The Ultimate TRUE TIRE SIZE Database

SilverBack said:
Just out of curiosity, does anyone have the mounted size of the Toyo Open Country AT II 285/75R17? Seriously looking into these..
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I have 285/75r17 in the nitto terra grappler g2 and it measured 33" with 30 psi when brand new. It should be exactly the same as the toyo considering they are owned by the same parent company
 
Mastercraft Courser MXTs with less than 500 miles
Size: 37x12.5x17
Height: 35.125" @ 30psi
Installed on my '07 JKUR loaded up with SB steel bumpers, winch, Hi-Lift, etc.


image.jpg
 
Mickey Thompson Baja MTZ
Size on sidewall: 315 / 70 R17
30psi
33 1/4" actual height with 20k
ImageUploadedByWAYALIFE1457390786.353172.jpg
 
GoldenJK said:
Yep. My MTRs are wore our and cupped bad. Someone please post Nitto Grappler M/T in a 37x12.5R17. That's next if it fits in parking garage
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I have those tires and should be putting them on soon, if no one has answered by then.

Edited: already answered in post #41.
 
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1. Goodyear Duratrac
2. 315/70/17, about 45k miles. 8/32 left
3. Almost exactly 33". About 33 1/4 when new mounted, 33.75 when new, off jeep. Angle is a bit odd on pic, was trying to hold flashlight in mount, and tape, and get a good angle on the photo

 
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wayoflife said:
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:
main.php


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:
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It might make sense to include the width of the wheel that you are running as well. I have these exact same tires, but mounted on a stock 17" x 7.5" rim, it measured 36.25". I don't have a picture as I just used that to correct the computer with the programmer. Verified speedometer reading with GPS. I'll have to go out and measure and take a picture now that I have a few thousand miles on them.
 
Tire: 37x12.50R17LT Nitto Trail Grappler
Wheel: AEV Pinter Beadlock
30 PSI
Tire mileage: 50
Tire height: 35.5 (almost)
Tire width: 10.5 (almost)
 

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So here is a question. IF you are using a programmer to adjust for your new tire size, are you putting in what the tires size says on the specs or are you going off your personal measurements. As seems from the above posts, most member's personal measurements seem to be 1-2" off from the stated specs. :thinking:
 
You would use the actual height of the tire not the specified size. As you can see here nothing matches the stated size and if you want an accurate speedometer you need the true size to make it correct.
 
Samlautranger said:
So here is a question. IF you are using a programmer to adjust for your new tire size, are you putting in what the tires size says on the specs or are you going off your personal measurements. As seems from the above posts, most member's personal measurements seem to be 1-2" off from the stated specs. :thinking:
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You need to measure the radius from the ground to the center of the wheel and then double it, this is the number you should enter in the programmer. It should be less than the overall height that you would post here.
 
Toyo Open Country M/T
Size Stated on Sidewall: 37x13.50R17
Actual Height: 35-1/2" with about 13,000 miles

1459101585242.jpg
 
BF Goodrich T/A KO2

34 x 10.5R17

Mounted on AEV Pintlers 17x8.5

Actual size with 35 psi - 32 3/8"

0 miles

BFG KO2 34s.jpg
 
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Samlautranger said:
So here is a question. IF you are using a programmer to adjust for your new tire size, are you putting in what the tires size says on the specs or are you going off your personal measurements. As seems from the above posts, most member's personal measurements seem to be 1-2" off from the stated specs. :thinking:
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The AEV Procal instructions, tell you to measure the tire.

ImageUploadedByWAYALIFE1459359866.595509.jpg
 
As a comparison to the above KO2s in 34x10.5 here are the tires they replaced.

A tad shy of 40,000 miles with about a 1/4" of tread left

BF Goodrich T/A KOs

285/70r17

AEV Pintlers 17x8.5

31 1/8" at 35 PSI

Pretty sure they were around 31.75" when new (I remember being very disappointed that my "33's" weren't even "32" :eek: ). Now that I know about real tire "sizes" I am over it

IMG_0077.JPG
 
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