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Author Topic:   Z-link vs. swingarm on RR
Dirt Roller

Total posts: 12
posted March 17, 2005 10:14 AM  
Trying to decide which to run.Any pros and cons for each.Have 4 bar on LR.

Dirt Freak

Total posts: 229
posted March 17, 2005 01:54 PM  
As far as thrust angles a swingarm and Z-link are the same, a swingarm basically is the same as putting the spring on the birdcage in front of axle, except it is on the lower link. When the car rolls over the birdcage is indexing towards the spring forcing it to compress, as the chassis is also coming down on the spring compressing it as well, in other words the top and bottom of spring are moving towards each other which promotes weight transfer to the tire and more foward bite.
If you put the spring on top of housing, you are simply using the spring to control how much the car rolls over on the right side and you are using dynamic thrust angle for traction (foward bite) Yes some weight is transfering thru the spring but only the movement of the chassis coming down and compressing it.
If you put the spring behind the axle on the birdcage the exact opposite happens from being in front of housing-The birdcage is indexing away from the spring and the top is chasing the bottom, it will allow the car to roll over a whole bunch and not transfer the weight to the tire as needed, and again you are relying on thrust angle to give you traction, remember the more you roll over the more dynamic thrust angle you will get so sometimes a Z-link with the spring behind is better, the spring behind will force the birdcage to index faster, promoting faster and more thrust angle.
It really is a driver preference on the rear suspension, any of the above combinations have their pros and cons, the biggest difference in any of the combos is how the car handles in relation to the driver, some drivers like the car to roll over a whole bunch and react real fast, others like a smooth slow reacting car and others like a in between car.
Hope I didn't confuse any one

Dirt Full Roller

Total posts: 49
posted March 19, 2005 07:20 AM  
66....Not too sure I agree with all that because a Z-link RR is neutral as far as indexing the bird cage. At least my car is, maybe it's because my links are the same length. I rarely move one bar, if I move the front bar I move the rear bar the same amount so they are always on the same plane. My bar angles determine how much rear steer and RR drive my car has, based on what you said, thrust angles. Indexing doesn't happen too much on a Z-link RR. I have talked a couple times with a LM family memeber of mine and will discuss again with him about what happens when you put the srping behind on the RR....from off the top of my head....its not a good idea.

Dirt Freak

Total posts: 324
posted March 19, 2005 07:32 AM  
spring position on a z-link mostly affacts the amount of leverage the spring has on the lower bar. mount it on the lower link like a swing arm and a 200 lb spring acts like a 175, on the housing it's a 200, on the back of the cage it's a 215.then the different mounts clamped to the huosing compound the actions and reactions of the spring on acceleration and braking.

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