Tire pressures and how to set them accurately.

[mikesxpress]

I posted this in the trailer/towing forum.

Tire pressures are a random guesstimate. The tire manufacturer and truck/car/boat trailer OEM's are also a guesstimate. None of them have any idea on what load you are actually applying or weather conditions (hot/cold) you are going to be running at. Full load of fuel and gear also makes a big difference. The only accurate way to determine the best pressure throughout the year is to chalk test the tires. I've done this for many years for my vehicles/trailer and established outdoor temperature guidelines as to when I adjust the pressure. This process gives you maximum longevity/performance of your tires. I found an excellent video showing the process:

[blades31860]

amen Ive sold truck tires for 41 years

[trashmanssd]

Simple but very effective way to get a good tire pressure for your specific vehicle and tire combo. If you are a very alert good driver you may want a little adjustment from there based on real word driving conditions and experience. I have had the experience on 2 totally different type vehicles (lifted jeep on 315/70/R17's and Camaro on 285/50/R20's) where I got them to ideal contact patch but in real world found I need 3-5 additional PSI as the very wide tires on both would trammel very badly on the rutted roads around where I live. Increase in pressure till the chalk test would leave just 1/4 to 3/8 of inch of slightly noticeable leftover chalk and the trammeling was gone. The both trammeled very badly on certain roads that have a look of big truck traffic and stop lights, it took considerable steering wheel effort and input to try and counter it and keep a semi straight track. Extremely scary in the Camaro on Summer high performance tires when its wet out with puddles in those tire ruts and you don't know if its hydroplaning trying to pull the vehicle or trammeling. Trammeling is annoying Hydroplaning is frightening on what were really track tires (Goodyear Eagle F1 Supercar 3). I hated those oem tires so bad that with only 8k miles on it I changed them to Continental extremecontact dws06 tires, also staggered the set up to 275 front and 315 rears. Not what you would want for the track but fine for the street and looked awesome from behind with those massive wide rear tires.