caster pills

tony guy · Joined: 11 Feb 2002 Posts: 5

Hello guys,
I am new here and would like to participate in your forums. I was wondering if any one could help me with the adjustment settings "pills" of my front end. How do the pills work and how do i adjust them?

Jimmy Moore · Joined: 26 Jul 2001 Posts: 664

You need a special Australian alignment gage made by John Learmonth.

Michael Romeo · Posted: Sun Feb 10, 2002 3:34 pm Post subject: caster pills

Tony,

If you have any further questions, or have trouble reading the chart, please do not hesitate to contact me. Good Luck!

Michael Romeo
Romeo Motorsports

tony guy · Joined: 11 Feb 2002 Posts: 5

Michael,

Thanks for the guide. Will this guide work for a mitox chassis or do I have to buy the adjustment pills.

John Learmonth · Posted: Sun Feb 10, 2002 5:36 pm Post subject: caster pills

quote:
Originally posted by Jimmy Moore:
You need a special Australian alignment gage made by John Learmonth.

Jimmy, thanks for the plug, but in this case it’s not quite on target. The ZTB System will do toe and camber (with or without the driver), and allow easy wheelbase equality and chassis twist checks, but it doesn’t measure caster.

‘Tony guy’, each eccentric adjuster works by moving an end of the king pin around in a circle as the cam adjuster is rotated. This affects the angle at which the king pin sits relative to the rest of the chassis. Be aware that the action of the cam changes both the caster angle and the KPI angle simultaneously (camber change being a by-product of changing the KPI, which is the inward lean of the king pin).

The caster angle is very important, but IMO it’s NOT very important to know what the exact angle of the caster actually is, but it IS important that the caster is equal on both sides of the chassis and to know whether or not you have relatively more or less caster at any particular adjuster position. When you rotate the top adjuster (assuming you have two adjusters at each king pin - one top and one bottom) if the top of the king pin moves forward as you rotate the adjuster you have less caster, but this is opposite at the bottom adjuster (ie if the bottom of the king pin moves backward as you rotate the bottom adjuster you have less caster). If the top of the king moves backward you have more caster, and if the bottom of the king pin moves forward you have more caster.

If as you rotate the top adjuster the top of the king pin moves inward then you have more KPI (and thus camber is moving toward more positive camber), and if it moves outward you have less KPI (and camber will move toward more negative camber). Eccentric cams are a clumsy means to adjust camber or KPI, because these two important settings can’t be adjusted independently (with a given adjuster), and you often have to compromise one setting (or both) against the other. Some karts have two adjusters in the same position (one inside the other), and these allow the compromises required to be a bit less. An adjuster on top and bottom is probably the best set up, as it gives a wider range of adjustment and more incremental settings. Some adjusters have an infinite range of adjustment within their range of adjustment, and others have a choice of ‘fixed’ positions.

In order to rotate the adjusters the king pin nut will need to be loosened, and on some karts there will also be a locating device (little bolt or cap screw) that will need to be removed in order to make any change of position. Make sure you re-check your adjustment after you’ve re-tightened the king pin nut as this will probably change the setting slightly. ANY change to your front end geometry will probably also cause the toe setting to change, so re-check that too. When turning the adjusters take note of the changing orientation of the mark(s) on the adjuster as you rotate it. On some karts (eg CRG) the adjustment marks are actually hidden under the king pin head and nut.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

quote:
Originally posted by John Learmonth:
If as you rotate the top adjuster the top of the king pin moves inward then you have more KPI (and thus camber is moving toward more positive camber), and if it moves outward you have less KPI (and camber will move toward more negative camber). .[/QB]

John, not being critical (i respect your knowlege of thes things), but isn't this the other way around ?
As the top of the King pin (and tyre) moves inwards, this is INCREASING the negative camber. Yes ? no ???

Mikko Nassi · Posted: Sun Feb 10, 2002 11:45 pm Post subject: caster pills

Another one from Malaysia!!

It would be good if you changed your nickname to your real name though, so I'd know who you are!

Here's a simple castor guide at romeomotorsports.com.

Mikko Nassi · Posted: Mon Feb 11, 2002 7:23 am Post subject: caster pills

quote:
Originally posted by tony guy:
Michael,

Thanks for the guide. Will this guide work for a mitox chassis or do I have to buy the adjustment pills.

I believe the mitox has the adjustment pills as standard.

For the mike wilson, it was a bit more difficult.

