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Author Topic:   Rayburn. Cross weight and set up Questions
Dirt Newbie

Total posts: 2
posted February 23, 2005 06:27 AM  
I have a 2003 Rayburn that has the long bar instead of the ladder bar that runs to the center of the car. Springs are 500/LF 50/RF 400/LR 275/RR. I have 57% rear and 56.5% left side and 55.5% cross with 277 lbs difference in the LR and RR wheel weight, or bite. We try to set up the car according to Rayburnís recommendation of + or - 2 % of left side. We tried to scale the car with a 350 on the LR but could not get our cross weight without completely destroying out ride heights. The best cross we could get was 50% which left us with 170 lbs. Bite. My questions are.
1. When we change cross weight, are we basically changing the bite in the rear wheels, or should we change the cross weight and keep bite the same? Also, if we change the bite by using the 350LR as described above, should we still be able to get the cross weight up?
2. If we use the 170 lbs. Bite, Should the 50% cross weight be a concern, basically, which is more important, cross weight or bite, or are they the same kind of duck?
3. How does more or less cross weight affect the car?
4. How does more or less bite affect the car?
5. I hear about cars having between 200 and 250 lbs bite. Do I have to much with 277 lbs or is it a drivers preference type thing?
Any and all questions, comments, opinions, and ideaís are welcome. Thank for the help. CHEK.

Dirt Forum Champ
Total posts: 505
posted February 23, 2005 12:26 PM  
Unless you want to physically move weight around in the car you need to either set the cross or the bite, not both. Cross weight is the percentage of the cars total weight that is supported by the lr and rf combined. If you increase by the weight jacks you are also increasing bite. You should be able to get the cross up with that 350lb spring in. When you are making large cross adjustments be sure to adjust all four corners. It should not matter what spring is in the car as long as the spring can support the weight of the car. You should be able to swap out springs and reset the ride heights and get the same wheel weights. If you only change the lr spring you should only have to adjust that corner and have the numbers come out close. I would check for a bind and make sure the car is settled on the scales after the spring change.

More cross and/or bite loosens entry and tightens exit (if the car is slowed mainly by the rear wheels which is typical on dirt.)

57% is alot of rear for a rayburn. Most guys run around 54-55% rear.

GO 24
Dirt Freak

Total posts: 366
posted February 23, 2005 01:21 PM  
I'll try to help ya out, on a swing arm it's typical to start out with 200lbs or so of wedge when the track is good & tacky, as it dries out you'll continue to add rounds and end up at or around 250lbs especially if it's real dry slick...if it's rubbered up it'll probably be less. Adding wedge tightens the car coming out BUT obviously you can go too far! I think 275lbs is alittle on the high side....some of it's driver preference as well.
Our setup sheet shows 54-58% cross, and that's typically what we paid more attention too, generally we'd start a night around 55% cross (scales showed it to be around 200lbs wedge) and then added 2 to 3 rounds as the night wore on---if you scaled after the added rounds your gonna be in the 57% range and 240lbs or so.
Your right, their sorta the same kinda duck!

As clear as mud right!?!?!
Hope that helps alittle!

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