Tire pressure

[jornvango]

Our Casita has one axle. The tire on the left is a newer Hi-Run load range E with max cold psi 80. The tire on the right is an older (unused) spare Goodyear Marathon load range C with max cold psi 50.

Is there any recommendation for psi? I was thinking 50 psi in the Goodyear and 80 in the Hi-Run.
Just thought I'd check as I have never had two different load range tires on a trailer with different psi...

Thanks!

[Cummins12V98]

down home wrote:
I have no idea of the weight rating of the trailer, however.... and especially with only one axle I would replace both wit the next size wheel diameter and the next size up tire size and Weight and speed rating...on heavier aluminum wheels, not steel. If you have15 inch rims go to 16s even 17s and D weight rating tire go to at least G rating, as long as they clear the fenders. Ride height increase of 1 inch will not affect anything. Michelin LT tires have long tire life ratings and warranties and uv resistance. I found out what the hot thin air desert sun can do on the right front tire, at 3500 ft last year.... And in 2002 to perhaps 2004 lost all four, not at one time, tires on two axles of a boat trailer. Cheap Goodyear Wranglers at the time, from sun and Armorall.

Single axle trailer and "G" tires???????

[JIMNLIN]

One axle with two different tire types/load ranges/tread design is a braking safety issues...especially a hard braking event on wet pavement. One tire with the better traction will lock up causing flat spotting... or control loss depending on situations.
Multiaxle trailers have a need for max sidewall pressure (stress from side scrubbing). A single axle has no side scrub issues and no need for max sidewall pressure in this situation.
The trailer came with load C at 50 psi which is a good fit for lightweight trailers. Now 80 psi tires are mounted. I use P tires on single axles for better long term wear and performance.
Using 80 psi can cause the tires to balloon the center of the tread and doesn't allow full tread contact leading to less braking performance. There are reasons for OEM C load tires on light weight vehicles.

If you don't want to weigh the trailer use its GVWR and divide by two. Now find your a tire pressure load chart and use that as a base and fine tune with a chalk mark across the tread. Pull the trailer in a straight line for a couple of blocks. Add or reduce psi for a even wear across the tread.
This is a old method we used when only a few tire dealers had tire load/pressure charts.

[down_home]

I have no idea of the weight rating of the trailer, however.... and especially with only one axle I would replace both wit the next size wheel diameter and the next size up tire size and Weight and speed rating...on heavier aluminum wheels, not steel. If you have15 inch rims go to 16s even 17s and D weight rating tire go to at least G rating, as long as they clear the fenders. Ride height increase of 1 inch will not affect anything. Michelin LT tires have long tire life ratings and warranties and uv resistance. I found out what the hot thin air desert sun can do on the right front tire, at 3500 ft last year.... And in 2002 to perhaps 2004 lost all four, not at one time, tires on two axles of a boat trailer. Cheap Goodyear Wranglers at the time, from sun and Armorall.

[Cummins12V98]

jornvango wrote:
Update: I replaced the other tire too so now have two load range E tires on the Casita.

Weigh your rig and use the weight/inflation chart to determine PROPER inflation and add 5psi to what the chart says.

[kellem]

Smart.

[jornvango]

Update: I replaced the other tire too so now have two load range E tires on the Casita.

[Boomerweps]

AFAIK, the same type tire recommendation was a left over of between bias ply and radials from when radials were the new thing.
Run both tires at the maximum rating of the less capable tire. Change out the lesser for a matching higher level tire when you can.

[BFL13]

A govt pamphlet on tires (Riding on Air) says, "To ensure proper handling, install the same type of tire on all four wheels"

The Michelin RV Tire Guide notes the 'corner weights' can be different, but , "for control of your RV, it is critical that the tire pressures be the same across the axle". so use the higher weight. They advocate some over-pressure per actual weight too, for shifting of load from side to side which is common in RVs so have some extra psi as a reserve for that temporary extra weight.

IMO there is also the tire tread designs where one might have a better grip so you could have a handling problem.

[CA_Traveler]

Thinking outside the box - How does one know that conclusion is correct? Every mfg recommendation I've seen is for the same pressure for all tires on a axle for a GIVEN tire type.

No mention of different tire types on a axle let alone different tire mfg.

I'm not a tire expert but what sidewall stress during an emergency maneuver. Let alone different tire compounds and traction capability with one tire providing more traction than the other?

[jornvango]

This article seems to indicate that having one tire being a higher load range is ok, as long as you inflate it to the same psi as the other tire. In my case: inflating the E tire not to 80 but to load range C psi = 50.

https://www.rvtiresafety.net/2013/01/can-i-mix-load-range.html?m=1

"If you are replacing the failed or damaged tire with a higher Load Range you can run it as if it was of the lower Load Range."

[jornvango]

Thanks. Yes, original 15 inch rim: it says "max load ...lbs E". I can't read the exact lbs but since it's original, the Casita trailer didn't suddenly get heavier.

Casita originally has load range C so E being able to carry more weight, I thought it would be ok. Not sure why having one tire with the ability to carry more weight is an issue? Does someone know?

P.S. Both tires are 5 ply.

[CA_Traveler]

This thread made me think about what's unsafe IF both tires are the same size and set to the mfg recommended tire pressure based on axle weight. And given that's it's neither a steer or drive axle.

What I come up with is a potential stability and braking especially in an emergency situation.

But whatever the real situation might be I default to liability not wanting to explain how my mismatched tires were not a problem.

[mobeewan]

Trailer tires should be inflated to the max tire pressure listed on the tire. You shouldn't use mixed load rated tires. Is the new tire on the old rim? If so what is the pressure rating of the rim? It should be stamped on the rim somewhere. If it will handle the pressure for the new tire, get a new matching tire for the other side.

[BFL13]

Sounds like a big no-no to me. You are supposed to have the same tire on each end of an axle. It is ok to have different tires on the other axle as long as they are the same at each end of that axle.

The C might be a trailer tire and the E a truck tire from the OP. You pick the psi of the truck tire from the weight it is carrying, while the trailer tire is usually at its max regardless of weight (from what I have gathered about all this)

IMO you have an unsafe situation there. Better to get a second new tire and maybe have the older C as a spare. If you do end up with the C on there after a flat, drive slowly to the garage and then put it back as the spare.