What is the bolt pattern on those motor homes? Also, how does the track width compare to that of the COE?
You are going to need tires that are about 36" to 40" tall to look about right.
19.5" wheels only get you 33" of tire, I have seen those on an AD COE, they look to small.
20 or 22.5" wheels will give you tires tall enough to look good.

Grigg

•1951 GMC 250 in the Project Journals
•1948 Chevrolet 6400 - Detroit Diesel 4-53T - Roadranger 10 speed overdrive - 4 wheel disc brakes
•1952 Chevrolet 3800 pickup
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"First, get a clear notion of what you desire to accomplish, and then in all probability you will succeed in doing it..." -Henry Maudslay-