Tire Pressure...explain that to me again...

[2FAST4U]

Here's the question. I SEARCHED the posts looking for a consensus on tire pressure adjustment if you have increased the wheel diameter from the stock size of say (235-70-17) to a (245-35-19)
I also read the replies about following the vehicle tire pressure placard for proper inflation pressure.
I disagree, and here is why

The Wheel / Tire combo I purchased are from a Jag in a 19 inch diameter with Conti Pro's. The sidewall has a maximum psi rating stamped on it of (51psi) whereas the OEM tires were Michelin Pilots and they have a maximum rating of (44psi)
After searching for some time I managed to find the recommended tire (Tyre) if you live in Great Britain, pressures for an S-Type are 36 psi with the 19-20 inch rim upgrade option.
The S-type weighs about 100 pounds more than the LS V8. So, with this in mind I am thinking the proper tire pressure for a rim in the 19 or 20 inch diameter should be in the 34 psi range.

 

[1bad4.6l]

Run the pressure around 40-45 or risk a good bend from potholes. I did tires for 5 years trust me. It will also ride like a slotcar on rails.

 

[tireman]

maximum rating

Your maximum rating is the PSI for maximum load handling per tire. The air pressure is what carries the load. So if you back off the PSI, the less load you can carry. You will also get a softer, smoother ride. The sidewalls will flex more and you could damage the rim if you hit a pot hole. These tires could most likely carry twice the weight of the car. I would try anything between 35-44 psi to start, see how you like it, if its not crisp enough, put in the maximum.

 

[lseguy]

i can imagine 45psi on 19's will be akin to the same ride quality Fred and Barney endured.

 

[1LoudLS]

i can imagine 45psi on 19's will be akin to the same ride quality Fred and Barney endured.

rofl

 

[2FAST4U]

i can imagine 45psi on 19's will be akin to the same ride quality Fred and Barney endured.

I gotta admit, you guys crack me up.

I guess patience and testing is the menu for the right pressure. I'll start at 40 psi and see where that leads. I just bought a Longacre liquid gauge because I don't trust my handy dandy walmart special anymore after measuring 36 pounds one day and 29 the next. Gotta start with the right tools if you want to get any benefit out of the details.

 

[Garbone]

I asume we are talking cold, as the pressure will increase with heat.
I set mine at 35psi cold, for a hot presure of around 40-42.