high pressure tires

[JohnnieB]

I'm not sure where to draw the line for Low Pressure vs High Pressure, but my guess is about 15PSI.

I can't remember who, but one forum member had some speed loss with 14PSI tires, so you might see a little with 18PSI tires, but probably not much.

There are other variables also. IE: Width and tread pattern.

[kojo]

yurtle, I'm kind of thinking that myself. I figured the wider the tire the more rolling resistance a cart would have. I kind of thought of it like a bicycle, you take one w/ narrow tires and take the same bicycle but w/ wider tires and pedal both to 20mph and stop pedaling. The one w/ the narrow tires will coast further than the one w/ the wider tires. Using that theory, I got 23x8x12's. If I get the other set of rims I'll prob. get 25x8x12 to swap around with. Wonder what would happen if you put around 18-20psi in a tire rated for 7psi. Kaboom?

[kojo]

Thanks JohnnieB, when I started the last post yours wasn't there yet. It takes me a tad bit longer to type than most I guess. I've seen a couple that were 18psi that I liked pretty good but, haven't made my mind up yet. I might end up getting a set like I've got now but in 25".

[JohnnieB]

Originally Posted by yurtle

Again, I know nothing about tires, but what we're really talking about is rolling resistance correct? I'm assuming that the more rubber on the road, the more rolling resistance. Wouldn't the stiffness and width and tread pattern matter more than pressure?

Rolling resistance is the end result, but there are several factors that add up to the rolling resistance, so it is a combination of inflation pressure, sidewall flex, tread width and tread pattern, plus some others probably. I don't know which ones are the greater contributing factors.

Perhaps sidewall stiffness offsets low air pressure. Maybe a mile wide tread is more efficient than a narrower aggressive tread.

The vehicles setting Land Speed records at Bonneville had skinny tires with no tread and extreme inflation pressures.
Dune-buggies have wide tires that are barely inflated with treads that will shake your teeth out if drive on a hard surface.

It depends on what you want to do with your cart.

[JohnnieB]

Originally Posted by kojo

yurtle, I'm kind of thinking that myself. I figured the wider the tire the more rolling resistance a cart would have. I kind of thought of it like a bicycle, you take one w/ narrow tires and take the same bicycle but w/ wider tires and pedal both to 20mph and stop pedaling. The one w/ the narrow tires will coast further than the one w/ the wider tires. Using that theory, I got 23x8x12's. If I get the other set of rims I'll prob. get 25x8x12 to swap around with. Wonder what would happen if you put around 18-20psi in a tire rated for 7psi. Kaboom?

Originally Posted by kojo

Thanks JohnnieB, when I started the last post yours wasn't there yet. It takes me a tad bit longer to type than most I guess. I've seen a couple that were 18psi that I liked pretty good but, haven't made my mind up yet. I might end up getting a set like I've got now but in 25".

I type slow also.

The standard cart tire is 18x8.50-8, so your tires are actually 0.5" thinner.
However, what is marked on the sidewall seldom matches the actual mounted dimensions of the tire, other than rim size.

Running at double the max inflation pressure stamped on tire is iffy, but tripling it might be asking for trouble. One thing is for sure, the center of the tread will wear out first.

[kojo]

I'll be either on a fairly hard packed dirt road or highway so I might just go w/ the 25" version of what I have now, their rated 20 or 22psi. Don't really want to slow down any if I can help it.

[yurtle]

The only reason I was questioning pressure vs. stiffness is I'm assuming some folks are using tires that may not be golf cart specific. I may be wrong, but a higher pressure tire designed for a lighter load MAY flex more than a lower pressure tire designed for a heavier load. This would affect how much rubber is on the road, but in actuality, it may be insignificant.

Merely a thought.

[sportcoupe]

Originally Posted by kojo

Wonder what would happen if you put around 18-20psi in a tire rated for 7psi. Kaboom?

No, no kaboom. I ran 15psi in tires rated for 5psi because of the high weight of that particular golf cart. No issues whatsoever with the higher pressure. Mind you, running higher pressure doesn't make it a high pressure tire either.

[sportcoupe]

Originally Posted by kojo

Sportcoupe, how much reduction in speed did you lose w/ the change?

It wasn't much, something like 2 mph but I should have went faster some, not slower by going from 23" to 26" tires. That was the point of my post. I had the power also so I blame the ATV tires.

[kojo]

I'll probably stick to a all-trail high psi tire. I'm happy w/ my speed now and definitely don't want to slow her down any. Dang it, why don't some of the atv tire companies make some versions in high pressure.