Tweak...... Perhaps....
 

Hi everyone

Just after some people's opinions on tweak.....

When I set my car up, I have the left and right shocks set to the same length (as measured with a vernier). I then set ride height by moving the collar down the same amount on the left and right shock (so both have the same distance between the top of the shock and top of the adjustment nut - again measured by vernier). I then set the droop to be equal left and right on Hudy blocks on a board.

I have sometimes then found that the car has a tweak in it (I have loosened and re-tightened the top deck and bulkheads in the usual manner). What should I use to remove the tweak - ie changing the shock pre-load or the droop screws? Or given that those are set equal, leave it with a slight tweak?

What do you do ....... or do you do any of the first part differently to me that may help remove this problem.

Many thanks for any advice

Oli

Take the chassis plate off the car, with no screws in the plate, place it on a known flat surface. Granite surface plate is ideal, however, not too many people have access to one. A nice thick piece of plate glass is the next common choice. Tap on the corners and listen for hollow clicking of the chassis plate slapping the surface from the corner(s) that aren't touching the plate. This is if you suspect that the chassis is tweaked.

Something that you can't rely on, however, is all springs being exactly the same length. Even when they are new. Setting the shock collars with a pair of calipers is good for getting them close. But, you will need to make fine adjustments to get equal weighting on the springs from side to side. This is where the tweak station come in handy.

Something else of note; I know a lot of drivers here state side that have given up on the blocks for setting droop. Most set-up sheets now-days is measured over ride height, even for rubber tires. Keep that in mind when looking at various set-up sheets.

It could also be that the your chasssis is un balance left to right or front to rear i had the same prob not to long ago..........front right 3mm......front left 1mm......rear right 1mm......rear left 4mm

The measurement is for how much the collar was screwed down

Don't forget that your tires are most likely not all exactly the same diameter. Even rubber tires wear and change size. That will affect your tweak as well, when checked on a tweak board. I've always played with the shock collar preload to tweak the car flat. Droop screws won't affect tweak, as they should not be touching the chassis until the suspension is at full down travel. Also, if you are using sway bars, they will affect tweak if they are bent, bound up, or the linkage is not exactly the same length on both sides.

Hi Oli,

If your still stuck and you're at Ipswich this weekend bring the car over and let us have a look. I agree with all the above posts, but sometimes another pair of eyes can help ;)

I am going to asssume a couple of points here!

The car when placed on a flat surface has radio, battery and motor fitted? yes?

When running sub C 4200's, the battery side of the car was significantly heavier than the radio side. Hence the tweak you are mentioning.
Generally the shocks onthe heavier side (or front or back) will need to be screwed down more than the lighter side of the car. To counteract the difference in weight from left to right, and front to rear.

Invest in a tweak station, and you can set the tweak in about 3 mins!