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Tire Size vs. Hub Height Survey

jjvw

0-60 in 18 seconds
Supporting Member
Feb 17, 2018
6,654
Colorado, USA
What is your tire size printed on the sidewall?
What is your hub height?
What is your psi?
What is your load range?
 

toximus

TJ Addict
Supporting Member
Mar 29, 2018
2,247
Northern WI
What is your tire size printed on the sidewall? 37x12.5x17
What is your hub height? 17.5-18" (0.5" to account for the weight of the Jeep not yet added)
What is your psi? 25psi (yes, I know this might be high)
What is your load range? D
 
OP
jjvw

jjvw

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Supporting Member
Feb 17, 2018
6,654
Colorado, USA
Just wait until the guy with 44" Super Swamper "slicks" messes with the data.
One thing I've been recently curious about is if the load range makes any meaningful difference in the hub height. Load range E often requires a lower psi than a C to made them comfortable. Does that translate into a lower rolling radius or does the stiffer sidewall balance that out? When I eventually switch to 15" wheels with a C rated 33 and get it comfortable, will I see an increase in height?
 
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fuse

TJ Enthusiast
Supporting Member
Jun 5, 2018
298
San Diego, CA
31x10.50R15
15" hub height
27.5 psi
Load Range C

But I measured roll out too.

3 revolutions of the front tire = 279.5" = effective radius of 14.83"
 
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fuse

TJ Enthusiast
Supporting Member
Jun 5, 2018
298
San Diego, CA
One thing I've been recently curious about is if the load range makes any meaningful difference in the hub height.
Speaking of nano-accuracy ... if that's what you're looking for, why not do a more controlled experiment instead of getting random data points?

Measure roll out with your Load Range D tires at 5 or 10 different pressures, and have someone with Load Range C tires in a similar size do the same. You won't be able to compare numbers directly, but slope of the trend lines will show you how much the Load Range affects tire size in relation to tire pressure.
 
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jjvw

jjvw

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Supporting Member
Feb 17, 2018
6,654
Colorado, USA
...

Measure roll out with your Load Range D tires at 5 or 10 different pressures, and have someone with Load Range C tires in a similar size do the same. You won't be able to compare numbers directly, but slope of the trend lines will show you how much the Load Range affects tire size in relation to tire pressure.
That's a good idea.

To add to the messiness of all this, I noticed that my current load range E Cooper Discoverer STMaxxes seemed stiffer than my previous load range E Goodyear Duratracs. That will effect the desired tire pressure one might run, as it did me.
 
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jjvw

jjvw

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Feb 17, 2018
6,654
Colorado, USA
What’s the hub height measurement?


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Center of hub to the ground. It's an accurate measurement of how high the tires are lifting the Jeep off the ground. Similar to how measuring the coils is more accurate than the advertised ride height; or how measuring the frame height bypass some of the unnecessary details when comparing vehicles. My 33s have never kept the Jeep 16.5" off the ground and my 4" spring lift is different than someone else's.

This measurement affects the final ride height (see the nominal frame height thread) and the speedometer and probably other nitpicky things.
 
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tworley

TJ Addict
Supporting Member
Ride of the Month Winner
May 23, 2018
2,269
Morrison, CO
35x12.5R15 MTRs
26 psi
20 and 1/8" framerail
15.5 hub
4" super lift with savvy tuck