Advice on tires, towing and Baja please

[tomcoz]

I’m still relatively new to the travel trailer world. I’m hoping someone with more experience will check my reasoning and calculations regarding tow vehicle tires. My tow vehicle is a 2018 Jeep Grand Cherokee Ecodiesel Trailhawk 4x4. JGC towing capacity is 7,200lbs. We tow a 2019 Lance model 1985 dry wt 4,045 lbs; Carrying capacity 1,655 lbs; GVWR 5,700 lbs; tongue weight 500lbs; with tandem torsion axle; total length is 23’8 . I have read that you should keep the TT GVWR at least 20% (1,440lbs) below the towing capacity. The difference between JGC towing capacity and the Lance GVWR is 1,500 lbs which is about 21% cushion. So that seems safe.

We do take some longer trips, spend time boondocking, and do travel Baja California. We selected the JGC Trailhawk ecodiesel for towing and serious off roading. The Trailhawk comes with factory towing package which includes Class III factory receiver and bigger brakes. We added a REDARC TT brake controller and the equalizer 600 weight distributing hitch (tongue 600lbs, TT GVWR 6,000lbs). The JGC is set up with rock rails and will soon have a hidden winch and extra front skid plates. I know to subtract the weight of the winch + armor + tongue wt of 500 lbs. (estimating 700lbs total) from the vehicle carrying capacity of 1,190 lbs. That gives me about 490 lbs of people and their stuff. Most of the time it is my wife and I and our two small dogs. That leaves us about 100bs for gear in the JGC. Everything else has to go in the trailer.

The JGC GVWR is 6,800 (dry wt 5,326 lbs and 1,190 carrying capacity). The stock tires are Goodyear Wrangler Adventurer AT with Kevlar 265/60R 18 110T load capacity of 2,337lbs diameter 30.5” and they weigh about 40lbs. Total weight capacity of stock tires is 9,348 lbs. I read online that I should subtract 10% to get the actual weight capacity for metric tires. The net capacity of the stock tires would be reduced to 8, 413 lbs.

To improve off road capability and add stronger sidewalls to better handle rough Baja roads, I’m considering upgrading my tires to Nitto Ridge Grapplers 275/65 R 18 116TXL. Their load rating is 2,756 lbs and diameter is 32.09”. (This will fit without rubbing.) Total tire capacity is 11,024 lbs. Subtracting the 10% gives a net tire load capacity of 9,922 lbs. Since the GVWR of the JGC is 6,800lbs this gives me a cushion of 3,122lbs. I could go to a LT tire which bumps the combined capacity of the tires to 13,660 lbs. However, I think the ride would suffer greatly along with gas mileage (the XL tires weight 45lbs while the LT’s are 56lbs). Another negative is the stiffer sidewalls of the LT tires mean I will have to air down even more to get flexibility/flotation of the tire when I’m off road in rocky terrain or sand. I know the larger diameter changes the gear ratio, but other JGC ecodiesel owners are pulling larger TT’s with no complaints or concerns.

Is my math and reasoning correct regarding the JGC tire upgrades? If not please let me know where I’ve gone astray.

Now to the TT tires. The lance is about 10 months old and we bought it new last year. It is a 2019 year model. It comes with Goodyear Endurance ST 205/75/ R 14 105N D1. For those of you that take your trailer down rough asphalt roads like in Baja, do you think this tire is up to the task or should I upgrade? What tire would you upgrade to?

Thanks for taking the time to read this.

[tomcoz]

Thanks everyone for the replies. After reading the comments here and on a couple of other forums and talking with a mechanic and Discount tire veteran who off roads and pulls a trailer, I went with the Nitto Ridge Grapplers 275/65 R 18 116TXL's. The handling and rider are better than the stock Goodyear Wranglers that came with the jeep even though the tread pattern is much more agressive and they are rated for a heavier load. I'll be sticking with the GY Endurance for my lance TT.

[Grit_dog]

All tires can come apart, but back in the day Kumho 857s were the best, but now they don't exist, so...
To the OP, you won't have a harsher rise with LT tires on the Jeep. Air pressure dictates ride about 99%. If the sidewall is stiffer, a bit less pressure makes it equal to a softer tire. Whether you need them or not is up to you to decide. Depends how hard you are on tires doing your serious off roading.

[patperry2766]

CALandLIN wrote:

patperry2766 wrote:

CALandLIN wrote:

tomcoz wrote:

I HAD (notice that word) a set of Kuhmo 857's, and I drank their KoolAid about the higher load capacity and speed rating. I thought I had found the holy grail of 14" tires, until I had a blowout with less than 6K miles on a 2 year old set. Religiously checked the air pressure every AM, never consistently drove above 65 MPH and kept the tires covered when not in use. Luckily Discount Tire gave me my money back after I showed them the receipt for the tire I had to buy somewhere in Wyoming....the damage to the trailer from the blown tire came out of my pocket.

