What can be done to prevent this from happening again? After a flip or accident, check the tightness of the jam nuts on all suspension and steering ball joints on the front and rear axles. If a jam nut is loose, it means the threads have been over-stressed, have started to fail, will eventually strip out and the part the ball joint is on must be replaced.
-- Don Searles
Thanks so much for the information. I’m curious, were the parts that stripped the threads made of aluminum? If so, it might be well to consider using steel parts, or a steel imbedded threaded sleeve so that this can’t happen.
It’s not that steel will not fail, it’s just that steel is much less likely to fatigue and/or fail than the much weaker aluminum parts. I have seen the aluminum Heim joints fail many times from stress. In this area of the car, a little more weight might make the difference in finishing a race or keeping your car from being destroyed or worse.
Loose In and Tight In The Middle
I’m currently working on a Late Model team in Maine. I’ve purchased a chassis setup book of yours and it had helped me a large amount. We have been experimenting with a lot of things on the car, for example we have been running 65-percent cross and we are by far the fastest and it’s making the car travel on entry more now.
One issue we have been fighting with is loose in and tight in the middle. I’m wondering what might be the diagnosis for that issue. One idea I had was to get a longer RF upper control arm to move the roll center more to the right and have it not move as much from ride height to dynamic.
Thank you for your time.
-- Mark Henderson
First off, installing a longer RF upper control arm and using the same mounting holes will move the roll center to the left, not to the right. It never hurts to move the RC to a more efficient location, but that is not necessarily your problem.
Most of the time, loose in is caused by either a stiff LR shock in rebound or too much rear brake bias. The 65 percent cross you are running sounds high. You would need a high rear percent of weight distribution in order for that to work. It may be that the LR shock is causing the loose in and the car is tight from the crossweight being too high. A normal range for a 50- to 51-percent rear car is 56- to 60-percent of cross in the high range.
The tight middle condition could also be attributed to a roll center, or moment center as I like to call it, that is too far right. The change you spoke of with putting in a longer RF upper control arm helps in two ways. It reduces the camber change and it moves the MC to the left making the front end more efficient and helping the car to turn better.
You don’t want the RF upper arm angle to be too little though. If the angle is less than 12 degrees or so, it’s probably too little and will cause camber loss in some situations.
Torque Arm Placement On Asphalt Modified
I run an Asphalt Modified at Stafford Speedway. The question I have is that I run a torque arm on the left side. How do you figure or change the antisquat on this design?
-- Steve, Car No. 86
Simply put, for a torque arm, the length of the arm, or distance from the center of the axle to the center of the front connecting device, determines the amount of lifting force the arm will produce. This is also the amount of antisquat.
What the antisquat device does is transfer load from the springs onto that part of the axle that the device is mounted on. So, if a torque arm such as yours produces 2,000 pounds of lifting force, that will be distributed as 1,000 pounds up at the front end and 1,000 pounds down at the axle. You are taking 1,000 pounds of loading off the rear springs and putting it on the axle at the point the torque arm is mounted to the axle.
Since you placed the torque arm to the left of centerline, a greater amount of that 1,000 pounds will end up on the LR tire than will end up on the RR tire. This may or may not increase rear traction, since more equally loaded tires produce more traction.
If, with load transfer and crossweight loading, the rear tires were equally loaded if the torque arm were centered in the rearend, then moving it to the left would cause unequally loaded rear tires (the LR being more loaded) and the rear would have less traction. Think about that.
Stock Appearing Bodies In Canada
Please take a look at Delaware Speedway in Ontario, Canada. They have had bodies like you have described for two years now in their Super Stock division. All three major manufacturers are available.
A local race car owner and part-time racer created the fiberglass body program and sells the bodies at low cost of $1,000 to $2,000. I really hope you follow up on this as it is a great program saving that class which up north here has run out of steel bodies.
-- Gareth Gonder
The new bodies that look more like street cars are gaining momentum and popularity just like we predicted. The major producers of stock car bodies here in America are stepping up and making these bodies available and the racers are doing their part by installing them and replacing the older styles.
The racers, fans, and track promoters like the idea and are helping to make it possible by altering the rules packages to allow them to compete. It’s a win-win situation for our sport and I’m very pleased to see it has expand as it has.
This has been tried and found successful at two Wisconsin racetracks that I know of… It works, in my opinion, because if you don’t own up, everyone else knows who is at fault and you are shamed as a race car driver by the fans and your fellow competitors.