Roush rear springs
09-22-2006, 11:57 AM
#22
4th Gear Member
Join Date: Jan 2006
Location: NC
Posts: 1,138
RE: Roush rear springs
ORIGINAL: CrazyHorse0217
Without going into a lot of detail, changing the shocks also changes the pinion gear and drive shaft angle...
Without going into a lot of detail, changing the shocks also changes the pinion gear and drive shaft angle...
10-17-2006, 01:14 AM
#27
3rd Gear Member
Join Date: Nov 2005
Location:
Posts: 794
RE: Roush rear springs
After installing the Roush rear springs, being told that the rear end is so far forward, that they were surprised to hear that its rides smoothly. Suggested items to add are lca relocation brackets for my spohn lca's, adj uca, and pan hard bar. Being told that it’s suggested to get the rear laser aligned as well. Anyone else go this route, just after installing the Roush rear springs only?
Thanks
Thanks
10-17-2006, 01:34 AM
#28
5th Gear Member
Join Date: Mar 2006
Location:
Posts: 2,544
RE: Roush rear springs
Here was a good prior post about this but I can't seem to find it right now. Maybe you'll have better luck than I.
Anyway, when you lower the rear there are three side effects. Each may or may not be a concern to you, but they are all fixable:
1. The rear axle will become offset to one side. This is a "cosmetic" issue as far as I know. You can re-align it by installing an adjustable panhard bar. This might be what somebody meant when they said rear-end alignment--but you can ONLY adjust it (align it) with an aftermarket adjustable panhard bar. It doesn't require a laser alignment. You can do it yourself with a tape measure, some string, and a small weight.
2. The pinion angle changes. That can result in vibration, strange noises from the rear, and increased bearing wear. This is corrected by adjustable control arms in the rear (either upper OR lower, both are not needed). There are many threads about pinion angle adjustment.
3. The angle of the lower control arms change. This affects the instant center of the car. As-is, it can prevent the car from hooking up well on launch. LCA relocation brackets will address this.
Do you NEED to do all these things? No. Is it a good idea? Yes.
I suggest the adj. LCAs, adj. Panhard bar, and the LCA relocation brackets. You don't need a laser alignment and you don't need a new UCA.
Anyway, when you lower the rear there are three side effects. Each may or may not be a concern to you, but they are all fixable:
1. The rear axle will become offset to one side. This is a "cosmetic" issue as far as I know. You can re-align it by installing an adjustable panhard bar. This might be what somebody meant when they said rear-end alignment--but you can ONLY adjust it (align it) with an aftermarket adjustable panhard bar. It doesn't require a laser alignment. You can do it yourself with a tape measure, some string, and a small weight.
2. The pinion angle changes. That can result in vibration, strange noises from the rear, and increased bearing wear. This is corrected by adjustable control arms in the rear (either upper OR lower, both are not needed). There are many threads about pinion angle adjustment.
3. The angle of the lower control arms change. This affects the instant center of the car. As-is, it can prevent the car from hooking up well on launch. LCA relocation brackets will address this.
Do you NEED to do all these things? No. Is it a good idea? Yes.
I suggest the adj. LCAs, adj. Panhard bar, and the LCA relocation brackets. You don't need a laser alignment and you don't need a new UCA.
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