Checking Caster

[Skip Fix]

So I got a DIY setup to do front end stuff.


So doing the 15 degree caster sweep 15 degrees one way then turn the wheel the opposite 15 past center and read. Well the brackets on the tire are then no longer perpendicular to the ground. So read it where it sits, change it back to perpendicular and read it?

Rear tires are chocked no no roll that way, double garbage bag "turn plates" but I really do not think front tire is rolling since the back is chocked down.

[no go nova]

Never done alignment with a kit like that. How about going on youtube to see a video on how to do it?

[Craig510]

The angle finder or caster gauge should be re-leveled after the sweep. IIRC the sweep angle should be 20 degrees, not 15. Even with the tires chocked and "ghetto" turn plates I have had my car walk to the side when taking repeated measurements.

[pitts64]

delete

[Skip Fix]

I thought it should be re zero'd but was not sure if the movement was part of the actual caster angle you should have. That changes it about .7 degrees. None of the you tube's I've seen even mention it might move.

I had read 15 degrees gives you the exact number and no multiplication factor.

It is a Quick Trick set.

[Ron Sutton]

Skip,
I have used the QuickTrick gauges. I'm a fan because they are easy to use, accurate & pretty affordable.

Ideally, I like to put the tires on "angle plates" or "grease plates" so the tire doesn't roll as we turn the steering. Then the tire ... and therefore the gauge ... doesn't roll. If you don't want to use "angle plates" or "grease plates" ... and the car is on the ground ... you don't have any choice. As you turn the steering, the tire "rolls" forward or backwards ... and the gauge rolls with it. In that case, you need to reset the gauge to be level, or you're reading can be off. Frankly, this method is less than ideal, because there is more margin for error in getting the gauge level again.

20° is the correct turn amount.

Best wishes !

[Skip Fix]

Thanks Ron. I thought I had a source that said 15, then another that said 20 for no multiplication factors.

Yea I would love to find some cheap used slip plates. Right now on the double garbage bags.

[David Pozzi]

At 15 deg turn each way, you multiply by 2. Some great instructions on it here: http://www.smartracingproducts.com/s...nal_update.pdf

[Skip Fix]

Thanks David. Any thoughts on readjusting it to perpendicular when doping the sweep?

[David Pozzi]

Yes, readjust it to level. Getting the turn angle correct is critical to getting repeatable readings. My bubble gauge has 20 degree flats on it. You can place a yardstick on the floor, parallel to the car centerline to use as a sight reference.

[Skip Fix]

I think the readjusting adds a new variable as it may not n=be grabbing the wheel exactly the same.