35" Tire Psi - Daily driving

ksmit88

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I'm looking to put 35" tires on my JLUR but I had a quick question about tire pressure. The larger tire will run a lower tire Psi than the stock KO2s, which should prompt the TPMS alert. On my JK, I had to buy a module which flashed the computer to look for 0 psi to avoid having the TPMS and low tire psi alerts. Is this the case with the JL as well?

I am weird about seeing alerts in my vehicles, and want to do what I can to avoid it with running different tires during my daily driving. Thoughts? Thanks in advance
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SaveUp41

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I'm running 35"s at 33psi - When I ordered my new wheels and tires, I specified new TPMS on all five. Sold my factory Rubi wheels/tires almost immediately without paying attention to what they were running at. I haven't set off any alarms yet, though when crawling, they will get dropped substantially. What were you thinking of running them at on a day-to-day?
 
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rizej

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I'm looking to put 35" tires on my JLUR but I had a quick question about tire pressure. The larger tire will run a lower tire Psi than the stock KO2s, which should prompt the TPMS alert. On my JK, I had to buy a module which flashed the computer to look for 0 psi to avoid having the TPMS and low tire psi alerts. Is this the case with the JL as well?

I am weird about seeing alerts in my vehicles, and want to do what I can to avoid it with running different tires during my daily driving. Thoughts? Thanks in advance
You will definitely need to reprogram to avoid the TPMS alert. I believe it happens under 30 PSI. You'll want to get something like this (https://secure.aev-conversions.com/shop/procal-module) when it becomes available for the JL
 
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ksmit88

ksmit88

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Thanks for the input. I'm planning on running the 35s at whatever the recommended psi is for the tire. I assumed it would be in the 28-32 psi range but I'm not sure yet. I assumed the psi for the bigger tire would be lower than the range of the TPMS computer.
 

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The load rating of the 35" tire will determine the PSI you want to run more so than the tire size. If you can find a C-Rated 35 I would go that route and keep pressures close to the factory setting 35-37psi
The TPMS light will come on below 30psi. I run my E-Rated 37's at 27psi and I am currently living with the TPMS light although there is a company that has already released a device to reprogram tire sizes/tpms threshold, along with other things.
https://zautomotive.com/product/tazer-jl/
 

STG01

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Running Nitto Ridge Grapplers 35x12.50r20

Suggestions PSI for daily driving? Have them at 30 and have heard suggestions to go a bit higher? Like 33 for better wear?


Also, can dealer program for the 35”’s? For speedometer and more accurate MPG
 

UNC Rubicon

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Running Nitto Ridge Grapplers 35x12.50r20

Suggestions PSI for daily driving? Have them at 30 and have heard suggestions to go a bit higher? Like 33 for better wear?


Also, can dealer program for the 35”’s? For speedometer and more accurate MPG
Chalk test your tires to determine the psi you should run.

Yes, dealers can calibrate your speedo.
 

STG01

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Chalk test your tires to determine the psi you should run.

Yes, dealers can calibrate your speedo.

Idiot dealer said they can’t program the electronics for the bigger tires. I would need to get one of those flashing sticks.

Any posts on the “chalk test”?? Exactly what am I looking for?
 

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Idiot dealer said they can’t program the electronics for the bigger tires. I would need to get one of those flashing sticks.

Any posts on the “chalk test”?? Exactly what am I looking for?
Google tire chalk test in youtube and you'll find it. there are a couple of jeep videos of them doing it.

To piggy back on this, I did the chalk test and I'm curious if my pressure is too low for daily driving. Or if it doesn't matter as long as your wear is even. granted, I have 37's but my pressure is at 25 PSI. Seems crazy low. Debating if I should raise back up to 30-32 since that seems to be where most run.
 

quietpeen

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Google tire chalk test in youtube and you'll find it. there are a couple of jeep videos of them doing it.