Michael--
On your webpage there is a guidline for seat positioning. I run the mike 8(with rotax), and according to your chart, a driver my height should have the seat set even further back than where we have it now. I have lots of understeer problems though, so I think moving it back could only make it worse. Why are the settings so different for the other chassis'(mike 5 etc.?). I think we'll try moving it forward and see how this changes things.

tony guy · Joined: 11 Feb 2002 Posts: 5

John,

Thanks for the very detailed info. I will try it out ASAP. Since I know the mitox comes with a standard pill and has arrows on the plate as a guide, are these what we call the fixed positions which is less tedious to work out? I haven't really looked under to see if there are arrows as well as you have mentioned to look for. This is the first kart(mitox) that I have recently bought that has an adjustment plate so this is all very new to me and appreciate it very much.

Michael Romeo · Posted: Mon Feb 11, 2002 12:24 pm Post subject: caster pills

quote:
Michael--
On your webpage there is a guidline for seat positioning. I run the mike 8(with rotax), and according to your chart, a driver my height should have the seat set even further back than where we have it now. I have lots of understeer problems though, so I think moving it back could only make it worse. Why are the settings so different for the other chassis'(mike 5 etc.?). I think we'll try moving it forward and see how this changes things.

Miko,

The measurements on our site are recommendations only. Usually they are very close, but occasionally they are off. In your particuler case I would agree that moving the seat forward will probably help you. This will put a little extra weight on the front end, alowing for a reduction in understeer. You may also want to try going to a stiffer axle. Good luck!

John Learmonth · Posted: Mon Feb 11, 2002 12:37 pm Post subject: caster pills

quote:
Originally posted by Chad Stapleton:

John, not being critical (i respect your knowlege of thes things), but isn't this the other way around ?
As the top of the King pin (and tyre) moves inwards, this is INCREASING the negative camber. Yes ? no ???

Chad, I could say that I was just testing to see if anyone was paying attention, but the reality is that brain fade doesn't just occur on the track! Of course you're right, it is the other way around.

[ February 11, 2002: Message edited by: John Learmonth ]

John Learmonth · Posted: Mon Feb 11, 2002 12:49 pm Post subject: caster pills

quote:
Originally posted by tony guy:
John,

Thanks for the very detailed info. I will try it out ASAP. Since I know the mitox comes with a standard pill and has arrows on the plate as a guide, are these what we call the fixed positions which is less tedious to work out? I haven't really looked under to see if there are arrows as well as you have mentioned to look for. This is the first kart(mitox) that I have recently bought that has an adjustment plate so this is all very new to me and appreciate it very much.

I don't think TonyKarts have 'fixed' positions (I haven't played with TonyKarts much). The arrow is there so you can see the position of rotation of the adjuster. Get some adjusters if you don't have them, they're easy to fit. As far as I know only CRGs and karts made by CRG (eg Kali) have the marks hidden under the king pin and nut.

Chad Stapleton · Joined: 19 Jul 2001 Posts: 4403

quote:
Originally posted by John Learmonth:

Chad, I could say that I was just testing to see if anyone was paying attention, but the reality is that brain fade doesn't just occur on the track! Of course you're right, it is the other way around.

[ February 11, 2002: Message edited by: John Learmonth ]

John,
I , and i am sure many others, ALWAYS pay attention to your comments.

Mikko Nassi · Posted: Mon Feb 11, 2002 2:10 pm Post subject: caster pills

quote:
Originally posted by Michael Romeo:

You may also want to try going to a stiffer axle. Good luck!

thanks=).

Stiffer axle......I heard that "everyone" at the rotax max finals was reported as using a softer axle to have the rear of the kart more free on the exit of corners....now I'm getting confused=).

Mikko Nassi · Posted: Mon Feb 11, 2002 2:16 pm Post subject: caster pills

quote:
Originally posted by Michael Romeo:

You may also want to try going to a stiffer axle. Good luck!

thanks=).

Stiffer axle......I heard that "everyone" at the rotax max finals was reported as using a softer axle to have the rear of the kart more free on the exit of corners....now I'm getting confused=).

oh btw, my understeer is definetaly turn-in understeer, especially in low-speed corners, I can easily get it loose on the exit under power. Also a tiny bit of understeer on flat-out corners is there for sure.

Thanks for the advice.

I think I have to check my caster settings as well to make sure they haven't moved anywhere=).

Initially I felt that I couldn't get the inside rear to lift, so I thought this was the problem(causing the push), but later(after narrowing the rear track, we also tried widening it first) my father said that the rear wheel came way off the ground, so that wasn't the problem, although it may be that the wheel came up only on the really slow corners.