Community Forums

mr. seaview · 02-21-2018, 01:26 PM

i have a 99 national 32 ft seaaview model 8310. the tires that are
recommended by National are 19.5 size tires. that is what i currently have
on my motorhome and they will probably be good for another 6-8 months.

was wondering if anyone with 19.5 tires have put on 22inch tires instead of
the 19.5 tires? when i get ready to replace my current tires would i be
better off putting on 22 inch tires instead of 19.5 tires? would i be gaining
anything by going to a little bigger tire size? is it possible to put on 22 inch
tires on my motorhome? would i have to put all new 22 rims on? i just would
like to know if there are any benefits of going to a bigger tire?
what would be the pros and cons other than cost or expense? thanks

TonyMac · 02-21-2018, 01:59 PM

In your example, 19.5 and 22 are the diameter of the hole in the middle, the size of the rim, so yes, you'd need to replace the rims. My rig has 265/70R22.5. 265mm is the measurement of the tire from the inside bead across the tread to the outside bead, about 10.5 inches. 70 is the aspect ratio, the height of the tire as compared to its width; lower numbers has shorter sidewalls and wider tread. 22.5 is the size of the rim. The rim also has a width, the measurement from the inside bead to the outside bead of the rim. Cartain sizes of tires require certain widths of rim.

Is it worth the change? I'd think not. Personally, I just stick with what the engineers call for. Spend all that money on beer.

Ljwt330 · 02-22-2018, 11:35 AM

TonyMac has summed it up pretty well. A lot of expense for questionable benefit, IMO. One other thing to consider is clearances for a larger wheel/tire combination. I'm not familiar with your rig, but it was designed for 19" rims and tires. Larger combinations may cause interference with body/suspension parts, especially in the steering. Similarly, there may be fitment issues with duals in the rear.

Richard S. · 02-22-2018, 03:34 PM

Ford did not have 22.5 tire option for that year, bolt pattern and hub size are also things to consider. The tire size was engineered to work with the chassis construction.