What you are describing, is a classic harmonic imbalance. This means that the tire can be balanced out statically, but because of an issue like a core shift during manufacture, there is more weight on one side of the tire than the other. On the road, there will be a speed range, starting somewhere around 50 mph, where the tire will cause a bounce or some other unbalance symptom, and this problem will seem to disappear as the speed gets above a certain speed. This problem will be repeatable, and will begin to become evident at the same speed. This imbalance is most commonly caused in manufacture. When the belts are being placed in the tire mould, the belts can become displaced, putting more weight on one side of the tire. There is also the possibility that there is a tread separation caused by a defect in manufacture or by over inflation. An easy way to check for a tread separation, is to have someone rotate the tire while you watch the treads from the front or back. If there is a wave pattern in the tread, then the tire is defective and should be replaced. Have them rebalanced on a good balancing machine should solve this problem. BTW, the tire can cause all these symptoms and still not be out of round. Bob
Your dead right. 3 out of 4 Vintique rims I bought were out of whack, really out of whack. 1 was perfect. They replaced them no problem, but I still wasn't that impressed with the replacements.
Luv too but the last time I did it was 2003 on a set of Dunlop 700-18's for Bonneville and did not take any photos. It took at least a day on each tire since i was relying of the rubber mounts on the 6" belt sander to hold it steady. I set the sander on my rough concrete drive way and lowered he tire ever-so-slightly against the edge of the roller of the sander. This worked for the edges. I brought the tire down on the sanders "table" just barely touching for the centers and pulled the tire backwards against the motion direction of the sanding belt. Like I said this takes hours of time. I probable didn't take off .005" at a time. the sander was trying to go one way and me the other. As I mover out from center I had to move the sander to used the edge of the sander wheel like i did for the corners. Also have a vacuum running because if makes a hell of a mess. I was lucky they were pretty true but for Bonneville i wanted them as perfect as I could get them.
Back in the biased ply days of the mid 60s, a buddy of mine was an alignment specialist, and worked at an alignment shop that had a tire shaver. He shaved the tires on his Corvette, and I can tell you that it made a considerable difference in the ride. One night, he further trued up the back tires, by side stepping the clutch at 4500 rpm and filling the car with tire smoke. That 425 hp 427 had a power to burn. I can well imagine why you would want the tire to be as true as possible when you are running at high speeds on the salt flats. I have to admit, that I would have been tempted to try something like this with an out of round tire, but your posting has convinced me that I don't need to go there. Bob
I have not talked to Coker but you would think they would offer this for a cost...it's like a missing link to the equation. I don't think they offer it or this discussion would not be here. even have a contracted company to do that service as part of the purchasing package. Its not a poor quality thing for the most part it is just a standard that's now missing.
@B Ramsey thanks that looks dangerous as hell but it achieves the goal. Since you so cleverly done what I never thought of doing I did a bit more digging and found this...this is the real deal on a vintage Hotrod...One thing you fellas might want to do is contact the shop with the video if its near you...
No sir...but thanks the cookies were enticing......I was out tonight doing up to about 65 mph and with the higher air pressure of 28psi the shaking/bouncing is actually smoother or less prominent. I have the beads on the way. If I could locate one of these shaver outfitted companies I would enlist the service immediately. One thing of note to the tire shave crowd it seems to me the new tire only shave thing is BS most of the tires they were shaving didn't really look new at all...
Great thanks for the videos. I did hear back from that tire shaving company in Maryland and they said they are not sure the wheel will fit there machine, I'll give them some more info and get back.
Now this is something, when going down the road the tire looks like it moves from side to side a lot, but at the house, jacked up it only moves side to side about 1/8". On the road it only looks like it moves up and down when it starts bouncing at about 60MPH, but at home it is out of round by 3/16". Now I say "looks like" because it is really hard to tell but I'm sure you understand. Oh, and the side to side tire movement does not line up with any run out of the rim.
