Tire pressure advice
- Thread starter D1sc
- Start date
The OE spec for the factory E range is 43psi. I’m currently at 41-42 cold per the TPMS and so far everything is great with my Geolandar G015
E range.
E range.
You can safely run them at 40psi for normal operation. Since it's a 1500, you can't load the rig near the max weight rating of the tires, so no need to up the pressure like with a heavily loaded rig.
If that is the factory size tire, go by what your door jam says. You can always email Michelin and ask them what they suggest as well. I personally chalk test all of my new tires the first go round and figure out which contact pattern and psi I like most. Good luck!
Calling Capri Racer - inflation pressure on tire size change
Ok, here is the scenario. Stock tires on my ZR2 are 265/65R17 with a load rating of 112S SL 2,469lbs @ 51 psi. The OEM suggests 35psi all around which I know lowers the load carrying capability of the tire...but to what? I want to run summer tires 265/50R20 to reduce noise and un-sprung...
bobistheoilguy.com
In this topic post #10 I explain some things, and give a list for the tire used there. So read that first, and then I can make a list for your old and new tires too.
Then you "ONLY" have to detetmine the axleloads in your use 99% acurate, and search them back in list.
Is the most tricky part in it all, and your responcibility.
- Joined
- Jun 8, 2022
- Messages
- 5,572
You could do a tire chalk test?
OK, this was an interesting rabbit hole to go down!
The first thing I always do is to verify the original information. I had 2 sources I looked at online and both said the original tire size was an18" in both P metric and LT metric versions. Then I looked at Tire Rack and they said there were 3 possibilities - a 17", a 20, and a 22"!
So I had to go to my bookshelf where I have hard copies of "Tire Guides" - a publication that lists the original tire size and inflation pressure for vehicles sold in the US - and among several different tire sizes I found P265/70R17 at 40 psi. This seems to match the OP's post. The wrinkle here is that a Standard Load tire maxes out load-wise at 35 psi, and it is unusual for a vehicle manufacturer to specify anything over 35 psi in an SL.
As was pointed out above by Skippy722, Tire Guides also lists an LT265/70R17 LR E at 43 psi.
Then if I do the math, converting a P metric at 40 to and LT metric, I get 46 psi!
And the rule of thumb says to add 15 psi if you are converting, but that assumes you are starting on the load table - which would be 35 psi = 50 psi!
So there you have it. Different ways to get answers and you get different answers!
The first thing I always do is to verify the original information. I had 2 sources I looked at online and both said the original tire size was an18" in both P metric and LT metric versions. Then I looked at Tire Rack and they said there were 3 possibilities - a 17", a 20, and a 22"!
So I had to go to my bookshelf where I have hard copies of "Tire Guides" - a publication that lists the original tire size and inflation pressure for vehicles sold in the US - and among several different tire sizes I found P265/70R17 at 40 psi. This seems to match the OP's post. The wrinkle here is that a Standard Load tire maxes out load-wise at 35 psi, and it is unusual for a vehicle manufacturer to specify anything over 35 psi in an SL.
As was pointed out above by Skippy722, Tire Guides also lists an LT265/70R17 LR E at 43 psi.
Then if I do the math, converting a P metric at 40 to and LT metric, I get 46 psi!
And the rule of thumb says to add 15 psi if you are converting, but that assumes you are starting on the load table - which would be 35 psi = 50 psi!
So there you have it. Different ways to get answers and you get different answers!
Your original tires load rating of 113 reaches max load carrying @ 35psi, which is 2535 lbs. It doesn't increase as you go past that. The 40psi may give you better handling characteristics while the truck is loaded. You want to match the tire pressure on the LRE tire to meet that same load load carrying as the original. Using load tables to a LRE in the same size, you would want to run ~55psi to reach about the same load carrying as the original. The LRE @ 55psi carries 2595 lbs. Although an LRE tire has a higher load carrying capacity, it requires higher PSI when compared to the original P-Metric.
Thanks. The tires are great,and without any load and with the upgraded general springs ride much rougher which makes knowing the minimum pressure more important.The extra capacity of the springs keep the back from sagging too easy and affecting headlight aim on long trips. I have a lot of info now,funny how much I didn’t know about tires but better late then never.
BrendanC
$100 site donor 2024
we only put load range E tires on our half tons. we have had no issues running an 80PSI rated tire at the 40ish psi rated in the door jam.
If you would like to know more about tires, our very own @CapriRacer has a website that is really informative and helpful. Spend some time there, it will be worth it, I promise.
A buddy does that on his F250 Super Duty. His tires last longer.
Not sure my dental work will last at all with that truly horrible ride. It feels like there are no springs at all. Like it’s going to shake the fillings out of my teeth…
I would run his truck at 40 PSI and buy tires more often if it were mine…
BrendanC
$100 site donor 2024
at 80PSI with no load in the truck, the centers should be wearing incredibly fast...
for 3/4 and 1 ton pickups with no load, i like 65psi all the way around and rotating every 5 k. these trucks are rough on tires.
They wear evenly across the tire at 80PSI.
Currently, he has the Michelin LTX. His truck is hard on tires. The super duty with the diesel is a heavy beast, and it eats tires. Michelin, Goodyear, General, Cooper, all of them. He wears them out, evenly across the tread, at far short of the warranty miles on every brand he has had.
When he ran them at 40 PSI, the shoulders were worn down long before the center. So, clearly, 80 PSI is the correct pressure for tire wear, but ugh, that ride…
In fairness, he’s a retired school teacher. He’s budget conscious, and in his position, I would probably run 80 PSI as well.
BrendanC
$100 site donor 2024
interesting, F250's arent that much heavier than the silverados we run and at 80 if the trucks arent loaded destroys the centers of the tires. im glad it works though! i couldnt imagine riding around on 80PSI 24/7, my back/ neck would be worse than it already is.
4WD
$50 site donor 2024
What I read here is LT(E) on 1500’s with 40 psi …
The last time I did that I ran 45 psi and reached 57k on the better GY Wrangler (Kevlar) … (tread was deep - but, rock chipping)
BrendanC
$100 site donor 2024
I hate to change the subject but can I ask another question about the e range regarding speed rating. My original wranglers
had a 114 rating and when dynoing the ram I am at eye level. Will this upgrade to e range at least make my chances better to come out unscathed because I have another dyno tune coming up for headers and exhaust.
BrendanC
$100 site donor 2024
trucks normally run into driveshaft limitations well before tire speed ratings.
