Any Nylon tires with no flat spot issues?

[Daniel Y.]

I need some help - I've purchased Coker tires for my 67 and they have flat spots. Called Coker and they suggested testing for out of round. They had me take it to a dealer that has a "Hunter Balancer". the tires are withing tolerance. after 15-20 minutes of driving they warm up and the flat spots go away. However, even after just a day, they get the flat spots - so bad it feels like you are driving down a road full of pot holes. Even though its been over a year Coker is willing to satisfy me. They tell me regardless of brand they are all made in the same factory. The only difference is the molds for each branding. They are all Nylon regardless of whats on the tire. Kelsey tire has same process. There must be some molds that are better than others. My 66 came with a set of "B F Goodrich Silvertowns" white walls when I bought it and I have no issues with flat spots. I can park it for 6 months and they ride smooth immediately. So I know its possible to get them without flat spots but both Coker and Kelsey claim they all have the issue of flat spots for first 15 - 30 minutes. I want either red lines or black walls for my 67. My question is: does anyone have a set of red lines or black wall 7.75 x 15 from Coker molds that don's have flat spot issues? Goodyear Power Cushion, Firestone deluxe Champions, Uniroyal Laredo, BF Goodrich in either redline or blackwall. Coker will exchange them for what ever I want I would like to hear from those that are happy. I realize radials are the answer but want the poly tires. I appreciate your responses. Thanks so much Dan Young

[Mike F.]

Re: Any Nylon tires with no flat spot issues?

Doesn't bias-ply and flat spots go hand in hand? Were the "Silvertowns" radials? If so, that's why they didn't flat spot.

[Michael J.]

Re: Any Nylon tires with no flat spot issues?

The Goodyears I have bought for my '67 at Kelsey are nylon, and they flat spot, the BFG Silvertowns I bought from Coker are polyester, as are the Firestone Wide Oval ones I have for my Mustang, and they do not. Check the cord construction closely, polyester are what you want if you don't want flat spotting. I think Coker has blackwall BFG, but remember that BFG did not make red line tires for the '67.

[Ara G.]

Re: Any Nylon tires with no flat spot issues?

Dan,
How are you? I very much missed seeing you in Lakeland. Mitch told me you had your hands full with work, so I completely understand. Deb says hello. I have Goodyear/Kelsey tires on my silver car and never have a flat spot issue. It may sit for 4-5 months at times. No issues at all. I have Repop Firestone red lines on my maroon car and they flat spot, but not horribly. However, this may be in part due to my climate - south Florida is a heck of a lot warmer than most places.....Am curious to see what replies you get here. My goodyears never flat spotted on me. I have another set of Kelsey/Goodyears I am putting on a set of rally rims in a week or two and will let you know how they do. Take care pal! Talk soon I hope...ARA

[Leif A.]

Re: Any Nylon tires with no flat spot issues?

As far as I can remember, ALL nylon tires flat spotted "back in the day" and will continue to do the same thing today...it's the nature of the material. Typically driving on them until they get warm will "round" them out and the ride will smooth out again. Old technology even though they still make them for our classic cars. If you're driving your car a lot, IMHO I would buy a set of radials for the road and keep your nylon tires for show. The radials will, also, give you superior handling over the nylon cord tires.

[Richard S.]

Re: Any Nylon tires with no flat spot issues?

I took my 69' Goodyear Polyglass tires to a facility that used a Tire Truer/Shaver. At a time when radials were not standard it fixed the problem. The Tire Truer/Shaver is still out there, just a matter of finding someone who spent the $8000 plus for this kind of odd ball machine.

[Duke W.]

Re: Any Nylon tires with no flat spot issues?

As far as I can remember, ALL nylon tires flat spotted "back in the day" and will continue to do the same thing today...it's the nature of the material. Typically driving on them until they get warm will "round" them out and the ride will smooth out again. Old technology even though they still make them for our classic cars. If you're driving your car a lot, IMHO I would buy a set of radials for the road and keep your nylon tires for show. The radials will, also, give you superior handling over the nylon cord tires.

That's correct and is why the industry got away from nylon cord bias-ply tires and went mostly with rayon cord tires even though nylon is stronger and continued to be used for HD applications like racing tires and trucks tires. The RPO P-91 backwalls from the early/mid sixties were nylon cord. Also, aircraft tires are almost universally nylon.

The flat spot problem can be minimized by keeping them at high pressure, and the sidewall placard probably states a maximum of 35 psi, cold.

