Castor correction advice please

[Ben-e-boy]

On a 2" lift how much correction will drop boxes give? If have thought too much?

He needs a minimum of 3 degrees to bring it into spec. That in itself is the fact of the matter. The advertised amount of lift installed is irrelevant.
Also too much is better than too little.

[Bidja]

All say that it is not necessary to meet the +3.5 degree factory spec as their is an error allowance from the factory spec

Recon we all would appreciate there will be a tolerance, that controls the min/max angle for caster. Been stated in this thread.

Appreciate you ask your SMEs: what is the accepted industry caster angle variation (range)? and post up their advice.

[timbo2410]

I think that is the biggest question really. What is accepted .. sure the caster angle is supposed to be 3.5 degrees, but, if Nissan already have an allowance for +/- 1 degree for instance, then a 2 degree correction is going to be pretty much bang on. Not one out of the many installers that I spoke to suggested to go to a 3 degree kit, in fact just the opposite. I can go with the flow and install a 2 degree kit which has been recommended by ARB, Ironman, Opposite Lock, West Coast Suspensions and the local tyre shops. The only odd one out was Pedders who said they do a 2.5 degree kit but the rear bushes would be polyurethane.
So who has done this to their trol and used a 2, 2.5 or 3 inch correction kit? What is the feedback on those ?

[timbo2410]

if generally a 2 degree castor correction is accepted as solving the issue (with the castor figures I gave them), by the industries involved, then I can assume that there is a 1 degree error accepted

[MudRunnerTD]

Interesting. I have drop boxes on both my cars are they are awesome. Normally they kick in at a 3" lift but if the math is in your favour and you can fit drop boxes and stay at tolerance then that is 100% what I would be fitting.

Technically they are illegal but imo are by far the best possible correction option retaining the factory bushes.

The difference will blow your mind.

[timbo2410]

Personally i don't want to loose any more clearance under body. I'm still running stock alloys and tyres .. cant see me changing them for a long time

[MudRunnerTD]

Personally i don't want to loose any more clearance under body. I'm still running stock alloys and tyres .. cant see me changing them for a long time

The clearance loss is a bit of a myth mate. I have never been hung up on my drop boxes on either car. Been running them in the GUIV for over 12 years and 200,000 kms at least.

I can drive my GU with my Pinky mate. or on Cruise Control will track no hands for kms. (Not recommended...)

[timbo2410]

so on a drop box, how is the caster angle set if it is a fixed mount? If the box is, say, a 2 inch drop, but say my lift (due to the heavier springs) is, say 70mm, how is the extra angle compensated? Is there still a need for a castor correction kit?

[MudRunnerTD]

so on a drop box, how is the caster angle set if it is a fixed mount? If the box is, say, a 2 inch drop, but say my lift (due to the heavier springs) is, say 70mm, how is the extra angle compensated? Is there still a need for a castor correction kit?

No. The drop boxes are generally rated for 3 to 5 inch lift which is why I had not mentioned them. Basically your dropping the back of the radius arms down which will give you back your factory spec. With your lift you will likely end up with a little more caster rather than not enough. This will just mean it will track solid to the centre. Your steering will be slightly heavier but your power steering will sort that out and you will hardly notice and quickly forget.

Everything else remains the same. You retain the factory rubber bushes which are arguably the best possible option.

You will have to buy extended front sway bar links though.

[timbo2410]

Had an interesting chat with another tyre company today who deals with 4x4 mods. They had a Toyota L/Cruiser customer who wanted his wagon done to factory specs after a lift. After a lot of research they could not find anybody who could tell them the exact specs on the castor angle. They contacted Toyota who couldn't answer them. They got a hold of the local Toyota dealer who brought down 4 brand new (unregistered) cruiser wagons to see what the castor angle was from factory. Not one was the same and there was a 2 degree variation between them! Very interesting. The chap I spoke to (who actually owns a GU Patrol) has said to go down to the local truck suspension specialist (the cheapest price listed above), and to get him to do his own alignment testing and come up with the associated "rubber" kit. He has access to 2, 2.5, and 3 degree kits. The apparent problem with the Ironman springs is that they may be upwards of 70mm in lift height, and where a 50mm height may get away with no radius correction kit, it is widely known (by them), that people often have a problem after they are fitted. I would like to thank everybody that has offered advice on this forum :-) I intend to go down the castor correction path and see where it takes me. I will of course post back to let you all know how it goes. Won't be for a while though .. cheers everybody