Width for 37s

[Allen0jason]

In doing research, I have come across the fact that one tire versus another can be two different widths( Boss AT=12.5 vs Ridge Grap=13.5) my question is given all of the parameters being the same, wheel size, backspacing and everything else, is there an advantage to one width over the other.

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[AcesandEights]

A narrower tire has a higher psi at the ground. Same vehicle weight spread over a smaller contact patch, maybe.

 

[Philly_]

A lot of it is going to depend on what the backspacing is on your wheels and how much clearance you have. If your wheels are snugged in pretty tight under the Jeep, a 13.5" wide tire will have a better chance of rubbing at full lock.

Also, your wheel may be better suited to a 12.5" wide (depending on how wide your wheel is) than a 13.5" wide, or the other way around.

13.5" wide will be heavier as it takes more rubber to fill the mold.

13.5" may be more prone to wandering as they will be less likely to sit in the wear grooves on the road, but most 12.5" tires struggle with this anyways, so it may not be a factor.

Personally, I would stick with 12.5" wide if at all possible, but I have also yet to run 13.5" wide. I am sure the extra width will help you out off road, but there seems to be more advantages to the 12.5" wide tire for my particular use case and wheels. I run 17x8.5r17 Method 704's with 4.75" of backspacing (0 offset).

 

[phageghost]

A narrower tire has a higher psi at the ground. Same vehicle weight spread over a smaller contact patch, maybe.

Given the same PSI (and ignoring the spring effect of the sidewalls, for simplicity, though it's not really negligible it just makes everything a lot more complicated), any two tires will have the same size contact patch, because the pressure of the ground against the outside of the tire has to equal the pressure from the air against the inside of the tire (otherwise there would be a net force on the tire patch and it would be accelerating upward or downward). The tire will deform to achieve a contact patch such that the weight of the jeep on that wheel divided by the air presssure equals the contact patch area. For a narrower tire, what this means is that the contact patch will be longer (forward and backward) to achieve the same area with less width, meaning the tire will deflect more downward to achieve this longer contact patch. Hope that makes sense.

[Edited to reflect @J0E's comments about sidewall force]

 

[AcesandEights]

Given the same PSI (and ignoring the spring effect of the sidewalls, for simplicity, though it's not really negligible it just makes everything a lot more complicated), any two tires will have the same size contact patch, because the pressure of the ground against the outside of the tire has to equal the pressure from the air against the inside of the tire (otherwise there would be a net force on the tire patch and it would be accelerating upward or downward). The tire will deform to achieve a contact patch area such that the weight of the jeep on that wheel divided by the air presssure equals the contact patch area. For a narrower tire, what this means is that the contact patch will be longer (forward and backward) to achieve the same area with less width, meaning the tire will deflect more downward to achieve this longer contact patch. Hope that makes sense.

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[Apples491]

A wider tire will make better contact with obstacles offroad and provide better grip. But, that increased contact and grip means more weight and worse fuel economy.

Thinner tires are better for snow, though I doubt an inch would make much of a difference.

 

[NoahVD]

A wider tire will make better contact with obstacles offroad and provide better grip. But, that increased contact and grip means more weight and worse fuel economy.

Thinner tires are better for snow, though I doubt an inch would make much of a difference.

I wouldn't say no to an extra inch

 

[Apples491]

I wouldn't say no to an extra inch

When you're already hitting the .. uh .. frame, that inch doesn't accomplish much.


Are ... are we still talking about tires?

 

[AcesandEights]

A wider tire will make better contact with obstacles offroad and provide better grip. But, that increased contact and grip means more weight and worse fuel economy.

Thinner tires are better for snow, though I doubt an inch would make much of a difference.

"A wider tire will make better contact with obstacles offroad and provide better grip". I think the opposite is true. Thinner tires can be better in snow.

 

[Apples491]

"A wider tire will make better contact with obstacles offroad and provide better grip". I think the opposite is true. Thinner tires can be better in snow.

More tread surface, particularly when aired down, allows the tire to conform around rocks and hard surfaces. And driving in sand is ALL about surface area.

 

[No IFS]

9” Minimum

 

[Anonymous]

9” Minimum

From rear to tip? I guess I’m good!!!

 

[roaniecowpony]

When you're already hitting the .. uh .. frame, that inch doesn't accomplish much.


Are ... are we still talking about tires?

It's been quite a few years since I hit the frame.

 

[Borderline Jeep]

If you run on sand a lot, I'd go 13.5. For everything else, I'd go 12.5 for the weight savings.

 

[2nd 392]

It's been quite a few years since I hit the frame.

Could increasing the size of the shed covering your tool over the years be an impediment! ?

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