Remembering why I
dislike working on
AO Silver Member
Join Date: Sep 2001
Re: tyre wear
Unusually for me, I had a bit of good fortune a wee while back and managed to pick up a previously enjoyed Dunlop Opti-track for £50. Normally £500 or so....
I did see your post asking 'how to' yesterday and even composed a great long reply...but didn't post it in the end as I figured someone more knowledgeable than me was bound to pipe up soon enough....
Since nobody has as yet, here's my method...
Centre steering wheel. This assumes no movement of rack on car or change in steering wheel to rack alignment. Big assumptions there, so be careful. If there is any doubt, you'll have to measure everything or the rack will end up off-centre as you drive along which isn't ideal.
Given I have the opti-track, this next bit is easy enough, I measure the tracking and adjust as required.
Go and test-drive the car. If it doesn't drive straight ahead with the wheel centred, I make a guess at the required correction and do it all again.
Best method would be to do this accurately ONCE, then measure up a definitive vehicle centreline so next time all that's needed is to measure from the inner edge of each rim to this mark, adjust as required then check toe with the gauges. This all assumes nothing major has moved of course....
Without access to the opti-track, a simple measurement between the inner edges of the rims, front edge & back edge is equally good, just a bit more tricky to do. Other things that work just fine are making up a fixed 'jig' that has the correct distance on it to go between the rims. Saw a decent 'how to' article in the Westfield mag a while back.
Always need to be happy that everything is straight, true, round, etc or all the assumptions go out the window.
End of the day, it's actually a pretty simple exercise that gets complicated by the physical difficulty of measuring a couple of distances.
One good method I saw was to make up a frame that goes around the entire car, reference it to the centreline, then take all measurements form there. Intended for DIY race buffs, but woulod work equally well for any car. Hard parts are making a rigid frame that is really square (that can be broken down for storage) and accurately determining the centreline.
If front and rear track are the same, you can even use string to good effect. Doesn't work on the wide body cars though for obvious reasons....
End of the day, if you do the job yourself with even the most basic kit and a bit of care, you are likely to get a better result than getting some monkey at a tyre place to do it. Many I have had the misfortune to meet don't seem to have the first idea about what they are trying to achieve nor how to use the equipment properly. Some are great, but many are not....and you only find out when you trash yet another set of tyres.
You could, perhaps, take the car to a known-good 4 wheel alignment place, get it set up, then make all your measurements & marks for future reference. This would give you the confidence of knowing it is right at a given point in time and your marks are accurate. Probably worth that £20.