Tire help please

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Jul 25, 2018 | 12:08 PM

corvair62

Thread Starter

Mountain Pass

Joined: Apr 2016

Posts: 172

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From: White Bluff, TN

Tire help please

I'm just about ignorant when it comes to tires. A little help is much appreciated. F150 2wd. Rims are not stock. Current tire size is 275/60/r15. I do not know how wide the rim is, but if I had to guess, I would say they are 8's.
I'm needing to replace my tires and wanted to know a good tire size and make that would be a little taller and a little narrower. I dont mind the width, but I was told a narrower tire might handle a little better. Just looking into different options to see what all of you experts think. As always thanks for the replies and the use of your knowledge.

Jul 25, 2018 | 02:53 PM

flatbedfordguy

Elder User

Joined: Apr 2018

Posts: 567

Likes: 3

Your best bet is to check out any of the numerous tire sites on the web and play around with the numbers using their tire size calculators. They will give you exact tire height, tread width, section width, and rim width measurements down to the tenth of an inch.

Jul 25, 2018 | 03:12 PM

corvair62

Thread Starter

Mountain Pass

Joined: Apr 2016

Posts: 172

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From: White Bluff, TN

Let me rephrase. Most tire sites do not elaborate for the dumb. I'm trying to see if any here have a 2wd with 8in wide rims and if so what tires width wise will fit. I have 275/60/r15 and havent found a 265/60/r15, so would a 255/60/r15 work. The tire sites i'm finding dont answer that ? with a yes or no. Please see 1st post, I know next to nothing about tires.

Jul 25, 2018 | 04:42 PM

D-rat

Elder User

Joined: Oct 2016

Posts: 712

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From: Mesa, AZ

Let's describe what those tire sizes mean. Those are metric sizes:

275/60/R15
Means the tire tread width is 275mm
The 60 is the aspect ratio - meaning what % of the tread width is equal to the sidewall height
R = Radial. (you may see an LT designation sometimes before the size - that would signify a light truck tire)
15 - this is the obvious one....rim size.

25.4 is the dividing factor to convert MM to inches. In this case 275 divided by 25.4 equals 10.83 inches. As a general rule of thumb the rim width should be 2-4" less than tread width, so an 8" rim is a good match for that size tire.

To calculate height, first multiple tread width times the aspect ratio: In this case, 275 x 60% = 165. Convert that to inches now: 165/25.4 = 6.49 inches. Multiply that times two and add the rim size for the tire height. 6.49 x 2 = 12.98 + 15 = 27.98"

Hope this helps you in your tire search.

Jul 25, 2018 | 04:57 PM

corvair62

Thread Starter

Mountain Pass

Joined: Apr 2016

Posts: 172

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From: White Bluff, TN

Thank you. This makes it alot easier to figure out. Now i can do the math a lot easier understanding the "a general rule of thumb the rim width should be 2-4" less than tread width". I dont believe i have ever read that bit of info and if i have, i had forgotten.

Jul 25, 2018 | 05:12 PM

72rtchallenger

Fleet Mechanic

Joined: Jul 2017

Posts: 1,276

Likes: 12

From: KY

Quote:

Originally Posted by corvair62

I run 8" rims P235/70R15 on front and have 10" inch rims on back an run th P275/60R15 on rear and get a good driving feel, if I had same rims all the way around I would run the same on all rims but I do like this setup I have , I have it on a few autos I own an have owned except my challenger but that's another reason ., but its just what I like to run, many may differ on tire size an how it handles an drives on there own truck or car