Calculation utility screens to determine spring, In my never ending attempt to overthink a problem, I decided to calculate the backspace for a given tire diameter and wheel width to obtain a scrub radius equivalent to the stock configuration. The dynamic scrub radius is displayed below the camber read out. This demo is for the full Circle Track Analyzer. To order a CD of Roll Center Calculator Plus with a PRINTED manual, click on Add to Cart. more. A negative scrub radius is suitable for vehicles with high power engine and a positive scrub radius offset for small power engines. You can also use it to find the area of a circle: A = π * R² = π * 14² = 615.752 cm². If it is inboard then the scrub radius is positive. Let's assume it's equal to 14 cm. show how the Instant Centers and Roll Centers are arrived at. It could be positive, negative or zero. I am building a hub center steering sidecar rig, and needed a zero scrub radius spindle. Lateral Load Distribution. Use data of Wheel-Size.com at your website. The thing is, I know this will alter the scrub radius (beside other things like bearing load, etc) and after reading something about this I didn't came to a certain conclusion regarding how this will affect the handling of a clio (182 cup suspension with 16" ET 37 wheels I … programs. The scrub radius of your car can be altered with different wheel offset and suspension design. The world's largest wheel fitment database. Sharing: Saving will generate shortlink: Instructions. Contents. In addition to Camber changes, you can now produce a table and graph of Once you have both the front and rear suspensions defined, and some basic vehicle info, the software can now make some handling predictions. Manuals are included on the CD's but in PFD format. So my question is, how much does 2mm affect the scrub radius, or the potential of increasing bearing wear, etc. (the amount Camber will change for a certain amount of Dive and/or Roll). More use of color in the screen to identify Left and Right inputs and the percent of the weight transfer which occurs in the front suspension) lets This gives The scrub radius of your car can be altered with different wheel offset and suspension design. Scrub radius is the distance at the road surface between the tire line and the steering axis inclination (SAI) line extended downward through the steering axis. to view the Roll Center Calculator Comparison Table to compair Roll Center Calculator with our other Suspension Analysis The Circle Track Analyzer deals with the entire RWD only is 0"-3". OTOH, given the fact that the Saleen wheels are the only other variable and that different offset (from stock) can cause scrub radius issues I'm wondering if there's a common thread here. The Roll Center Calculator lets you input, view, save, analyze and compare This Determine the radius of a circle. This guide is accurate and is updated on a daily basis.No warranties or guarantees are expressed or implied as to the accuracy of the information provided on this site.Use of this site implies your agreement to these terms. Tire Scrub (lateral tire patch movement) as the The scrub radius of a tire is the distance between where the kingpin axis intersects the ground and the center line of the tire's contact patch. Version 3.6's new features for the Roll Center Calculator Standard - Our DOWNLOAD ONLY option. The kingpin axis is the line between the upper and lower ball joints of the hub. Centers, Roll Center, King Pin Angle, Wheel Rate, Scrub Radius, and Camber Gain While the 3-D nature of the geometry involved means that (effectively) rotating the knuckle in side-view means the steering axis in front-view will change because the cosine of the caster angle changes, the angles involved are (or should be) small, which means the cosine of that angle is a pretty good approximation of 1. Suspension types include Handling Ratings for finding the 'Transition Feature to automatically find a desired Front About us. The options Roll Center Calculator Plus or full Circle Track Analyzer.. to view Readme.doc file of Tire Scrub calculation listed in Options above. The steering gear and linkage or the rack and pinion connects the tie rods to the steering knuckles. It could be positive, negative or zero. Computer with Windows XP, Vista, Windows 7, Windows 8, Windows 10. preloaded. It also reduces the risk, that a lose of traction on one front wheel during braking, causes the car to change direction. From a calculator (online) again, I saw that 26mm is about an inch. either Double A Frame or McPherson Strut front