A Post by Andy

Maybe you noticed the tires. Maybe, like me, you love tires. We have fancy tires, and I would like to tell you all about them. Let’s start with what we had.

Pretty standard look for an 80’s era Class-C RV. The Turtle’s stock tire size was 215/85R16 on 8-bolt Ford rims. Single wheels in front, and dully rear.

We wanted to be able to go most everywhere, up dirt roads, over snowy passes, through water and mud, so we wanted a taller tire for more clearance, with an aggressive mud and snow tread. Also, as a general rule I am a fan of tall, skinny tires. Pizza cutters, some people refer to them as. Lots of trucks these days have big, fat tires, and they look pretty cool, but for most conditions they are less than ideal. I really like the Cooper A/T3 tread and have run it on other vehicles, so that was the choice for sure. As to the size: to get added clearance, a greater load rating, and to keep it nice and narrow, we went with 235/85R16.

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The new tires are almost 32″ tall- a significant improvement over the stock height of about 30″- so we gain almost an inch of clearance with the new tires. Additionally the 235’s have a load rating of 3042 lbs per tire vs. 2680 lbs for a typical 215. The additional load rating does not increase the load we can carry, but it is just a stronger tire so they will live a long and happy life rolling along far below their load limit.

After selecting a tire and size, special consideration was given to the rims. It seemed reasonable to replace the 30 year-old rims, and due to the tire size change, this was actually necessary. You see, dual tires need an air gap between them to stay cool. The gap is a function of how wide the tires are, and the distance between the center of the rim and the plane where the rim bolts to the hub (a measurement called wheel off-set). Because the new tires chosen will be slightly wider, we needed rims with a greater offset, so we ordered 7 new rims with a 5.35″ offset (the old rims had a 5.15″ offset).

The rims actually lived in our house for many months before we were ready to get the tires. Though they did finally get their tires attached.

And they finally made it onto the Turtle.

Some additional touches included new lug nuts all around, and lug nut covers. We could only find the covers in stainless steel, so we ordered them, had the 32 brand new covers powder coated black for $40, and installed them. They add a nice, finished look, and will keep the threads clean too!

You can see we have a nice narrow tread but a taller traction tire. I did add a 1/4″ wheel spacer for the front tires to cancel out the additional offset of the rims and preserve (within 0.05″) the stock wheel center line for the steering. Luckily, the front hub was just proud enough to accommodate that and still have the hub-centric wheels centered properly.

The spacing between the rear tires actually increased slightly. All in all, it really worked out pretty great. The new tires will keep us safely stuck to the road in all kinds of weather and terrain, and I sure think they look pretty nice too! Maybe someday we’ll get even bigger tires…