The Ultimate TRUE TIRE SIZE Database

wayoflife

Administrator
Staff member
Before I get this started, it needs to be made clear that when it comes to things like lift kits and tires you can run with them, EVERY manufacturer, shop and person in the industry will always refer to what is written on the sidewall and NOT the true height of the tire. In other words, if a 2.5" lift kit states it'll clear 35x12.50R17 tires, they are referring to what is written on the sidewall and NOT a tire that has an actual measurement of 35". In order to get a tire that tall, you would need to be running a 37x12.50R17. Why is that you might as? Because ALL tires have a true measurement that is SMALLER than what is advertised. The ONLY time true tire height matters is when you're recalibrating your speedometer as that's what your speed sensors will be reading.

With all that said, I am asking all of you to help me create a database that can help everyone better understand the difference between advertised tire size and true tire size. To do this, I would be grateful if you could please make a post and based on the following guidelines:

TRUE Tire Size Database Guidelines
1. State the brand of your tire.
2. State the size of your tire as written on the sidewall.
3. With your tire installed, aired up to 30 PSI and with the full weight of your Jeep on it, use a tape measure to measure to the edge of the tire's shoulder (NOT the highest point on the tread) and photograph it as shown in the sample below:
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4. State the TRUE measurement you are seeing as well as how many miles you have on the tires.

It is important that everyone follow the exact same metric in order for us to obtain an accurate database. Please let me know if you have any questions and thank you for your help :cool:
 

wayoflife

Administrator
Staff member
To kick things off, I will start with a set of tires that I just installed yesterday.

Cooper Discoverer STT Pro M/T
Size Stated on Sidewall: 37x13.50R17
Actual Height: 35-1/8" with ZERO Miles

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wayoflife

Administrator
Staff member
Nitto Mud Grappler M/T
Size Stated on Sidewall: 40x15.50R20
Actual Height: 38-3/16" with about 10,000 miles

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wayoflife

Administrator
Staff member
Toyo Open Country M/T
Size Stated on Sidewall: 40x13.50R17
Actual Height: 37-1/4" with about 10,000 miles

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wayoflife

Administrator
Staff member
BFGoodrich M/T KM2
Size Stated on Sidewall: 31x10.50R15
Actual Height: 29-7/16" with about 200 miles

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wayoflife

Administrator
Staff member
Cooper Discoverer STT Pro M/T
Size Stated on Sidewall: 225/75R16
Actual Height: 28-7/16" with about 3000 miles

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Wethy

Member
GoodYear Duratrac
Size Stated on Sidewall: 285/70/R17
Actual Height: 31 7/8" with about 10,000 miles

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wayoflife

Administrator
Staff member
Will add photo later

285/70/17 good year duratracs

Actual height 32"
Stated sidewall height: 33"

Please do add a photo as that's more what I'm after than anything. Also, what's stated on your sidewall is 285/70R17 - NOT 32". I would prefer that people not include what they think their tire size is supposed to be or what is stated on the manufacturer's website. This will help keep the information here as objective as possible. Last but not least, I'd like you to verify that you are running 30 PSI as is instructed and we need to know how many miles you have on them.

Thanks for your help.
 

Wethy

Member
Please do add a photo as that's more what I'm after than anything. Also, what's stated on your sidewall is 285/70R17 - NOT 32". I would prefer that people not include what they think their tire size is supposed to be or what is stated on the manufacturer's website. This will help keep the information here as objective as possible. Last but not least, I'd like you to verify that you are running 30 PSI as is instructed and we need to know how many miles you have on them.

Thanks for your help.

Ha ha I'll change it for sure! And I went to the good year site to find what they say the side was is supposed to be and that's where I got the 33" from. and I will take a picture once I get home today!

Edit to have changed previous post

I was running 30psi when I did the original test when I calibrated my tires. I'll take it an update with complete accuracy tonight when I get home from work!
 
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wayoflife

Administrator
Staff member
And I went to the good year site to find what they say the side was is supposed to be and that's where I got the 33" from.

LOL!! I hope you don't take this the wrong way but if what is stated on Goodyear's website were accurate, we wouldn't need a thread like this to point out what the "TRUE" height of all our tires are. That is why I am asking everyone to post up pics EXACTLY like the ones I have posted, with a VERIFIED 30 PSI in the tire and with a note as to HOW MANY MILES are on that tire. You still have not posted any of that.
 

swampdog

New member
BF Goodrich A/T K02

Stated Size on Sidewall - 35x12.50x17

Actual Measured Size - 33-3/4" with 2,500 Miles (aired up to 30 psi for picture from typical 28 psi)

Side note - tire shine was NOT added by me, car wash guy snuck it on...ashamed

ImageUploadedByWAYALIFE1456940698.500339.jpg
 
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WJCO

Meme King
BFG Mud Terrain (non KM2)
Size Stated on Sidewall: 255/75R17
Actual Height: 30-1/8" with unknown miles. Tire measures 10/32 in outer tread groove. New tire measures 19/32 in same groove.

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Used tire. Unknown mileage.
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New tire:

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Wethy

Member
LOL!! I hope you don't take this the wrong way but if what is stated on Goodyear's website were accurate, we wouldn't need a thread like this to point out what the "TRUE" height of all our tires are. That is why I am asking everyone to post up pics EXACTLY like the ones I have posted, with a VERIFIED 30 PSI in the tire and with a note as to HOW MANY MILES are on that tire. You still have not posted any of that.

Don't worry I don't take it wrong. I just was on lunch and posted the info I did as 32" was the actual height at 30 psi when I put the tire on and hadn't gotten a chance to take a picture to verify with a tape measure and I will do so when I'm at home later! I do apologize for any confusion I may have caused
 

noe25304

New member
B.F. Goodrich km 2
265/70/R17
About 7000 miles.
30 1/4
 

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