Caster Angle 2001 TXT

[tplasek]

I recently put a 5in All Sport lift on my 01 txt. After installing the lift, it darts all over the road now. Any imperfection in the road will grab one of the tires and make it dart in various directions. The tires are the same as before, the tire pressure is the same, just the lift was installed and it went haywire. I have dialed in 1/4" tow out, 1/8" tow out, dead on, 1/8" tow in and 1/4" tow in. It acts best with 1/4" tow in but is still not like it used to be. I noticed the bolt pins for the spindles are rotated forward with one side having 4 degrees caster and the other having 5. They are in a position rotated forward where the top of the pin is further forward then the rear. This is the complete opposite of the geometry on automobiles. They usually target 3 to 5 degrees rotated backward where the lower ball joint is forward of the upper. This is what makes cars drive straight and returns the wheel to center after a turn. I can't for the life of me figure out why my cart would be the opposite. Does anyone know what angle this is supposed to be. I am considering cutting off the spring perch from the All Sport axle and welding it back on with 3-5 degrees of caster with the top being rearwards. I don't know if that is is called positive or negative caster, but I always thought the bottom should be forward. Looking at my four wheeler, it too has a caster in the same orientation as an automobile.

[pachanga90]

You have "Negative-Caster".Anything 0 or more negative will hunt/wander,lose steering-return(back to straight on its' own),and feel very heavy while driving.I've been tweaking the ends of the springs on our Marathons to correct this(I work for a spring-shop).If you look at the springs,they have an "arc" to them,which pulls axles Negative as lifted,unless corrected by axle-seats or modifying springs.You could also add a tapered-shim to do this.If you loosen the spring-clamps at the axle,and tilt the axle to where you want it,measure the difference and have the springs bent accordingly.I've bent them about 3/8" upwards the first 3"-4".The other option is to cut and tilt the seat as you stated.I have been getting mine in the +2 to +4 range and they handle great.The biggest downfall of block lifts is Negative-Camber,but axle-lifts should have this corrected.Is the axle in backwards if possible,or made incorrectly?Toe should be set 1/8" toe-in.Hope this helps.

[scottyb]

Good info Pechanga
So you are saying that the Allsports lift has incorrect alignment geometry?

[pachanga90]

I'm not saying they have a problem,I've never used one,but the possibility is there for a defect in manufacturing.They may have the seats on wrong for the springs which would turn the axle around and cause Negative-Caster.Anyone can make that mistake.

[racin161]

pachanga90 is right on the money as per caster-camber settings and this info will help a lot of people as long as you understand and read all of the post. I might add that FORD used tapered shims years ago on the rear ends to correct pinion angle.This would be the simple way to correct king pin angle for a diy in your shop. Thanks pachanga90

[pachanga90]

The shims are availiable thru any suspension/alignment shop or supplier.Also at race,street-rod,off-road centers or online.They usally start at 1/2 degree and go up from there.Glad to help.

[tplasek]

Thanks for the replies! I just knew tilted forward like that couldn't be right. Just as a test (before I cut off and re-weld the perches), I loosened all six spring perch bolts and stuck two 3inch long 1/4 inch bolts sideways, just in front of the rear two bolts. I didn't have any shims on hand so I used this as a temporary test. I tightened the spring plates back down and with the bolts between the axle perch and spring, it rotated (tilted) the axle rearwards (top to the rear) , just enough to measure 0 degrees caster (the spindle pins were exactly vertical). If my wife sat in the cart it would measure 1-2 degrees positive with the deflection of the springs. With this small adjustment in the correct direction, it made a night and day difference in the way the cart handles. It is like a totally different cart now. It actually drives straight down the road. I am going to cut off and reweld the spring perches back on, because I can do that for free and quick in the garage whithout having to order and wait for shims to arrive. I hope it will even get a little better when I dial in 3-5 degrees ,but I would say it is already 90% corected on handeling issues and perfectly drivable after I put in the tempoary bolts for shims. Once again, for anyone else having wandering issues after lift, this made a HUGE improvement. All I used was a magnetic angle finder from Home Depot to measure the angle of the c channel on the ends of the axle.
Also on a side note, the spring perches are welded exactly perpendicular to the spindle bolts. Maybe my cart is different then most, but there is no attempt to correct any misalligned caster angle. I also thought maybe I had it in backwards, but with the triangular spring plates, it will only go in one way.

[madoc1]

do you have a pic. showing the type of lift? good info pachango, i forgot all about axle shims.

[pachanga90]

Another option is still to have the springs tipped up at the axle-end,but if you have a welder,its' definitely cheaper and faster to reset the caster.Just remember not to get carried away with the base-setting,as it will increase positive caster as you add riders.2-4 degrees is good for a base-set.