The Stovebolt Site Forums The Shop Area General Truck Talk the difference tire truing can make

I enjoy old GMC and Dodge trucks. Currently I have a '52 power wagon I just finished restoring.
I have had a problem with vibration and the sensation of a slight hopping effect ever since my resto was done when driving on the road. Off road I do not notice it. I have 9 X 16 bias Power Kings mounted on the stock Budd wheels. They have an aggressive lug pattern.
The vibration and shaking seemed to be noticed especially above 25 mph, and was present after they were hot and the flat spot gone.
After researching this, I took the power wagon to a place over in Easton, Maryland (Elliott-Wilson Trucks) that had a tire lathe. They found I had about 1/4" run out with the tires on average. The picture is of the mechanic with the tire lathe or truer in action . After this was done he was able to balance things without difficulty.
A considerable improvement was noticed in the ride immediately afterword. http://photos.imageevent.com/share/powerwagonrestoration/icons/IMG_4832.JPG

Dave - back in the 60's when bias ply were the norm and belted tires were just appearing, a lot of shops had that same machine - yes, it does make a real difference and you were lucky to find someone that had that retro-tech, getting pretty rare now

Bill

I worked at a custom shop back in Detroit in the early 70s and had to do this any time a customer wanted wire wheels on their pimpmobile. I often wonder about what happened when it came time for a tire change. HA!

Several years ago I tried to find someone in the KC area to do this & never could.

check this out:
http://www.tsissg.com/711-amermac-tire-truer

This is the company that makes the truer. They also have a video you can click on at this link showing how it works that is very interesting. They are doing a modern radial tire on it.
I called the company and they gave me a list of the shops that had the truer in my state.
Then I called a few and found the place I mentioned.
Dave

Actually, see the link below as this is the model of the company's truer that works with the wheel and tire mounted on the vehcile. I have heard this is the better way, rather than off the vehcile.

http://www.tsissg.com/amermac-tire-truers-balancer/405-w-porta-trues

Dave I've been thru hundreds of dollars worth of ballancing and tire rotation on the rims and three sets of tires because of the hopping at 35-45 mph. Same tires as you seem to have, Power King bias plys.
Think you could please post that list so we can all see it? I'd be willing to give that a try.

Denny Graham
Sandwich, IL

Had a simular experience with tire balanceing on my wifes 88 mustang. Had paid the big dollar computer balance job and still bad. Was ready to get new rims when a friend said he got tired of the tire problems and bought a on-the car tire balancer like he used in High schools days and the local gas station. He balanced the tire, used 1/2 The weights and now rides nice. He also went online and found a shop in Michigan that shaves the tires for roundness and his problems are totally over.

The balance job will only be as good as the operator of the equipment. A tire can come up as "balanced" on the machine, but if the weights aren't in the right spot, you'll still get a static vibration. Took a customer away from Wal-Mart for that very thing. Weights everywhere on the wheel, showed "balanced" on their machine. I put it on mine (Hunter Road Force), it showed 1.5 to 3 ounces off. Customer had me rebalnce them after Wal-Mart couldn't do it right or refund him the money. When i was done, smooth as could be.
Now, if a tire/wheel assemblt is not true round, no amount of balancing will correct it. Only correcting the out of round situation will fix the problem. Most shops do not true tires anymore, we haven't done it since about 18 years ago, as most modern tires tend not to be out of round.

I have what i call a waggle at highway speeds. if you watch a nature show about bees you will see what i mean. at speed it seems to wiggle back a forth. in town and at lower speeds nothing. maybe that is the solution. thanks for posting. Ron

Boy Bill, we could open up a complete new volume on this one. I went thru this exercise back in 2005-2006 when I brought my 1950, 3600 home. In the interest of keeping everything as original as possible I decided the very first thing that I would do, was replace the old dry rotted tires with five brandy new ones. My two piece 15” rims were in amazingly good shape, very little rust and not all dinged up. I had them blasted and I repainted them with good PPG DBU paint. I live out in the middle of the state, mostly farm country and my tire dealer I’ve been using for several decades. They were used to working with the two and three piece truck rims and they installed my New Power King tires, new tubes, new flaps.
They said they had one ell of a time balancing them. After bringing them home and installing them on the truck it hopped all over the place so I drove it back up to the dealer and gave him the truck. They rebalanced them again and I still had the hopping which came in at about 35 and maxed out at around 40 and got better after about 45mph. Something was setting up a vibration that resonated with the natural flexing of the trucks frame or springs. At that point I found another tire dealer that had a brand new (less than a year old) Hunter Road Force Balancer. Had them rebalanced by them and still had the same vibration at 40mph that was there before.
At this point I decided to check the run out of the wheel hubs, rims, tire side walls and tread myself. Being a half arsed good machinist I set up the dial indicators and logged all the run out in chart form for all four wheels. I did a lot of research on what was a realistic expectation for run out and nothing was out of spec. That was four years ago so don’t ask for the numbers, they’re long gone. The other constant problem with the Power King bias plys was the flat spots. After setting for a spell it would take 10-15 miles before they would round out. The first drive in the morning would literally shake your teeth out, the front fenders and hood would bounce around so bad at first that I thought it was going to knock the bulbs out or shake a fender loose.
After a few months of this I finally gave in and put some new Cooper Radial LT SRM II tires mounted on a nice set of 70’s eight bolt 16.5” rims. Did the run out check on them also and had the same results, all with in specs, no bent rims, no bent axle flanges and no lumpy tire tread. They gave the truck a 100% better feeling and no lumpy tires in the morning. But that vibration at 40 was still there which lead me to a couple of weeks of intense measurements checking the drive shafts, u-joints and other rotating part of the drive line, nota thing bent or out of balance.
Never did find the problem and the truck has been down for a year and a half now with other things getting in the way.
I’d gladly take all of my tires in to have them trued up if I could find someone locally that had on of those machines. Would only do it with them off the truck though. That has to be a much more stable way than a portable unit.

