First, seeing that this is your first post, welcome to iRV2.com.
The nominal diameter of a generic 225/75R-15 is shown as 28.5" - see HERE
. The advertised diameter of the LT225/75R-16 XPS Rib
is 29.4". If you can give up 1" of clearance between your tandem axle tires and still have, say 1.5" clearance after the switch, that should be acceptable. Of course, you'll want to ensure that the additional 1/2" radius of the XPS Rib will not generate any clearance problems above the tire when the suspension is at full compression.
As far as a wheel and tire package that will fit your lug pattern and stud diameters, I'd suggest that you give Scott a call at Trailer Tires and Wheels
as they specialize in these conversions.
If you can pull it off, you shouldn't have any more tire worries. The commercial all-steel construction XPS Ribs performed admirably on our previous 5th wheel.
2016 Ram Longhorn 3500 Dually 4x4 CCLB, 385/900 Cummins, Aisin AS69RC, 4.10
2014.5 DRV Mobile Suites 38RSSA #6972
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