I have an 85 GT I acquired 3 months ago. The car sat on a concrete garage floor for 2 years with a bad fuel pump. when I drive it there's lots of vibration from flat spotted tires. When you look at the tires they appear fine, no cracking or bulges in the sidewall, etc. I saw an Ehow thread that said to inflate the tires to the maximum sidewall pressure and drive for 150 miles and that should eliminate the flat spotting. Anyone ever done this? Thanks

Thats about all you can do. I have had tires that I could feel flat spots in, I just made suire they were properly inflated and drove it, they went away. It may depend on how low of air pressure the tires were while they sat those 2 years.

I wouldn't put them to the max. psi, but I would fill them to about 34PSI and drive them.... as long as they were not cracked. Even then you may have an issue. I have had "flat" tires, and they seemed to bounce back with just normal PSI and driving.

Ditto that on the pressure.
32-34 psi and drive on them.
My 86 sits all winter and in the spring it's the same issue. bump, bump, bump

I had the same issue with tires that sat on a tire rack for a while. Just drive on them and they should be good in about a week or two

Warming them up will help too... find a nice clover leaf and make a few laps. Don't go nuts though.

[This message has been edited by carbon (edited 03-27-2014).]

If the compound and belts are right, getting them warm helps sometimes. Some belts will take a permanent flat set and nothing you can do about it. Never store a car on its tires for any length of time. Either take them off, or jack it up by the A frames (dont let the suspension hang). You may have to wait for warm weather too. I run 40-42 pnds of air in all my cars tires and have for 20 years with no problems at all. I dont get any tread edge wear thats common these days. Mine wear completely even across the tread. Ride might be a bit harsher, but not enough to bother me. Gets better gas mileage too.

you might be able to "fix" flat spots... flat spotting are common w/ some belt design. should "fix" itself in a mile or two w/ normal pressure and driving. very cold, below 0°F, 2-4 miles.

see also https://www.fiero.nl/forum/Forum6/HTML/101471.html
3 digit code should be junked. They were made in '90s or older.

Any damage are problems but old tires can be bad even looking like new.
tires get filled w/ "shop air" or even small 12v pump often contaminated w/ oil, water, etc. and can get weak from inside. Flat spot mean all contamination in same spot and can work on that area.

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Yes have a feeling that I will have to replace them. Just drove about 38 miles round trip to walmart with 38 punds of air in tires and there is no change, bad vibration at many different speeds and less vibration at other speeds. Stopped halfway back and let out air down to 32 lbs and no change. I think the tires are probably old too.

Are they the same tires?
Could be tread wear numbers?

they are all the same goodyear 205/55-16 tires

Wise move. Goodyear tires tend to get hard as they age, so even with no flat spots you probably will not like how they perform.

Burnout pics!?

quote Originally posted by Csjag: I stand corrected: two of the tires are Goodyear Eagle T/R's with DOT MKT2 VCHR 319 and 419 on them. The other two are Goodyear American Eagle's they ate all 205/55-16 tires. I don't see any DOT numbers on the American Eagles I guess those are marked on the inside edge. Are these tires from the 90's?

20 years old minimum... 1993 1994 or 1983 1984.... 60 mile on iffy old tires... lucky didn't blowout on the highway.
Date code label only 1 side of tire.

I guess I live dangerously. My GT40 kit had the big outline white letter Goodyears from the late 60s/early 70s. They looked good on the car with practically new tread. I kept them on it after I rebuilt it since they dont have anything like them anymore except for off road. They didnt go flat setting for a year while I worked on it, and didnt shake at all on the freeway. I picked it up probably 2002 or thereabouts, so they were 30+ years old.

I guess they don't make Goodyear's like they did in the 60's and 70's but I thought you had said before that you never let your tires sit on the ground for extended periods?

I dont let them set long unless the cars jacked up. BUT.. I rarely let a car set still for more than a week or two. I believe in driving them all. I drove the GT all the time I was working on it. I pretty much even drove the motorhome a few miles every few weeks all winter...when there wasnt snow or ice on the road. Vehicles that set for extended periods almost always have problems when you do drive it. Im completely against the 'winter storage' idea. At the very least, the gas turns to crap....and if your tires are on the ground they flat spot...sometimes permanently