Not sure we're to ask, so decided to ask here! When scaling a car or truck for dirt does cross% play any part of the process? Or just worry about lr bite and your left% and rear%. Trying something new on dirt and not sure we're to start. Full frame (3 x 4 frame rails), 2x3 front and rear clips (rear is ovER rail), 3 link with steel tube qc, 5x5 hubs, weight is 2800 with driver and no lead. Added 90 lbs to right frame to get 54.6 left% rear is 52.1%, LR bite is 105.
Lf spring 500 rf 550
Lr 250. Rr 225
Any recommendations. ....
Cross % is typically something you only hear referred to in the asphalt world, at least from my experience. In dirt you'll usually hear/talk about left side%, tail weight (rear %), and bite (amount LR is heavier than RR). Where and what are you racing (a Sportsman type car? Tires? Engine?)? Is it coilover or conventional type springs?
15 x10 steel wheels on Hoosier D-35s, coilover, 355 with Holley 500cfm carb, will be running in a sportsman division until division grows (if it does), T-10 trans with 3 disc clutch. 1/2 mile track semi banked. This was a South East Super Truck(asphalt)...
I have converted an asphalt mod to dirt so I have a little exp with this.I would swap those front springs, because ur going to need to be much tighter.I would also increase rear % to 54. Try moving the lead as close to the rearend as possible, even right behind it, if that's what it takes.You can start with that and then look at raising motor/fuel cell if you don't get enough side bite. Good luck!
Back in the day, I was told by CJ Rayburn that crossweight was to be within 2 or 3 percent of your left side weight. If he still believes it or not I do not have a clue. One of my older still very competitive friends swears by 2 percent MORE than left side numbers, he has raced pavement and dirt for over 30 years now. I have not worried about crossweight in years.
Partially true. More of one certainly means more of the other but how the numbers correlate differs depending on left% and rear%.
Cross% actually makes way more sense to track as it takes the entire weight of the car into account where as "bite" doesn't.
In other words, 100 lbs of bite in a 2300 pound car will provide VERY different handling characteristics than in a 2800 pound car.
If you keep the cross% the same...not so much...
Assuming total car weight is the same, more bite=more cross and more cross=more bite. There's no way to make just one corner of a car heavier without adding weight. And even just trying to add weight to one corner usually results in changes to the opposite corner.
If you saw down one leg of a table, the opposite leg is the one most affected by it.
Senior Member
Not Sure......
Originally Posted by bob75
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