A week ago I paid 160 to get 4, 1984 Z28 rims and tires. Tires are practially mint, no dryrot, 2K miles on them...

I put 2 of the better looking ones on the rear of my car today... now when I go over 20 miles per hours I get this kinda "bump" feeling... I don't physically go over the bump as if I was a busted belt, rather it makes the noise... I wanna say it feels like the tire is flatspotted, but I really don't know because I've never actually driven on a flatspotted tire before... the tires have no protrusions and -look- fine...

What do you think it could be and do you think a local tire dealer can fix it?

 

When the price makes the deal seem too good to be true, it probably is.

Flat-spotting is what happens when you lock up the brakes while driving down the highway, and especially if the car slides sideways for any appreciable distance. You can usually run your hands around the tires and feel it. Separated tread is where air gets in between the layers of rubber and makes a sort of "bubble" on the outside. Those are wasy to feel too.

Sounds to me like you actually got 4 wheels with some round black rubber garbage stuck to them that needs to be cleaned off.

 

So in otherwords... they're probably flatspotted...

And in order to remedy this... find a nice deserted area and spin 'em up for a minute and round 'em out again? Sounds like fun!!!

I can feel it at pretty much any rate of speed on smooth pavement.... and it's definatly wheel/speed related...

I will say, for the few minutes I drove on these Firehawk GTA's... they suck! Sidewall flex, horrible rain traction...

 

It sounds to me like the tires have a "hop" to them, or in other words they are no longer round. This may not be very easy to see just looking at them, unless your used to looking for such problems. Those tires are pretty sucky anyways, ive sold them in the past... ditch em if you can.

Hellraiser

 

Thanks for the info and advice guys... The reason I bought these at such a cheap price is because I needed the tires and I don't have alotta $$ to throw around... I'm going to spin these puppies up one at a time and see if I can't re-true them that way...

Also, I'm going to try to put them up to spec on air pressure... they're at 25 PSI now... I'll put them up to 35 (max tire spec is 40)and see if they get better, if not, powerbrake here I come...

Hellraiser: "Hop" is the perfect word to describe the way it feels... no visual bulges, just generally not true...

 

Xeno,

Before you grind a 32nd of rubber off the tires in an attempt to "true" them, check the information on the tire sidewall. If they are "Z" rated tires, or the tire composition includes nylon belts, teh tires will feel like they have a flat spot until the tires are warmed up by driving a few miles (longer in colder temperatures).

It may help to inflate them to near the full rated cold tire pressure, then drive them until they are warm. If the "bump" doesn't disappear, the tires may have a slipped or broken/tearing belt.

My nylon 245/50s Gators generally do the "bump" thing for about 3-5 miles after the car has been sitting for a week or so. Nylon belted truck tires are a WHOLE lot worse, and take a lot more driving to warm up and smooth out.

 

Sorry, I thought you understood... they are 1984 Z28 rims that I bought, with practically brand new Firehawk GTA's... 4 for 160 is a hell of a deal.

Oh and I found the problem. It seems that somewhere in jockying my car to face the other way to put the other rear tire on (in the street, had to face away from the curb) I must've run something over, because my front drivers tire has a 1/4 piece of metal in it, with a screw embedded in it... I pulled it out (old tire, going bye bye anyway) and drove it... solved the problem, just now that tire is flat. Tomorrow I'll put my other 2 new ones on and be good to go.

Thank you all though for the initial help!


P.S. I didn't take too much rubber off before I realized this... no real loss.