Warning Danger Welding or Heating on Tire Rims Pyrolosis

Ok Guys and Gals.

I posted this in another thread earlier and it was suggested to me that I repost it again.

Till it was suggested and I looked I was only worried about the heat expanding the air in a tire. Found out that the heat from welding or heating a rim can set off a reaction that can take up to 22 hours to cause the assembly to explode.

Watch the video, it is a little dry but may very well save a life, even your own.

jt
Pyrolosis

Tires should always be removed from the rim when doing any welding or heating on the rims. People have been killed by tires exploding. Dave

I posted that about a month or so back, but it needs repeated every month to be sure everyone sees it.

I posted that about 2 weeks ago.

This was a common occurance on yesterdays over the road tractor trailers before the common use of the Jake Brake. Long down hill runs over heated many a tire and wheel.Think about the technology that goes into a cup car running the NASCAR circuit where break discs glow red hot a great deal of the time. Knowledge makes us all safer. Great post definatly worth reposting.

a guy around here was killed a few years ago, tire had some kind of sealer in it and the assembly exploded

That is a real eye opener. I would have never thought that would happen. Stan

I would never even think of welding on a rim without removing the tire.
It would be just common sense me thinks.

Dang, you just gave me a scare for something I did 30 years ago. Tire on the rear of our Gleaner F kept going flat. Finally found out it was leaking through a hole or very small crack in the rim. I know I welded it and that fixed it. But it's been so long ago I dont remember if we took the tire off or not. I doubt it.

Guess I am luck, or stupid, probably both.

Gene

The original post, as I recall, was warning about heating lug nuts to remove them and the video showed welding briefly on a rim which is somewhat different. In the lugnut case, the solution is simple, just let all the air out of the tire first. If wheel is off and welding on the wheel is needed, then the obvious precaution is to remove the tire. A small amount of welding on the rim could be done with the air out of the tire and then cooling with water before putting air back in, but it's much better to remove the tire.

A local tire man complained about a different heat problem. His employees would keep running a inch square air drive trying to remove a truck lug nut until the socket heated up and cracked. Usually air tools will either get a stubborn lug nut off or break the stud. A separate problem occurs when the lug turns part of the way out and then the stud spins in the hub. I tried to help a young couple with that problem on the interstate once. The stud had backed out and was hitting part of the brake assembly. No room to get a vise grip in to grab the end of the stud, so I took some wire and wrapped it between the lug nut and the wheel, pulling the stud away from where it was hitting. They went down the road so they could get somebody at a garage to deal with the problem. I asked a tire man what they did in that situation and he said they used a zip gun? which is a small air chisel to cut the stud off hopefully behind the hub, but otherwise between the wheel an the lugnut, explaining to the customer that they would damage the wheel probably. I have that problem on a small trailer and fortunately the splines on a new stud were sharp enough to catch in the hole enough to tighten the lugnut, and yes, I did oil the threads before running the nut up.

KEH

I watched the complete video and the guy cites an example where a tire"s bead was unseated from the rim and the valve core removed.
The pressure buildup was so fast, the tire reseated itself and exploded anyway.

I"ve been in the fire service for 26+ years and never knew about this, and I had 2 years of vocational school and Army mechanic school. I"ve known about pyrolosis in general, but always thought it was a slow process. I don"t usually mess with tires except putting them on a taking them off a vehicle. Usually in vehicle fires, we just assumed tires blew from the outside heat source, we didn"t know that there could be internal problems. I did know that the big tires on earth moving equipment can blow (actually detonate) a long time after the equipment was involved in a fire.
Obviously there has to be a reason that the tire in the video went up so fast, would it have to do with the age of the tire? Would a tire be more prone to pyrolosis if it has deteriorated on the inside?
Thanks for the post, it"s really an eye opener!

I am a retired firefighter (30 years) - I went on a lot of car/truck fires - always noticed that the tires would re-ignite after we doused them - now I know why!

Did you watch the whole video? Letting the air out isn't enough. Dave

That is an informative video, guess i had no idea of that kind of danger. I have never welded on a wheel but have used a torch to heat rusted lugnuts several times, but the tire was usually flat to start with. This may be a dumb question, but can this happen with a tire with tube or is it more likely with a tubeless tire?

Anyone in the welding & repair business should be informed of this. Also anyone teaching welding in all levels of school.

Can pyrolosis occur when using either to seat the bead on truck rims? I know either is not a safe option, but seen it done many times.

I don't know. I only forwarded this on. My guess would be it is more likely to occur with a tube due to the thinner nature of that peice or rubber and being much easier to get hot enough.

After seeing the video I am not real inclined to try either.

Have seen the ether trick done myself even tried it once myself. Always ran away when I saw pros do it though. After seeing this I am not real inclined to try that again.

Funny thing is the pros I see do that have the proper equipment to use air to seat the beads, and they do truck tires all day every day. Go figure