if original equipment tires are a 245-16" , What size 15" tire gives the same outside diameter so as to not t

Question

I want to use 15" winter tires so I do not subject my aluminum wheel to the winter salt. My truck has 245/75/16" as original equipment, What size 15" tire would give the same outside diameter so as to not through the speedometer off??

Answer 1

Your tire is about 30.4" tall

(245*.75*2) + 16*25.4 = 30.4" = 773.9

773.9/25.4=30.4"


260/75 15" = 30.35"
230/85 15" = 30.39"

I don't know if these sizes are available or not.

The first number is the tread width. (245mm)
The second number is the ratio of the sidewall to the width.
75% of 245mm
Multiply by two for the top and bottom.
The wheel is in inches so you need to convert that to mm.
Add it up.

A 260 tire is wide for winter. So look for a 85 series tire.

There is about 1.25" width differance between a 230 and a 260 tire. Depending on the width of you wheel a 260 wide may be too big.

Answer 2

Yep, 175/70 15 tyres will be virtually the same rolling radius, but it's a very odd tyre size. Try 195/65 15 which should be easier to find. If you're intent on using the thinnest possible, then a 155/80 15 will be OK on your 6" wide wheels.

Answer 3

a 31 x 10.5 r15 is the closest size that will work. you will not notice a speedo difference. the general rule for keeping the speedo accurate is to stay within 3% of the original height of the tire. this is very important if you have abs brakes. i've put these tires on many trucks with no problems.

Answer 4

245/80-15 would give the closest reading. When your speedo is reading 60 mph, you're actually going 59.9 mph. Here's how you check...

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