I just changed My rims and tires, I now have Toyo's. On the side wall it says 50 PSI, They are filled to 40 psi by the installers but my Tire pressure alert constantly is going off and is quite irritating, is there a way to set it to alert me at different pressure?

 

The pressure on the side wall is MAX pressure. Also don’t trust installers, they always over inflate. Start at the stock recommended pressure of 30psi and adjust according to tire wear. You can not change the warning limits from the DIC.

 

Screamer,

You are not the first person to fall victim to this myth... I say myth because there really are a lot of intelligent people that have been led to believe that the tire pressure on the sidewall is what they are supposed to run.

As previously mentioned, the pressure on the sidewall is the maximum pressure the tire is rated at and applies to the maximum load rating of the tire. Typical passenger tires are rated at 1500#. Therefore if you had a 6000# vehicle and the weight is evenly distributed, you would probably want to run the maximum pressure. Since most of our Corvettes weigh considerably less than 6000# there is no logical reason to run the maximum pressure on the sidewall.

This is one of the reasons why manufacturers place a sticker in the vehicle with recommended tire pressures. Frequently the sticker will even reflect different pressures if the vehicle was offered with an optional tire. Additionally since there is some variance in tire construction between manufacturers, a different brand tire could have a different ideal pressure for even the same size tire.

While the vehicle manufacturers recommended pressure is an excellent place to start, the best way to determine the ideal pressure for your tire is to measure the surface temperature when the tire is fully warmed up. You can do this by driving the car until the tire is fully warmed up and testing the temperature across the tire surface, outer edge, center and inner edge. If the temps are equal across the tire the pressure is correct. If the temp is hotter in the center than the outer edges, there is too much pressure and you can lower it a couple of pounds and test it again. (Cooler in the center than the edges indicates pressure is a bit low.)

I have an IR temperature gun that I use in this manner to verify the manufacturers recommended pressure is good for this particular vehicle.

Needless to say, I'm always surprised when a tire store passes this myth on... they should certainly know better.

Good luck... GUSTO

 

What gusto said is absolutely correct. And any tire dealer worth your money should know better.I have been a tire dealer for 30 years or so and read many posts on this same question with the typical myths. The only thing I might add is if the temperature is hotter on one side than the other it could indicate an alignment issue. Had a twin I- beam ford that I set up the way gusto suggested, got 110,00 miles on the fronts.

 

thanks for the temp profile idea, gusto!

 

A tire dealer who gives out such bad info should be banned from business IMHO.

Thats a great write up Gusto

Even though the manufacturers recommended pressure is 30 cold I found that the hot temperature would vary. In Vegas in Summer 30 cold gave as high as 36 hot whereas in winter it was only 33 or so. In England I get about 33 hot.

I tend to leave mine at about 29 cold which gives me about 32 hotand the wear seems to be about even so far after 15 k miles on my AS ZPs.

 

Dead on 29 cold works for me.

 

I'll "second that"

 

Thanks for all your input everyone, I will follow your advise. I was just worried the tires would be next to flat with 30 PSI on a tire that says its max is 50, lol. I dont have as much rubber as it did with the stock tires :-) I didnt want to ruin the Rims.
Lisa
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Hey Lisa,
If you don't have an i/r temp gun, you may get close to correct tire pressure by holding a straight edge to the tread on the tire. If the tire goes away from the s/e in the middle, the pressure is too low. If the tire goes away from the s/e on the sides, the pressure is too high. If it is even across pressure is correct.

Doug

 

Thats a great Idea Ill try it!! Thank you Doug!

 

Also, Sears has relatively cheap i/r temp guns, and they can be handy for other things - checking the temperature of the thermostat housing if you suspect overheating, as an example. Might also be handy in the Valley in the summer, just to check the temperature of the seats if you have the glass top (local humor).

I'm not sure how accurate the straight-edge would be, but it sounds like it should work fairly well. Only issue I can think of is that centrifugal force would make the centers of the tires want to "bulge" a bit more at speed. Still, it's a start, and if you drive at high speeds, watch for uneven wear.

Interesting thread... good topic!

 

I had them do the same thing to me!

You do not need the tires at 50 PSi just set them to the 32 -35 recommended PSI for the C5 Vette!

You cannot change the PSI setting in the BCM!

Thanks,Matt

 

Quote: Might also be handy in the Valley in the summer, just to check the temperature of the seats if you have the glass top (local humor).

Tim, Forget the I/R temp gun when it gets that hot I'm going to the One Mile. Ha, more local humor.