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jornvango

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Posted: 11/26/20 02:20pm Link  |  Quote  |  Print  |  Notify Moderator

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!

Lwiddis

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Posted: 11/26/20 02:50pm Link  |  Quote  |  Print  |  Notify Moderator

An “older” tire on a single axle trailer is asking for trouble. Replace them both. Load range D is probably sufficient. Usually 65psi. Use the Hi-Run as a spare for very limited miles.


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Posted: 11/26/20 02:51pm Link  |  Quote  |  Print  |  Notify Moderator

I would use the tire pressure, and load range tire stated on the driver's side front of trailer placard. I would not use tires that are mismatched, as to plies, load range, or physical size, when towing any trailer at speed, even a light wt Casita.

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BFL13

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Posted: 11/26/20 03:03pm Link  |  Quote  |  Print  |  Notify Moderator

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.


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mobeewan

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Posted: 11/26/20 04:01pm Link  |  Quote  |  Print  |  Notify Moderator

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.

CA Traveler

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Posted: 11/26/20 04:24pm Link  |  Quote  |  Print  |  Notify Moderator

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.


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jornvango

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Posted: 11/26/20 04:25pm Link  |  Quote  |  Print  |  Notify Moderator

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.

jornvango

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Posted: 11/26/20 04:31pm Link  |  Quote  |  Print  |  Notify Moderator

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."

CA Traveler

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Posted: 11/26/20 04:54pm Link  |  Quote  |  Print  |  Notify Moderator

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?

BFL13

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Posted: 11/26/20 05:15pm Link  |  Quote  |  Print  |  Notify Moderator

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.

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