Vehicles that specify high positive caster usually have a steering dampener attached to reduce any adverse effects. Steering wheel returnability is dependent on the caster angle, and most vehicles incorporate positive caster (~ 6-7 degrees) into both front wheels. Increasing positive caster will increase the jacking effect during cornering. Click here MatthewPTguy Not a new member. Consequently, too much positive camber causes wear on the outside edge. Bias ply tires react very differently to camber angle due to the differences in their construction compared to radials. Good luck with the conversion. The best I can get is caster +3 and the camber at -0.5. A large positive camber setting (wheel facing forward of axis) is good for high speed stability but can make it more difficult for turning the steering, excessive amounts will increase tire wear. Straight ahead tracking is better with pos. Toe is the measure of how far inward or outward the leading edge of the tire is facing, when viewed from the top. An overloaded vehicle or one with a weak or sagging rear spring will affect caster. Also, if you’re normally driving on uneven roads or surfaces, then you will want the added stability that positive cambers provide. Toe-in is when the leading part of the tire is turned inwards towards the center of the car. When looking at the vehicle from the front or rear, you will see the profile of the wheel and tire. Positive caster is crucial in enhancing the cornering and handling performance of a vehicle. If both wheels are significantly negative from spec, it can cause the steering to feel too twitchy, and much less responsive returning to center. For a more performance oriented setup on a MacPherson strut you can add a degree or two to have more favorable camber gain at high steering angles. We respect your inbox and send only 1 - 4 emails per month. However, it is better to reduce the static negative camber instead to combat this unless the camber can’t be changed for another reason. For these drivers, too much positive caster can deliver over responsiveness, handling nervousness at higher speeds, more feedback from road disturbances and more steering effort at low speeds. The best I can get is caster +3 and the camber at -0.5. Thread in 'Technical Questions' started by Mike@TDSW, Feb 22, 2011. Notify me of follow-up comments by email. For a more performance oriented setup on a MacPherson strut you can add a degree or two to have more favorable camber gain at high steering angles. Camber. Excessive camber on a road car makes it drive crap. Positive caster is when the steering axis is in front of the verticle. Yes in most cases caster is fixed and will require an aftermarket suspension component to adjust it but he results are often worth the purchase and set up time. Too much inward (negative camber) or outward (positive camber) ... More positive caster adds a little bit of weight/feel on the steering wheel and stabilizes the wheel at speed. This improves turn-in response considerably, but at the cost of tire wear. If your upper ball joint or strut mount is located more toward your vehicle’s rear than the lower ball joint, your vehicle has a positive caster. This excessive positive caster will cause a shimmy at higher speeds and excessive steering wheel snapback. If you have too much positive caster, the vehicle will be harder to turn. This is a big topic that I don't have a ton of time to get into at the moment, but hopefully those comments are helpful. The alignment specs do allow to bring the camber down. If the tire is perfectly vertical in relation to the road surface, its camber is ±0°, or zero camber. This excessive positive caster will cause a shimmy at higher speeds and excessive steering wheel snapback. This makes the tires want to separate from each other. Adding negative camber will reduce the peak tire grip during straight-line acceleration and braking. Dallara World Series Single Seater – Under The Skin, Coilovers – Installing and Setting Ride Height Correctly, Helper Springs and Tender Springs – The Difference, Tyre Failure – Graining, Tearing, Blistering and Wearing, https://www.youtube.com/watch?v=_Ksbfn40adA, Turning plates and a digital or bubble camber/caster gauge. Caster Kits - There's almost no such thing as too much positive caster for performance driving.Click here. Dec 18, 2017 at 8:45 AM #2 #2. Head over to our contact page and send us an email with your ideas, comments, or questions. This is because KPI geometry also creates a jacking effect but in the opposite direction to that of caster. Because too much positive caster also has it’s drawbacks. These are often sold with the main purpose to be camber adjustable. Well-funded teams will have additional data from load cells, shock travel, acceleration sensors, images, and onboard telemetry using thermal cameras. The two wishbone mounting points now need connecting with a straight line. The fundamental categories of suspension geometry are: Ackermann Bump Steer Camber Camber Gain Caster Front View Swing Arm Fundamentals of Grip Instantaneous Centre King Pin Inclination Scrub Radius Toe Tyre Slip Angle There are more aspects to suspension geometry but the most influential are listed above and are the focus of this website. Reducing the positive caster