Tire pressure overinflation

[WSL91]

Was going over the XJ I picked up last week. Checked the tire date codes and the rear is 4 years old Kenda and looks like new, the front is 5 years old Dunlop and looks like new except with cracking around the bead and sidewalls. PO reports both were put on new last year. Went to check air pressure and the rear was around 25lbs. The front was somewhere near 80lbs. I lowered it to 40 which is what I run on my Honda and I think the tire says 25. I think I know the reason this tire failed prematurely. I have a new front tire on order.

[skids]

I was told by a car tire dealer that overinflating tires can cause separation of the meat from the carcas. I am not sure how much over you can go before damage occurs, because this is sometimes done when seating the bead on a tubeless tire to the rim.

[cywelchjr]

I was told by a car tire dealer that overinflating tires can cause separation of the meat from the carcas. I am not sure how much over you can go before damage occurs, because this is sometimes done when seating the bead on a tubeless tire to the rim.

If you inflate the tire to max pressure cold and then ride the bike, it WILL exceed the max pressure. This is however fine, as the max pressure is a COLD pressure and the pressure rise from heat rise when riding is figured into the equation.

Now here is where the arguments start. What tire pressure to use. If I try to use the pressure the manual states with modern tires, the bike wallows like a pig and the tires wear really fast. If I run 40 on the rear and 38 on the front the bike handles well, and I get good even tire wear. This of course assumes the tires you are running have a max pressure that is at least 40 psi. The true calculation of proper tire pressure is only able to be determined by determining the max load of the tire and how much load the bike is putting on the tire as loaded compared to max load.

[Stoffa]

temperature

I use an rule of keeping the pressure rise in the tyre to less than +4lbs, all things being equal. ie - cold to hot should not be more than 4 lb if so increase (or decrease) cold inflation by the difference. Has worked my old bikes and 4WD for years.

[WSL91]

I replaced the front tire today. First motorcycle tire I've changed. I've changed truck tires before. The sidewalls were very stiff on the tire I took off, the new one was much more pliable. Bought a Harbor Freight bead breaker and wheel balancer.