12 replies to this topic

[mkw]

I'm planning on setting up my suspension geometry on my car this weekend but i'm wanting to know a bit more about caster. I understand camber and toe, i've got my measurements ready and i know what my plan of attack is from reading previous posts.

 

Am i right in thinking that caster is the placement of the front hub when measured of the vertical? i.e closer to the front/back of the car gives you the degree of caster? I don't think i've explained that well really!

 

Anyway, is there a way to measure this without having professional tools? Like the distance from the front hub to the back hub? If so, does anyone have the distance i should be looking for? 

[nicklouse]

Nope.
Caster is the angle made through the ball joint pivot Centers to the vertical when viewed from the side.

[mkw]

So that would give a specific distance between the front and rear wheel centres?

[nicklouse]

So that would give a specific distance between the front and rear wheel centres?

Nope.

[mkw]

Thanks for your help, where would people be without you.

[AlexMozza]

I'm planning on setting up my suspension geometry on my car this weekend but i'm wanting to know a bit more about caster. I understand camber and toe, i've got my measurements ready and i know what my plan of attack is from reading previous posts.

 

Am i right in thinking that caster is the placement of the front hub when measured of the vertical? i.e closer to the front/back of the car gives you the degree of caster? I don't think i've explained that well really!

 

Anyway, is there a way to measure this without having professional tools? Like the distance from the front hub to the back hub? If so, does anyone have the distance i should be looking for? 

 

King pin angle is the imaginary line the hub sits on, more to the front or rear etc

 

 

This is a picture of caster angle

 

[Swift_General]

Hi. The rear wheels don't come into it. Imagine looking at the one of the front wheels from the side and drawing a line linking the top and bottom ball joint. The difference between this line and vertical is the castor angle. The greater the angle the greater the self centering effect of the steering. It can be measured if you can measure the camber change as the steering is turned by a known amount.

[nicklouse]

Thanks for your help, where would people be without you.

Happy to help.

One way you can get close is put it in revers and then take your hands off the wheel and if it makes a turn you know they are not equal.

But you will have no idea what angle you have. Also every time you change the bottom arm it will also change the caster. And when you adjust the tie bar it will also change the caster and camber.

Without having the kit to measure what is going on there is no point having a set of numbers you have no hope to set?

If you want it set and you know what you want it set to take it to a place that can measure and see if they will let you spanner while they tell you what the settings are.

[mkw]

I'm planning on setting up my suspension geometry on my car this weekend but i'm wanting to know a bit more about caster. I understand camber and toe, i've got my measurements ready and i know what my plan of attack is from reading previous posts.
 
Am i right in thinking that caster is the placement of the front hub when measured of the vertical? i.e closer to the front/back of the car gives you the degree of caster? I don't think i've explained that well really!
 
Anyway, is there a way to measure this without having professional tools? Like the distance from the front hub to the back hub? If so, does anyone have the distance i should be looking for? 

 
King pin angle is the imaginary line the hub sits on, more to the front or rear etc
 
 
This is a picture of caster angle
 

Cheers, that makes more sense. I'll have to take it in somewhere then.

[mkw]

Thanks for your help, where would people be without you.

Happy to help.

One way you can get close is put it in revers and then take your hands off the wheel and if it makes a turn you know they are not equal.

But you will have no idea what angle you have. Also every time you change the bottom arm it will also change the caster. And when you adjust the tie bar it will also change the caster and camber.

Without having the kit to measure what is going on there is no point having a set of numbers you have no hope to set?

If you want it set and you know what you want it set to take it to a place that can measure and see if they will let you spanner while they tell you what the settings are.

That's better, a proper answer. It's more useful than "Nope." that's for sure.

[Broomer]

I think you will struggle without a proper gauge. I bought a magnetic gauge made by Sealy which did castor and camber.
That coupled with some homemade turn plates (two floor tiles with grease invetween) made it relatively simple to do.

And as mentioned before any change to camber has an effect on castor and vice versa.

Edited by Broomer, 02 April 2015 - 06:46 AM.

[Spider]

An easier appraoch.

 

Before fitting the adjustable Caster Bars, set them to the same length as the originals, or if you don't have them, make them the same length as each other starting off with one being at mid-range in it's adjustment then make the other exactly the same. That will get you going.

 

Then when adjusting, just count the turns on one side and make the same adjustment to the other side.

 

As I say though, this will get you going, but ideally, take it to someone who has the right gear to do the inital setting.

 

Adding more Caster (making the Caster bars shorter) will give you more Neg camber on your Turn Ins. So you can set your Camber to zero (if it's adjustable) in the straight ahead, but then gain neg Camber when Turning (which is when you'd normally want it). Some guys I know run as much as 6 deg (pos) Caster, though you'd find the steering rather heavy at that and you may also have issues with the wheels fouling the wheel arch having this much, but for most road stuff, around 3 degrees is a sensible amount.

[nicklouse]

Thanks for your help, where would people be without you.

Happy to help.
One way you can get close is put it in revers and then take your hands off the wheel and if it makes a turn you know they are not equal.
But you will have no idea what angle you have. Also every time you change the bottom arm it will also change the caster. And when you adjust the tie bar it will also change the caster and camber.
Without having the kit to measure what is going on there is no point having a set of numbers you have no hope to set?
If you want it set and you know what you want it set to take it to a place that can measure and see if they will let you spanner while they tell you what the settings are.

That's better, a proper answer. It's more useful than "Nope." that's for sure.

No it is a pile of words that have nothing to do with your question.

Sorry but ask the question you want the answer to.

If you want to know about how to go about setting your suspension without the correct tools then ask that.

Saying you have some numbers that you want to set your suspension to and asking if it can be done without the correct kit only has two answers. Yes or no.

Without the kit all you can do is as the Spider says set things to a length and then make the same adjustments to both. But unfortunately it is rare for the mini to have the same numbers on each side.
Things to think about. And I give these in order.
Ride height. Keep it constant. As the suspension moves the angles change. So consider adding your weight to the drivers seat and footwell to represent normal usage and if you are being correct you should be checking corner weights as well.
Camber. But remember ride height and tiebar length change will effect camber.
Caster. But again as you change the tiebar length it will change the camber so you will need to reset that which means you need to redo the caster.

And all of this is rather pointless if you don't have 4 level points for your wheels.
Now a lot of this can be removed by not having some parts being adjustable but you might find the handling not feeling great.

Oh and don't forget the tracking will need resetting after each around.

There is nothing "difficult" and things have got way easier with these "new" electronic systems. Understanding how all the parts/adjustments effect and react to each other is the first thing. But without any means to read the angles you are back to the seat of pants feel.