Did i make the right choice on tires

[chicknnhead]

I just switched from 16.5 to 16 inch wheels, i then needed new tires.
now for some back ground. my motorhome is 22 feet bumper to bumper. it's chassis is a mb400 with a gvw of 10,500. the front axle is a 3300lb and the rear is a 7200lb axle.
Tire Type: Light Truck-
Sidewall: Outlined White Letter
Speed Rating: T
Load Index: 106
Speed Rating Translation: 118 mph
Load Index Translation: 2094 lbs.
Model No.: 1008718
Shipping Weight (in pounds): 31.7
Product in Inches (L x W x H): 29.3 x 8.86 x 29.3

the tire size on the side of the tire reads P225/75/16 and when i went to have them installed they gave me a hell of a time saying i should not mount these on a RV or dually at all.
in May my saftey inspection comes up so i'm a little worried there.

my argument was this, my front axle is 3300lbs. max weight for both tires is 4188, so i think i'm fine there. the rear same thing 4188 per side(8376 total weight) with only a 7700lb rear axle.
the way i'm thinking is the rear will give out before the tires.
but after hearing everyone tell me it's not right i'm not sure which way is up anymore!!!

thoughts?

[JDxeper]

when I replaced my 16.5 I went with 235/85/16 load range E (3042 lbs rated).  all the gurus seem to think a load range D or E.  My problem was getting a fitment with space between the duals, which I now have. your weights should be OK.

[TommyM]

The "P" tires (for passenger, as opposed to "LT" for light truck) are just not tested/rated for dually service, so the dealer & manufacturer just don't want to be liable if something goes wrong. 

That said, you are probably okay if you have ample load rating, and the spacing between the duals is adequate. 

For load rating, truck tires are usually de-rated (a lower load rating) in dual service.  I don't remember exactly, but it seems like it's usually something like 20% less load when used as duals.  Just be sure you have lots of surplus weight capacity compared to the ratings and you should be fine.  And of course, it's the ACTUAL weight of the coach compared to the ratings of the tires that matters more than the GVWR of the chassis.

You should probably crawl under and be sure there is no way the dual pairs can rub, even under the heaviest load.  I think I'd feel comfortable with a half inch between the sidewalls at the bottom where the sidewalls "bulge" a bit.  Rubbing duals will very soon be two blowouts on the side of a hot highway.

Tommy

[chicknnhead]

JD, the 235/85 are to big for the van front of the motorhome i have to bring them down a notch, but your right most everyone is running the 235-85 on theirs.

Tommy, I get what your saying as far as rating for duals, the 16.5's i took off were rated 1090 for single wheel and 940 for dual wheel. difference of 140. now i know not all tires are the smae but taking that same difference of 140 on the current wheels I'm at 7816 with the current tires, with 7700Lb rear axle. so that might be a little concerning i guess, considering i'm not sure if 140 is the correct factor

i have been under there and there is plenty of room between, seems like more then the 16.5, but that could just be me...

maybe i need to get my coach weighed

[JDxeper]

I have plenty space between the duals with the 235's so yours should be even wider. My old 16.5's were rubbing(po didn't understand)  N:( but they were 9.50, really filled the wheel wells.

[chicknnhead]

I have plenty of room in the rear wheel wells for any size, but the van front of the rig can not have that big, the biggest i can get without rubbing is 225/75/16. So in order to keep all the tires the same size i went with  the 225's.  So far it seems the ford van fronts can run the 235's but not the dodge van, smaller opening