So a urethane bushing wont flex? You're right thats why they went with longer arms, but longer arms dont allow for more twist, they twist the axle less which increases movement. Or is that what you were trying to say???
The urethane C-bushings nearly always have some Caster compensation built into them - I don't know of any that do not. That reduces the bushing's thickness in one large area per bushing (there being 4 of them in a front suspension) and results in a stiffer bushing in one direction and a softer bushing in the other. Unfortunately those stiffer directions always gang up on you. Now factor in that the urethane C bushings are generally less compliant than the rubber C bushings, so even the 'soft' side arm in articulation is stiffer than with rubber. The guys who do a C-Bracket mod (= to a swivel ball rotation) and can run the over-all softer rubber bushings have greater articulation than any of those running urethane bushings.
The longer arms twist the axle less per unit of force, but have greater leverage to twist the axle with. It's win-win. This aspect is really no different than tuning a race car's sway bar.
Again agreed. But why a CV, it wouldn't matter CV or U-Joint.
Well, yes it does matter. If the operating angle at the pinion does not change or changes only a minute amount then w/o a CV at the transfer case the drive shaft's operating angles aren't the same and it will NOT be happy. Any drive shaft guy worth listening to will tell you that in such a situation the joint at the transfer case needs to be a CV. I suppose that you could run a std. UJ there, but the operating angle has the potential to get very large. Add needing some power at that high angle and the U-J will be done.
