Too much castor produces hard steering, whereas too little causes wander. However, too much caster can lead to oversteer due to the jacking effects. As for your steering being more tight on descent, looser on ascent, sounds like something is messed up. If the caster is out of adjustment, it can cause problems in straight line tracking. With the screw locked in place the gauge can be removed to the bench and its protrusion measured with a Vernier. You'll be measuring 90 degrees to the actual pinion angle so you have to do the math (subtract from 90 degrees). IMPORT : No liability is accepted for incorrect use of this product. Caster angle and trail are of importance when designing the suspension geometry. Yea nevermind. That angle is the caster. I believe 15 degrees in and out is multiplied by 2. * Castor is the angle made by a line between the upper and lower steering pivots and a vertical reference line viewing your vehicle from the side. Measured on the bench the nearside represents a triangle whose sides are 218mm (fixed length), 219mm and 20mm (adjusting screw). Yea nevermind. 5 degrees spring slope plus 3 degrees castor on axle less 2.5 degrees axle wedge. Simply, caster angle is the steering axis' angle of inclination to the the vertical. First, and most obvious, is with an alignment machine. An example of a chopper with a raked fork at an extreme caster angle. Your email address will not be published. The beam axle has an inherent castor angle of 3 degrees. A forward tilt is known as negative caster. Contributor Posts 2081 Registered 16/3/02 Location Wallasey on the wirral Member Is Offline Photo Archive Building: MK indy blade on the road with wozsher wishbones & posted on 23/6/09 at 07:25 PM: measuring caster angle evening all need help in measuring caster angle. The beam axle has an inherent castor angle of 3 degrees. Positive caster also creates a jacking effect when the wheels are turned. What is Caster Angle? It is also the type of caster that is used on a shopping trolley and is the reason why wheels can wobble and turn with ease. (see Table 1) this is augmented by the slope of the … These cookies do not store any personal information. Cypher Well-Known Member. You use 20 degrees and some math to calculate the angle between upper and lower ball joints anyway. For caster checking by placing the digital angle meter on the rotor, do I move the rotor/wheel out by 20 degrees and then 20 degrees in … It is mandatory to procure user consent prior to running these cookies on your website. Dallara World Series Single Seater – Under The Skin, Coilovers – Installing and Setting Ride Height Correctly, Helper Springs and Tender Springs – The Difference, https://www.youtube.com/watch?v=_Ksbfn40adA. can I use the diff cover surface to measure? Make a fixture that will fit between … That reading is the ammount of caster … Now with the angle finder, is that the measurement I set the caster to? A backward tilt at the top of the kingpin is called positive caster. The weight of the car brings about a “reset” effect, forcing the wheel to return to its lowest (straight ahead) base level. Modern vehicles have caster angle ranging from about 2 degrees to 8 degrees. Most MGBs have heavy steering. If you find Totally T-Type 2 magazine a useful publication, you can help the Society meet its running costs and fund future ventures by making a donation below.
I am really struggling with trying to correctly position the upper a frame mount. Although the castor steering feature is similar to a castor wheel fitted to a trolley, where the wheel’s centre trails behind the pivot axis, an alternative explanation is more suited to the specific geometry of a car. Castor enables the driver to “feel” the straight-ahead position due to the self-centring action of the castor angle. Thank you mrblaine. Turning the wheel about the pivot axis results in an edge of the tyre lifting up the wheel (see Figure 3); this can be illustrated by holding a tin can in the hand and holding one’s arm vertically with the can resting on a table. Had to read it after I typed it for it to sink in. Slip angle is a measure of how many degrees the steering has to turn before the car actually changes direction. Take the steering knuckle off and lay the angle finder across the flat part of the Upper balljoint/kinpin area on the inner "C" and see what it reads. To read CASTER first turn the wheels 20º to the right when setting the RF and to the left when setting LF. It is mandatory to procure user consent prior to running these cookies on your website. Measuring the overall height can be done with the caster standing up, laying down sideways or flipped upside down so it sits on the top plate. Caster is measured in degrees by using a caster camber gauge. Notify me of follow-up comments by email. 