The Stovebolt Site Forums The Shop Area General Truck Talk 1940's Split Rims

I have a restored '40 3/4-ton with split rims. And I was just wondering if someone that's knowledge able about these tell me the why they made these style wheels and the advantage of them were? and from a historic point of view how did the old timers change these back in the day, where they so the home/ local business owner could change tires themselves? How would one change them back in the day safely?

**disclaimer: I'm not looking to try it and Yes I know they can kill you. This is just for historical information...thanks in advancd

These wheels were made for the ease of repairing them.they typically used a liner that went between the rim and tube. This was to protect the tube from chaffing on the rim,and as time goes on from dirt and rust build up. What made them easy to repair is that one did not need a tire machine to take apart, A tire hammer and a couple of tire bars were all that was needed.the biggest point of safety in working with split rims was in airing them up. That's what made them dangerous. If the ring wasn't seated right,or stretched to big,they would blow off when the tire would pop up when it seated. I used different methods to prevent a disaster should the ring blow off. I would put the tire/rim under the hoist and dropped the hoist down on it,use a chain and wrap it around the rim and tire (if I could,)in several places,stand the tire up and lean against a wall or door,put the air chuck on and take a walk.of course the safest way and legal way was to use a tire cage. Most tire shops had one and would roll the tire in be foe airing it up and should it blow all the parts stayed in the cage.As tubeless tires became the new norm,and safer,the tunes and split rims went away.many tire shops won't touch the split rim now because of the safety issue and also a lot of guys don't know how to work with them. Not sure what style of split rim you have, I recall 4. A single split ring,a double ring set,a solid ring with a smaller split ring that acted as a lock ring,A solid ring that had a oval shaped inside diameter that allowed a person remove it much how one would remove a tire. The last was the true split rim. The split was in the center of the rim and the two halves would be collapsed and the lock ring removed and the rim halves could then be separated..this topic brings back a lot of memories,I never had a incident working with them,but a co-worker was airing one up in a cage with a clip on air chuck,the ring blew off,the air chuck came off a whipped back and hit him in the knee. It broke his knee cap. The shop I worked in (in the early 80's) was built in the 40'same the roof raised in the 50'same to accommodate a hoist.the ceiling had a few ring marks in it made from tires blowing up and rings flying up. I hope this helps you,I probably missed something. If I did...ask away.

you have to be extra careful airing it up if the tire goes flat too, my 47 gmc grain truck had splits with coop tires on the back, the story was why I got it so cheap ($700) was the old guy fixing it up for himself it let it sit while installing a new motor and a rear tire went flat. he tried to air it up and the rim came apart, sending his hand and wrist up through the stake pocket. ouch.

Are they safety ring or true "split rims"...ie...two separate halves to the rim itself? I have seen a variety on 40's era trucks. Nearly all 20" x 5" but in different configurations. My '46 1.5 ton bus had mostly "standard" ten lug rims with safety rings but I discovered one of the rear (dually) was the notorious RH5 "widowmaker". Big difference between them.

Some pretty good discussion and info here...

Rim Info http://www.bigmacktrucks.com/topic/43135-split-rim-question/

This Tech Tip about wheels is pretty comprehensive. It's for Advance Design Big Bolts but perhaps some of the historic information you are looking for is there. And if not, Grigg may have insight as to "why did they make them anyway?"

Peggy M