What size tire = 30" diameter on 15" rims?

I'm in rear end ratio hell today. I'm just trying to play with some numbers before I buy any parts.

The tires on my pickup with 15" rims are: P205/75 R15
These yield a 26" total rear wheel diameter.

What size tire would I buy to go to a 30" diameter? This would add 2" to the tire's side wall. A web site or formula would be great.

Here's a chart I've been playing with. I now know I have a 3.78 rear. This chart shows RPM reduction by changing tire diameter.

Thanks, Mike

 

try this site, they have all the dimensions of various sized tires, radial and bias. www.cokertire.com

 

the 205/75 15's are actually 27.1 inches in dia.

lemme figure out what size 30 inchers would be

 

.





Why not move up to a 16" rim and tire?

 

225 85 15 would be close if they make em...

245 75's would be about 29.5"

 

235/75R15 tires are standard for most 1/2-ton pickups and measure about 29" tall. That may not be exactly what you're looking for, but it's a popular size so tires are cheap and available with many different tread patterns & sidewalls. They mount well on 6 or 7" wide rims.


Ed

 

you need a 285/70x15 30.8 inches in diameter, 'bought 10 inches in section width.........

BFG T/A is the only animal that this is available in as far as I know......

-SAM

 

I don't know if it's close enough for you or not, and the application may be totally wrong, but a 315/60-15 is 29.9" tall, with 11" of tread, and fits perfect on a 10" rim.

 

Thanks for the heads up on the tire sizes. I only threw out 30" as an approximate diameter. Seems like the 235/75 R15's may be the call.

I'll look at 16" options too.

Thanks,

Mike

 

Oh,

And I found a site that clearly lists the height. I still don't understand the formula. I'm the kind of guy that likes to know that stuff, but if I search a little harder I'll find it or figure it out.

http://www.whitewallsplus.com/products.htm

Thanks,

Mike

 

````````walmart has the 235's $33 a tire and you can grind the white wall if you want. 40,000 mile warantee. Cant beat that with a stick. Im gettin two wednesday night afterwork and using portawalls for the whitewalls for my ride.

 

if you want portawalls I have a secretconection on the portawalls but you hamers wouldnt like it cause its conected to the "V" word. Cheap though. $50.00 for a set of 4

 

like 5SPOKE sed, the BFG 285/70R15 is the size you describe,

good quality name brand tire