How to know wheels are square? (toe)

[Frank818]

Hey guys,

How do you make sure when you align your rear wheels toe that the wheels start off square?

If they start like the below picture, your toe will be sideways! But the below pic has same distance for A (front of rear wheels) and B (rear of rear wheels), just like a square, except you'll be off even though your toe would read right in the end.


RearAlignmentSquare.jpg

I put the lower lateral links the same length but when I insert the long bolt at the bottom of the spindle it comes out half an inch in front of the other link, like if the spindle is pulled by something else. Maybe it is. Tried the control arm and upper links and it didn't change much.

Which is why I ask, if I decide to lengthen one of the lower link, they won't have same length anymore, then would it mean I'll be like on the picture?
Or am I already like on the pic cuz the spindle is pulled half an inch at one end while the links are the same length?

Ha, tough one, eh?

[wallace18]

I use a laser level and square the rear wheels to the frame for starters, Then set the rear alignment. Then using a laser I set up the front wheels square with the rear and set the front alignment.

[Frank818]

Laser is good. And... without a laser, how would you do it?

Maybe I could use a rope from the front wheels and back to the rear wheels, but that is not good if you can't know if the rear wheels are a little more outside or inside of the front wheels, which I don't know. I could use the frame and have same distance on the frame for both wheels and flush on both front and back of each wheel. I didn't think about that and didn't see anyone mentioning this on his build thread, or I somehow totally read over it...

[lclevert]

You can do it with string. You don't necessarily need the tool in this link to do it, but you should get the idea. http://www.smartracingproducts.com/smartstrings.html

Do a google search. There are youtube videos and all sorts of references on it.

[Loring]

The angle you're referring to is called Thrust Angle. If it's off, it'll require some steering angle to keep the car from turning from the rear, which is what makes a car 'dog track'.

You'll want to have the thrust line match the centerline of the vehicle. You can do it with string, but I prefer an alignment machine.

[Frank818]

Trust angle, tnx.
I'll try with strings, hopefully tomorrow after another 8h on the car it'll be enough to set trust angle to 0.

[DSR-3]

sorry for the double post

[DSR-3]

I admit that I haven't opened my copy in a few years, but this is a good read on alignment.
A Chassis Alignment Procedure: For Formula Cars

[Buzz Skyline]

I do mine with string and a measuring stick with fine markings (1/32, I think). It takes a while, but I do all my cars this way, including my Evo 8 and Grand Caravan. It's not too hard.

[THE FURNACE]

Hey Frank, you can make a homemade trammel bar, which would be helpful for taking accurate measurements. Plywood, 2 x 4's, some aluminum sheet. Easy to make and some instructions online. That's what I'll probably do.

[Hindsight]

I did string alignment on mine. Works great! Takes a long time though....90% of it being setup.

[mikeinatlanta]

Set rear toe and camber to zero. Using a 2' laser level, mark a straight line on the floor either in front or back of the car using the laser off of both rear wheels. Use the 3,4,5 method to find a perfect square off of one line (both if you want to verify). Use that square line to measure how far forward or aft each wheel is in reference to the square line. After setting wheelbase, reset toe and camber. Using this method, a 1/16" wheelbase accuracy is very achievable.

[wallace18]

You can get a very nice laser level from Harbor freight for very little money, IMO. It also has digital readout of angle as well.

[Frank818]

I just did it with strings, not sure how accurate that is, after all 4 corners done at the same time where perfectly levelled (to 1/32 and less), I checked rear toe with my QuikTrick alignment kit. It was off about 3/16s to start with, I was expecting 0.

I gave up and assumed it was ok. Did my alignment that way, to the eye it looks ok, I'll see if the car tramlines or has weird behaviours once I drive it. I can't care much for perfection at this point, all I want is to get this thing plated and then I'll drive to a full techno alignment shop for fine tuning or equipped myself (tools+knowledge) better.

I have tiles on my floor and they have a seam between each of course, every foot. Perfect line on the floor. I thought of using that as a ref, when I did think it was too late, I had spent already 15+hours on alignment and was almost done. I'll certainly try once I'm ready to get it registered, once everything is ok and I wait for my day's rdv I'll play with that.

I might consider laser stuff, could be useful in the future too. It's so easy to be off!

[wleehendrick]

Frank, why would you want your wheels square?

[Frank818]

Frank, why would you want your wheels square?

Cuz I think it's damn cool.