Did you discover the cause of the failure?

Never did.

Was going about 60 and all of a sudden it just let go. The tread wrapped around the axle so bad that it took me over an hour just to untangle it and I literally had to cur thru the tread with a pair of wire cutters. I had to do it on highway shoulder that gave me less than 2 feet bubble to work without being in the actual highway...and not every driver is courteous enough to switch lanes to allow a safety buffer.

I've done a lot of things that have put my life in jeopardy, and changing a tire on the side of the road ranks up there pretty highly!!

Bit of advise....when you check tire pressure on the trailer, every so often check the spare...nothing worse than having to use an almost flat spare tire.

[CALandLIN]

patperry2766 wrote:

CALandLIN wrote:

tomcoz wrote:

I HAD (notice that word) a set of Kuhmo 857's, and I drank their KoolAid about the higher load capacity and speed rating. I thought I had found the holy grail of 14" tires, until I had a blowout with less than 6K miles on a 2 year old set. Religiously checked the air pressure every AM, never consistently drove above 65 MPH and kept the tires covered when not in use. Luckily Discount Tire gave me my money back after I showed them the receipt for the tire I had to buy somewhere in Wyoming....the damage to the trailer from the blown tire came out of my pocket.

Did you discover the cause of the failure?

[patperry2766]

CALandLIN wrote:

tomcoz wrote:
It comes with Goodyear Endurance ST 205/75/ R 14 105N D1. For those of you that take your trailer down rough asphalt roads like in Baja, do you think this tire is up to the task or should I upgrade? What tire would you upgrade to?

Thanks for taking the time to read this.

You probably already have the best RV trailer tires for your travel plans. The GY Endurance tires have built-in sidewall scuff guards and are, to my knowledge, the only ST tires available with that feature.

Kuhmo 857 tires are a European commercial grade trailer tire with a higher total load capacity available with a 14" tire.

I HAD (notice that word) a set of Kuhmo 857's, and I drank their KoolAid about the higher load capacity and speed rating. I thought I had found the holy grail of 14" tires, until I had a blowout with less than 6K miles on a 2 year old set. Religiously checked the air pressure every AM, never consistently drove above 65 MPH and kept the tires covered when not in use. Luckily Discount Tire gave me my money back after I showed them the receipt for the tire I had to buy somewhere in Wyoming....the damage to the trailer from the blown tire came out of my pocket.

[ppine]

Take two spares for you TV and TT each.
Don't drive too fast on the crummy pavement and rough stuff.
Your stock tires should be okay if they are new.
I would not upgrade for a couple of years.

[CALandLIN]

tomcoz wrote:
It comes with Goodyear Endurance ST 205/75/ R 14 105N D1. For those of you that take your trailer down rough asphalt roads like in Baja, do you think this tire is up to the task or should I upgrade? What tire would you upgrade to?

Thanks for taking the time to read this.

You probably already have the best RV trailer tires for your travel plans. The GY Endurance tires have built-in sidewall scuff guards and are, to my knowledge, the only ST tires available with that feature.

Kuhmo 857 tires are a European commercial grade trailer tire with a higher total load capacity available with a 14" tire.

[tomcoz]

Ultra low sulfur diesel is widely available in Baja. I was there for a week in February and had checked it out before hand with a friend who has been leading RV caravans to Baja for over 30 years.

[bartlettj]

How do you plan to handle finding ULSD in Baja? Mexican diesel is high sulfur and will foul your catalyst and DPF system. My trucks owners manual says specifically to avoid Mexico for that reason and that warranty is void if ULSD is not used.

[carringb]

Your tongue weight won't actually be 500 pounds. Published dry weight is 550 pound, so your actual empty tongue weight will be more like 700-750, once everything is installed by the dealer and you add even a modest amount of personal belongings. Total trailer weight is a good match. But that tongue weight is probably going to put you over GVWR, with all the items you are adding to the Jeep. You might want to upsize to the next size up WD bars, since you be over 600 pounds tongue weight, the Jeep is somewhat softly sprung.

Upping your tire diameter by 1.5" will likely be noticeable when towing. Also beware that some Jeep dealers aren't so kind to owners when it comes to warranties and oversize tires. Might want to hang onto the stock set in case you ever need to go in for powertrain repairs. Or by the larger tires from the dealer, so you can push back on them easier if they give you grief later.

https://jalopnik.com/the-secret-to-not-getting-screwed-by-your-jeep-warranty-5620613

The Endurance tires seem good so far. I'd probably stick with those. Especially since they're already Load Range D.