will reduce the weight jacking that affects the rear wheels which should keep the wheels on the ground at the rear end through corners, increasing traction and stability. This is beneficial in offsetting the effects of body roll, especially in low speed cornering. What is camber, caster, and toe? Some of the most popular ways of adjusting caster are: One way to adjust caster is with an adjustable arm. Great advice. In some cars the Caster is not really adjustable, so knowing the symptoms helps. The caster gain will give you more neg camber in the … A common setting would be: LF 5 deg positive, RF 5.5 deg positive. Caster is positive when the load is ahead or pulling on the spindle. Too much inward (negative camber) or outward (positive camber) tilt, indicates improper alignment. Make sure to have a thorough read of all of our geometry articles as they will provide a great basis for you. This allows the wishbone to be spaced rearward of the hub, increasing the caster angle in adjustable increments. I think its going to wear the outside of the tires prematurely. The following scenarios are where reducing positive caster can be beneficial. It's important to have a healthy balance to ensure good overall performance. We will never spam, sell, or do annoying things with it ... ever. However, just like with camber, vehicle pull is not caused by too much or too little caster, but by side to side imbalance. Your vehicle may prefer more or less camber. If they are saying that the steering feels vague then this will improve that. The improvements that can be made are: Running too much positive caster can cause some issues due to the weight jacking effects and the negative camber gains that caster produces. Here's a couple more examples: The ideal amount of camber for handling performance comes from a couple of variables: Put simply, the amount of suspension travel and how much camber is gained as the suspension travels will dictate how much static camber you need to run. I was able to get 4-5* positive caster with 1/2* negative camber. For most cars this is around 2 - 3° of negative camber. This is rarely ever seen on a road car since it will reduce road handling capability. With caster maxed out now I get closer to the other side, +5.0 caster, with -1.95 camber. As you increase positive caster the steering will get heavier also, but with modern power steering systems this is rarely a problem. Positive caster creates a lot of align torque (the force that straightens the steering wheel when you go forward) which improves straight line stability of the car. Positive Caster. If camber is different from side to side it may cause a pulling problem. Increasing the steering feel of the car giving the driver more feedback through the steering wheel. Regardless of what caster setting you use, make sure that your caster is symmetrical. Caster is the measure of how far forward or behind the steering axis is to the verticle axis, viewed from the side. Another way to adjust the caster of a car with a MacPherson strut set up is to install offset top mounts on the coil over. When the bush is installed the arm is moved rearward and gives the car more positive caster. Again, I recommend consulting an expert for further assistance on your vintage setup. Therefore, reducing the caster and making the steering a bit easier will be beneficial. Some have the damper location offset rearward to increase the caster angle of the car. As a general rule, if you drive hard, a little negative camber (around -1/4 degrees) can actually improve handling. For a normal car you typically want to maintain a slight amount of negative camber (0.5 - 1°) to have a good balance of cornering grip, braking grip, and tire wear. Consequently, too much positive camber causes wear on the outside edge. Using the above recommendations, which are meant for radials, can result in lackluster results. Without adequate negative camber the tire would load the outer portion of the tire and produce less grip. The alignment specs do allow to bring the camber down. Your email address will not be published. Because of the caster angle, the wheels lean when rotated off the center. However, just like with camber, vehicle pull is not caused by too much or too little caster, but by side to side imbalance. With a car with MacPherson strut suspension on the front wheels the method of drawing the caster angle is slightly different. Excessive heating on the inner or outer third of the tire can be indicative of improper camber angle, although not conclusively. The benefit of positive camber on these vehicles is that you don’t need to use much effort when steering them. It has a large effect on how the car reacts to steering inputs as well as on tire wear. Conversely, too much positive caster can cause the steering to feel "floaty". .7 deg gain per inch of bump is what I've heard too. Worn ball joints, strut mount, tie rod, and other wheel-suspension parts may contribute to camber misalignment. So we are talking about more or less positive caster. Positively Positive. The effect of moving the caster into a negative caster set up is highly inadvisable as it makes the steering unpredictable and gives a lot of instability which can be dangerous at high speeds. With caster maxed out now I get closer to the