spring over
- Thread starter Di0z0r16
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Mark W
Yep, I really don't really care that much I guess.
Yep, like Mace said. 
The extra wheelbase of all the *J4* series compared to the '40s is all behind the T/C. The front half is the same so the same considerations apply.
It's easier to fit extra drivetrain in the longer wheelbase rigs so tossing doubler in there is lots simpler. That gains front driveshaft length even if you don't move the axle forward. I wouldn't install on just for that reason, but it is additional argument for it. Just like in the '55 and '60 series rigs.
Mark...
The extra wheelbase of all the *J4* series compared to the '40s is all behind the T/C. The front half is the same so the same considerations apply.
It's easier to fit extra drivetrain in the longer wheelbase rigs so tossing doubler in there is lots simpler. That gains front driveshaft length even if you don't move the axle forward. I wouldn't install on just for that reason, but it is additional argument for it. Just like in the '55 and '60 series rigs.
Mark...
i will. i just means that you can't get your pinion as high and i do think you definitely need to extend the front wheelbase. i've done two cruisers with no c&t, the same guy who helped me did two others, no c&t. at least two of those cruisers run 85-90 mph regularily with no more steering issues than a stock swb vehicle.
make sure your ujoint angles are within a degree or so of each other.
the degrees on caster apply to sua rigs becuase of the way the lift springs rotate the axle. you need shims to rotate axle back to a stock caster
wheres my soda
wheres my soda
I hear ya.
My personal cruiser with a SOA and no C&T drove like crap. It followed every crack in the road. Having stock stearing didn't help. Adding castor shims just pointed the pinion down even more and the drive shaft would bind at certain angles and would reach out and grab every rock. It sucked. I did a C&T on the axle and it made a world of difference. 6 degrees of castor and it would drive down the road without wandering.
Most people do a SOA because they want the lift and an improved ride. Not that you cannot get that in a SUA but you cannot slap just any set of lift springs on a cruiser and expect to get the same articulation and ride that a SOA has to offer. Mark W is proof that SUA can be done right. But the main reason I did a C&T was because I wanted the castor and wanted my pinion out of the way.
Another note: I don't have a DC shaft. Have yet to see a need for it because I don't have a need to drive the cruiser in 4wd over 40mph.
Cruiserdrew
On the way there
I guess the way to think about this is as follows:
The most important thing is getting the caster right. If it isn't, it won't drive properly or even safely. If you set caster at say 4 degrees, your pinion on a stock 40 axle will be nearly flat. That does make for a steep driveline angle. You can either live with the angle, or do a cut and turn, so that you can have your cake and eat it too, ie both proper caster and a good driveline angle.
I don't know how much it would really add to the cost of a spring over-Mark can comment on that. As I said previously, though, the argument to do it, is stronger than the argument not to.
One last wrinkle--FJ62 axles have a different relationship between the caster and the pinion angle than FJ60(or FJ40) axles. They are already partially rotated in stock form! So if you were doing a SOA, and using an FJ62 axle, it might be worth setting it up and looking at the driveline angles before doing the cut and turn.
My pinion points exactly at the t-case flange. I don't run a CV shaft, because it would not fit, due to the reverse gear buldge of the SM420.
The most important thing is getting the caster right. If it isn't, it won't drive properly or even safely. If you set caster at say 4 degrees, your pinion on a stock 40 axle will be nearly flat. That does make for a steep driveline angle. You can either live with the angle, or do a cut and turn, so that you can have your cake and eat it too, ie both proper caster and a good driveline angle.
I don't know how much it would really add to the cost of a spring over-Mark can comment on that. As I said previously, though, the argument to do it, is stronger than the argument not to.
One last wrinkle--FJ62 axles have a different relationship between the caster and the pinion angle than FJ60(or FJ40) axles. They are already partially rotated in stock form! So if you were doing a SOA, and using an FJ62 axle, it might be worth setting it up and looking at the driveline angles before doing the cut and turn.
My pinion points exactly at the t-case flange. I don't run a CV shaft, because it would not fit, due to the reverse gear buldge of the SM420.
i'm betting that's more steering and having shackles in the front than c&t
I think we might have scared him off.
