2003 986S Steering Frustrations...
11-15-2016, 11:22 PM
#16
Rennlist Member
Remove front tires from wheels, mount bare wheel on balancer, spin balance bare wheel, observe wheel spinning to check for up & down or side to side movement. What you see is what you get on the car.
11-25-2016, 10:29 AM
#17
I agree with evcerything MAcster suggests and asks...
The fact that everyone finds problems with the previous job says *something is changing*. By the way, i have found that 95% of shops are incapable of balancing tires properly, regardless of what equipment they have. If your balancer moves - its off. If the wheel is not snugged to the balancer's hub true, its off. If the tech doesn't look at run-out, its a waste of time.
I have no idea what 2.5% means either. A true wheel should be within 25/1000" run-out radially. Wobble cannot be fixed. and often confuses a balancer too.
Find a really good shop.
G
I have no idea what 2.5% means either. A true wheel should be within 25/1000" run-out radially. Wobble cannot be fixed. and often confuses a balancer too.
Find a really good shop.
G
Agree with NA6. Your approach has been good.
Couple of things. Hard to believe 4 different shops would botch a simple wheel/tire balance. When tires don't stay balanced this is often a sign of a bad tire. The belts are moving.
But you replaced the tires and the symptoms remain.
Did you balance the rear tires? As these tires wear they can go out of balance -- assuming they were in balance to begin with -- as the heavier spots wear away. Often when I have the rear tires replaced on my cars the fronts need to be rebalanced. The fronts have worn enough (at around 20K miles) to be out of balance a bit. The rears get out balance too but often I live with this if it is not too bad since I know the tires will soon be replaced.
Very important: The tires must be the proper tires for the rims. I trust you aren't running some unsanctioned wheel/tire combination? I'm thinking some weird width/cross section tires, or non N-rated tires. Also, if the tires are unidirectional they must be mounted in the right direction.
The tires must be identical side to side and front to back, identical in that are the same brand, style, N-rating, and of course as I touched upon above mounted properly.
Be sure the tire inflatation pressures are correct. I found in my 2002 Boxster that just a few extra PSI over the 29psi in the front tires caused the car to develop a shimmy/shake -- a mild case though -- that mimiced a tire imbalance.
That leaves the wheels.
Don't know what "2.5%" means regarding wheel straightness.
I don't have the numbers for the Boxster or those wheels but my 996 Turbo manual has this to say (regarding 18" wheels/tires): Max lateral/radial runout for "light alloy wheels" is 0.7mm. With tire: 1.25mm with < 1mm better and 0.5mm best.
So you need to find a place that will check the wheel/tire runouts to the above specs.
If you find the wheel/tire runout too much then you probably need to consider replacing the wheels. I'm not a fan of straightening alum. wheels. Once bent they lose strength and resistance to bending is reduced. They can leave the shop straight but they won't stay straight for long.
Regarding other explanations...
If the wheels/tires prove to be ok then you need to find a highly regarding Porsche suspension specialist.
Generally the suspension on these cars is long lived but of course there are exceptions.
My SOP is if the tire wear is ok, even across the tread face and even from side to side, and the car doesn't manifest any behavior to make me think alignment I leave the alignment alone.
But in your case it might be worth the money to have a proper alignment done. Let the suspension/alignment specialist advise you.
He should road test the car and inspect the car in the air for any signs of problems. The best alignment is no cure for a bent or damaged or worn out suspension component.
Be sure you get a detailed *before* and *after* printout.
Couple of things. Hard to believe 4 different shops would botch a simple wheel/tire balance. When tires don't stay balanced this is often a sign of a bad tire. The belts are moving.
But you replaced the tires and the symptoms remain.
Did you balance the rear tires? As these tires wear they can go out of balance -- assuming they were in balance to begin with -- as the heavier spots wear away. Often when I have the rear tires replaced on my cars the fronts need to be rebalanced. The fronts have worn enough (at around 20K miles) to be out of balance a bit. The rears get out balance too but often I live with this if it is not too bad since I know the tires will soon be replaced.
Very important: The tires must be the proper tires for the rims. I trust you aren't running some unsanctioned wheel/tire combination? I'm thinking some weird width/cross section tires, or non N-rated tires. Also, if the tires are unidirectional they must be mounted in the right direction.
The tires must be identical side to side and front to back, identical in that are the same brand, style, N-rating, and of course as I touched upon above mounted properly.
Be sure the tire inflatation pressures are correct. I found in my 2002 Boxster that just a few extra PSI over the 29psi in the front tires caused the car to develop a shimmy/shake -- a mild case though -- that mimiced a tire imbalance.
