Wheel alignment

[Gary Schulz]

I have always had a concern about the ambiguity of what to use for a reference datum for wheel alignment. In this case I am going to be setting front wheel toe. I have a very accurate setup with strings but it is tricky to come up with a good reference for what to use for parallelism.

20200517_112450.jpg

I am guessing that most people use the vertical side of the sills however these aren't exactly parallel with each other on either side of the car. They might be close but it is not perfect. does it make sense to look at each side individually initially and make each front wheel parallel with the respective sill for that side? The end result will not be zero toe but it should result in an initial center position with the steering wheel straight ahead. Then I am thinking I could apply equal turns on the tierods to get the final toe I am looking for.

Does that make sense or am I over thinking this?

20200517_112535.jpg

[bwaminispeed]

Or, you could just get one of these brilliant devices.....

http://www.minispares.com/product/Class ... o%20search

[Gary Schulz]

Or, you could just get one of these brilliant devices.....

http://www.minispares.com/product/Class ... o%20search

Yes, that is very clever...

[Spider]

I run a center line under the middle of the car.

On the rear, I use the rear most subframe mounting bolts for a reference and on the front, the very front subframe mounting bolts. I measure between these at each end, put some masking tape on the subframes that I can draw a line on, then drop a bob-weight center from those.

These are not only reasonably easy to access but are some of the master datum points of the shell.

[Gary Schulz]

Spider, makes sense to come up with a reference center-line as you suggest. That is probably the only true reference that you can come up with with respect to the body shell. I also think if I make both front wheels perfectly parallel to each side of the car and then adjust each tie rod in an equal manner I can get a true result with respect to the body shell.

Since I have it on a lift I will come up with a center-line to use as a confirmation/second method.

Thanks for the suggestion.

EDIT: How do you then measure from the front wheels (front and rear of the rim) to the center-line reference? I guess two plumb bobs, one at either end and a string between them...

Gary

[GraemeC]

Find the centre line of the shell, set your parallel strings down each side with reference to the centre line and then measure from those to the front and rear of each wheel.

[Gary Schulz]

Here is what I did. I found center at the front and rear per Spider (and ref data in the workshop manual). I then ran two plumb lines at the front and rear from those points and ran a line between both plumb lines. Now I can measure to the inside of each wheel rim at the front to get toe and I can monitor the measurements as I make the adjustment to the tie-rod ends.

This does work pretty well especially with good access to the underside of the car.

20200517_151048.jpg

[surfblue63]

Or, you could just get one of these brilliant devices.....

http://www.minispares.com/product/Class ... o%20search

£30 cheaper on fleabay

https://www.ebay.co.uk/itm/DIY-Steering ... .l4275.c10

[Spider]

Gary, nice work. And your Mini is stunning

I don't have a lift, I've since made my own lazer, that works off the same reference points, but before I made that, I would transfer the center marks to the ground. I then have a long straight edge (3 metres long !) I can slide under the car, place on the center line marks, weight it down and then I can measure off similar to how Graeme suggested.

Or, you could just get one of these brilliant devices.....

http://www.minispares.com/product/Class ... o%20search

I have seen these about and as best I can see they might be OK with new tyres, or ones that have worn square, and if you have next to no camber dialed in.

[Polarsilver]

I was Not impressed with my Trackright pad .. so i now use the Dunlop alignment kit .. this is the look down the Tube & Mirror system.I also use this on the rear toe but it takes some effort as there is a need to work the Dunlop system in Reverse .. due to the reason the Exhaust Pipe under the cars floor restricts vision onto the Dunlop Mirror .
To establish the Center Line of Vehicle & String alignment that method is equally as good if you have no other way.. as example we used to Track Large 8xAxle Mobile Cranes in this way ..all before Lazer methods became available.
When doing any tracking make sure after any adjustments that the Car has moved in a forward direction before a re-check of the dimensions.. this eliminates any odd Tyre loading that can effect readings.