Tire Pressure Question

[Brian B-P]

Correcting a typo and resulting numbers:

A rise of temperature from 40 F to 65 F is a rise from 500 Rankine to 525 Rankine, a 5% increase in temperature of what you might ideally call a fixed volume of gas (air)... which would then mean a 5% rise in pressure. That's an increase from 50 psi to 52.5 psi... hey, it looks like the rule of thumb is good enough in this case.

[thoer]

Has anyone replaced their original ST205/75R14 with ST215/75R14?

I think the size difference is quite minimal (0.6" diameter) and should have no clearance problems, so why not go for slightly higher load capacity which should make the tire less stressed?

[Brian B-P]

Originally Posted by thoer

Has anyone replaced their original ST205/75R14 with ST215/75R14?

No, but I have considered various alternate sizes for my similar trailer.

Originally Posted by thoer

I think the size difference is quite minimal (0.6" diameter) and should have no clearance problems, so why not go for slightly higher load capacity which should make the tire less stressed?

I agree, and Escape's changes to larger sizes suggest that Reace agrees; however, there must be a point at which the benefit of larger sizes is less than the cost. Costs include higher purchase cost, likely higher rolling drag, slightly higher trailer ride height (less stability and more air drag), and slightly less effective brake performance (due to tire diameter increase without a brake drum diameter increase). This slight change is probably nowhere near reaching the "too big" point, but I don't know where that point arrives.

This change would be more than generally advised for tire swaps on a motor vehicle, but motor vehicles have implications for drivetrain gearing.

[gbaglo]

Toad came with the high lift axle and ST205 75R15 tires.

[J Mac]

Originally Posted by gbaglo

Toad came with the high lift axle and ST205 75R15 tires.

Your sticker says your tires are ST205-75R-14. Did you change tires?

[gbaglo]

The sticker says "Minimum" size.
The 15" tires came with the high-lift axle option.
I too missed that little word "minimum" and went out to check my tires.

[J Mac]

Originally Posted by gbaglo

The sticker says "Minimum" size.
The 15" tires came with the high-lift axle option.
I too missed that little word "minimum" and went out to check my tires.

I guess the closet sticker is different. I was reading the exterior sticker. That one just states tire size.