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Author Topic:   What is wedge and how can it help me?
34Racing
Dirt Full Roller

Total posts: 42
posted April 19, 2001 06:59 PM
This is my second year racing and I'm still trying to learn as much as I can. I know this is a really general question but maybe someone can try and help me. I run a metric bomber car and I was wondering what exactly wedge is and how can it help me go faster? As of right now I am running stock rear springs with pigtails on both ends and I think they are around 150# springs. In the front I am running afco springs 1000# RF and 800# LF. I can not run any jack plates or spacers but if anyone knows any other ways I could maybe bent the rules please feel free to let me know. Any help is appreciated.

awkwardjeff
Dirt Freak

Total posts: 218
posted April 20, 2001 01:05 AM
34, Wedge or cross weight is the same thing..
if you put the car on a set of scales you add the right front weight to the left rear weight to get the cross weight or wedge.
let's say you have a car that weight total is 3200 pounds........right front is 800 pounds.......left rear weight is 900.....you would have 1700 pounds of cross weight....some people talk different than others......so then we talk in percentages...
see one person may say you have 100 pounds of cross weight.....the reason this person will say that is because half of the total(3200) is 1600 pounds......so in their mind you have a additional 100 pounds of cross weight.......they may just say the car has 100 pounds of cross or wedge......again put this in a percentage......then we all talk about the same thing......about 53 percent. You can do the math, I didn't.....but in this example 53 is close enough to the right answer for me.
How to change wedge........If you put a smaller left rear tire on the car this will help turn the car......MORE STAGGER....but it will also take wedge or cross weight out of the car......if you can't run jack *****s or adjuster cups......then maybe you can quitely change the mounts on the rear end, I know people do this all the time around here.
You can get a longer spring from a station wagon and cut it to length, this isn't too great but does work......
But for a person starting out try working with tires.......I prefer to get the stagger right in the car so as you idle around the track the car will turn to the left on it's own.......let go of the wheel while idling around while going into the turn, the car should roll through the corner without much input from you on the steering wheel......
then use the front tire size to adjust the wedge or cross weight............Jeff

34Racing
Dirt Full Roller

Total posts: 42
posted April 20, 2001 06:06 PM
Jeff
My car pulls to the left when I am going in a straight line. So I guess I've got that much right. When you say adjust your wedge with the front tire you mean just the right front tire, right? If I put a bigger tire on the RF will that loosen the car up by putting more weight to the rear of the car? I have never scaled my car so I don't really know exactly what I am working with as far as my weights.
Thanks for the info Jeff
34RACING

awkwardjeff
Dirt Freak

Total posts: 218
posted April 20, 2001 11:10 PM
34, use which ever front tire you need to change the cross weight.........this will depend on ride heights and how much cross you have now........and how big the tires are that are on the car now......
Adding cross weight or wedge will tend to loosen a car on entry and tighten a car on exit........less cross will have the opposite effect.......GENERALLY.......there are times this doesn't hold water. But for the average person with the average car this is a good rule to go by........
handling is a package deal, the roll centers need to be located correctly, instant center, and rear steer or roll steer....which ever you care to call that, another one of those things that are inter-changeable.........adding a little wedge can help a car or taking some out....but this isn't a cure all.......it's PART of the package........just like air pressure and wheel off-sets.......
see when people add air to the tire it will raise that corner of the car......they just add weight to that corner........so if you add air to the right front or left rear you are increasing the wedge......if you take air out of the right rear or left front you accomplish the same thing......
Wheel off-sets work the same way, if you move the left rear wheel closer to the center of the car, say you have a 2 inch off set wheel on the left rear then change to a 4 inch off-set wheel you will add wedge to the car........
The fast guys have scales at home and will scale the car with one off-set then change the wheel and weight the car again......this way you know how much weight you are moving when changing wheels at the track......this can also be said for air pressure and turning jack bolts.........I can tell you our car changes 17 pounds with one turn on the front springs.........and 13 pounds with 1 inch of wheel off-set........knowing the amount of change will help at the track...
I hope I haven't mixed you up now......Jeff

34Racing
Dirt Full Roller

Total posts: 42
posted April 26, 2001 04:47 PM
Thanks for the info Jeff. It seems like the first thing I need to do is get my car scaled in. That way at least I'll have a good starting point. Then I can change offsets, tire pressure, and stagger and see just how the car acts with each change.
Thanks again Jeff.
34RACING

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