OT: Flat spotted tires
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From: Boston
OT: Flat spotted tires
Not a specific Porsche question, but the general knowledge around here is so high ...
I borrowed my father's 1999 BMW 740iL which, until now, has been driven rarely and sporadically. The car has 23,000 miles on it. In 2007, the car had new tires installed. Since then, it's been driven perhaps 600 miles per year.
I picked it up three weeks ago, and took it out on the highway, got some vibration up around 65 mph. Took it over to the tire place, had the wheels balanced and checked for true. Vibration remains.
Drove the car 1600 miles to Austin. The vibration remains. Took it to the dealer, they checked the suspension out, seems fine. Tech sez the tires still have flat spots on them.
Is this likely to go away over time, or should I just spring for a set of tires? Obviously, there's plenty of tread left on them. Seems like the 2000 miles I've put on the car in the last three weeks would have taken care of it if it was going to get taken care of.
I borrowed my father's 1999 BMW 740iL which, until now, has been driven rarely and sporadically. The car has 23,000 miles on it. In 2007, the car had new tires installed. Since then, it's been driven perhaps 600 miles per year.
I picked it up three weeks ago, and took it out on the highway, got some vibration up around 65 mph. Took it over to the tire place, had the wheels balanced and checked for true. Vibration remains.
Drove the car 1600 miles to Austin. The vibration remains. Took it to the dealer, they checked the suspension out, seems fine. Tech sez the tires still have flat spots on them.
Is this likely to go away over time, or should I just spring for a set of tires? Obviously, there's plenty of tread left on them. Seems like the 2000 miles I've put on the car in the last three weeks would have taken care of it if it was going to get taken care of.
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Joined: May 2008
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From: Arlington Heights, IL
Were the tires road forced balanced? What brand of tires? If flat-spotted from sitting, they usually rebound after a good heat cycle.
The tires were installed in 2007 but what are the code dates stamped into the side wall of the tires?
The tires were installed in 2007 but what are the code dates stamped into the side wall of the tires?
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From: Winston-Salem, NC
Unless you can actually see and feel the flat-spotted areas, I'd say it's not the tires. BMW's are known for their predisposition to vibrate at speed. Suggest that a competent indy wrench check the front lower control arm bushings. They deteriorate over time, temp and mileage.
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From: Huntington Beach, CA
Unless you can actually see and feel the flat-spotted areas, I'd say it's not the tires. BMW's are known for their predisposition to vibrate at speed. Suggest that a competent indy wrench check the front lower control arm bushings. They deteriorate over time, temp and mileage.
Possibly the thrust bearing/bushing. It's a regular maintenance item on BMW's. Our '03 X5 encountered a similar vibration. While a wheel balance helped slightly, bushing replacement solved it.
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They were road force balanced twice ... they are Hankook tires, not the best, I suppose. Date was late 06. BMW tech said he sees them hopping a little in spots when he spins the wheels, but they are balanced correctly.
The dealer said they checked the bushings, tie rods, etc., and it was all good. The thrust bearing vibration is supposed to appear at 45 mph in the 7 series, from what I've read. But I'll see if I can find a good independent in Austin.
The dealer said they checked the bushings, tie rods, etc., and it was all good. The thrust bearing vibration is supposed to appear at 45 mph in the 7 series, from what I've read. But I'll see if I can find a good independent in Austin.
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From: Winston-Salem, NC
Hankooks aren't that bad a tire. My wife got 30k mi./set out of two sets of Hankook K104's on her old MINI and I'm running Hankook RS2's as my street/track rain tires on my MINI. Here's an old trick to check if it may be the tires: Run the pressures up to 50 psi in all tires, then find a nice, smooth highway to run at the critical 50-60 mph for a couple of miles. If the vibration goes away or minimizes, stop at a safe place and lower one tire at a time to, say 35 psi and run again to see what happens. If it returns, you've found one tire at fault, if not, lower another until you've found the culprit. If it's one or all four, then your dealer is right. If not, they're wrong and it's in your front end.
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From: Long Island, NY
FWIW, when I park the car I put both front tires/wheels up on 'tire cradles'. I've found the FRONT tires to be more susceptible to flat spots and to readily 'transfer' any wobbles to the steering etc.
I REALLY like that idea of pumping them all up to 50psi and then - by process of pressure-release elimination - finding out which one 'wobbles' (the most - or not). Kudos!
Gerry
I REALLY like that idea of pumping them all up to 50psi and then - by process of pressure-release elimination - finding out which one 'wobbles' (the most - or not). Kudos!
Gerry
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From: Boston
Well, took the car over to Discount Tire, spun all four wheels on the balance machine. Both fronts were hopping and one rear was shimmying. Four new Michelins and the car is riding perfectly.
Almost makes that $350 Tire Cradle thing seem worth it.
Thanks for the assistance ...
Almost makes that $350 Tire Cradle thing seem worth it.
Thanks for the assistance ...