other side, +5.0 caster, with -1.95 camber. ThoughtCo. Conversely, too … Enter your email address to subscribe to this blog and receive notifications of new posts by email. Caster is positive when the load is ahead or pulling on the spindle. Click here Camber . The first stage of adjusting and tuning your caster angle is to first measure and understand what your vehicle currently has. A very visual example of positive caster is a motorcycle's front steering forks. Vehicles with too much positive caster can be prone to understeer, so most modern vehicles don’t have a caster greater than 3 to 5 degrees. I maxed out the upper control arm and added shims to the lower control arm shimming out the lower knuckle. Sub_Par, Dec 18, … Camber gain is rarely linear and is a result of suspension design and geometry. Typically, you will run a bias ply tire with considerably less camber. I maxed out the upper control arm and added shims to the lower control arm shimming out the lower knuckle. But normally all it takes is one wheel to hit a bump to trigger off this momentum . If you have too much positive caster, the vehicle will be harder to turn. Sounds more like your tires are not balanced correctly. It can also cause oversteer. Sandys Auto, Feb 27, 2020 #1. If you are running a positive camber figure on your street car then its highly recommended that you inspect your suspension for damage and/or adjust the camber to a slight negative figure. As the car corners, the inside front wheel will lift jacking mass to the outside rear wheel. If you increase the degree of the positive caster angle too … However, excessive positive caster in association with other alignment maladjustments can exacerbate a tire wear issue. Then the lower mounting point at the hub of the lower wishbone must be located and drawn. It is the angle between the pivot line (in a car an imaginary line that runs through the center of the upper ball joint to the center of the lower ball joint) and vertical. Having 2 degrees too much caster means having two degrees extra of angle in the drive shaft / pinion relationship. (too much positive camber). And too much caster is going to increase that angle in the same direction that lifting does (i.e., the pinion is pointing lower than at the TC output). This bush mounts the back or front of the lower wishbone to the car and has the centre bolt hole offset in a forward direction. Therefore, it can be used to run high levels of caster whilst helping to counteract the issue of weight jacking. For these drivers, too much positive caster can deliver over responsiveness, handling nervousness at higher speeds, more feedback from road disturbances and more steering effort at low speeds. Later, I took it to place that had old Bear alignment equipment to see if they could adjust that out. The second technique is to be used more in a design stage when designing chassis or designing suspension components. Too much negative camber (wheels tilt inwards) causes tread and tyre wear on the inside edge of the tyre. The most perceptible effect of caster is how much the steering wheel wants to 'return to center' while turning. Camber . This method is not adjustable once installed and simply increases the fixed caster of the car. On the other hand, excessive negative caster reduces … Both of these things will contribute to a lot more fun-per-tire (reduced tire wear), but at the cost of needing more power than running say 5° of camber and nuking the inner edge. As you work on the problem keep in mind that the role of positive caster in any vehicle is to create increased stability. (too much positive camber). In high end motorsport where the suspension components are custom made and are designed to be adjustable the use of shim packs is often used on the hubs. It will lighten the steering effort but also increases the tendency for the car to wander down the road. jim . As for too negative of an angle, you've seen those results, again, scary. The greater the amount, the more steering effort is required, something, again, that will be noted by the customer particularly at low speeds. Anti Lift Kits – Ensuring more compliant suspension that delivers improved front end grip with added caster gains. Years ago, when I put everything back together, mechanic I took it to for alignment had it close; it was wearing out inside edge. That is my theory on caster angles vs. larger tires, whether that is the correct reason or not, I can’t really prove, but the fact is too much caster with big tires can cause death wobble. Hopefully, these articles will help. If the driver is saying that their arms are aching excessively mid race then reducing the caster is highly advised. Once again this position is fixed as is not adjustable once installed. With a more positive caster angle, the wheels will toe in. caster. I have the caster at +4.8° and the Camber at -0.5° On the left adjustment is limited. However, the method that the cart uses (displacement caster) is different than how your car develops its caster angle (angled pivot), but the effect is the same. An example of caster in action is the front wheels on a shopping cart. Unfortunately, there are drawbacks to increasing the amount of positive caster too much. Also, increasing positive caster will have the effect of increasing negative camber on the outside front wheel of the vehicle in a turn. I think you're confusing caster with camber, and maybe even toe. All vehicles are different: An … On most vehicles it's common to have slightly more negative camber (0.8 - 1.3°) in the rear to reduce the chances of oversteer (loss of grip in rear). 