Wheels Not Rated as Tires

[MASTERDRAGO]

Our new3791RD has Sailun 235/80R-16 tires rated at 4,080# per side wall marking. Recently I crawled under to check labels on axles, wheel, etc and found the embossed max weight on the rims is 3,750. I know that the margin for these rims is ~250# each so shouldn't be an issue but I just thought it was strange that they are not the same. Gross is 17,000 and pin is ~3,000.

I'm actually looking at replacing the tires and wheels with some rated higher 17.5" H rated but don't want to spend the $2k+ right now.

[Iwannacamp]

3750 x 4 plus a 20% pin average gives you an 18k gross....is this the right way? No, but they count that close a lot of the time. YMMV

[CALinSC]

It’s not a safety violation for the vehicle manufacturer to fit 4080# load capacity tires to 3750# wheels as long as they are not required to use more than the 3750# per axle end. So, what are the axles GAWR ratings (on the certification label)? And, what is the vehicle manufacturer’s recommended inflation for the tires (also on the certification label)?

If the GAWRs are higher than 7500# the wheels are a safety violation and should be recalled. If the certified recommended inflation pressures provide more than 3750# of load capacity it’s a safety violation and requires a recall or satisfactory adjustments by the vehicle manufacturer.

It’s very unusual to see any vehicle manufacturer fit Original Equipment tires on wheels that cannot support the maximum load capacity of those tires. IMO it's a misapplication and needs to be corrected at no cost to the owner.

[wingnut60]

You have good tires, just need to match the wheels to the loads--IF you are going to carry more weight than the wheels are rated for. Don't forget to take the pin weight from the gross to figure how much you could be loading on the wheels/axles.

[MASTERDRAGO]

<snip>
It’s very unusual to see any vehicle manufacturer fit Original Equipment tires on wheels that cannot support the maximum load capacity of those tires. IMO it's a misapplication and needs to be corrected at no cost to the owner.

I thought it was odd also. But, the axle gross is 7,000# x2 = 14K. Wheels 15K, tires 16,320# so if 3K is on pin, 14K could be on the 2 axles.

I'm having 8K capacity MORryde IS and disc brakes installed in 1st quarter of '18 so things will change. Also considering changing to 17.5" wheels rated 6,005# and upgraded tires. While here, any disadvantage to using the Sailun S637 S8244381 235/75R17.5 rated at 6,005#? Would that better tire beat the crap out of the RV even with the IS suspension?

I'm really wanting the best safety capacity touching the road.

[wingnut60]

I used the 17.5 Sailuns at the 4805 rating and never had a problem before trading for current unit. I would get them again. Unless you have a real need for the extra capacity, I would not get 6000 tires. But I don't think you will hurt the suspension if you use them, especially with the Morryde.
If you have 14k potential on the axles with 6k tires--gives you 2500lbs/tire overcapacity.
With the 4800 tires, 1300lbs overcapacity.
I think the lesser tire is plenty, but no harm in the higher rated ones.
Might ask MR their opinion of the tires with their suspension....
Joe

[MASTERDRAGO]

So I had a full tire weight done on the way to Canyon of the Eagles by Trey & Susan at RVSEF. Turns out fully loaded with a pile of firewood in the bed but low fuel our combined was only 24,525 (9,425# margin). Our pin was 3,050, tow 15,100, margin 1,730. The only tire that had less than 1,000# margin was the left rear (reefer location) which had 720# margin. So my tires are good to go. The left rear wheel turns out to have ~500# margin. There is no way to lighten the load on the left rear (maybe get Joy to move canned goods and bottled water) but I don't need to. The rear axle had a bit more weight than front but that might get some correction at MORryde later in the year.