How a Cal-track works

Originally Posted by Chris Hill

On a very basic level, does a cal-track work like a four link once the lash is removed from the system at the spring eye mount?

The bottom bar of the cal track is same as bottom bar of four link.

Leaf spring would be the top bar of the four link?

That's what I came up with Chris after plotting it all out two years ago. The front spring section has to be part of the equasion leaving the rear section as a spring. If it were solid I would say it is a slapper/ladder bar.

[Mark Yacavone]

Originally Posted by Barry Polley

That's what I came up with Chris after plotting it all out two years ago. The front spring section has to be part of the equasion leaving the rear section as a spring. If it were solid I would say it is a slapper/ladder bar.

Barry, I'm still going with the ladder bar. I see the lower link that pushes, but I fail to see the upper link that will pull.
If I might clarify, I see the Cal-trac as a sophisticated form of a slapper bar, better able to control spring wrap up..thereby acting as a ladder bar.

Originally Posted by Mark Yacavone

Barry, I'm still going with the ladder bar. I see the lower link that pushes, but I fail to see the upper link that will pull.
If I might clarify, I see the Cal-trac as a sophisticated form of a slapper bar, better able to control spring wrap up..thereby acting as a ladder bar.

Mark. To point I agree but...In my thinking... The front spring section is a link correct? From the housing to a pivot point (spring eye?. The lower CT section is also a link, correct? If it were all connected (ladder bar) at some point I would agree but it does not. In any case they work GREAT!

[Jeff Lee]

Trivia: Competition Engineering made the "slide-a-link" back in 1972 or so. A friend of mine has them on his '72 Demon 340 G/S (?) that hasn't changed since he built it from a new car in 1972. Based on that, I'm under the impression John Calvert borrowed the concept and improved on it by eliminating the soft spot in the middle of the bar.
Which begs the question; which version is better? Personally, I see no use for the urethane shock absorber in the middle of the bar. But I see there are some real fans of the design. It would be an interesting test on the same car. Anybody here try testing the two?

[George Mirza]

Originally Posted by Jeff Lee

Trivia: Competition Engineering made the "slide-a-link" back in 1972 or so. A friend of mine has them on his '72 Demon 340 G/S (?) that hasn't changed since he built it from a new car in 1972. Based on that, I'm under the impression John Calvert borrowed the concept and improved on it by eliminating the soft spot in the middle of the bar.
Which begs the question; which version is better? Personally, I see no use for the urethane shock absorber in the middle of the bar. But I see there are some real fans of the design. It would be an interesting test on the same car. Anybody here try testing the two?

Jeff,
That would be an interesting test. I do know of one racer who switched for the slide a link to the Cal tracs and saw a major improvement.
I think the difference between the two is the slide a link will work with a steel multi leaf spring, where a Cal Trac works best with a mono leaf. From what I've seen, I'm yet to see a car with multi leaf srpings work like one with a mono leaf when using the Cal Trac set up. But I've seen some good working cars using Slide a links and multi leaf springs.
George (still using SS springs)

[B Parker]

Jeff the opposite is true. Cal Tracs came before slide o link. I had gone threw Moroso when they were designing the slide o link. Guess what was lying on the table. Are you sure your friend didn't have the Steve Hanby set up. Barry

[Jeff Lee]

Originally Posted by B Parker

Jeff the opposite is true. Cal Tracs came before slide o link. I had gone threw Moroso when they were designing the slide o link. Guess what was lying on the table. Are you sure your friend didn't have the Steve Hanby set up. Barry

The car is a time capsule. Built in 1972 from a new car. He put the Comp Engineering bars on it. Were they called slide-a-links in 1972? I don't know. But they look the same as todays slide-a-link with the rubber cushion in the middle. Although I'm thinking the bars may be fatter in diameter. The last time the car was raced I think, was 1982. Hasn't hardly moved in 30 years!
I'm pretty sure the Cal-Trac bars came after 1982.
Not trying to take away anything from John Calvert because as I mentioned, he improved on the concept, took it to a whole 'nother level and I'm sure his accountant is very happy with the results!
And I think the split leaf is pure genius. He built a great system. I have the bars, springs and wheelie bar going on my car.

[Lee Jordan (3223) A/S]

Originally Posted by Jeff Lee

Trivia: Competition Engineering made the "slide-a-link" back in 1972 or so. A friend of mine has them on his '72 Demon 340 G/S (?) that hasn't changed since he built it from a new car in 1972. Based on that, I'm under the impression John Calvert borrowed the concept and improved on it by eliminating the soft spot in the middle of the bar.
Which begs the question; which version is better? Personally, I see no use for the urethane shock absorber in the middle of the bar. But I see there are some real fans of the design. It would be an interesting test on the same car. Anybody here try testing the two?

Jeff, you think alot like me. I still have the Comp "Slide A Link" bars. The reason we switched to the Cal-tracs is because I took the rubber sleve out and ran a bolt through the bars and made them solid. My dad almost fell over when I told him but the car hooked way better and the 60' went to the hi 1.30's. That was from consistant 1.45's or so. The springs were Hemi Cuda leaf packs with the length changed on all but the main leaf. Of course this was along time ago and everything works better now. The Cal-tracks allowed us to go to the soft clutches too. In 1980 my presure plate was set at a 3500lb base!!! Wow things have come along way huh?

[Mark Yacavone]

Originally Posted by Barry Polley

Mark. To point I agree but...In my thinking... The front spring section is a link correct? From the housing to a pivot point (spring eye?. The lower CT section is also a link, correct? If it were all connected (ladder bar) at some point I would agree but it does not. In any case they work GREAT!

Nope..Don't think so.
Semantics aside, I'd say they constitute one link, all inclusive.
The "missing link" would have to be above the axle center line on the housing to function like a true 4 link.