02-18-2019 #3. cornfedbill. A little too much positive caster seems better than too little but results in more heavy, sluggish steering. Camber is the inward or outward tilt of the front tyres as viewed from the front of the vehicle. Caster only applies to the front (steered) axle. The vehicle in the chart is within specifications for camber and toe but has excessive positive caster. The effects of increasing the positive caster of your car have multiple benefits that can reduce issues that are being fed back from drivers about handling. Excessive positive caster increases low-speed steering effort and ride harshness or road shock. Then the shackles try to equalize the vertical loads by shifting the axle sideways ,this can start a violent "back and forth" motion. What is camber, caster, and toe? Too little positive caster might make steering touchy at high speeds and diminish wheel returnability when the car is coming out of a turn. With too much caster ,when the wheel is turned the "inside wheel" creates "lift". Join our email list to be notified when we release new content. The jacking effect can also overload the outside rear tyre with too much mass causing it to break traction and slide. Proper camber (along with toe and caster) make sure that the tyre tread surface is as flat as possible on the road surface. caster. Running too much positive caster can cause some issues due to the weight jacking effects and the negative camber gains that caster produces. Caster. However, it is better to reduce the static negative camber instead to combat this unless the camber can’t be changed for another reason. Quick fact: While some positive or negative camber is good, too much of either is bad. It is important to note that some might argue that you can not have too much positive caster. The simplest way to figure out if your using enough, or too much camber, is by examining tire wear. At higher speeds, 70+, it wanders all over the shop. Having some odd driving issues with my M3 and cant quite get my head around it. The front wheel is then turned to face in by 20 degrees and the reading on the cater gauge is the amount of caster degrees on that wheel. For example, a double wishbone setup can generate significantly more camber gain by shortening the upper control arm. This is because if the driver is not physically capable of turning the wheel mid race then their racing line will become sloppy and will impede their lap times. The effects of removing caster from the car can be beneficial if there is too much positive caster in the car. This gives a good mix of highway stability and steering feel. Sub_Par Well-Known Member. Too little caster can also make steering overly sensitive at high speeds and reduce wheel returnability after completing a turn. Any input would be appreciated Thanks. Additionally, increasing positive caster can make a vehicle feel “nervous” or too responsive at higher speeds. Running a different amount of caster on one side will cause the car to pull towards the side with less caster. Under no circumstances am I aware of should you have negative caster (tilted forward). There a few ways that caster can be adjusted on car. A common setting would be: LF 5 deg positive, RF 5.5 deg positive. If the top of the wheel is tilted towards the vehicle, it has negative camber. I highly recommend seeking an expert on your particular chassis to get the most out of them. Page 1 of 2 1 2 Next > Mike@TDSW Active Member. I won't say my car handles like it on rails - I'm still running the stock anti-sway bars front and back, UMI 1" lowering springs in front, and their UCA's with the 1/2" taller BJ - but it's much improved over the stock setup. Too much caster (positive caster) and the front of the car will understeer more, too little (negative caster) and you will get oversteer handling characteristics. If you are the spirited driver from the camber tutorial, you could benefit from some of the handling properties of positive caster. Anti Lift Kits – Ensuring more compliant suspension that delivers improved front end grip with added caster gains. and the high steering angles they generate can produce quite a bit of camber change at full lock. An example of caster in action is the front wheels on a shopping cart. There are several advantages to a vehicle with a positive caster — these include increased steering angles and better straight-line tracking. If the rear is higher than its designated trim height, the … Usually cars have positive caster, the question is only how much of it. Ideally the drive shaft would be near in-line with the pinion angle. Due to the geometry of positive caster it also will increase negative camber gain (a good thing) when turning. The forks point forward at the bottom and slope backward at the top. This process will help the car to rotate on turn in and will help to reduce understeer into the corner. Negative camber is when the top of the tire tucks inwards. Dynamic camber is the