That's what I thought, Coker makes the Firestone tires, but the two tires are different, the tread is different and the sidewall (pie crust area) is different, close but they are different. Now this does not mean the Firestone tires are better. Do people have less trouble with the Firestone tires?
So the tire shaving company in Maryland that a link was posted to on the first page just got back to me, they said that they cannot do it with the old steel wheels. so I guess if it gets done I will do it. I really would not mind just buying another set of tires, but only if I would know that they would be round. Any tires that someone could recommend?
Many, many Hambers have bought Coker with no issue. Some have had issues with positive outcomes with some not so. The positives definitely outweigh the negative and you can buy Bias like those elsewhere but the source would still be Coker. You may have 2 different lines of bias Firestone tire as they have several.
There may be nothing you can do but it would be worth shaving as it was a done deal till the tires evolved.
I just came back from Samaritan tire in Minnetonka Mn. I had to go back and pick up my wheels they could not true my tires they were so far out of wack. They put one on the machine to show me and there f""""cked. I'm amazed my 32 went down the road as well as it did. New tires on the way.
[QUOTE="46international, post: 12674375, member: 59827". I really would not mind just buying another set of tires, but only if I would know that they would be round. Any tires that someone could recommend?[/QUOTE] Yes,I'm an OLD OLD guy.but n the late 50s,early 60s..WE always has our tires TRUED,,,and all tires needed it..Tire stores by name of O K Rubber Welders had the proper machine for this...
I just replaced a tire with a tread separation on an O/T vehicle, and had been thinking of making a tire trimmer using my wheel balancing machine to rotate the tire, and a jig that mounts a router or a circular saw. The biggest problem I can see at this point, is to duplicate the curvature of the tread face so I can cut it equally. The more I think about truing the tires, the more I think it is worth doing. Crap, I just committed myself to another project, just what I need. Bob
Years ago I worked at a large tire retail store. I won,t mention it's name... The new tires that we sold there, that came from their source ,many were ( not round !! ) Balancing was a waste of time. When one spun them on the balancer it was evident. The boss pushed them through... Make money at the customers expense..... Gene
Here is a link to a youtube of what a shifted belt looks like on a new tire. This problem of shifted belts has nothing to do with the mold, it has to do with how carefully the rubber and the belts are loaded into the mold. Makes a person wonder about all those times I had my wheels balanced and they still didn't feel quite right. Bob
I recall buying tires at the Winston tire store many years ago, Winston tires were pretty popular brand around So Cal at least, not sure about the rest of the country, but trueing the tire was an optional service you could purchase, and I did. The tires were mounted on the machine during the process, not on the car, a guard was lowered down over the process so I couldn't see how it did what it did, but you could hear it working, and it sounded more like a sanding or grinding process than the cutting tool/slicing process in the above vid's.
When searching for those tire truing vids above last night there was another machine that used a modded disc sander and the jig was fairly hi tech I will post it if I can find it again as it was something 46 was thinking of using. This is the grinding type set-up and they have several locations. This is another video with a more traditional type machine and there are templates for profiles and the machine cut on a chosen/measured arc.
I have a teflon coated 10 inch sanding disk that has 180 on one side and 300 on the right. I was thinking of mounting that in a side grinder that has been secured to a track that would follow the tread profile. My other thought, was to mount a skill saw and a blade. I think either one would work well, it is just a matter of which one would be the easiest to secure. Bob
So I got home yesterday and tried the sander on the tire, It is a slow process, after an hour I think it was somewhat better. I got down to less than 1/8" or so. I was just using a jack stand to steady the sander and I know that could be better but I just wanted to see how it would go, kinda works...a little. I'll do more tonight and take it out this weekend if the rain stops.
You will have to let us see what you end up with. I would think the saw would be better, it looked like it worked in the video. The router may turn too fast and you may end up with melted rubber all over the bit. I was surprised at how slow the sander takes the rubber off, cutting would be the way to go. Maybe a saw with a dado blade?
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