The Ultimate TRUE TIRE SIZE Database

OverlanderJK

Resident Smartass
Hummm, although this is a great thread, i take some exception to the measuring methods. i went out and measured my new jl 2019 jeep tires(I'm new, haven't figured out how to post photos yet). i used a square clamp and measured like a caliper in the center of the wheel while hanging on the wheel rack(no weight). the tire is 245/75/r17 printed on the side wall. this metric equals 31.5". the tire measured 31.47". then i did as the post instructions requested, and went to the ground up measurement. it was 30.9375. the .5" difference is the "belly" of the tire sinking in a bit. all tires do the same thing. at 30 psi the tires still have the belly sag. the second issue is how we look from the tape measure to the tire thread, and at what angle. if a 12" level was laid across the tires, and measured would be more accurate. by analyzing the data posted, there is a direct correlation by the tire sizes small to large by the difference of the stated size vs actual size. as 1 example an BFG MUD_TERRAIN T/A KM3 lt295/70/r17 states the overall diameter at 33.3" at proper pressure. the company states the max psi is 80 psi. if this tire is deflated to 30 psi im not surprised to see a 1.5" to 2" smaller measurement. bfg's "35" is stated to be 34.6". i think this is closer to correct than 33" reported here. also consider a tire rolling/spinning at 624 revs per mile, at 70 mph, is probably larger in diameter.

the question i'm trying to answer, is what is the maximum size tire i can install on a stock/no lift 2019 jl sport 2 dr Jeep wrangler? has anyone had first hand experience ?

Holy fuck. Leave all that other shit out and just ask what tire size.


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2nd.gunman

Caught the Bug
Hummm, although this is a great thread, i take some exception to the measuring methods. i went out and measured my new jl 2019 jeep tires(I'm new, haven't figured out how to post photos yet). i used a square clamp and measured like a caliper in the center of the wheel while hanging on the wheel rack(no weight). the tire is 245/75/r17 printed on the side wall. this metric equals 31.5". the tire measured 31.47". then i did as the post instructions requested, and went to the ground up measurement. it was 30.9375. the .5" difference is the "belly" of the tire sinking in a bit. all tires do the same thing. at 30 psi the tires still have the belly sag. the second issue is how we look from the tape measure to the tire thread, and at what angle. if a 12" level was laid across the tires, and measured would be more accurate. by analyzing the data posted, there is a direct correlation by the tire sizes small to large by the difference of the stated size vs actual size. as 1 example an BFG MUD_TERRAIN T/A KM3 lt295/70/r17 states the overall diameter at 33.3" at proper pressure. the company states the max psi is 80 psi. if this tire is deflated to 30 psi im not surprised to see a 1.5" to 2" smaller measurement. bfg's "35" is stated to be 34.6". i think this is closer to correct than 33" reported here. also consider a tire rolling/spinning at 624 revs per mile, at 70 mph, is probably larger in diameter.

the question i'm trying to answer, is what is the maximum size tire i can install on a stock/no lift 2019 jl sport 2 dr Jeep wrangler? has anyone had first hand experience ?

So in summary, we’re all doing it wrong but you want our opinions anyway?


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sm31

Active Member
Pro Comp Xtreme MT2 35" x 12.50" x 17, on 17" x 9" wheels. About 800 miles...

33 5/16's.
 

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Wildlee

New member
So I’m prepared to get blasted on here for asking questions. So here goes lol. Read every post, so if I wanted a “true” 35 based on this forum I should get a 37? Say for example the cooper STT Pro’s. I look forward to the replies.
 

WJCO

Meme King
So I’m prepared to get blasted on here for asking questions. So here goes lol. Read every post, so if I wanted a “true” 35 based on this forum I should get a 37? Say for example the cooper STT Pro’s. I look forward to the replies.

But then you'll be disappointed that your 37s aren't 'true' 37s, and then you'll have to get 39s.
 

Jsouder53

Hooked
So I’m prepared to get blasted on here for asking questions. So here goes lol. Read every post, so if I wanted a “true” 35 based on this forum I should get a 37? Say for example the cooper STT Pro’s. I look forward to the replies.

That’s not a question you’ll get blasted about... but yes a true 35 is basically a 37
 

WJCO

Meme King
How does that affect/apply to all the threads referencing lift required for tire sizes? Max tire size recommendation for axle types, etc?


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It doesn't apply. If the lift manufacturer says 35 inch tire, that's what should be printed on the sidewall, not the actual measured size.
 
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