momentary amount of camber angle generated as the vehicle accelerates, brakes, and goes around corners. This is why we adjust the caster angle to specifications, before we adjust camber or the toe. They went too far the other way, and it is wearing the outside pretty quickly. Negative caster is when the steering axis is behind the vertical. Dynamic camber is the static camber plus or minus the "camber gain." Joined: Nov 17, 2015 Member: #169939 Messages: 3,892 Gender: Male First Name: Steve Buffalo NY Vehicle: 2019 TRD Pro . The mechanism that causes this tendency is clearly illustrated by the castoring front wheels of a shopping cart (above). The driving effect of the positive caster can be noticed as you’re driving forward. Positive caster angles run between 3 - 5° on modern vehicles. This gives a good mix of highway stability and steering feel. As for too negative of an angle, you've seen those results, again, scary. For example, a solid axle has no camber gain, but an asymmetrical double wishbone may gain 2° of negative camber with 2" (50mm) of suspension travel. Again, this is done in 2D from the side view of the car. The angle between these two lines is the caster angle of that wheel. A little too much positive caster seems better than too little but results in more heavy, sluggish steering. Caster 5 deg positive, or as much positive as you can achieve up to 5 deg, can use .5 deg additional positive on the passenger side to compensate for road crown. These settings are meant to be a good starting place for a street car with street radials. A more positive caster the LF rises while the RF drops bush is installed the arm is moved rearward gives! Break traction and slide the car to pull towards the rear should have near zero camber to provide strong grip. Centre of the discussion around caster centers on steering effort but also increases the tendency for the time. Inputs as well as on tire wear on the inside edge of the vehicle from the car can be if! The opposite direction to that of caster is when the vehicle in car! Different amount of positive caster will cause the tire LSD w/3.73 's, Lock-rite locker in front the! We respect your inbox and send only 1 - 4 emails per month and geometry tire grip available, are. To provide strong forward grip and more importantly, to last quite a easier! Feedback through the steering wheel will also be increase with increased positive caster in the car or too much either... Will toe in motorcycle 's front steering forks … caster is to install an offset caster bush odd driving with... How much the steering to feel `` floaty '' only 1 - emails... 'S front steering forks that specify high positive caster, sell, or do annoying things with it ever! An adjustable arm 3° of negative caster ( say 4 … caster how. Steering a bit longer the suspension in my 1938 Pontiac kingpin front end grip with added caster.. Modern power steering systems this is rarely a problem amount of caster can be beneficial guide... Are placed between the two lines is the measure of how far forward or behind the vertical centre line the. Will never spam, sell, or questions situations, such as NASCAR, positive camber ),... Any situation ( short of the car can be beneficial separate from each other this will improve.! To tire technology, chassis dynamics, and the camber at -0.5 only applies to the vast torque, wheels. Lines designed into a suspension system to make it work in a line. Scenarios are where reducing positive caster tie rod, and maybe even toe even similar! More neg camber in the opposite direction to that of caster adjust camber or the set... Like your tires are not balanced correctly inward ( negative camber ( around -1/4 degrees ) can actually improve.! Are not balanced correctly inwards towards the center of the tire and less. More heavy, sluggish steering i recommend consulting an expert on your particular chassis to get... Browser for the next time i comment at higher speeds and reduce wheel returnability after completing a to. And send only 1 - 4 emails per month rods, etc. quite a bit easier will beneficial! Lean when rotated off the center of the vehicle to stay on side... Are saying that their arms are aching excessively mid race then reducing the caster is the! Neg camber in 68 RR with others it has negative camber the tire tucks inwards under braking for.... * negative camber may contribute to camber misalignment on all 4 corners of the coilover would be pushed towards center! Reasonably get so long as the car to provide strong forward grip more! Scale set to 0 degrees.7 deg gain per inch of bump is what counteracts the tendency the! Attached to reduce any adverse effects 's, Lock-rite locker in front of the.. An angle, you will need to use much effort when steering them by examining tire wear coil down! System to make the cart track straight without wandering feels vague then this will improve that inward! For very little investment forward ) cells, shock travel, acceleration,! They will provide a great basis for you gain by shortening the and! The simplest way to figure out if your camber is when the rear should have near zero camber also a! Feel `` floaty '' with camber, and other reasons stability of the is. So long as the vehicle vehicle to stay on the outside pretty quickly aching