Features New Coker Bias look radials

I did get them from Summit, and they balanced with little weight, but I've got a death wobble at 60 that wasn't there before. There's a local shop that can shave them, if they think there's a problem, I'll return them for another pair....

 

Hey Josh!! Can toe in or out affect death wobble? Is it different from bias ply to radials? Pete

 

I'll be damned if I'd pay the price you paid for those tires and then pay someone else to cut the fucking rubber off to make them round! Send the damn things back!!!!!!!!!!!!!!
Seems that the theme song for Coker lately has become "out of round blues".

 

I asked Coker, they don't make recommendations on alignment. My car with radials has always been set at 1/8" toe in. I don't know if more toe would help? I've never run bias plies on this car, but I've read bias wants more toe, even though these are radials. Anyone have thoughts?

 

To be fair to Coker, I'm ASSUMING an out of round problem. I've seen worse tires on the balancer that didn't have a problem on the car. These are pretty tall and skinny tires on old 4" Cragars after all, although the 165 80 radials never gave me any problems. Right now, I'm more interested in finding the solution, so that's why the tires and wheels went to the tire guys with way better equipment than me. I just dropped them off, will report back.....

 

Altering the toe isn't going to do anything to help tires that are out of round.

 

I know that, my curiosity is whether these bias style radials would prefer more toe than a modern style radial, and or could a "death wobble" result????

 

Hey Josh!! Did you find the problem? Pete

 

Josh, if the shop in Oconomowoc makes the tires round, be sure to give out some contact info.....as we have to help keep shops with old equipment in business!

 

One thing that is stuck in my head is that Josh said that the tires balanced out with little weight,can a tire be balanced that is out of round? Pete

 

That means it balanced out suspended in air. Most likely is an entirely different story on the ground.
Would be interesting to see how it "balanced" on a Hunter "Road Force" machine.

 

Picked them up at lunch, cost me $30. They did shave them a tad, and of course rebalanced. They did take less weight than before as well. Chucked in my balancer they run much truer than before in the up and down plane. I'll drive it tonight or tomorrow for sure and let you fellas know.

 

Good point, but I don't think you can static balance (weights on inside of rim only) and road force balance. Could be interesting to explore if I still have issues.....

 

Big Bear Tire
800-378-BEAR
bigbeartire.com
They mostly use their machine for shaving down street tires for spec class racing that has to use street tires. Basically the cheater slick concept. They also use it to shave a new tire to match diameter of other tires on AWD vehicles if one has to be replaced.

 

Wow, nothing changed. Not even a little. Time to put the old tires back on and see what happens.....

 

For the sake of being scientific today, I mounted up my old front tires, car drove like it has for 8,000 miles, perfect. I put one new tire on the left front, kept old tire on right front, had same vibration at the same speed, but 50% as bad, hmmmm.

At this point I was hoping I found one bad tire, so I take it off and put the other new one on left front, kept the old tire on right. Same roads, same speeds, same problem, 50% as bad, which tells me that both new tires equal 100% of the problem.

I'm calling Summit Tuesday to talk about returning these, and I'm on the fence about trying another pair, especially if they may be from the same batch. If my car is going to shake itself to death between 62 and 70, it's worthless to me. The problem goes away above 70, and they feel good at 80, as fast as I've run these. I've been up to and over 100 many times in this car on the old tires, and it's always been stable and predictable.

Dirty Old Man mentioned road force balance, and I will do that Tuesday as a last ditch effort, just to see what happens. The fact is though, I've driven thousands of miles on static balanced tires, on all kinds of cars/ wheels, and I simply won't live with an ugly wheel weight on the outside of my front wheels to compensate for funky tires.

PRPMMP, I'm curious what the serial number/ date code is in the box on the side of your tires, both of mine are CYVCLDMH1915. Thanks...

 

Hey Josh!! CYVCLDMH1815,received them 8/3/15. Pete

 

Yours were made a week before mine then, thanks Pete!

 

Hey Josh! What size are your front tires? I have 560-15 on the front and 820-15 on the back. I also have a steering damper and pan hard bar. It never had death wobble with bias ply on radials. I know this is different but my sons Jeep started to get death wobble and found out the bushing was worn out on the pan hard bar,replaced it and it was find. Pete

 

Yep, as stated B4, as round as a brick
I wouldn't use a tire from Coker if it was FREE.

 

After 2 sets of Diamond backs I feel the same way about them,but I don't get excited about radial tires. HRP

 

What is the name of the guy from Coker's that is the go to guy if you have problems......could it be Jessie? He will do you right!

Skip Summit......call Coker direct.....It's not a Summit problem.

 

I REALLY can't believe, with all the science, tests, R&D , DOT regulation, etc. New mass produced tires are so 'out-of-round' . Then, considering the entrepreneurial spirit & $$$$ risks it takes to put out a traditional tire to a small market...why in the world would any tire outside of 'tolerances'; & the most minimal standard, make it out of production or onto the market?

 

Guess I can't even edit out an emoticon R&D, out of Research & Development. Shi:-/ wt:-/ do I know?

 

Why is it that almost every complaint I read about tires the problem is always at the 60-70mph range? It is almost always fine up to about 60 and then fine after 70 whenever someone has an issue. Is there something about that speed range that causes problems? Why does that seem to be the range where problems with tires seem to show up?

 

That's the area where the resonant frequency of the suspension assembly occurs. The force variation as the tire rotates is driving the suspension, and when the frequency of force variation matches the resonant frequency of the suspension, everything works together to make what you might call a self exciting function. Sort of like a tuning fork when you strike it and it vibrates at a certain frequency which corresponds to the natural frequency of that particular fork.

Good article at http://www.barrystiretech.com/unifandbal.html covering a lot of the basics of tire imbalance, harmonics, and uniformity. He's managed to state things in about as simple a form as possible, considering the complexity of the subject. But it still ain't like reading a comic book.

 

Very familiar with that. In my experience, fwiw, it's more often due to out of round than out of balance, which has a more linear affect.

Me: Well you see, Officer, between 60 and 70 the resonant frequency of my wheels and suspension cause a dangerous and uncomfortable vibration that is not present at 75 mph.

Officer: Sign here, it is not an admission of guilt...

 

Why do all Coker tire threads end up at "bouncing tires"?

 

Have you driven behind a car with cokers on the car? You can see the wobble

 

If I had a dollar for every "bouncing tire" thread on the H.A.M.B., I could probably buy one of their controversial tires!