That leaves the wheels.
Don't know what "2.5%" means regarding wheel straightness.
I don't have the numbers for the Boxster or those wheels but my 996 Turbo manual has this to say (regarding 18" wheels/tires): Max lateral/radial runout for "light alloy wheels" is 0.7mm. With tire: 1.25mm with < 1mm better and 0.5mm best.
So you need to find a place that will check the wheel/tire runouts to the above specs.
If you find the wheel/tire runout too much then you probably need to consider replacing the wheels. I'm not a fan of straightening alum. wheels. Once bent they lose strength and resistance to bending is reduced. They can leave the shop straight but they won't stay straight for long.
Regarding other explanations...
If the wheels/tires prove to be ok then you need to find a highly regarding Porsche suspension specialist.
Generally the suspension on these cars is long lived but of course there are exceptions.
My SOP is if the tire wear is ok, even across the tread face and even from side to side, and the car doesn't manifest any behavior to make me think alignment I leave the alignment alone.
But in your case it might be worth the money to have a proper alignment done. Let the suspension/alignment specialist advise you.
He should road test the car and inspect the car in the air for any signs of problems. The best alignment is no cure for a bent or damaged or worn out suspension component.
Be sure you get a detailed *before* and *after* printout.
12-03-2016, 04:56 PM
#18
Cruisin'
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Thanks for all the help all. Wanted to fill you in with an update....to recap:
I went ahead and got one of the specialists to do my front control arms and front wishbones at a fairly steep cost -but worth doing to tighten the car up and solve it, I thought? Well, that did nothing - 75, same problem. You can imagine my face.
Took it back, asked them to just try a different set of wheels on it. Seems that was it. They swapped in a set of 997 wheels, took it out and the problem is gone.
The simple solution it felt like from the bloody beginning after all... so now I'm on the look out for a replacement front wheel. Expensive little journey but at least everything is new under there now in time for track days in the new year....
I went ahead and got one of the specialists to do my front control arms and front wishbones at a fairly steep cost -but worth doing to tighten the car up and solve it, I thought? Well, that did nothing - 75, same problem. You can imagine my face.
Took it back, asked them to just try a different set of wheels on it. Seems that was it. They swapped in a set of 997 wheels, took it out and the problem is gone.
The simple solution it felt like from the bloody beginning after all... so now I'm on the look out for a replacement front wheel. Expensive little journey but at least everything is new under there now in time for track days in the new year....
12-03-2016, 07:49 PM
#19
So, i'd go back and ask how...
The shops that re-balanced the wheels missed this.
Long back, several of us said the wheels needed to be spun and true checked on their own. As i recall you had a wheel straightening place check them and there was some uncertainty about what they said (you mentioned 2.5%, which is not a valid measure for out of round).
Bottom line: something broke down when both of those shops failed to find what turned out to be the problem.
Find new shops.
Anyway - great that you found it; never bad to replace older control arm bushings, but I'd be rather unhappy with some of the techs that worked on your wheels/tires.
G
Long back, several of us said the wheels needed to be spun and true checked on their own. As i recall you had a wheel straightening place check them and there was some uncertainty about what they said (you mentioned 2.5%, which is not a valid measure for out of round).
Bottom line: something broke down when both of those shops failed to find what turned out to be the problem.
Find new shops.
Anyway - great that you found it; never bad to replace older control arm bushings, but I'd be rather unhappy with some of the techs that worked on your wheels/tires.
G
12-03-2016, 08:00 PM
#20
Cruisin'
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Indeed. Bored of figuring out who got it wrong, as I am talking about two very well respected Porsche Indys (both said it was suspension), and two mom and pop tyre fitting places (said each other balanced them wrong and showed me both wheels coming up greens on their respective machines), Plus one wheel refurbishment specialist who is the go to guy in my county and refused to take my money as 'they are fine'. My wheels have been on balancing machines more than the car this month!
Anyways...changing the wheels solves it so thats what I'll do
Onwards and upwards
Anyways...changing the wheels solves it so thats what I'll do
Onwards and upwards
12-04-2016, 04:30 PM
#21
Burning Brakes
Any chance of borrowing for one run a set of wheels known good to eliminate a bunch of the variables and put the problem as inside the car and not the wheels/tires, etc
12-22-2016, 05:37 PM
#22
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I have a similar problem. I have solved it to a great extent by straightening the wheels and getting new bushings etc. but I still have some shake. I guess when spring comes I will do what the OP did and ask my shop to try a different set of wheels up front. I bet that shall be the cure. Thank to the OP for documenting the issue so well. GL