Jeremy
Jeremy
When I got my cruiser it already had a C&T. Only thing I did to it was C&T. Nothing else changed. going from 1 degree to 6 degrees made a huge difference.
1 degree plain sucked with big tires.
Mark W
Yep, I really don't really care that much I guess.
I hear ya.
My personal cruiser with a SOA and no C&T drove like crap. It followed every crack in the road. Having stock stearing didn't help. Adding castor shims just pointed the pinion down even more and the drive shaft would bind at certain angles and would reach out and grab every rock. It sucked. I did a C&T on the axle and it made a world of difference. 6 degrees of castor and it would drive down the road without wandering.
Based on my experience I also have to assume that you had other problems causing your steering issues. Like I said, I've done lots of them and none have had these sort of problems.
??? I don't do SUA lifts. Almost exclusively SOA for me. ???
Almost all of the rigs I build for people are driven on the street as well as the trail. Up here they all see highway speed four wheel drive all winter long. Vibration at highway speeds is not acceptable for them.
Mark...
Mark W
Yep, I really don't really care that much I guess.
A non-C&T does have steep driveline angles. But so long as you clearance your Ujoint assemblies bind is not an issue. Ujoint life is shortened a bit but not enough to worry about it from what I have seen.
If you are doing your C&T yourself then it doesn't cost much more to do a C&T (don't forget to factor in the cost of the DC shaft compared to simply legnthening a standard one). It does add a good bit more work. But work is play sometimes.
If you are having someone do it for you it can add a bit. You have to tear the axle down before you can do the C&T.
In my opinion the "one size fits all" C&T axle housings that you can by (and ship yours back for a core) are not the way to go. You want the pinion pointed withing a fairly narrow range. Every rig sits a little differently depending on the springs, the way and other components as well as how heavy the rig is or is normally loaded.
Mark...
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I did an SOA and did not extend the wheelbase OR C&T. I will say this: Pick 1 of them and do it! mine is enough to bind the DS at the pinion but just barely. If you're not on pavement you won't notice it, err at least until your brand new u-joint is toast anyway. Hopefully I will figure out what I'm gonna do to resolve this before I run it again.
Mark W
Yep, I really don't really care that much I guess.
You *could* do both an extended wheelbase and a C&T if you wanted to.
Mark...
Mark...
Mark W
Yep, I really don't really care that much I guess.
For what we're talking about here, you don't touch the frame to extend the wheelbase. Just reverse the springs or use different (longer) springs.
Mark...
Cruiserdrew
On the way there
This is what I did.
I agree that every set up is different, and there is no one size fits all cut and turn.
I have between 4 and 5 degrees of caster and the flange points right at the t-case.
Mark W
Yep, I really don't really care that much I guess.
I considered this on my tan '40. But with the extra Tcase and the really extended wheelbase that I have in this rig the C&T REALLY wasn't needed. I did have to turn the rear pinion up and use a DC in the rear shaft.
Mark...
Mark...
Shackles in the front has nothing to do with wandering..
I ran a c&t housing from Proffitts, extended my wheelbase about 4" and did not run a DC driveshaft. I have about 12-14" of travel and no binding, I have also driven it in 4wd at low speeds, under 35, and I have not experienced and driveline vibration. Now swamper vibration is another story. I have not measured any angles, but I could if anyone is interested.
Jeremy
Jeremy
This is my first post here! I'm now in the process of doing a soa on my 77 FJ40 and I herd that using the FJ55 rear springs with a 2" lift will do just find. The issue that I have is where can I find a set of four rear Fj55 springs that have a two inch lift built it? Im also going to use the 4x4 labs raised steering system. 
I have FJ55 stock height springs in the rear and I can run a 39" tire. If you put 2" lift 55 springs on you need to run 38.5" tires minimum. You could probably get away with 42's. You will be lifting your ring fromt stock to about 8"s, plus raise the COG quite a bit. Plus I wouldn't expect any lift spring to fflex very well. I would stick with stock springs. 55 lift springs are hard to come by. No one even makes them except for Alcan anymore.
Jeremy
Jeremy
