Whats everyone run for tire pressure?

 

30 Cold

 

31 cold all around

 

A forum member wrote this...You must not have seen it......

"Some one wrote in that thread, GM spent alot of time and recommended the 30 psi cold...

I am GM and the label on the door is there for product liability issues only.,

Someone else said they don't care about a few miles per gallon or tire longevity..

MY post was a means by which you could use your DIC to tune your tires, and subsequently get the most performance by translating engine torque to the ground at 100% optimum tire pressure... it had nothing to do with saving a few cents.

All racing teams use this method to get 100% of the HP to the ground... get a few extra laps from the tires and a few extra laps from the fuel... when they do it right they win races..

The same applies to your everyday driver..

some one said what's the difference between 30 mpg and 33 mpg....

that's 10%...

In a car that produces 350 HP, that's a drop of 35 hp that is not transfered to the ground because the tires are not tuned properly..

People spend thousands to get a few hp, but fail to transfer that hp to the ground because their tires are too hard.. and they can loose 10 to 15 % of transferable HP . IN a 500 HP car that can be as much as 75 hp.

I am an engineer, I keep forgetting who I'm trying to help...

Many Engineers and those with some real car savvy understand how this all works... The other here on the forum ,about 90% ,know little or nothing about real automotive engineering and what it takes to make these cars talk...

I am done trying too teach Back yard mechanics, wannabe mechanics, the principles of automotive engineering. I get nothing from this forum, when all the good work is counters with disrespect and abuse.

OK here is the answer to your question... and you can take this to the bank...

You Runflats work best at around 30/31 psi hot...

It is not as difficult as the wannabe's would make it out to be.,..

there is little variance in road temps in the winter, spring and fall.. in most areas..

20f to 50 F... is common..

The real tire tune is done in the summer when cold tires in the morning are sitting on 50 F surfaces...
In the summer you can take a cold tire out on a blacktop surface reaching temps of 140F to 150F.

This will take your tires up in the 36 to 38 psi range...

So in the sumer when you are seeing 85 and 90 degree days, you need to lower your tire pressure to a point that when you actually using the tires they are not in the 35 to 38 psi range..

I didn't check where you live,,, but tire tuning is based on where you live and how hot it gets...

The sticker on the door is generic and covers a multitude of sins..Its like a tire alignment.. ther is a + - tolerence for all the specs. but there is perfect spot...it is called the mean... a typical spec will be 3 degrees plus three, minus 2... but the perfect number is 3 degrees... same with tires. Sure they will work at 30 psi cold, but they will work better if tuned to the perfect spot.

To get the most out of your car, having the right footprint will give you the best miles per gallon and the best tire life...

Using the DIC to display mpg over a know distance tells you if your getting the most out of your car.

Its a very simple tuning trick used by real car people.."

In the summer I now keep 27 cold and they go up to 30/31 and thats what the pressure should be for best performance and tire wear on runflats and others...