Thursday, August 06, 2009 - 11:44 am, by: Andrew Robb(Leggstt)
got new front tyres.Done about 500kms and outside edge wearing,Went back they adjusted alignment,Then inside started getting chewed bad.Went to another place they readjusted now the inside inch of the fronts left and right is down to the canvas.can anyone please explan?have lowered springs and 18's on the car.I do alot of country driving at highway speeds and a little above.
Ian Johnston DieHard South Australia UZZ30 GT 4.0, UZZ31
Thursday, August 06, 2009 - 12:46 pm, by: David Vaughan(Davidv)
Could be what Ian said. Wear that fast seems absurd. It may also be influenced by lowering the car. The suspension arms will now be working in a sub-optimal arc unless your springs are also very stiff. For practical purposes it becomes harder to get an ideal alignment other than when the car is static.
I know I am gradually developing a theme on this in different threads so let me add some background. Back even only 20 or 30 years, most cars still had primitive suspensions and lowering was a good way of improving handling by lowering CG. The Soarer was designed with a full wishbone setup at a time when suspension theory was now quite well understood compared with earlier times. Lowering it does not have the same payoffs as on older cars because wishbones are rather more sophisticated than leaf springs or swing axles and small variations in their parameters can have considerable effects on the car's dynamic performance.
The payoffs from lowering a Soarer are not what they were from lowering a Kingswood or a Pulsar, and I am gradually forming the view that it is causing many people here more trouble than it is worth, just like low-offset wide wheels.
I reiterate though, for that apparent wear you are probably getting dodgy alignments, have sloppy bushes, or are driving like a maniac.
Thursday, August 06, 2009 - 12:54 pm, by: Andrew Robb(Leggstt)
nobody has said anything about the bushes,Will get them looked at.Getting a friend of a friend to look at the wheel alignment on the weekend fingers crossed.How hard is it to do the bushes at home by myself?? and what type of bushes does the majority of everyone out there use and where can i source them from please.
I doubt you can fit them yourself unless you are fairly well equipped mechanically but I could be wrong.
The effect of worn bushes will be that any alignment you do will be right for the position in which the suspension arms happen to be sitting on the bushes at the moment, and randomly wrong as soon as you drive off.
There are dynamic effects on steering and handling as well. I was talking only about the effect on alignment. A car with VFT (or new Toyota) bushes will feel a lot tighter, smoother, and track more truly.
Ashley Leach Goo Roo South Australia Supercharged GT Limited UZZ31 V8
Thursday, August 06, 2009 - 03:06 pm, by: Ashley Leach(Ashlar)
I'd agree David but I'm running 285's on the rear with an airbag controller (limited only because I need the guards rolled cause they scrape if I go down too much and hit a bump) and I don't seem to have any issues with excessive wear. I have had the front bushes replaced though... with VFT
When they do wear I get inside edge wear. But that would be after 18 months and I don't think I've ever had a car that has had tyres last longer than that, even on my Rolla. Not the way I drive.
Miles Baker Goo Roo Vic 66 Mustang GT Convertible, 55 Chevy Bel Air, 69 Firebird 455, 69 Nova SS Clone
Thursday, August 06, 2009 - 11:17 pm, by: Miles Baker(Milesb)
David.. we're talking about front suspension right? All of my old GM products have double wishbone front suspension, all the way back to the 55... and they were doing it back in the 40s too.
Friday, August 07, 2009 - 08:05 am, by: David Vaughan(Davidv)
Well, I wasn't suggesting that they had leaf springs and a solid axle at the front . That went out over most of the world many decades ago. However, saying that double wishbone suspension existed earlier than the seventies is unimportant in the present context. Alfa (and others) had DOHC quad-valve engines before the first world war but that does not mean there is nothing important to know about a Hayabusa or a Honda S2000 motor today.
Only the late 60s Kingswoods had leaf springs at the rear. They changed to coils in the early 70s but it was not until nearly a decade after release, in the late 70s, that the suspension was other than a heap of sloppily connected, under-steering, wallowing rubbish; not a great set-up . Therefore, the easiest improvement to the car was to stiffen its springs and lower it.
In 1977 GM engineers designed and implemented what they called "Radial Tuned Suspension" and it was not just marketing speak. The car actually handled (the subsequent Commodore was even better), so to introduce compromises to the suspension set-up now mattered whereas before there was nothing terribly important to affect.
I chose the Pulsar also because, without having looked it up, my recollection was that it was an example of a McPherson strut setup of no particular merit. Corvairs and Volkswagens come to mind for swing axles, where keeping the CG low and the car flat was your best hope of staying alive.
Miles Baker Goo Roo Vic 66 Mustang GT Convertible, 55 Chevy Bel Air, 69 Firebird 455, 69 Nova SS Clone
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