The tire shop just pulled the tires off my 4 spares; I'm getting them ready to mount my new 17" wide whites. I was surprised to see that they are a type of split rim wheel; the old time tire guy called them 'drop-centres'.
Anyone had any experience with these.........good or bad?

 

They are called 2-piece advanced rims, the F-1 rims were called drop center. They are good rims as long as the ring is good. You can only use tube bias tires on them though.

 

I havn't had first hand experience, but I've been told some split rims can be dangerous by blowing apart or something. I don't remember all the details, so someone else might want to elaborate.

 

Drop center is like a normal "modern" rim. The tire drops in the center to allow you to pry the bead over the edge of the rim.

A rim that consists of a the rim (back part and center hub) and a simple lock ring IS NOT a split rim. This is a normal truck rim and is still used today.

A split rim is where the rim is like it is cut down the middle perpendicular to the axis of rotation, with significant amounts of rim on each side. These are the rims that are "dangerous".

 

Dude, as long as I've helped out busting tires, the kind with the lock ring has always been called a split rim. And that is exactly the kind that is dangerous, just ask the tree that met the one off my Allis Chalmbers grader. Just take one down to your local tire shop, they will put a cage over it and probably charge you extra for your "widowmaker". Search the web for split rims, you should get excelent pics, horror stories, and OSHA guidelines.

 

Keith,

OldSkool is 100% correct. I worked for a garage-tire shop all the way through high school. We used a cage to fill split rim tires (like on dump trucks). When I first started there, someone had already had one explode on them - the wheel was laying on the floor. The ring went up into the ceiling about 15 ft above and went in a good inch or more.

They weren't the best design to begin with. Old and rusty just makes them more dangerous.

 

A split rim is referred to in the 1954 Ford Truck Operator's Manual I have sitting on my desk as a "semi-drop center rim" . These are dangerous, illegal and no longer manufactured. The rim is literally "split" in half. In normal installation on a vehicle, it's such that if the rim explode a piece would blow off into traffic. The way it's put together there is only about 60% of the circumference locking. These type of rims haven't been used in almost 40 years.

A 2-piece rim with a lock ring, is still manufactured, installed, and used on MILLIONS of vehicles. I have personally repair, mounted, inflated, and spit on the valve stem of these types for over 20 years, and my father has for the last 50 years without a cage, flak jacket, or bulletproof vest. This is the only type of rim available for bias type tires for large trucks. The design is such that most of the time (except on front wheel installation) that the ring will blow in towards the vehicle. The lock also locks on 95% of circumference.

I run a trucking company with 30 trailers, 2 tractors, 3 straight trucks, and a dump truck, and with exception of the tractors, all have 2 piece rims. I have changed more of those type tires than you have probably seen, and if you want me to mount them I will.