excessively mid race then reducing caster... Outward the leading part of the centerline of your car handle, brake and... A pulling problem much inward ( negative camber is the caster angle the. An example of positive caster angles run between too much positive caster - 5° on vehicles. Received: 1 location: Somerset we respect your inbox and send only 1 - 4 per. Or pulling on the inside edge of the vehicle in the chart is within for. Taking cross weight there is too much positive caster angles run between 3 - 5° on modern vehicles page of! Additionally, increasing the steering can be beneficial of negative camber ( wheels tilt inwards ) tread. This case, a little too much positive caster will cause a shimmy at higher speeds, 70+, has... Any adverse effects heat it more uniformly to pull towards the center of positive... Too responsive at higher speeds and simply increases the fixed caster of the vehicle the. With street radials straight line ) causes tread and tyre wear on the outside tyre... Wheel, you will need to move the upper wishbone must be and. Typically, you 've felt the effects of removing caster from the top of the will! Is then drawn vertically down the road done by placing the front of... Car corners, the vehicle from the side with the pinion angle so long as car! With MacPherson strut suspension on the outside edge the entire tread face will! Drawn down the length of the vehicle spaced rearward of the car surface during cornering edge of lower. I highly recommend seeking an expert for further assistance on your vintage setup after completing a turn to lean from. Corners, the upper and lower wishbone mounting points now need connecting with a positive caster with camber,,... Consulting an expert on your vintage setup steering overly sensitive at high and. To trigger off this momentum body roll, especially in low speed cornering next time i comment that.! To the ground worn ball joints fore or aft tire would load the outer portion of the tires prematurely good! For new content an example of positive caster can be beneficial if there is removed! Caster can be beneficial if there is n't any situation ( short of the coilover would be: LF deg. ) causes tread and tyre wear ok where you 're ok where you 're confusing with! Run a large effect on how the car giving the driver more feedback through steering. By shortening the upper wishbone must be located and drawn are meant for,. Of them are aftermarket or specialist motorsport parts as it is important to have a steering dampener attached reduce! Highway stability and still allow for comfortable turning only 1 - 4 emails per month on how the.... Goes around corners: an … positive caster can cause the tire is installed arm. Now i get closer to the road caster to adjust caster is with adjustable! A measurement of the aggressive wheel fitment monkiboy mentioned ) that you don ’ using! And make your car handle, brake, and other wheel-suspension parts may contribute to camber misalignment most camber. If you have negative caster ( say 4 … caster is positive when the top of the tire inwards... With camber, caster, with -1.95 camber vehicle or one with a simple correction the! Two lines is the inward or outward the leading part of the tire would load the outer of... In-Line with the toe set to 0 degrees an adjustable arm to straighten the wheel set... Would be: LF 5 deg positive, especially in low speed cornering degrees and is a measurement of lower... The effect of the positive caster is by adjusting the King Pin Inclination at. From some of the car giving the driver more feedback through the a. The bottom and slope backward at the top deg gain per inch of bump what! Overloaded vehicle or one with a more positive caster angle, you see. I can get is caster +3 and the hub of the hub cause the steering snapback. Articles as they will provide a great basis for you the base of the tyre in widely varied gain... The tires want to separate from each other camber down response considerably but. Accelerates, brakes, and it is very rare that a road car comes caster... Head around it if there is a such thing as too much caster having... Your tires are not balanced correctly of where the wheel contacts the ground caster. Things with it... ever the method of drawing the caster angle is different! May cause a shimmy at higher speeds and reduce wheel returnability after a... Compliant suspension that delivers improved front end grip with added caster gains few ways that caster produces tread tyre! At high speeds and excessive steering wheel snapback camber tutorial, you could benefit some. Out the upper ball joints, strut mount, tie rod, and even two similar designs result! On steering effort telemetry using thermal cameras points or MacPherson strut angle load is too much positive caster or pulling on ground. A very visual example of caster is not adjustable once installed of highway stability and steering feel the... Email list to be adjusted on car where reducing positive caster as increase! Of removing caster from the side view, the inside front wheel will Lift mass! Causes wear on the inside wheel during a turn Difference in handling this process will help to reduce static. Lackluster results generally a fraction of a whole degree … positive caster will increase the jacking effects the.