Denny Graham
Sandwich, IL

At one time, my school shop had the tire truing equipment, and we taught it as part of the basic orientation course. Then the bean counters and lawyers at the school board got concerned about liability with that spinning razor-sharp blade, and made us send the equipment to surplus!
Jerry

Denny, I think you'd be more likely to find someone with the "portable" setup, specifically because the process has little to do with "stability" and a lot to do with treating the whole assembly .... you've already found trying to deal with individual components in isolation didn't work

my first experience with truing was about 1965 with new tires on a '47 Buick .... same deal, tire shop had a hard time balancing them, had odd vibrations at certain speeds, took a recomendation to see an old mechanic who listened to my description and said I should true the front tires - I watched him do it and it worked perfectly .... a few years later when I got new tires on a '56 Chev sedan I had them done too, amazed at how out-of-round a brand new tire could be

as the other Bill says above, modern radial car tires don't seem to be so bad, but for the heavier truck tires and bias ply, I'd be inclined to think truing right away with speed related vibes - didn't know until this discussion the machines were still being made and used

Bill

The big problem I see with having to true bia ply tires is the tread wear you lose by having to do that (shaving tread to make the tire round). Boy this thread brings back the bad memories from the coker tire bias ply issues I had last year on my '38.

They imply that truing them although it does remove tread will result in longer wearing tires. That makes sense to me, to a point.

Grigg

Tiny - you don't really lose much tread, just takes the high spots off, which aren't doing you any good anyway! really, the cut is minimal unless the tires are really terrible, there's not a lot left on the floor

Bill

Something that I'm sure enters into the equation is tire growth. They may look round in the static condition, all of mine were but who knows what happens when they are up to speed. An extreme example of what I’m talking about is what you see on the dragster tires. All be it on a much much smaller scale, I'm sure you would see the same thing happening to a street tire. That was the reason I had both sets (bias & radial) of tires spun up on a road force balancer.

Resonance can be just prevalent and just as confusing in mechanics as it is in electronics, music or any other science. No matter what you do to a tire it’s gonna have a tiny bit of out of balance the will show its face as you pass thru it’s critical speed. This can resonate with other things like the springs, frame, a body part or engine-driveline part and the vibration will be amplified. I think that is the only explanation for some of the weird vibrations that are encountered in a vehicle.
There were a lot of these nodes in the aerobatic airplane I built and flew. But just as there is in any vehicle that I’ve ever driven, there is that sweet spot where every thing feels just right.

I’m always up for trying something new and I would like to locate a shop and see if they could true up those Power King bias ply’s any more than they are. They only had a thousand or so miles on them when I took them off the ’50. The ’54 needs tires before I can drive it, the skins that are on there now were installed in 1988. So I’d like to try them on that truck and see if I get the same period of vibration at the same speed as I did in the ’50. Only problem is I’m still gonna have to put up with that dang flat spotting when I wake her up in the morning.

Denny Graham
Sandwich, IL

Don't know if any of you Bolters have road racing experience, but shaving tires to make them round is common practice in road racing.
I'm not sure about the U.S. but here in Germany all of the racers have such machines and those with tire sponsors get it done for them by the tire manufacturers.
Maybe it's the same in the U.S.A. ??
Can tell you from my own experience that making them round greatly reduces vibration & harshness and also extends the tire life.
Must admit watching them do it to new tires is kind of scary. Removing 1/4" or more is common on extra wide tires.

Tires wear out fast enough without shaving some off. You can some times break the tire down and rotate on the rim and get a smoother ride. Tires when new ane not perfectally round and the wheels have spots that are higher than others. If these high spots are in the same location there can be trouble. Don't wast good traction by cutting your new tires up.