Castor Correction

[Mudrat]

Just a quick question - does the castor angle have to be corrected when giving a 2 inch suspension lift? If it isn't changed how badly would it handle / drive on-road? Just wanting to know as i am going to do the lift in the shed over the next couple of w.ends and want to have all the components ready.

Cheers

[HSV Rangie]

FAQ

[tony cordell]

3 degree for 2" lift

[110 TUFF]

Ive approx 3 inch lift, no problems on my truck.

Drew

[Mudrat]

Cheers everyone, I havn't done the lift yet, still getting the parts. Been really busy with the other things in life. LOL. Will probably correct the castor while im doing the job, once i get around to it, save hassels later on.

Thanks anyway.

[A*D*A*M]

I've got around a 2 inch lift with no castor adjustment and have had no problems until today. I just replaced my 245/70 16 Michelins with a set of 265/75 16 Coopers. The car used to drive straight, now wanders like a boat and follows any ruts in the road. I'm thinking its probably not the tyres causing the problem, its just exagerating the existing wrong castor setting. The guy at the tyre shop said that the castor should be about 3 degrees but is only about 1 and a half.

Is it better to put in a set of offset bushes or get adjusted radius arms? Is there another option? I'm leaning towards getting some radius arms from Rovertym because I want to put in a set of Sam's holey bushes down the track.

Thanks,

Adam.

[malibu9]

Where can you buy offset bushes for the correction?

[HSV Rangie]

Castor correction bushes stuf up our articulation.

MIchael.

[malibu9]

What can you do to fix the issue if you put a lift in? Replace the bushes more often?

[HSV Rangie]

rotate swivell housing.

Michael.

[J Top]

Press the radius arms to increase castor, I have never done this but it is a common "fix" over here.
They are forged so apparently do not stress.
J Top

[HSV Rangie]

Yes I have cranked radias arms on my RR.

easy to do.

Michael.

[malibu9]

Correct me it I am wrong the swivel housing is what houses the front cv's?

[HSV Rangie]

Correct me it I am wrong the swivel housing is what houses the front cv's?

correct.

[Mudrat]

How badly does the castor correction bush's affect suspension travel and what is involved in rotating the swivel housings? Is this as easy job, or do they have to be machined or modified?

Cheers

[HSV Rangie]

How badly does the castor correction bush's affect suspension travel and what is involved in rotating the swivel housings? Is this as easy job, or do they have to be machined or modified?

Cheers

The bush is cast with the centre tube off set. the front is all ready restricted in travel. this just helps stiffen it more.

To correct castor correctly you shold do this.

1: bend radias arms in 2 places.

A: up near chassy mount to realign arm with bushing.
B: down near axle housing mounts to correct pinion angle.

2: have wheel alignment done get print out of castor.
A: if less than 2 degrees (std is 3 degrees) remove swivell housings and have the hoiles either slotted or filled and relocated to the correct place.

Rangie spare, Gragham cooper, davis motor works ect all do this.

Once all this is done your car will dive perfectly. ( this not the cheapest option) most people will just fit bushes and put up with everything else.

Michael.

[Bush65]

I don't think you will have a problem with a 2" lift. In any case do the lift and see how it drives before going any further with castor correction.

[Davidh]

To correct castor correctly you shold do this.

1: bend radias arms in 2 places.

Michael, where did you get your arms bent in Melbourne? Are there many places that do it?

My bushes are pretty stuffed and i've thought about getting the arms cranked while they're out. How's the strength of the arms after being bent?

[HSV Rangie]

I bent mine myself.

at that time I had access to a forge.

But you can achieve the same result using a large heating tip on an oxy acet torch.



THis is what my radias arm loks like now.

Michael.

[HSV Rangie]

I don't think you will have a problem with a 2" lift. In any case do the lift and see how it drives before going any further with castor correction.

I agree with this.

with only 50mm spring lift the RR should drive ok. some do some dont.

Michael.

[tim]

Or you can relocate the radius arm mounts on the axle housing so you sort out the castor angle and the diff pinion angle. Currently getting an axle housing modded like this here in the UK.

