Original factory tire diameter?

[MaDDscientist]

I’ll be taking a long road trip (pretty much all highway) and no off-roading. I’m likely going to go back to my factory tires and wheels. For the life of me, I cannot remember what the factory tire diameter settings were. Anyone have an idea? 2024 Sport S with max tow. Factory tires - 245-75 17, Bridgestone Duelers.

Sponsored

 

[rharr]

Just measure the height of the tire installed and use that value in jscan

 

[MaDDscientist]

Just measure the height of the tire installed and use that value in jscan

That is plan b…

 

[rharr]

That is plan b…

That is how jscan tells you to do it.

 

[Janster]

Am I totally missing the question? Cuz I feel like I am…..

If you google the conversion….. 245 75 R17….gets you 31.47”

 

[Gvsukids]

Am I totally missing the question? Cuz I feel like I am…..

If you google the conversion….. 245 75 R17….gets you 31.47”

That's too easy.

 

[MaDDscientist]

Am I totally missing the question? Cuz I feel like I am…..

If you google the conversion….. 245 75 R17….gets you 31.47”

The original tire size that was programmed into the JT’s computer was 30.something. I changed it when I upsized my tires. Was just trying to see if anyone else knows what Jeep programs the computer to for these tires…

 

[jjdustr340]

If you used JScan, there’s a place in the settings that show every change you’ve ever made. That will show you what the original tire settings were.

Edit-after tapping the gear in the upper right, it’s “trace and restore adaptations.”

 

[MaDDscientist]

If you used JScan, there’s a place in the settings that show every change you’ve ever made. That will show you what the original tire settings were.

I didn’t realize JScan had that built in. Thanks!

 

[Janster]

The original tire size that was programmed into the JT’s computer was 30.something. I changed it when I upsized my tires. Was just trying to see if anyone else knows what Jeep programs the computer to for these tires…

I understand what you’re trying to do… You’re splitting hairs…

Think of it this way…. The numbers that Jeep uses is a ‘mass production / average‘. .You’re much better off programing something that’s true to actual. Your speedo & odometer will be YOUR data and not what Jeep thinks you should use.

 

[Sandman 4x4]

I’ll be taking a long road trip (pretty much all highway) and no off-roading. I’m likely going to go back to my factory tires and wheels. For the life of me, I cannot remember what the factory tire diameter settings were. Anyone have an idea? 2024 Sport S with max tow. Factory tires - 245-75 17, Bridgestone Duelers.

31.6”

 

[MaDDscientist]

I understand what you’re trying to do… You’re splitting hairs…

Think of it this way…. The numbers that Jeep uses is a ‘mass production / average‘. .You’re much better off programing something that’s true to actual. Your speedo & odometer will be YOUR data and not what Jeep thinks you should use.

Very fair statement. Thanks for the input!

 

[biplaneguy]

The spec for the OEM 245/75R17 is 31.5", but Jscan tells me the tire size on my Sport, which I've never changed, is set to 32.25.

I do need to change it as I swapped to 285/70R17 Mojave takeoffs, so do I use the spec (per tire size.com) 32.7 or something else???

 

[MaDDscientist]

The spec for the OEM 245/75R17 is 31.5", but Jscan tells me the tire size on my Sport, which I've never changed, is set to 32.25.

I do need to change it as I swapped to 285/70R17 Mojave takeoffs, so do I use the spec (per tire size.com) 32.7 or something else???

When I measure my 285s, they measure at 32.0. But my Speedo matches GPS better at 32.5.

 

[Vincent]

Mine was set at factory @ 30.9.

Sponsored