Steering wheel vibration is back -- do I just not drive the car enough?

[DL4567]

When I bought the car in 2004, I don't remember there being a bothersome steering wheel vibration. Over the following years, one started and it seemed to get worse over time, and I shrugged it off to needing new tires one day to make it smooth again.

So then in January 2010 I got new tires, and on the drive home from getting them installed it vibrated WORSE than with the old tires. Took it back to NTB and they re-balanced them, but they are idiots, and that's a whole 'nother story. Finally a trusted mechanic friend spun them on his machine and determined they are "egg shaped" new tires. Said that was unfortunately common with BFG's.

By August 2010 I took the car to almost the only place in Atlanta that does the old method of "tire truing" and had the tires shaved to be perfectly round. Then they spin-balanced them on a machine, and then balanced them on the car. Can't get ANY better than that!! The drive home was amazing, the car never drove smoother.

So now that it's one year later, August 2011, a feel-it-in-the-seat vibration and steering wheel shake is starting to creep back at around 55 mph. Below that it's ok, and above that (65-70) not bad either. What the hell is going on?? Usually the car never sits for more than a couple weeks at a time, worst case 3-4 weeks go by sometimes. Is that really not enough and it causes flat spots to build up again? Looking at my mileage over the 7 years of ownership, it's been driven a little over 1,000 miles per year, but I think it's been more than that the last couple of years because now it's in my garage at home, and is driven more often than before the new tires.

The wheel bearings have been checked, as well as the hubs. Nothing wrong there.
Does anyone else have these tire vibration problems as I take it most here don't use their D's as daily drivers?

[TheDutchTexan]

I am afraid you do have once again flat spots going on there. Usually flat spots end up going away after a few miles of driving, but if a car sits long enough the tires could be permanently misshaped. I always thought it would take a lot longer than 2-4 weeks for that to happen. Maybe it's a BFG thing?

I don't own a DeLorean, so I don't know what's what. My 05 mustang actually vibrates lightly for the first mile after even being parked for ~9 hours outside, but when the tires are warmed up it is smooth as butter.

[WelmoedJ]

Besides flat spots and unbalance of tires there also are:
- play in steering rack
- play in steering knuckles and ball joints
- brakes that get stuck a bit after first use
- play in the rear (trailing arms)
- worn out bushings
- combinations of the above

[john 05141]

Flatstoppers or tire cradles are the answer to prevent flat spots.
It is 2 inches high, have the shape of the tire on the top. Your car "rests" on it and should prevent flat spots on your tires.
These things are about 250$ for a set of 4. Not very cheap, but they are all over the internet.

I never bought it becasue I think it is not worth this kind of money. In the wintertime when I do not drive the Delorean about one a week, I push the car a few inches. after a month I go back the other direction a few inches every week. Brake if off anyway so just a gentle push and the pressure on the tire changes.

John

[David T]

It may be flat spots but that is not so common as it once was with bias belted tires. Modern steel-belted radials don't have a flat-spot problem and if they do it generally goes away once the tires warm up. My guess is you have one or more defective tires and if you shave them again they will just go bad again. The manufacturer shaves the tires when they are made and that should do it for the life of the tire. The fact that you had to do it at all means the tires are garbage or a wheel weight fell off. If it takes anymore than spin balancing the tire shop should replace the tires for you. Worn or loose parts only make any vibration worse, they do not cause it.
David Teitelbaum

[Rich]

.... that does the old method of "tire truing" and had the tires shaved to be perfectly round. Then they spin-balanced them on a machine, and then balanced them on the car. Can't get ANY better than that!! The drive home was amazing, the car never drove smoother.
Does anyone else have these tire vibration problems as I take it most here don't use their D's as daily drivers?

No, this isn't normal with DeLoreans or with tires on other cars.

It's not true any longer that a shaved/trued and on-car-balanced tire-wheel cannot get any better. See the linked article below and then get your wheels/tires checked on a road force measurement machine. If THAT device says they are good then they are good. Not otherwise. If your tire shop doesn't have a RFM capability then find a better tire shop or buy new tires and hope for better results.

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=40

The cause could be something else. This is how to eliminate the tires/wheels as the cause.

[DL4567]

I can't remember for sure, but I think the NTB that installed the tires and re-balanced them shortly afterwards had a road-force balancing machine. The guy doing the re-balancing on the 2nd visit came and told me something like... an acceptable wheel and tire to them falls under the number 15 or something like that... (don't know what the number represents) and that all 4 tires balanced below that. He even moved one tire on the rim to improve it. Of course, this was the kind of guy that just lowers the hood over the tire as it spins and doesn't even look at it while it's spinning.

As I left there, of course it had almost no improvement. And based on previous experiences at NTB, I was tired of arguing, knowing there's almost no point. So that's when I decided to get them shaved. And it worked great so far, but now the shake is creeping back. Just checked, I've put on 1,050 miles since the shaving exactly 1 year ago.

I read once that some flat spots go away with 100-200 miles of driving, and while I generally only drive the car 40-50 miles at a time, this past weekend I drove it about 150 miles, and it shook just as bad at the end of the drive.

I could try putting on a set of the Michelin Pilot Exalto's on the front to see if that fixes the steering wheel shake, but it just sucks to blow another $250 to do that if it isn't the real problem. This is when I wish one of the vendors was here in town so they could check it out.

[David T]

A "quick and dirty" check you can do yourself is to jack one wheel up at a time, put a block of wood next to it and rotate the tire. If it moves away and towards the wood you have to much run-out. Could be a bent rim and/or a bad tire. Another check is to run you hand around each side of each tire and feel for lumps and bumps. You can also run your hand over the tread. If you feel any discontinuities it means the steel belts are moving inside. Before driving the car check the tire pressures. The wrong pressures will make the car feel like sh-t. The tire pressures are on the label on the glove box door. Use an accurate pressure gauge and check before driving the car.
David Teitelbaum