I'm not sure what an m135 is and the truck may or may not have the original wheels on it. Even if original might be a few different width options when new. Only sure bet on what width you're dealing with is to measure and or find it stamped on the wheels in question.

Here's the new link to the Accuride catalog, found it on their website:
http://www.accuridecorp.com/files/2012/10/Accuride-Wheels-Product-Catalog-Summer-2011.pdf
Page 38 shows the 5* and the 15* bead seat wheels, be sure the tire matches the wheel you have (likely 5*).

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-