Front tire wear = worn suspension?
 

Hi guys. Here's a puzzle.

Further to my recent post made under "AWS - myth or miracle"

Recently discovered my outside front tire was badly worn on the inside edge-after only 35,000 kms - images are attached of the wear.

A laser align checked out A-OK. Everything within tolerance according to the machine. Replaced the tire.

The vehicle is a R/hand steer '91 CXD AWS with 198,000km on the clock.

Has anyone got info on how to check for wear in the lower control arm bushes?

Thanks,
Ian

looks like the tyre has been rubbing - more wear in one spot than even accross the surface. Is it both sides on front or just one side?

I have not had control arm bushing problems on my subaru but on another car I have, I did have a problem similar. It would eat up tires like no other, unusually within 5k-10k miles the belts would be showing on the edges. Once it started to eat away at the tires it would make the front end wobbly like it needed balanced. It would also make cracking noises when stopping suddenly do to the weight shifting.

I have experienced the exact same wear - and on two sets of tires. When I first bought the car, the PO had put 18's on it, but with a good camber correction kit. The two fronts were gone at 25K miles of use, but only because the cord wore through on the inner most edge; the rest of the tire had a good 10K miles left on it. I wrote it off as running the tire possibly too low on air and misalignment. I bought a lifetime alignment from Firestone and they showed me that front toe was out on both sides. I replaced the worn tires with a set of new Firestone Wideovals - great tires by the way. At 25K miles, I noticed that the inner edge was wearing thin again. I took it to Firestone and they did an alignment again for free - gotta love that lifetime alignment - and said that the toe was out again. Not as bad as the first time, but enough to prematurely wear the fronts. Because they had performed the last alignment less than a year earlier, they prorated the two worst ones and replaced them with new. The manager recommended that I come and get it aligned every 6 months from now on. The rears by the way looked perfect and have at least another 10K left on them - not bad for 18" rubber. According to the manager, the alignment checks out to spec, but his analysis is that the suspension bushings have lost some of their strength and elasticity. If I have him check and tweak the alignment every 6 months, I can get the most out of my tires without doing a suspension rebuild. Outside of that, If I want to make it right, I probably need to replace a bunch of bushings. If I could get them in urethane, I would. By the way, I have a 92 with 140K miles, so it's a plausible explanation. Rubber bushings don't last forever. I hope this helps - you are not alone!

I agree. The damage appears to be so specific. Something narrow has been in contact with the tyre as it has rotated. :confused:

Front inside wear.
 

Worn lower A arm bushings, allow the wheel to move forward, under drive. As the rack is in front the ball joint, it steers the wheel out, as it moves forward, to wear the inside edge.

Harvey.;)

The extraordinary tyre wear illustrated, would require extreme ball joint play, such that the car would not have been granted a warrant of fitness. :(

Harv, that's my thought too. But is there an "easy" way of establishing if there is wear in the lower control arm bushes? i.e. a leverage point to apply a pry bar to view any movement perhaps? Are replacement bushes available?

Trev , the wear is pretty constant around the circumference. The vehicle has been religiously maintained by Winger - the local agent - for the last 7 years.

Ian

I gather winger have been issuing a warrant of fitness. If so and they have not detected the sort of play in a bushing required to cause the damage pictured, they should have their license suspended. VTNZ who I go to, always apply a pry bar as you suggest, if they have any doubts concerning a soft bushing.

How much is your lifetime alignment? It's nice.

Lifetime as of what? As that set of tires? As per car? Or as of your life? :eek:

Thanks Trevor. I'll pass that tip on...there's a WOF check due in Feb.

In the meantime - any suggestions for replacement Control arm bushes . . . with better compounds than the originals?

Also, if I am looking at the front end, I guess I should consider shocks, sway bar and associated hardware.

Any suggestions for replacement shocks if needed?
How much are the sway bar bushes being offered here?

Best
Ian

i fully agree... also i would like to mention that just because the numbers from the alignment were "in spec" doesnt nessisarly mean they are good... thats one of the most basic alignment rules "GREEN DOESNT MEAN GOOD" did they give you a print out? check the numbers and see how close they are to the middle of the min. and max. numbers if they are leaning toward one side by more then .4 degrees you may have a problem

Spot on John.

Please excuse me butting in, but I would add that I have had personal experience of a fancy computer based machine, which was a mile out. Very few are constantly checked and there is one hell of a lot which can be out of calibration. Human error is also a huge factor. Some have the idea that these things are monkey proof! :confused: :eek:

Sure. I got a printout.
Remember, this is a Right hand drive model.
These are the front settings (as recorded by a Beissbarth ML4600 wheel aligner):

Castor: Left: +4.59 Right: + 4.50 (target: +4.50/ +0.45 -0.45)

KPI (kingpin inclination): Left: +16.11 Right: +15.59 (target: +16.00 +- 0.45)

Camber: Left: -O.55 Right: -0.59 (target -0.25/ +0.45 -0.45)

Toe: Left: -1.5mm Right: +0.6mm (target: +0.0mm /+- 1.6mm)

They look in-target to me (but I know squat about alignment) :)

Ian

At the time I got my alignment, Firestone's one time deal was around $40 and like $100 for a lifetime - as long as you own your car. When I bring it in and they lift the car, I get to crawl all over it and do my own visual inspections of the undercarriage and thing you normally can't see without a shop lift. Worth the price for a older car IMHO.