Wrapping Leaf Springs
I'm crew chief on a dirt Camaro Super Stock. We're not that up on leaf spring suspension technology but we've done a pretty good job. What I'd like to know is I heard that some people wrap their rear springs with electrical tape to keep them lubed and mud free is that true?
Steve Whisman
I really think that teams wrap the multi-leaf springs for several reasons. First, it keeps dirt out of between the leaves. If dirt were to accumulate, then it could build up and increase the preload on the spring, which would change the rate and the ride height of the car.
Another aspect of wrapping is to keep water out of the springs to reduce rusting of the metal. The thing to remember is that a wrap may keep water out, but if some water does collect in between the leaves, the wrap will trap it and allow it to form rust. So, if you intend to wrap your leaves, you'll need to unwrap them often and let the spring dry.
Remember that a multi-leaf spring must be free in movement between the different length leaves. If rust were to form between the leaves, then the movement would become restricted and you might end up with a very stiff suspension. It would be like welding the ends of the shorter leaves together. With no ability to slide as the suspension goes through compression and rebound, it would almost be like a solid suspension. Remove and clean the leaves regularly.
BBSS Guidance
To Bob Bolles,
I'm requesting help and guidance on BBSS set up. I read all your articles in Circle Track; have your book, Stock Car Set Up Secrets; and have three software programs. The past two years, our team has been racing locally at I-70 Speedway located in Odessa, Missouri, because of the economy and fuel cost. The low car and fan count finally took a toll on our racetrack forcing the owner to shut it down. I-70 Speedway is a high-bank racetrack with the banking at 30 degrees, so we never had to convert to BBSS.
Now, our racing plans are to race in the ASA Late Model Challenge Series in 2009 on a shoestring budget. We don't have the funding to do hardly any testing. I'm hoping that you can answer some of my questions and maybe get me in the ballpark if I provide you enough data?
Your article in the March '09 issue on Big Bar Soft Spring Setups is very good but also has me more confused on what to do with BBSS. The puzzling part about the article is that the first picture at "The Rock," or Rockingham, with banking at 22 to 25 degrees. You mentioned that most teams are running on bumpstops or coil bind despite the 22-plus degree banking. In the meat of your article you make a statement, "If your track is above 12 degrees of banking don't think about it." This is a little confusing. Our very first race of 2009 in the ASA Late Model Challenge Series is at Rockingham. The '09 rules for the ASA Late Model Series are going to allow teams to run on bump rubbers. I've never experienced using bump rubbers, so I need some technical advice.
At Rockingham, we'll be using bump rubbers with a Port City Chassis that's a straight rail, and weighs 2,700 pounds; approximately 450 horsepower; 21/2-inch coil springs; a left-side weight of 59 percent and a rear percentage of 50.5 full of fuel; using Hoosier Bias Ply 10-inch tires; and a three-piece spline sway bar:
How soft of front springs can I use for "The Rock"? How do spring rate and bump rubbers relate on the front end? How does the size of sway bar (rate) figure in with spring rate and bump rubber rate? Is the sway bar preloaded using BBSS and bump rubbers? Using bump rubbers/bumpstops, can softer springs be used?
Does the crossweight need to be increased using bumpstops? Which shock manufacturer and bump rubber manufacturer do you recommend? Can you run pro-dive in the left front with BBSS and bump rubbers? Is a crossmember height of 1 inch off the ground reasonable? Do you need more clearance or do we need to run it closer to the ground?
Bump rubbers-do you need to run them in both the left front and right front? Do both sides with bump rubbers need to touch at the same time? What if the left front bump rubber contacts first before the right front bump rubber?
The lower A-arm strut arms-do they need to be level with the lower A-arm at ride heights? I notice when I lowered the front crossmember down to 1 inch off the ground, that the back of the strut pivot Heim was almost an inch higher than the frame lower A-arm pivot. Do I need to raise or lower my strut arm pivots for BBSS?