Initial upper control arm setting for newly rebuilt front suspension

1WildRT said

Problem with wheel clamps is there's usually deviation in the bridge from wheel edge to wheel edge so part of using the clamps is reading the error and compensating for it.... Most electronic equipment has that built into the software...

It's more accurate to use the mag base with a platen nut off the spindle...

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I’ve been able to achieve repeatable results with the SPC FasTrax that have later been confirmed within what I would consider error in just reading the bubble gauge at an alignment shop with modern equipment.

It does take a little practice, but if you take your time and pay attention to how you’re attaching it to the wheel it’s really not that hard. Not foolproof by any means, but it’s not difficult to get it right. Heck a lot of the modern alignment equipment works off of wheel clamps of some kind just because there’s a ton of non-magnetic hubs and wheels on modern cars.

Magnetic attachments aren’t foolproof either, you have to make sure they don’t pick up any little metal bits that will throw off your measurements and if you use an adapter you’re still at the mercy of the manufacturers tolerances. Plus it means several extra steps, you have to remove the wheel caps which may require removing the wheels, then you have to pull the cotter pin, remove the spindle nut and thread on the adapter. And then you’ve got to reset your bearing play after.

Definitely easier if you’ve got cast iron hubs, but I don’t!