I wouldn't add the BB to your 4.5" kit. I'm with Mike (krazieXJ), if you are planning to trim and properly bumpstop, then 4.5" is plenty for 35's. You sound like you are on the right track with the trimming and bumpstops (although hacking the rear quarters is not necessary, but it doesn't hurt). Check the tech page of my website for some articles I did on fender trimming and properly adjusting bumpstops to help you out there. Dirk (
www.dpgoffroad.com) only has 5" of lift and 35's and it flexes great without rubbing, because his trimming is in check and his bumpstops are properly adjusted. I was running 6" of lift and 37" MT/R's without any major reconstructive surgery to the rear wheel wells. Here's Dirk's XJ flexing with 5" and 35's:
As for the driveline, you're doing pretty good with setting up your suspension very well, so why mess with cheap alternatives that actually don't fix anything except vibes caused from UJoint binding. Do it right and get the SYE/CV driveshaft and forget about it. Vibes are a very minor problem. The real problem is the stress on the TCase and the output shaft/bearing. The taller you go, the more downward pressure is applied to the end of the output shaft. Downward pressure causes bowing. Bowing a rod that rotates at high speeds is bad. I'll try to give a visual of what is going on with your output shaft/bearing. Take a wooden dowel rod, put the middle of it over your knee/thigh, put downward pressure at one end while leaving the other end stationary, then roll it back and forth over your leg while maintaining the downward pressure. The bow will be at the fulcrum which is your leg. When a rod is bowed, and neither end can move from it's plane, and it is spinning at high speeds, the most stress will be at the crest of the bow at the fulcrum. If you roll that dowel rod over your leg for awhile, it will disintegrate at the fulcrum. The dowel is the output shaft of your TCase and your leg is the output bearing and the downward pressure is from the angle of the driveshaft. This is what is happening to your TCase. Anyone can do this experiment. The taller the lift, the more downward pressure at the end of the rod, the faster the output shaft will fail. When it fails, the TCase components will grenade, the housing will split, and your wallet will be empty.
A SYE shortens the length of the output shaft, which makes it stronger. Take a dowel rod, bend it over your leg like before, but shorten the side receiving the downward pressure by 2/3, and repeat the experiment. The rod doesn't bend as easily with the same pressure applied to the longer rod, therefore it will last longer before failure. Then the CV shaft and shims take care of the UJoint vibe problem. Many people think it is all about the vibes, and if you don't have vibes, you don't have a problem. They think if you have a pre 96 XJ, you don't have a problem. Wrong. There may not be a vibe problem, but there is still the same stress on the TCase, and failure will still occur.
I would rather have vibes with a SYE and replace UJoints, than not have vibes and save UJoints with a TCase drop, shims, longer yoke, longer driveshaft and have to replace the TCase. What sense does that make? Then, after saving a few dollars on cheap vibe solutions and blow up the TCase, your back to where you started...a stock TCase and vibes. Would you put that cheap crap back on again knowing it blew up the last TCase? People think they are saving money by not getting a SYE. If you have to replace a TCase, and then install a SYE after learning a lesson, how much money did you save?
Blah, blah, blah, ok I'm done. Hope that helps and makes sense.
I think i will be able to flex enough after the BB and geting disconects to keep me rubber side down more or less. Im going to chop the lower half of the quarter panels too to give me more room and extend the bump stops to reduce rubbing if not illiminate it. My only real concern is involving the driveshafts at the moement. but i think an extended yoke along with my Tcase drop will work. if not, Ill just have to get a SYE and driveshaft or extent existing driveshafts and hope it works out. Of course if im overlooking something or you know something i dont. Which is very likley. let me know. Thanks for all your Imput guys. keep it comming. i still dont know how much to extent the bump stops after the BB with 35s.
