My 2018 Pro4X has new shows and they are E1 rating instead of the SL that came on it. I pull a 7000# travel trailer. Anyone see any problems with these tires on stock rims?
I appreciate the input. I'm actually running 60 PSI without a load and adding 4 lbs on the rear for towing. The truck rides well at that pressure but I have only pulled the trailer while testing a new WDH. I have been using a chain bar type WDH but set up a new Husky Centerline which should tow better. I just don't want to have to be concerned about the stock alloy wheels not being able to withstand the E rating pressures. The current pressures are as high as I intend to go. I'm a little amazed in this age of technology that there is no place to find the actual pressure rating for these rims.I've been running E-load rated tires on my OEM rims for going on 100k miles. There is zero issue with it. As for what pressure to run, it depends. For around town with no load on it, look at something in the 38-46lb range. If you need to, do the chalk test (google it) to determine the pressure for your setup. When you're towing the trailer, you will likely want more pressure. I tow a wakeboat which runs 5500-6000lbs, depending on gear aboard, and I usually put an extra 4lbs in the rear tires to help steady the load. With your setup, I assume you're using a weight-distributing hitch, so pressure for all four of your tires will need to be adjusted.
The rims will take the pressure, I'm sure, provided they are not damaged. I'd take a good look at your contact patch as you may be shortening the tire life by wearing the centers more quickly at 60lbs. At 50lbs unloaded, I'm not hitting the outer 2" of tread on either side of my E-rated treads.
I had emailed a rim site and just received this reply.i really didn't even know the rims had ratings for psi. well, i guess i did but never thought it applied at the level of wheels and tires we deal with since the manufacturer would be liable if the rims couldn't handle hauling what the truck was rated for
I bought chalk to do that test. I'm beginning to believe I should have just stuck with the General Grabbers again. I'm not seeing the 2,300 lbs. I will take a look at the tire mfgr inflation tables. My placardsI 2nd reconsidering the 60 lbs unloaded. I run my E1s at 42 unloaded based off tire inflation tables.
E.g. you can understand the intended weight loading Nissan planned for the original tires (for example 2,300 lbs/ tire at the placard psi).
Then you look up inflation tables for your new tires’ size and load range to find a similar load, then reference what psi attains that same load. Then you’re at least +/- 2 psi from ideal.
As for the wheel rating, I must admit this is the first I’ve heard of anyone considering this. My feelings are that any wheel that couldn’t sustain at least 80psi really shouldn’t be used on any vehicle ever. Forces at the hub and others would exceed air pressures I would think. Idk.
I really appreciate you taking the time to help with this. I did discover the difference between the tires shortly after making the change. I found it out when I finally discovered where I got the 44 PSI towing pressure from. Unfortunately, Cooper, which I have run for many years doesn't make an SL or P-rated tire in that size. They drop to a 65 sidewall for that.Quick clarification:
The original equipment General ATPs were p-metric (not “LT-metric” or E or 10 ply load range).
In this case the closest rating appears to be 2,680, which correlates to the 50psi column.
So that’s where I’d start.
Here’s here it gets tricky:
1) This is Toyo chart, and they seem to offer this size in a load c range. That may differ slightly from a true load e range. But it’s still closer than guessing. Your tire store may have tables for your specific brand.
2) Generally, placard pressures are set by mfrs at or near gvwr / max payload. But most people bump up from placard pressures when loaded, and down when completely unloaded. So you’d do the same with LT tires, but around the higher pressures.
So in this case that 50psi should give you the same performance as the stock ones would at 35 psi. Go up or down from there as you would with stock tires.
If you read this far hope it was legible and helpful. Usually don’t launch into these things but I’m a bit of a tire nerd and thought it might help.
Thanks for the input. I have my pressure figured out. The General Grabbers weren't squishy or at least they didn't seem to be. I haven't towed a great distance yet however so we will see how the difference is.I had D rated Toyo Open Country tires on my Titan. I ran them up to 60 PSI, but only when towing. I stopped using the P metric OEM tires for towing because they were too squishy when driving on curvy canyon roads. I used the Toyo inflation chart for setting the unloaded PSI. It worked good. The tires wore well.