The main thing I'm looking for is how little caster can you run and have "safe" handling at speeds up to 75mph. I have a rock krawler 3.5" lift 35's with a double cardan front drive shaft. After having new gears installed (spinning the shaft faster)I have notice more front drive shaft vibration. I believe my caster is around 5* currently. My diff side u joint appears to be at an angle 6-7*. If I change my caster to 2* to get my drive shaft closer to 3-4* is my steering going to be terrible. I'm thinking its smarter to have the drive line more correct than the steering but would love some input.
Thanks

 

I think it will wonder quite a bit at 2* on the Caster. I would want to stay as close to 4* as possible. Too bad lock out hubs are so costly when they used to be standard issue.

 

Dude, get her a caster corrected housing like I run. Your wife needs the Jeep to handle safely.

Edit: I thought you were my buddy Johan! His screen name is similar to yours. Sorry, I wasn't calling your Jeep your wife's jeep to be rude, his JK on 35" rubber is his wife's and he drives a Cherokee on 35" tires.

 

There is absolutely no reason to run 2 degrees of caster with 3.5" of lift. You should not be getting any vibes with a dc driveshaft with 4 degrees of caster. I have 3.5" of lift up front and run high 4 degree of caster with no vibes up to 95 mph. If you are still getting vibes with 4 degrees of caster your driveshaft is not balanced properly or you have a bent yoke

 

My Caster is currently at 2.9 and 2.5 after installing my Mopar 2in lift (3 1/8in lift in the front actual). I was going to increase the length of my front LCA's to increase the caster but the recommendation on this forum was that if I didn't feel any vibrations, it steered and drove fine, which it does, to leave it alone or get a caster correction housing if I wanted to chase after caster.

So I guess I can tell you that as low as 2.5deg of caster feels fine at 75MPH, because I drove over 500 miles on the highway on a trip and didn't feel anything abnormal. No pull, no drift, steering seems fine.

 

I appreciate the input. Scheduled an appointment for an alignment mon. I'll get some confirmation of where it is spec wise and go from there. I know the track bar needs some adjustment as well. The axle is about 3/4" more driver side.

 

I did not see what you regeared to? Unless really numerically high you should be able to run at least 4 degrees caster I know many drive fine with low caster but I have had mine various from 3to 5 and while 3 drove fine I really prefer mid to high 4's. I have a Dana spicer ds and is like silk up to 95 I regularly cruis 80mph for hours at a time. One finger steering at any speed never any correction needed.

 

Something else is going on. I have RK 3.5's with a double carden. 4-5° caster w/ no vibes and handles fine.

Do you run steering correction ?

 

No steering correction, yet. Gears are 4.56. The shop that did the lift didn't give me a alignment printout. I'm estimating using an angle finder. My vibrations seem to be limited to between 55-60 mph. It's not terrible but is noticeable. The jeep handles fine. Take your hands off the wheel at 60mph and tracks dead straight.

 

Also after turning the wheel returns to center without any driver input.