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Wed May 19, 2004 10:33 am

Hello!

This is going to sound stupid but here goes. What do the #s in a tire size mean? e.g. 165R15. I know the "15" is the wheel size they fit, but what is the 165? Is there something for width?

I ask because I'm trying to fit a set of 165R15s (Cooper relabled) on my '68. Wheels are some aftermarket 8 spokes. The tires are a bit wider than the old ones. Fronts fit with a little modification to the calipers. The rears though are a problem. When I lift up the car, the rear tires tilt in on the bottom. When I lower the car with the new wheels on, the tires don't tilt out again and the fender edge sits right down on top of them. So I assume I need a thinner tire. Right? Wrong? Insane?

TIA!

Wed May 19, 2004 12:25 pm

Well... this could sound like a stupid answer, but it would be the easiest. Are you sure that the fender is catching them or are the springs still holding it a tilt, because I know with my ghia that I have to roll it first before the tires will straighten out.

Wed May 19, 2004 12:29 pm

Not a stupid answer! I thought of rolling it, but I was worried that the fenders would start shredding the tires if I did that. Is there another artificial way of getting them to stand up straight?

Wed May 19, 2004 4:16 pm

i had the urethane torsion bar bushings replaced and the drivers side spring plate adjusted one or two notches and it leveled out my 73 coupe. a fat guy must have been a previous owner.

Wed May 19, 2004 4:29 pm

Cobey wrote: Hello!

This is going to sound stupid but here goes. What do the #s in a tire size mean? e.g. 165R15. I know the "15" is the wheel size they fit, but what is the 165? Is there something for width?

I ask because I'm trying to fit a set of 165R15s (Cooper relabled) on my '68. Wheels are some aftermarket 8 spokes. The tires are a bit wider than the old ones. Fronts fit with a little modification to the calipers. The rears though are a problem. When I lift up the car, the rear tires tilt in on the bottom. When I lower the car with the new wheels on, the tires don't tilt out again and the fender edge sits right down on top of them. So I assume I need a thinner tire. Right? Wrong? Insane?

TIA!

Back to your original question: 165 should mean your tires are 165 millimeters wide.

Wed May 19, 2004 6:13 pm

ok so stocks are 165/15 what series are the equal to? what I mean by that is I want to put on my bus 195/50/15 so this would mean that they would be wider by 30mm and shorter than stock by how much??????

Wed May 19, 2004 7:32 pm

vwtony2 wrote: ok so stocks are 165/15 what series are the equal to? what I mean by that is I want to put on my bus 195/50/15 so this would mean that they would be wider by 30mm and shorter than stock by how much??????

http://www.miata.net/garage/tirecalc.html

Wed May 19, 2004 7:34 pm

Thanks Icy and all. So, is there a manual way to get the springs to release the tires from a tilt without needing to roll it?

Wed May 19, 2004 8:47 pm

:idea: I think I have it figured out. Using a level and tape measure, I measured the distance from the inside of the rim to the outside of the tire on both the new and old wheels. The old wheels have 1/2" more on them which, if I am thinking on this correctly, means the new wheels cause the tire to protrude out an extra 1/2" from the axle. I am fairly certain getting that 1/2" back will fix me up. So, I'll have to go find a shop to swap the tires onto the old wheels. Which is what I was going to do anyhow. :)