[RCrosby257]

O.K., I know that the "correct" answer is to follow the PSI recommendation stamped on the tire, but..........
90 PSI? I called my local dealer who said, "I know it seems high, but that's what the manufacturer recommends and we stand by that."
But,
When I bought 2 new tires on rims from this retailer, they were both inflated to 45 PSI, which seems more reasonable.
My camper is a Viking 1706.(?) About as small as they come.
So, do I really double the pressure? The 45 shows me fully rounded tires with no telltale "flattening" on the pavement.

 

[artmart]

It's hard to tell. Look for a Tire and Loading sticker on your trailer. It should have the tire size and the PSI recommendation. Then check the tire to see that it's the size called for and check the sidewall for the tires maximum psi. If the sticker shows something higher, then maybe the wrong tire is mounted. On the other hand, the tires mounted on your trailer might provide the tire weight rating for the trailer even though it does not match the sticker.

Is the trailer used? If so, it is possible that someone replaced the tires with underrated, lesser inflated tires. Then contact the trailer manufacturer and confirm what to use and they might even be able to recommend what brand that would satisfy the pressure and weight rating and why some would be at 45psi and others at 90psi.

Not all tires are equal even if they are the same size. Some might have more plies making them stronger to meet the needs of a trailer.

I do recommend you investigate this and get the answers.

Don't be surprised it you need that high of a PSI. It sounds like the wrong tires might be on the trailer or they could be different but still acceptable. A higher psi for a particular tire tends to carry more weight and maybe this is what's needed. After all, my bicycle tires say 90psi on the sidewall and that's what I try and use and me and my bike weigh under 200 lbs. I use 80 psi on my trailer, 75 psi on my truck, 40psi on my car and all these are within what's called for in tire size, psi and weight ratings. Yes, even my car has a weight rating and so does yours.

You must also make sure the rim (wheel) is rated for whatever the psi being used. Again not all size rims have this same psi rating so you have to check on this, too.

Let us know what you find.

 

[RCrosby257]

Artmart,
Thanks for the thoughtful and informative reply.
I bought the camper new, many years ago. Tires and rims were original and the replacements are identical.
I'll look for that load sticker tomorrow and let you know what I find out. Will also call back the dealer and ask about the discrepancy between what they told me on the phone (i.e. go with the 90 psi) and how they delivered the wheels. (45)
Will definitely resolve before I hit the road and will let you know what I find out.
Rob:thumbup1:

 

[artmart]

Come to think of it, I had a 1986 Coleman popup. The sticker called for a high PSI for a certain size, but when I bought the popup used (about 1.5 years old), I was told that the original owner requested a different tire and size that only required 45 psi. Maybe this is what happened. In my case what the sticker required and what was on the trailer (a larger and noticeably wider tire) were obvious differences and met the ratings. I am going on years ago and with my old mind but I tink this about right.

I do like your plan. It's much better to ask and know, than not ask then have a problem.