The lesson here is if you want to run OE reproduction bias-ply tires, avoid nylon cord types and go with rayon or polyester construction, but you'll have to do some Web research and make some phone calls. The type of cord and number of plys is always placarded on the tire. It's a federal requirement, so don't take "I don't know" as an answer from any vendor.

Duke

[Daniel Y.]

Re: Any Nylon tires with no flat spot issues?

I have tried it all. Over inflating. And then letting out just before driving. Same result. I'm pretty sure its a "mold" issue since I have heard from Ara - he has had luck with Kelsey Goodyear. As I said earlier my white wall BF Goodrich are flat spot free. If I can't get some from Coker that work maybe I can find someone to sell me some that are flat spot free.. I'm looking for more owners that can confirm better tires. Yes - I know Radials are everyday better..... Anyone else with baised ply Nylon that are flat spot free???

[Duke W.]

Re: Any Nylon tires with no flat spot issues?

Trust me: It's not a "mold issue". It's a materials issue - the nylon cord. Some nylon cord tires may be worse than others, but all will have the issue to one degree or another. If you don't want to deal with temporary flat spotting, avoid nylon cord bias-ply tires.

The problem is also evident in many H and above speed-rated radial tires that have a nylon cap belt, but is rarely as severe as nylon bias ply tires, and a little vibration for the first few miles of driving is a small price to pay for the additional safety margin since the nylon cap belt will prevent the tire from disintegrating if there is an internal structural failure.

Duke

[Joe L.]

Re: Any Nylon tires with no flat spot issues?

Trust me: It's not a "mold issue". It's a materials issue - the nylon cord. Some nylon cord tires may be worse than others, but all will have the issue to one degree or another. If you don't want to deal with temporary flat spotting, avoid nylon cord bias-ply tires.

The problem is also evident in many H and above speed-rated radial tires that have a nylon cap belt, but is rarely as severe as nylon bias ply tires, and a little vibration for the first few miles of driving is a small price to pay for the additional safety margin since the nylon cap belt will prevent the tire from disintegrating if there is an internal structural failure.

Duke

Duke and Daniel------


I agree. The flat-spotting has absolutely NOTHING to do with the mold. Among other reasons, if it had to do with a mold problem, then it would NEVER improve after some period of driving; it would be just as bad after a 3,000 mile trip as at the beginning.

[Michael J.]

Re: Any Nylon tires with no flat spot issues?

You are all correct, not a mold issue, nylon is the kind of chemical material that has a "memory", all things nylon are like that.

[Edward C.]

Re: Any Nylon tires with no flat spot issues?

Trust me: It's not a "mold issue". It's a materials issue - the nylon cord. Some nylon cord tires may be worse than others, but all will have the issue to one degree or another. If you don't want to deal with temporary flat spotting, avoid nylon cord bias-ply tires.

The problem is also evident in many H and above speed-rated radial tires that have a nylon cap belt, but is rarely as severe as nylon bias ply tires, and a little vibration for the first few miles of driving is a small price to pay for the additional safety margin since the nylon cap belt will prevent the tire from disintegrating if there is an internal structural failure.

Duke

I totally agree with Duke, its the materials. The other way to avoid flattening on a non daily driver is to put the car on jacks if you don't plan on driving it often. It's a pain but it helps. After driving on the flat spots they even out after a short drive.
If it was a mold issue then they would always flatten in the same spot. But they flatten on the bottom were the weight is with respect to the last time it was parked.

[Russ S.]

Re: Any Nylon tires with no flat spot issues?

Daniel, I have repo Good year Power cushions which sit for months at a time and I am sure they are probably getting some flat spotting but if so I don't notice it when I drive it.

[Daniel Y.]

Re: Any Nylon tires with no flat spot issues?

Micheal. I asked Coker regarding the "Polyester" brand - asked maybe that was why they ride so good. That told me regardless of what is on the tire they are all Nylon - made in the same factory but different molds. I thought the same thing as you but was disappointed to find out they are not really Polyester

[Michael J.]

Re: Any Nylon tires with no flat spot issues?

Well then they are violating federal law, because my 7.75X15 BFG Silvertowns clearly stated on the sidewall they were of polyester cord construction. So now Coker now longer has BFGs that are polyester cord? My tires are about 5 years old, so maybe they have changed?

Added picture of sidewall, I also have a set of 6.70X15 Coker BFG Silvertowns that are the same polyester construction.