Wheel Alignment Jig
 

Its been a slow few days on the forum so I thought I'd put up something I did recently. Also Melb weather hasn't been conducive to Cobra driving too :-(

My Wheel alignment/camber had been concerning me lately as the rear drivers side "looked" very toe=in and excessive neg camber

Rather than take it to a shop and explain the peculiarities of a my Cobra and its suspension etc I decided to have a crack at making my own Wheel Alignment jig.

Also I got a welder for XMAS and was looking for something to try my hand at - (note I haven't welded before so please don't look too hard at the welds).

So I searched for some ideas on the inter web and made up a jig that attaches to the front and rear overrider/bumpers. I liked this idea as you need to jack the car up, adjust the alignment and then put it down and move it back and forth to "Settle" the suspension multiple times to get it right. Having the alignment tool attached to the car makes this easier.

Anyway here it is.

BTW: I found my suspicions were true for the rear drivers wheel - the camber adjustment was loose and the bottom of the wheel and moved out causing the toe in - all fixed now. Also used it to reset my front toe after I pulled the steering rack out to change tie rod ends etc.

I reckon its pretty handy - saves a bit of time and money take it to the alignment shops etc.

Once you have squared it up on the car, I then marked it with some red insulation tape. I can take the jig off and on again very quickly and a quick square check and ready to take measurements.

I made some little adjusters to set the square - did do it on the front bars yet. Also I only attached and lock it in with cable ties at the rear at the moment - am working on a better approach to that. It does "locate" sideways correctly in the same place each time though.

Its probably not uber accurate but does the job for me.

Cheers Gregg

http://www.clubcobra.com/photopost/d...lignment_6.JPG

http://www.clubcobra.com/photopost/d...lignment_2.JPG

http://www.clubcobra.com/photopost/d...lignment_1.JPG

Hi Gregg,

Nice job. Even top race teams use the string method. The string height should be level with the hub centre though.

Thanks Geoff.

Its probably the angle of the photo but the string is pretty close to the centre of the hubs.

cheers Gregg

Flat floor & a square, works also. Pencil mark on floor for front of tire & rear of tire. Measure distance, from left & right tires.

I always string our race cars have done so for years also having a caster /camber gauge that mounts off the hub helps . I paid to get the race car scaled and wheel aligned and it handled like a pig in mud after a practice round and one race I set it back up with the string method and the car handled like it should .. good on ya for having a go I bet you learned heaps as well .
cheers dean

sure learned heaps - I reckon it would be even easier to make for a car with quick jacks too.
cheers Gregg

Looks great. Might have to have a crack at that myself to get mine in the ball park. Thanks for sharing.

Great idea.

I think Tenrocca has perfected doing alignments with his iPhone, perhaps he will chip in with comments.

Nice work Gregg. I had a go at something similar with my initial alignment but the car didn't feel completely "right" until I took it for a proper laser alignment. Plus I had other problems with geometry that I won't go into here - all fixed now though. :D

How did you check for squareness with those two bars? They could be parallel but not square... just wondering. Also how would you measure camber and caster? I have a camber/caster gauge and some home made turn plates if you'd like to borrow them.

I bought one of these a while back

QuickTrick Alignment Pro System Wheel Alignment Tools 90004 - Free Shipping on Orders Over $99 at Summit Racing

Pretty handy for changing street settings to track settings.

Ooooo I like that QuickTrick tool - you know I googled my little heart out for something around that price and came up zero. Looks pretty neat.

Regarding Squaring up - essentially you make sure each end where the string connects to the bars is the same width - i.e. you pick a width that is great than the car.

Then to square it you need to ensure the strings are the same distance either side from the front and rear hubs.

Its a little bit of initial fiddling because the front and rear tracks are different (thats why I made the slide adjusters). But once you get it square I then just put insulation tape marks on the front and rear square alignment bars.

I have had it on and off the car multiple times and all I do is double check the square and hub distances and it comes up the same each time.

For Camber I have a very crude method - I have a square bar attached to a spirit level and I put it against the wheel rim edges and measure how far out the top edge is from the rim for a vertical spirit level etc. I then use a little spreadsheet with a TAN formula in it and I enter the value and it gives me the angle. Its probably not uber accurate but does the job.

Caster - I havent done that. Too hard for my small brain to figure out :-)

My car tracks pretty well at the front and the feel is right with the power steering and all so I am assuming caster is ok.

Its been too cold and wet here to test my new adjustments though. So I might have stuffed it up.

Attached is what I ended up with.

http://www.clubcobra.com/photopost/d...Settings_2.jpg

The camber is a bit much for street but I left it for Nationals in Oct. The rear camber is adjusted all the way in so thats the best I can do.

cheers gregg

That's an interesting approach. With my car I just couldn't assume the wheels were square in the first place (don't go there). Two other methods:

1. Scribe a centre line on the underneath of the car, then run string lines parallel to that

OR

2. Lay a large builder's square over each corner where your alignment bar intersections the string lines and check for 90 degrees at each corner.

If your car is stable at high speeds and doesn't pull left or right then I'd suggest not messing with caster. I found it really hard to maintain a fixed camber setting while fiddling with caster. Gave up in the end!

I thought about the car/suspension being square so I measured that the two chassis round tubes were parallel and then measured from each rail to the hubs to check they were the same for the two fronts and two rears (within the measuring accuracy of my method).

It actually handled pretty well prior to this but the excessive camber on the rear (I found out was due to loose camber bolt) was buggering the rear toe.

Also I had to change my steering arms and tie rod ends so I needed a way to set it up again.

All good stuff - I like this as it helps me understand things better.


Totally different topic - Has anyone seen the "remote wireless QA1 Shocker adjustment system". I saw it in a mustang forum. You can modify your shocker settings via a wireless remote. Apparently you can retrofit it onto you existing twist knob click etc systems.

cheers

gregg

A couple of mm toe out is the go for on the track.
I usually leave the rear square.

As Ben said I made a simple mount to put my phone into and used a level app to measure camber. Have to have a level floor and make sure you have your phone square to the other 2 axis.

Saw the string setup being used at the V8 supercars at homebush a couple of years ago - was virtually identical to what your doing.

Cheers