Funny Car Front End Alignment

Everyone sets the wheels on their funny car to have from 1/16 to 3/16 of toe-in, or whatever number you like, but how do you know that each wheel is straight and the toe-in on each wheel is 1/2 the total amount. Your toe-in could be 3/16, and the wheels be on a 45 degree angle to the frame. Your toe-in could be 3/16, while one wheel is straight and the other is in 3/16.

 

There is probably a more scientific method....but here is what we do:

Set the toe at 1/8-3/16 at the shop....and we measure on the ground and then roll the car forward and double check just to make sure any slop (there should really be none) is out of the steering....

At the track we tow the car down the track or return road and have the driver hold the steering wheel straight - then watch which way the car goes and adjust the pittman arm rod end until the car tracks perfectly straight...usually just a 1/2 or one turn and it tracks straight...

Hoping a chassis builder chimes in with a better method....but this is how we do it...hope it helps....

 

alignment

I have a dragster but always wondered the same thing. I used a billet aluminum, high quality level with a laser.

I (carefully) clamped a nice straight length of tubing to my front wheels while the car was on stands, and shot the laser back to the rear of the car.(putting some trust in the front wheels doing this) made marks on the drive hubs on the rear end and adjusted so I was satisfied they were aiming the same and towed in properly. just checked and verified a few times.

 

You have to "string" the car. I have also used a laser, but nothing beats a string for a straight line. Measure from wheel edges to string.

 

string method

String method -used to be the only way to do it and my prefered method also, lazers are great and likely way more acurate, but if you haven't got one, plus its much easier to see string.

using string of approx 1/32" to 1/16" Dia, tie one piece for each side to centre of rear of car, pull it around the rear tyres ( make sure tyre diameters are perfectly equal) - unwind string to beyond length of car, tie these off to something substantial eg heavish axle stands one for each side -so you can move them in and out and put tension on the string.

pull the stands forward to tighten the string, go back and check the string against the side wall bulge at front of the rear tyre till its just touching and no more. may take time adjusting to get it perfect - but really worth the effort.

go back to the front of the car - look down the string to make sure there is no deflection, then using a reliable measuring tape or steel rule measure back of front wheels to string line and same for front of front wheels to parallel them with string line - obvoiusly one wheel will be parellel then set the toe in.

its quite likely this is where you may find one wheel is over to one side more than the other - to your horror probably.

also works well using just rear rims mounted on car, as no deflection here.

if front wheel/s have camber its time to sort this.

rotate wheels a little to check for wobbly rim syndrome

 

Thread jack. Anyboody run with a little negative camber? Thread un jack.

 

Just wanted to say thanks for the help. I tried string and laser methods and they are really good ways of checking. I would think that the string is good way to check at the track if you were in a rush to see if everything was ok, perhaps after brushing the wall. We now have string in the trailer...hopefully we won't need it.