New guy with some questions.

Hello,

I'm new here. I just found this forum and registered here this evening. I've been having a strange problem with my '59 Skyliner and thought I might get some ideas/suggestions from someone more knowledgable than myself.

This spring I bought a new set of Coker Classic WWWs (215 75R14s) for the car. One of the tires required more weight than I would have liked, but supposedly they're all balanced properly. I test drove the car at various speeds and didn't notice any issues.

A few weeks later, I drove the car again and noticed what I would call a 'hop' at around 50 MPH. It felt to me like a ply separation on one of the tires. I made plans to take the car to the shop and check the tires. On the way to the shop, the car rode perfecly smooth at all speeds.

Next time I drove the car it was 'hopping' at fifty again. It took me a while to realize it, but eventually I discovered that the 'hopping' only happens when the top is down. As soon as I put it back up, everything smooths out.

I figured it had something to do with weight-shift on the suspension, maybe too much weight on the rear or too little on the front. The shocks seemed to be ok but since they were the original equipment and more than 50 years old, I figured it couldnt hurt to replace them. I replaced all four shocks (with KYB gas type). The problem didn't change one bit.

I rotated both the rear tires to the front and fronts to the rear...still hops with the top down.

Any ideas/suggestions?

Clark

By the way, the car is basically a one-owner car, 38,000 miles, all original but the paint. Never restored, only maintained.

Clark

Glad you found the forum. I took a picture of an article that was posted in the Skyliner club magazine. http://www.flickr.com/photos/6362254...n/photostream/ Hope you can read it. It discusses some issues with wide whitewall tires. I have an older set of bias ply wide whitewalls on my car and they will develop a flat spot when the car sits for long periods of time but they get round quite quickly when you drive it. As far as the weight shift issue you mentioned I can't imagine how it would affect this. The caster angle of the front end alignment would change slightly with the top in the trunk. I would not think this would cause the issue you have, however its important to remember that the shocks do not support any weight of the car and simply absorb the roughness of the road. If you can read the article it mostly discusses a hubcap issue when changing to radial tires. I don't know if any of this information will help but I thought I would post it. If you're not already a member of the Skyliner club give it some consideration, it is a very good club.

Jim

Here is the contact for Dave Dudt one of the clubs technical advisors. He should be able to help you.

Technical Adviser
Dave Dudt
104 McCrerey Road
Claysville, PA 15323
Phone: (724) 948-3861
E-mail: 0dhdudt@earthlink.net

Thanks Jim,
I was able to read every word in the article you linked. Very nice of you to do that and a very interesting article. I did a lot of research and asked a lot of questions before buying the Cokers. In the end, I bought them because they offered the tallest OD. It could be that I made a nine hundred dollar mistake. :( If I had enough money to mount up another set of modern radials, I guess I could settle the question.

Thanks Dave,
Dave Dudt was the author of the article posted by Jim. I'm sure he is a wealth of info. I'll try to contact him.

Clark
Here is a interesting article on tire problems
http://www.aa1car.com/library/tires2.htm
Also if think it is just one tire causing your problem maybe you could use your spare tire to check this ?
Good Luck Jim

Hi,
I have had some issues with Coker tires in the past. This time around I switched to "American Classic" radial tires. This tire is based off of a 1980's Michelin tire and is made in America. The difference with this tire is the mold is not as old and the main stream production tire it is based on was very reliable.
It seems no one has a perfect experiance when switching to radial tires but so far I have had no issues. I cruised at 80mph for about 7 hours straight and nothing. But, like I said, I don't think there is a "clear" magic bullet when switching.
Hope this helps,
Rob