Global west cat 5 leafs

[dolf]

What is it about the cat 5's that make them the best OTS performance leafs? Is it just the shackle kit or something in the entire design? What is the difference between them and the L2's?

[dipren443]

I would like to know this as well. I can assume that it is the reduction in bind, allowing a certain level of articulation.

[Randy67]

Here is an interesting point from http://www.landrumsprings.com/ on pivot bushing used in leaf springs. This is under technical, leaf spring tech.

Pivot bushings are bushings that were designed to remove the bind between the chassis and the spring. However, the negative effects of these bushings greatly outweigh their intended purpose. Our extensive testing has proven this component to produce very erratic handling characteristics. When the front bushing is allowing the front leaf spring to pivot, it transfers all the side loads and lateral forces to rear portion of the leaf spring and shackles or sliders, which were not designed to handle the additional stress. This leads to bent shackles, warped sliders and misaligned axis points. Furthermore, because the front eye is allowed to pivot, it does not have any solid displacement to drive the car forward.

Problems with front pivot bushings are:


Loose on corner entry, loose coming off
Tight on corner entry, loose coming off
No forward bite
Bent or warped suspension components
Reduction of spring life due to high stress loads on the shackle end of the spring.


Urethane and aluminum bushings tend to transfer more energy and loads directly to the spring. This prevents undesirable chassis and rear end movement, thus creating favorable synergy between the chassis, springs and rear end. These bushings produce a solid rear housing displacement for added traction. Furthermore, these solid bushings control and enhance chassis performance by resisting chassis roll/torque. Solid bushings provide stable and predictable handling characteristics that lead to more consistent lap times.

Interesting to know who is right on this, as I sure don't know.

[79T/Aman]

caution must be exercised when reading tech info, the Landrum tech in this case is geared mainly for dirt track cars that litreraly drive around corners in an oversteer situation, they also use torque arms and panhard bars, the tires are also like baloons.

[Lowend]

I'll add that the Cat V's come with a SUPER heavy duty set of shackels

[MadBadger]

I'm really interested in reading responses to this too...I was leaning towards the Cat 5 springs, mostly because they are more affordable than a four link set-up...

[David Pozzi]

The Cat5 leafs are great if:
You have over 400 engine horsepower and wide fairly sticky tires.
You don't mind a stiffer harsher ride, they are around 240 lbs/inch, where an L2 is probably around 175 where most other tuner leafs are.

The springs are very well made and we like the ride height on our second gen Camaro. Less squat when hammering the car hard in first and second gear autocrosses. Downside is a little rougher ride due to the stiffer rate and heavier spring weight, also more shock transmitted to the car through the spherical bearings when you hit a sharp bump or pot hole. The shackles are beefy and have held up well.
A four link is going to ride better, mainly due to the lower unsprung weight. You will still need a 250 to 275 coil spring on the four link rear depending on mounting location. But it won't feel as stiff because leaf springs are rising rate and heavy.

The Landrum tech is for circle track use where they don't use a rear anti-roll bar. They like solid bushings which twists the leaf to get more rear roll stiffness. I see they blame corner entry oversteer and corner entry understeer on spherical bearings. I think solid spring eye bushings are a bad idea for a street or track car like we would build.

I did some testing on a 175 lb leaf with stock front eye bushings and poly rear bushings. If I remember right, it adds 25 ft lbs per leaf per deg of roll, so 50 ft lbs per deg roll, this is not much at all and if you remove it, you will need a stiffer rear bar to compensate.

[Skip Fix]

But David isn't a Global Del a lum for leafs basically a solid bushing? That Delrin sure doesn't flex much

[Lowend]

The Del-A-Lum is a solid style bushing, but on the Cat-V the front eye (which is the one that matters) is a Spherical bearing, not a bushing

[Skip Fix]

The Del-A-Lum is a solid style bushing, but on the Cat-V the front eye (which is the one that matters) is a Spherical bearing, not a bushing .

Yes but my point was Global has sold Del a lums for years fro street and cornering and they should act the way aluminum does as they are solid too basically, although they have the side washers most aluminum bushings don't. David felt those were bad for street or cornering.

I've run the aluminums in my street/strip TA foo a number of years with no ill effects on the street but no hard corners either. Springs are Tri City Launchers -copies of Mopar SS for GMs. The second leaf goes all the way to the spring eye.

Cal Tracs also use an aluminum front eye bushing and I know several folks running them on the street. Not sure of any cornering with them.