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Author Topic:   Castor Changes.....Please explain the effects
Dirt Newbie

Total posts: 3
posted August 27, 2005 11:23 PM  
I'm currently running
+1 1/2 castor on the left side
+3 3/4 castor on the right side
My question is ... If I increase these how will it affect the car?
Some of the books I've read say anymore than 2 degrees of split between left and right on castor will make it rought to drive...True or not?
The track I run is a very dry slick 1/2 mile, My car works good except for a real fast loose condition in the middle of the turns.It gets real loose for about 5 feet then it's okay with much throttle control exiting the turn.
Will castor changes affect this loose problem in the middle of the turns or allow for more throttle coming off?
Metric Chassis
Cross 53.1
Left 52.3
Rear 52.4
Wedge 177 lbs
Total 3222
Springs LF-1200 RF-1400 LR-275 RR-200
Ride Ht LF-7 RF-8 LR-8 RR-8 3/4
Air Psi LF-11 RF-13 LR-11 RR-13
Shocks LF-1021 RF-e.up LR-t.dn RR-1094
Front Stagger-0 Rear Stagger-1 inch
8 inch wheels with American Racers(mandatory Hard RR)

Dirt Roller

Total posts: 16
posted August 27, 2005 11:35 PM  
Castor will effect the way the car turns in, I run 4 degrees split, on a VERY similar track, I would check to see if the rearend is bent and or bound in any way, could also try a softer right rear spring rate, less rear stagger, move RR in and LR out. JMO what ya all think......8~)

Steve Dupree
Dirt Freak

Total posts: 316
posted August 28, 2005 09:54 AM  
Hey there well one thing i see is that looks like a lot of split in the rear. I think i would look more at maybe a 25 to 35 lb. split in the rear instead of 75 lb. Also the front seems a little stiff for the total weight you are running we weigh in right at 3500 and we run 1078lf and 1148 rf and i still think that might be a little stiff for us. My guess would be if you have the time get your front to a 100 lb split with a little less spring up there and a 25 to 35 split in the rear. As far as caster goes as long as you have power sterring you can run about anything you want as long as it feels good to you. We run 1 1/2 left front and 4 right front. More caster to a point should give you better foward bite because of balljoints pointing to the rear of the car

Donald g man
Dirt Roller

Total posts: 14
posted August 28, 2005 12:12 PM  
Caster in the right front helps load the rf to lr diagonal in a loose setup which tightens the car as oversteer begins to take effect. This will help pull a car out of a possable spin if power is applied during over steer.

Dirt Maniac

Total posts: 120
posted August 28, 2005 04:11 PM  
Positive caster on both LF and RF causes the LF to drop and the RF to raise when the wheels are turned left. The result is a dynamic loss of crossweight and sometimes a loose-in condition of you've gone too far. If you haven't gone too far, it can help the car to turn in better.

I think Donald G is saying that caster will add cross back in when turning to the right to fight a loose condition. That probably is true, but seems like the wrong way to fix the problem that may in fact be caused by too much caster in the first place.


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