545svk

What cause the inside shoulder of the front tires to wear much more than the rest? Mine is worn, but not fuzzy.

The car track straight, but follow the road camber like a bloodhound on the scent.

Thanks in advance.

Jetdriver69

My 82 did the same thing, get it aligned or it will eat the next set of tires up very quickly.

I believe it was a toe issue.

joejoe

looks like car not settled before alignment.

dr bob

That's toe-out for sure. It's almost a crime doing unsettled alignments.

545svk

Thanks guys. The joys of owning and driving a 928 on our Aussie roads. I've had this one nearly 2 yrs and 14 000 miles on these tires, so think in this case I will blame the roads and not previous owners and fiddlers.

I hope my friendly tire shop will be able to help. They were very respectful when we did balancing.

Mrmerlin

well since you have probably had the front end lifted to swap in new sneakers,
you will need to drive 50 miles or so before you go to the alignment center

545svk

New tires, front and rear, is the next challenge. Either 16" again, or look for 17 / 18 " combination that I like the look of . Something to ponder over December on the beach

AO

My take is that it is probably slightly toed out and probably too much camber. Your wear is not nearly as sever as I've seen on other 928 that have been improperly aligned (or should I say mis-aligned).

As Stan says, you need to make sure you drive the full 50 miles to get the front end to settle fully. It's amazing how long it takes. You'll get 80% there in a few miles, but that last 20% takes a while.

The most important thing is that the alignment shop needs to have a drive-on setup.

Hilton

The only reliable way I've found to get tyres/alignment done locally, is to make it a 2-stage process.

First I take the wheels off the car at home and taken them in sans-car for new rubber at whichever tyre outlet gives a good price locally. That way I don't have to worry about them over-tightening or busting alloy wheel nuts or screwing with the alignment.

Then for alignment, I drive the car to settle on the new tyres (100+ kms usually - a few trips to work and back), and then go to my favourite alignment place where they listen to the "don't lift the car" request and also where they do a lot of track/race car alignments, so I know good care will be taken.

Last tyres I bought were Toyo T1R's in stock 16" S4 sizes (225/245 front/rear) - I got them ordered in to my local K-Mart tyres after they price-matched a place in Sydney about an hour's drive away.

545svk

Thanks Hilton. There is a KMart close by, and a TyrePower that have a Toyo sign up.

I was very happy with the Toyo's my car came on. They were fitted in Melbourne, also at a KMart.

Not where I would have gone looking if you didn't mention them.

FredR

Front camber does not seem to influence inner shoulder wear on front tires much at all and i have run with up to -3 degrees on the fronts.

If the car is well settled you might consider checking alignment first, change the wheels and then check with the new tires when well settled.

You can also check visually to see if there is too much toe out by looking along the side of the car- if you look along the wheel centre line axis from the rear and can see the leading edge of the tire up front you know you have toe out. You can adjust this in small increments with the wheels on the ground until that appearance is corrected- not brilliant but using a string or a laser level helps a lot until you get it on a proper laser alignment rig.

Anyone with a 928 and half a clue should personally insist on checking alignment and better still, do like I do and do it yourself on the shops rig if they will let you. My local tire shop is very friendly that way.

Good luck

Fred

mark kibort

toe out .... you can adjust that yourself with a magic marker and a level . make sure you drive the heck out of it for a day or so, and then measure the distance between front of the tires and rear of the front tires. use the marker to mark the distances on the driveway, and then measure the distances . I would bet the front of the front tires is about .25" greater/wider than the rear of the tires. the distances is something like 70"out side of the front tires to each other.... you want it about even or slightly toe'ed in by 1/8".

Randy V

You need to find an alignment place that uses the newer Hunter system with laser zeroing.

Most Sears auto centers have the new Hunter units.

Before you install the new tires, take a measurement from the ground to the center of the fender lip to determine how much you need to drive the car to get it settled back down to that measurement.

hacker-pschorr

Or you can follow the workshop manual and pull the suspension down once it's fitted to the alignment rack.

That is the proper way to do it.

Arbitrarily driving it X miles hoping it fully settles before having it aligned is not.

A proper alignment starts with lifting the car off the ground to inspect the suspension. This cannot be done with the weight of the car on the tires / suspension. A good alignment tech will insist on doing this since a bad ball joint, tie rod, suspension bushing etc.. can effect the alignment and you cannot properly check these parts with the cars weight loading up the suspension pieces.


If you are really ****, you will load up the drivers seat with ballast close to your weight.


Here is my reoccurring post on this subject complete with WSM pages on how to do a 928 alignment:

https://rennlist.com/forums/928-foru...l#post11159541



Yup, this is why most shops with mechanics on book time have a motto: "Set the toe and let it go" since that has the biggest effect on tire wear.

dr bob

Additional negative camber is probably a Good Thing on modern tires. I know that the PS2's on my car like additional camber, and in fact the tires are almost 'pre-worn' with less inside tread depth as they come from the factory. More camber reduces some of the outside-edge chunking that can happen under hard but medium-speed cornering.

Wear from excessive camber shows up as relatively even across the tire, with only slightly more wear towards the inside. On the PO's example, wear is even except for the scrubbing at the inside edge. Were camber the cause, the inside rib wear would be distributed better across the whole tread face, only slightly more towards the inside.

All that said, alignment adjustments are very interactive when it comes to the car tracking straight down the road with hands off the wheel. As camber is increased, the car becomes more sensitive to caster adjustment, and to road camber. Road camber is the slope that causes water to drain to the outside edge. In a car with perfectly-balanced camber and caster, the car will tend towards the outside edge of a cambered road. Alignment techs will take your perfectly-adjusted car for a drive, then make a final caster/camber tweak to get the car to drive "straight". They don't want the rework, and a car that 'pulls' to one side will be back in a heartbeat.

Back at the 928, --ANY-- camber or caster adjustment demands that toe be readjusted. 'Murican cars with double-wishbone front suspension use shims at the upper control shaft bolts to adjust both camber and caster. For those cars with Chapman struts, those adjustments are made by moving the tops of the shock/spring assemblies. Meanwhile, the 928 adjusts caster and camber by moving the lower balljoints front and rear, in or out, respectively. The steering on the 928 puts the tie rod plane just above the lower ball joint plane, so adjusting either caster or camber has an immediate and significant effect on toe settings.