max tire size on 14" rim

We just bought a 99 27/20. I did the wheel well Mod ( slight damage on one side from previous blowout) this weekend

I currently have 3 mismatched 205 /14" tires.

Can I go to 215 tires on 14" wheels?

Or how wide a 15" wheel do I need for an up grade.

[Barb&Tim]

Ooops, thanks Bobby, 255 was a typo, corrected now to 225!


TM puts ST225/75R15 tires on all TMs now. It should fit yours also but you may need a lift kit if you have less than 3" clearance from top of your current tire to the wheel well. The following search link should give you some relevant info:

http://www.trailmanorowners.com/foru...earchid=647904

Tim

yes it has a lift

Originally Posted by Barb&Tim

TM puts ST255/75R15 tires

I believe that was a typo and Tim meant ST225/75R15.

[Bill]

Perhaps I am confusing myself, but ...

Originally Posted by 1gopokes1

Can I go to 215 tires on 14" wheels?

The answer ought to be a simple yes. A 205, 215, or 225 tire will fit fine, as long as it is a 14-inch tire.

And

Or how wide a 15" wheel do I need for an up grade.

The word "wide" and the word "15 inch" do not go together. As Bobby told me once, somewhat to my embarrassment, the measurements "14-inch" and "15-inch" refer to the diameter of the hole in the middle of the tire, and thus to the diameter of the steel wheel that the tire will be mounted on. These two must match, of course, so a 14-inch tire will fit on a 14-inch wheel, and a 15-inch tire will fit on a 15-inch wheel.

You can't put any 14-inch tire on a 15-inch wheel, or vice-versa.

"Width" is not directly related to either of these diameters. When discussing the wheel, "width" refers to the width of the steel wheel at the rim, and thus to the dimension across the tire bead. The tires that we use as TM'ers tend to be 6 inches wide, and so they will fit 6-inch wheels. (Since tires are flexible, some of them will fit 7-inch wheels - but don't do it.) In other words, a 14-inch wheel spec'ed to accept a 6-inch wide tire is called 14X6, and a 15-inch wheel spec'ed to accept a 6-inch wide tire is called a 15X6 wheel.

The wheel width is not part of the tire's numerical description. Most of our tires are 6-inch width, so most anything you buy will be fine. But if you are upgrading, be sure to buy 15x6 wheels, not 15x7.

That is probably not what you meant ... And to make it more confusing, there is a width spec for the tire, related to the 205-215-225 number, which is something else entirely. Bobby, what have I messed up? Go to it ...!

Bill

Originally Posted by Bill

Bobby, what have I messed up? Go to it ...!

You're doing great!

Since I am having a slow day at the shop, I will go ahead and bore everyone some more with this.

Most metric tire sizes are divided into 3 parts (or the one most commonly used, on our vehicles and OE tire sizes)

1. You have your section width, which is the measured width between the two bulging parts of the sidewall, when the tire is loaded at it's nominal carrying capacity. This is the first number in your tire size (Ex 225)

2. Now you have your aspect ratio (aka section height). This is a ratio (or percentage) of the section width, and is the measured distance of the sidewall from the ground to the rim. It is the second number in your tire size. (Ex 75, which means the tire is 75% as tall as it is wide)

3. The last number is the rim diameter. It is the width of the hole in the middle
of the tire. (Ex 15)



Now to the part about widths. Each tire size made is supposed to conform to an industry standard (but can vary a little). It all has to do with the section width, and just exactly where the sidewall bulges out. Remember that the section width is supposed to be the measured width at nominal loaded capacity. Some tires have this bulge higher or lower up on the sidewall, which can account for different tires from different manufacturers being a little taller or smaller than the competition. It's not supposed to be much difference though.

When you read a manufacturer specification chart for a tire, it will have a recommended rim width range for each size tire. You can see this on the chart below. (ex 5.5 inches to 7 inches for a 215mm section tire)

You also may notice another part on the chart called the "Measured Rim Width". This is the true rim width that the tire was measured upon to get the numbers that are on the chart. (the 215mm tire was measured on a 6" wide wheel).

If you place a tire on a narrower or wider wheel, it does affect the section width measurement (and the overall diameter slightly). We've been told that the section width is affected between 1/10 and 2/10's of an inch for every 1/2 inch in rim width. If you mount it on a narrower rim than "measured rim width", it narrows the section width and stands the tire up just a hair taller....and the opposite is true with wider rim widths.

Are we bored to sleep now?

[mjlaupp]

Originally Posted by wmtire

Are we bored to sleep now?

But Bobby, what about backspace, offset, hub-centric, lug-centric, etc.

Originally Posted by mjlaupp

But Bobby, what about backspace, offset, hub-centric, lug-centric, etc.

Mike, I'm not having THAT slow of a day.