Hate always putting air in the 22s and the way they ride

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Anyone change from 22 to 20" tires?

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Do you mean rims?
22" tires would be very small. Most are 30-34" tires.

If rims, I've never had 22" rims.
If you're looking for a better ride, look at even going down to 18" rims.

factory 22 in rims and tires, wondering about switching to 20 rims ant tires, same height so odometer/speedometor correct

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Today I learned that different sized rims leak more

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They don’t leak more, it’s the ideal gas law

Sure if two tires are leaking air at the same rate the one with less volume is gonna run out sooner, but they shouldn’t be leaking to the point you need to “always” add air in the first place. I could buy that a smaller stiffer side wall on a larger rim allows more air to leak out around the bead cause they ride rougher, but I had no idea that was a thing before today.

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Sure if two tires are leaking air at the same rate the one with less volume is gonna run out sooner, but they shouldn’t be leaking to the point you need to “always” add air in the first place. I could buy that a smaller stiffer side wall on a larger rim allows more air to leak out around the bead cause they ride rougher, but I had no idea that was a thing before today.

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I don’t think it’s leaking around the bead any more than a smaller rim. That could be the case with certain rim or tire combinations. Also some tires might allow air to permeate more than others, but overall I believe it’s because if two tires are leaking air molecules at the same rate, you will see a larger pressure drop in the tire with less air molecules in it.

Assuming constant temperature and volume, I calculated the difference between my truck tires 275/65r18 and my wife’s tires 255/55r20 if both tires lost 3 moles of air. If both tires started at 40 psi, I figured that mine would drop to 28.9 psi while hers would drop to 23.2 psi.

When I originally replied to you, I was just trying to be a smartass, although I’ve always figured the reason I had to fill up her tires more often than mine was related to the ideal gas law. I never actually tried to figure out why until now.

I could be wrong, and I hope someone corrects me if I am. But that makes more sense to me than larger diameter rims sealing worse than smaller diameter rims.


ETA: To the OP, sorry for the derail. But if you want better ride quality, as others have said going to a smaller rim will make a big difference. I don’t think there’s anything wrong with an 18” wheel on a full sized truck. It rides better, looks better IMO, and is more functional for navigating obstacles on and off road. You will also have to add air less frequently, although the reason why may still be up for debate

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Permeation would be worse with a tire with more surface area, and it’s a very tiny amount compared to leaks around the valve stem or bead.

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Good discussion I think it depends on a lot of factors, but a lower profile tire will generate a higher temperature on the road, making the air more permeable, leading to more loss from permeation. A low profile tire will also deform more with a drop in tire pressure which would also worsen permeability. I agree that more surface area would be more permeable, but I also didn’t consider that my tires are 10 ply compared to my wife’s 4 ply which I’m sure makes a difference as well.

I’ve only ever had my tires vs my wife’s for comparison. I’m not positive my theory is the reason why I air hers up more, but I’m still not sold on the theory that a lower profile tire doesn’t seal as good on the rim.