1.5 degrees difference from driver's side to passenger's. 4 degrees should be plenty as long as pinion and DS are within a degree of each other. Budget to Premium Coilovers – Whats The Real Difference? The castor angle is made up from two components. If the line tilts forward then you would have negative caster. Materials Needed. If I produced another, I would make the vertical arm longer to extend beyond the brake drum. Australia's hottest 4x4 video producer! Also, zero caster provides easy steering input without the extreme unstability of using negative caster. Another way to get positive caster is when the two mounting points are on the same vertical line as each other but are both infront of the centre line of the wheel. Caster will definitely effect steering wander and driveability. Ok, I have finally figured out what "caster angle" is. However with power steering systems this is not an issue. Most vehicles come from the factory with camber set slightly positive in the front and negative in the rear. The caster wheel on shopping carts are an extreme case - the system is undamped but stable, as the wheel oscillates around the 'correct' path. 1. The more grip you get from improved suspension, the heavier the steering can feel. Last edited: Jan 27, 2020. If you don't have a set of turn plates you can use the angles machined on the corners of the gauge as a reference. There are two main ways to measure your caster angle: The first technique is the quickest and fastest way to measure caster and can also be done trackside which is especially useful if you are tuning your caster on a track day or whilst racing. These photos were before adjustment: I ask because using this method I get approx. Huw Davies writes about the Motor Assemblies Durban built TDs. Castor or Caster angle . Then turn the wheel 1/2 turn in, and read the gauge. 2 degree at diff is 4 caster. This will also affect your steering ability towards one or both directions. Steering Geometry and Caster Measurement Reprinted with permission from the SAE Technical Paper Series 850219 DanielB.January HunterEngineeringCompany Bridgeton,Missouri With the bubble gauge installed on the hub, turn the tire inboard 20 degrees and level the gauge. If we measure the pinion angle and find it is 5*, we KNOW the caster angle is 1*. Instagram: @tylerfialkosongs:6foot4honda song in outrosnoop dog next episode at very end Necessary cookies are absolutely essential for the website to function properly.
Hopefully, these articles will help. The angle between the drawn line and vertical is the caster angle. 866-734-8848 I think I am thinking of IFS where a "plate" is mounted to the rim and the wheels are turned to indicate the caster? Negative caster gives no feedback to the driver in terms of wheel position. Positive caster provides the directional stability. www.pathfinders4x4.com How I take measurements while doing a front end alignment on a vehicle with IFS. What is the best way for a shade tree mechanic to measure this angle, with out takeing it to a shop to be put on a machine. I have a empty axle case with the balls bolted onto the ends and a round bar that is a good fit in the bearing holes I am planning on using this to measure the caster angle which I think should be 3 degrees I know what the correct caster angles should be ( 2°, 30 Minutes +/- 20 ) but I can see this won't be easy to measure/ adjust directly. Jack Woolridge traces his 58 years of ownership. Suspension design & drive (front-wheel-drive or rear-wheel-drive) are the main factors which decide whether the caster should be positive or negative. This can create a positive turn in effect as it helps to rotate the car on corner entry. I think I just need a small adjustment after the lift on my 99. Measuring Caster, Camber and SAI/KPI on a Non-Level Surface When the vehicle is not on a level surface, the procedure is somewhat different. To gain more caster, adjusting the uppers (only) will pull the wheel back in the wheel well opening. Maybe maybe not? These cookies do not store any personal information. (see Table 1) this is augmented by the slope of the front springs, which for the TA and TB was also 3 degrees. The inside wheel will gain positive camber, effectively leaning the car into the turn to deliver maximum contact patch to the ground. Jump to Latest Follow 1 - 3 of 3 Posts. However, unlike KPI, the effects are beneficial. My first question is why is a multiplication factor necessary at all, and what is the supporting math that dictates a … The 2 holes in front of the axle if it measure 0 = 6 degrees caster. Now with the angle finder, is that the measurement I set the caster to? This is achieved by two arms of exactly the same length locating on the outside diameter of the short king pin protrusion at the bottom and the central ¼ BSF tapped hole at the top. Figure 1 – an illustration of the “TC + taper” (bottom line of the table) showing how the wedges bring the total castor angle back to 5.5 degrees i.e. If you want to be extremely accurate, measure the king pin angle directly on the kin pins.
Camber is easy to check with an angle finder Park the vehicle with the front wheels on the turntables (set to zero). You can also measure the angle on top of the lower shock mount. If the line tilts forward then you would have negative caster. Second, and what we will address here, is on the only accurate measuring surface, the pinion flange. Phil05LJ ... Im trying to figure out where to measure the caster on the front axle. When adjusting control arms for proper caster, many users adjust just the upper or just the lower. Castor or Caster angle . Caster is the measure of how far forward or behind the steering axis is to the vertical axis, viewed from the side. Camber is easy to check with an angle finder adjustable camber, the job can involve adding shims between the control Yes in most cases caster is fixed and will require an … An example of caster in action is the front wheels on a shopping cart. This creates a jacking effect putting more mass on the rear outside wheel when cornering. Your email address will not be published. 2 degree at diff is 4 caster.
Great stuff, very useful ! Hi all. Caster angle measurement location? Part 1 of a rust and paint removal article from Matt Sanders.