After a blowout or flat will tire pressure increase on remaining tires

Jethrine

New Member
May 27, 2019
6
Been an auto mechanic since 1984. A couple years ago while setting TP for the 10,000th time with a car on the rack I had a thought, TIRE PRESSURE PROBABLY CHANGES WHEN THE CAR'S WEIGHT IS ON TIRES!!
I let the car down and the change was not detectable.

The surface area of tire/wheel torus is too great for the weight to have a big impact pressure/area squared.


This is going from ZERO live load on tire to full weight of vehicle on tire.
 

brettstoner

Active Member
Jun 17, 2014
130
Toledo, OH
Physics speaking the tire pressure will go up on other tires because of increased heat and increased load. But in reality will this be measurable? Maybe....

Load
Measure tire pressure with tire off ground. Then drop trailer back on ground and measure tire pressure. You just added a couple thousand pound load. How much did tire pressure change? Negligible. The tire deformed, contact patch changed, sidewall flexed, tire carcass shape changed, etc. to accommodate increased load. The air volume inside the tire probably decreased very little causing a very minor increase in pressure.

Heat
The change due to heat may be noticeable. It is generally recognized for every 10 degree change in temp results in 1 psi change. If you got a flat how much weight will increase on the other tires. If its a tandem tire then a lot as it is now taking that load. If its on the other side of the axle probably not much. The flat tire will still carry its weight. Increased load causes increased heat as the tire carcass is now flexing more generating more heat.

So with that being all said would I rely on noticing changes to other tires if one tire was low. No I wouldn't. Your best case would be noticing a change in pressure on the tandem tire as the load would be increased significantly causing more heat to be generated and a corresponding increase in tire pressure. How much increase of tire pressure? Who knows. It all depends on the load, speed, air temp, tire sidewall flexing, etc.
 




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