Anybody got any experience of doing this?

Tim

[HSV Rangie]

The only thing not corrected but relocating the axle housing mounts is the arm to chassy bush it is still heavily loaded, by cranking ther arms the std geometry is returned.

Michael.

[will_warne]

Or you can relocate the radius arm mounts on the axle housing so you sort out the castor angle and the diff pinion angle. Currently getting an axle housing modded like this here in the UK.

Anybody got any experience of doing this?

Tim

Tim have you gone up 2" or 4"? I find handling fine with 2" but I guess the issue for you is really the pinion angle with the extra travel you've got.

Also, your other option would be to cut the axle either side of the diff and rotating the housing (ie cut the axle where it was welded originally, adjust the angle and reweld). its a lot of work and not a DIY job but with all the effort your going to, might it be worth a though?

[tim]

Will

I have about 2 or 2.5" lift. Was out yesterday giving it a real test! We managed to pop both front springs (dual rate 490 mm uncompressed) out so am having to put longer cones on the front. Plus longer brake hoses before the event this weekend. The vehicle stayed amazingly flat.

I might change the springs for a higher rate as well.

Cutting the axle seems like a load of work. Tomcat or QT are rejigging the mounts on the axle and I am going to do that. I appreciate the extra load on the chassis mounts but so far we are not having problems there. MAy in the future look at making an angled chassis mount.

We modeled a standard radius arm and it is an amazingly good piece of engineering design so I am interested in staying close to it (well on one sideanyway!! lol). A straight forged design (like standard) is the ideal.

Tim

[Maggot4x4]

I bent mine myself.

at that time I had access to a forge.

But you can achieve the same result using a large heating tip on an oxy acet torch.



THis is what my radias arm loks like now.

Michael.

Have you got any more pics? I need to do this to fit the 80 series diffs.

[Vogue]

i had same problem as A.D.A.M, i was running 245/70 with my 2" lift and it was ok, as soon as on put the 265/75 on it was all over the road. I went the castor bushes. Wanted to rotate swivells but ran out of money. IMO save and rotate the swivells.

[cutfenders]

Same again,went from 245/70 Bfg/s to 31x9.5 Jt11 and the steering is very vague. LRA has a price of $650.00 drive in drive out. SOUND FAIR? Cheers Dean.

[Michele]

I resurrect this thread for a min just to be sure of
a 3 degree rotation for 2" lift...is it right?

I have to say I'm much used to the truck after the lift,so I could put up with it and not to mess the chrome balls.

But,in case,should I measure the gap between the bumpstop and the spring mount before and compare it with a standard one to be 100% sure of the real amount of lift?
Then re-check for the degree rotation needed?


Another (un)happy idea I'm playing with is to fit johnny joints instead of the front chassis bushing so they automatically compensate whichever the lift...

Uhm...

[Bush65]

I resurrect this thread for a min just to be sure of
a 3 degree rotation for 2" lift...is it right?

I have to say I'm much used to the truck after the lift,so I could put up with it and not to mess the chrome balls.

But,in case,should I measure the gap between the bumpstop and the spring mount before and compare it with a standard one to be 100% sure of the real amount of lift?
Then re-check for the degree rotation needed?


Another (un)happy idea I'm playing with is to fit johnny joints instead of the front chassis bushing so they automatically compensate whichever the lift...

Uhm...

If you get you wheel alignment checked, they will be able to tell you what your current castor angle is. Standard is 3 deg.

Regarding using a j-joint instead of the front chassis bushing. From what I can see, j-joints are designed for the principle load to radial, not transverse. But to replace the rover chassis bush the principle load would be transverse. I would do that unless someone else has proved it with heavy use over a reasonable time.

If however you use a clevis to go in the chassis mount and the j-joint in the fork of the clevis and build new radius arms (for the j-joint), then that could work well. This is similar to what I am doing on my rangie with 3'rds production arms. But I'm using a rubber bush instead of a j-joint.

[6.5 rangie]

How do you measure castor without going to a front end joint, i want to slot my swivel housings on my toy conversion before it goes in.