Quote:
Originally Posted by HWYSTR455
Taller springs (free height) don't really change your pinion angle measurement, but it might change a little through the entire sweep of travel but shouldn't have a negative effect.
Longer shock stroke? That doesn't sound right either. But, if a spring is too tall, that could be. And suspect the wagon spring is just that, since it's the wrong application.
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Free height is nearly the same for HD and Std springs since the force applied to them will result in similar ride heights, given the proper application per model. HD springs in the shorter WB models (Cat/GP) will result in a taller ride height than how they react in a Bonne/Star Chief. The rear section doesn't really weigh a lot more, it the moment due to the longer car with a longer wheelbase that creates a higher downward force at the axle.
Since the Catalina cannot compress the HD rear coil to the same height as a Bonneville, the shocks have to be longer than the typical extended length shock like the KYBs. I had those in my car and there wasn't much extension left once installed. Why didn't I notice when I installed them? It was a bare chassis with no load, even with the body on it was light since the car wasn't fully assembled and weighted down. Once the car was done, I did note that the rear sat kind of high and didn't settle like I thought it would.
The moral of this is that the springs and shocks must match to provide adequate compression and extension.
Eaton does give you the option of changing the spring ht taller or shorter, you just need to know how that will play out ahead of time. In retrospect, I could've ordered a shorter HD spring that would've worked with the KYB shocks, but I assumed, all stock parts, all is right. It wasn't right. One of the Eaton springs broke on the pigtail from a violent wheel hop episode where the shock was topping out like a slide hammer.
Pinion angle does change when you install taller (installed ht) springs. Also changes the lower control arm angles. This can lead to drive shaft vibration (pinion angle), or if you like to launch your car, the lower arm angles do affect how it hooks, so that's also an issue, but not a deal breaker if you don't race or pound on the car.