To piggy back on this, I did the chalk test and I'm curious if my pressure is too low for daily driving. Or if it doesn't matter as long as your wear is even. granted, I have 37's but my pressure is at 25 PSI. Seems crazy low. Debating if I should raise back up to 30-32 since that seems to be where most run.
if you raise up to 30-32 you will most likely not get even contact patch and wear the middle of the tires faster.. You might get slightly better gas mileage though. I'm running 35x12.5x17 on my stock rubicon wheels and I'm at 30 front and 28 rear and i'm still not getting full contact patch but close. I do notice that mpg's is low, but I didn't get a jeep and put 35's on it for gas mileage lol.
 

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I'm running my Trail Grapplers (37x12.50R17)'s on AEV Borah beadlocks (17x8.5 @ 5.72"BS) and I run 35 PSI. I haven't done the chalk test yet. These are D rated as opposed to the factory C. My guess is chalk test will also show 25 is best, but I think where I have them is fine... they'll just wear quicker.
 

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Rim width vs tire width will effect the psi that gives an even contact patch, as well as weight.
No Mfr publishes an optimum psi # for their tires as it depends on the vehicle (weight). Only thing the mfr gives you is the MAX cold psi for the MAX load the tire is rated at.

My Sport TPMS goes off at about 32 psi. when cold they are at 30 psi and warm up to 33 psi (10%) after driving at highway speeds for a while. I go by this guide.

If you drive on gravel then on tar for a few blocks and look at your tires.......you can see if the edges of the tread are touching the pavement. if the edges are not black you are a little over inflated. If your Psi goes up more than around 10% then you're under inflated as to low causes tire to run hotter/more friction thus increasing psi more than 10% or 3-4 psi when at 30 psi cold.

https://www.4wheelparts.com/a/tire-wheel-package-guide-tire-pressure-checker
 

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Good thread. I used the chalk test to try to figure out my pressures. My setup is Toyo R/Ts 35"x12.5" R17 on Stock wheels (7.5") on a JLUR (doors off).

Using the chalk test, I found that even down to 29 psi, I am still not getting a full contact patch. However, I do not want to go much lower (for daily driving) as looking at 37 psi on the Stock K02s, load C, it looks like 37 psi supports 2150 lbs. For the Toyos, that load support is at around 30 psi.

I am thinking because of the narrow wheel, it might be difficult to get the correct tire patch to contact the ground due to pinching in the bead. The best I can do is minimize the wear until I get new wheels!
 

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Good thread. I used the chalk test to try to figure out my pressures. My setup is Toyo R/Ts 35"x12.5" R17 on Stock wheels (7.5") on a JLUR (doors off).

Using the chalk test, I found that even down to 29 psi, I am still not getting a full contact patch. However, I do not want to go much lower (for daily driving) as looking at 37 psi on the Stock K02s, load C, it looks like 37 psi supports 2150 lbs. For the Toyos, that load support is at around 30 psi.

I am thinking because of the narrow wheel, it might be difficult to get the correct tire patch to contact the ground due to pinching in the bead. The best I can do is minimize the wear until I get new wheels!
I think you are correct. I came across a tire review where the same issue was mentioned. The reviewer did follow up after changing to wider wheels and it solved the problem. You should prob be at 9" width range.
i have 12" wide tires on 8.5" wide wheels. Any lower than 30 psi cold and they get to squishy and handling suffers.
 

Tommy1569

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Good thread. I used the chalk test to try to figure out my pressures. My setup is Toyo R/Ts 35"x12.5" R17 on Stock wheels (7.5") on a JLUR (doors off).

Using the chalk test, I found that even down to 29 psi, I am still not getting a full contact patch. However, I do not want to go much lower (for daily driving) as looking at 37 psi on the Stock K02s, load C, it looks like 37 psi supports 2150 lbs. For the Toyos, that load support is at around 30 psi.

I am thinking because of the narrow wheel, it might be difficult to get the correct tire patch to contact the ground due to pinching in the bead. The best I can do is minimize the wear until I get new wheels!
I want to use my JL stock wheels till i can get the right Lift Kit. Please Post Photos of your Setup!!! I want to go to 33s from stock tires.
 
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