The Stovebolt Site Forums The Shop Area General Truck Talk Need For 8-19.5” Bias Ply Traction Tread Tires

I’m coming to you GM guys hoping to get your support in my attempts to get Coker Tire and/or STA to add 8-19.5” bias ply traction tires to their product lines. I sent the attached letter and spread sheet to them last fall on this subject, with no response. I’ve emailed each again today hoping for their replies. As is seen in the spread sheet, all truck manufacturers of the 1950s/1960s offered these optional wheel tire combos. None of the OEM wheels were approved for use with radial tires, and no tires today resemble the old bias tread patterns.

As Grigg and others here know, I am a student of these old wheels and mostly hang out on the Ford and Studebaker sites. But GM owners are equally exposed. So hopefully you agree there is this need and share your views with these companies. Thanks. Stu McMillan

Why were the wheels not approved for radial tires?

Ed

Riveted center discs. Every manufacturer’s catalog of the 50s/60s had disclaimers that said warranties would be voided if radials had been mounted. (Edit - this is specific to the 17.5”, 19.5”, and 22.5” sizes. I’ll have to look at the 16.5s, but think by the time they came into wide use welding had probably become the practice). I have an SAE study that was done for Budd that shows the increased lateral forces radials transmit to the wheels. To combat this problem the manufactures began fully welding the disc to the rim during the 1970s, and on the big trucks they fully redesigned the 22.5s to eliminate what were called “well welded” designs (along the drop center) in favor of “ledge welded” designs. Stu

I got a reply back from STA this week telling me they have no interest in adding the 8-19.5s to their line. The gentleman had also spoken with Coker. They don’t think there is a big enough market to make it a viable offering. In my reply I cited tires seen in their online and catalog listings that can have but a fraction of the market potential of the 8-19.5” traction treads. By way of example I referenced the set of their 7.50-18” uni-directional traction treads that I bought a few years ago. So I continue to believe there is an underserved population of truck owners, and hope owners of these trucks and wheels email them to share your views. Stu