Another wheel alignment thread ( but different ! )

[Avocet]

I just fitted my winter-wheels last week ( just in time as there have been heavy falls since ) and would like your views on the following.

These Avon WX7 tyres were fitted on my Vectra C in Jan 2022 and have covered 10 700 miles since. Tracking was done at the same time and new drop-links were fitted. One drop-link failed after 6 500 miles and was replaced.I can't be certain if worn tyre was on this corner but think it likely. I'm not aware of any bangs on wheels from hitting kerbs or pot-holes to knock wheels out of alignment.

Before fiting the wheels I measured the tread -depth ( was 6 mm when new ) and found three tyres with 4 mm on the outer edge and 3 mm on inner edge. One had 4 mm outer and 1.8 mm inner.

1) Would you normally expect to find a differential between inner and outer edges ? I am not certain if tracking is meant to (hopefully ) eliminate any effect of road camber ( I sometimes think the camber seems quite sharp here: no idea if mountain roads have different specifications ) as well as contributing to steering ability.
2) Would a worn-drop-link have any effect as seen on the excessively worn tyre ? I had it changed about 120 miles after I first heard clunking.
3) Is tracking adjusted per wheel or per side i.e. could a screw-up have affected one wheel but not the other on the same side ?
4) Is it likely that a well-established small garage selected by personal recommendation would make an error ? I'm assuming it's not a particularly difficult job.

Now awaiting your inrush of ideas.

Edit: I will get the tracking checked asap, but garages are inundated as the first snow-falls mean ..........a big rush for winter-tyres, especially as the law now requires winter-tyres or chains/socks for the car in mountainous regions.

Different wear across the width of the tyre isn't unusual. My car eats its rear tyres on their inside edges because it runs a lot of negative camber at the back. Looking at the back of the car, the tops of the wheels lean inwards. It's supposed to be like that. At the front, tracking can also have an effect. Too much toe-in and the outside edges go. Toe-out and the inside edges go, but there are lots of other things that can mask this (like camber on the front wheels). Also, someone who "horses" it into roundabouts a lot, can expect to scrub the outside edge of the left hand front tyre a bit worse than the right hand one. All you can really do, is go on a model-specific forum and see if lots of other Vectras do that, or whether you should be concerned. Knackered bottom balljoints will also wear the inside edges, as you're effectively running with more negative camber than the manufacturer intended. That said, I can't see how a droplink would affect tyre wear.

Tracking doesn't HAVE to be "per wheel", because whatever each of them is set to, in order to make the car go in a straight line, you'll just turn the steering wheel to "average" the toe-in (or out) on each side. What generally happens, is that if the steering wheel is pointing straight ahead when driving straight ahead, they'll probably make even adjustments each side, to ensure that the wheel remains straight. On the other hand, if the wheel is crooked when diving straight, and there's an obvious cause (like one side having just been kerbed hard), they might adjust predominantly on the damaged side.

Rear wheel alignment ALWAYS has to be done "per side", of course, as you have no means of steering the rear wheels to average out the misalignment.

 

[Avocet]

My experience too..

I wonder what everyone thinks of those DIY gagets, where you simply run the car onto a steel plate, which is free to move on a second plate, calibrated with angles?

I often thought to build a laser alignment system of my own - it's just a matter of distance and angles, with a bit of trig..

Someone has beaten you to it!

Trackace DIY laser wheel alignment tracking gauge. Poor wheel alignment wastes fuel, damages tyres & increases your CO2 emissions carbon emissions.

Poor tracking will not only increase your fuel bill, but can dramatically reduce tyre life, increase your CO2 emissions, increase stopping distances & possibly earn you three points on your licence

www.trackace.co.uk

I've got one, and it has paid for itself many times over. I'm very happy with it - it's accurate and repeatable. However, it does take a long time, as it has to be set up from scratch after every adjustment. You also can't use it on rear wheels as will only give a "total" figure, not "per side".

 

[Harry Bloomfield]

I've got one, and it has paid for itself many times over. I'm very happy with it - it's accurate and repeatable. However, it does take a long time, as it has to be set up from scratch after every adjustment. You also can't use it on rear wheels as will only give a "total" figure, not "per side".

My idea, wasn't like that, rather it was to have two separate laser pointers, mounted on frames, and precisely aligned with the frames. You mount them on the wheels, laser dot pointing forward, to hit a target a precise distance in front - 1m ? You measure the precise distance between the laser pointers on the wheel, then the distance between the projected laser dots. From that, you can easily calculate the angle.

 

[Avocet]

My idea, wasn't like that, rather it was to have two separate laser pointers, mounted on frames, and precisely aligned with the frames. You mount them on the wheels, laser dot pointing forward, to hit a target a precise distance in front - 1m ? You measure the precise distance between the laser pointers on the wheel, then the distance between the projected laser dots. From that, you can easily calculate the angle.

Yes, it would work, and laser pointers are cheap-as-chips now, but you'd need to get the screen exactly at right angles to the centreline of the car, and, as you say, exactly the right distance away on each side.