 51-54 psi.

 

Absolutely true. Less rubber on the road means less grip.

In my own personal case, I drive my TCH like a "hybrid" car, meaning I don't take any high speed curves. I also live in Phoenix, where the rain is SCARCE to say the least.

That's why my DISCLAIMER above. What is OK for me might not be OK for YOU - so each person needs to assess their own situation and make their own decisions.

 

Wow, great discussion. I had no idea that so many ppl went above the Car's recommended pressure rating. I might increase my PSI to like 35. I also agree with the hyperinflation leading to possible loss of grip... I've read that in several sources.

As someone discussed earlier, I also use the method of measuring cold tire pressure, driving to the gas station, rechecking the warm pressure and adding the difference.

Orcrone, my s/n comes from the fact that I was "duped" by the dealer into signing onto an extended warranty plan at the time of purchase for 1800 bucks. But I have since cancelled it thanks to advice from fellow TCH owners on this forum.