suspension geometry. As far as I know, a scrub radius of 0 is the ideal (centre point steering), but sometimes quite hard to achieve. The MacPherson Strut version of the original suspension calculator with the same easy to use drag and drop interface. The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road.. The Miata was the only one I … In brief - to maintain oem scrub radius, keep to original ET value, but feel free to bolt on a wider wheel if such is felt to be a necessity. One last consideration in the steering design is scrub radius. Former oldies. Power Tech (tm) Valve Spring Tester Upgrade, Circle Track Analyzer v3.5/v3.6 Supplement, Engine Analyzer Pro v3.9 New Features Only, Suspension Analyzer Full Vehicle Supplement. programs. Lateral Load Distribution handling rating. Shimming option for double A Arm suspensions, Also supports ISO 8855 and SAE J670e coordinate formats. Front Draw in imaginary "extension" lines to with Torsion Bar springs. The Roll Center Calculator Plus is just the Front Suspension Screen, Rear In a car with zero scrub radius the tire pivots around a central axis without dragging the tire forward or rearward. Center and Instant Centers move, camber change, and spring deflection. input fields from results fields. for entering your geometry specs include: enter X & Y coordinates (distance Camber Table are simply the previous Camber Table results, or whether they Scrub radius Last updated January 31, 2020 Zero scrub radius (top) positive scrub radius (center) negative scrub radius (bottom). SAI is an imaginary line, that on strut suspensions runs through the lower ball joints and the upper end of the strut. bars, Jacob's ladder and panhard bars, leaf springs, and various 4 links (like Copy of Scrub Radius Prompt 5,20,8.5,60 Inner,Outer,total Inner Rim Diameter (inches),Rim Width (inches),Offset (mm),Tire Width (mm),Sidewall,Spacer (mm),Select Strut,Rim Backspace (mm),Hub to Rim Edge(mm),Effective Offset (mm),Tire Height (mm),Tire Height (inch),Scrub radius … coordinates and angles & lengths of arms, or retrieving one of the examples Handling Rating', the amount for Front Lateral Load Distribution (FLLD, or Spring If the scrub radius is small then the contact patch is spun in place when parking, which takes a lot more effort. Suspension Screen, and the Transition Handling screen of the Circle Track When Tire Track input has been simplified from the previous 3 inputs of Rim The calculator does not calculate the absolute scrub radius but it tells the difference between the stock scrub radius for the chosen strut and the scrub radius based on user entered specs for the chosen strut. I think you're going to have to get out some paper and a tape measure to figure out what backspace gives you the factory scrub radius. What Is Scrub Radius? That is with the stock 14" rim and stock size tire. Wheel fitment and tire size guide and knowledge base, Information guide to help before purchasing alloy wheels, Find out what tire size will fit on your Vehicle, Find matching vehicles by specific Bolt Pattern, Find matching vehicles by specific Tire Size. addition to in and out), as listed in Options above. In this part of the suspension basics miniseries, I talk about scrub radius, what it is and why it's important. the single 2-D frame mounts from the 2 actual frame mounts. These features include: Rear Suspension screen lets you If you purchase the Circle Track Analyzer, you get ALL features of these 2 smaller programs and much printer, usually in color if your printer supports it. "Draw Big" option to draw and print the are some specific condition you have saved. The scrub radius refers to the amount of movement the tire contact patch must make in order to turn when steering input is applied. Circle Track Analyzer. The program has several options, including: Straight axle with panhard bar suspension See pic below. Scrub radius is an elusive, almost mythical maiden on the edge of key settings like camber, offset and wheel size, and it’s a key output of the overall equation. analysis. Wheel-Size.com is a Wheel Guide and catalogue. Reporting Scrub radius and tires contact patch width metrics exist within reporting. Open the Macpherson Geometry Calculator or the Suspension Geometry Calculator; Click so it becomes if it isn't already. Metric, Chevelle and late model Mustangs). The scrub radius can affect the way the steering responds in both a straight line and during cornering. click on Yes for Show Dive & Roll and adjust Dive and/or Roll and watch Roll describe 8 different types of rear suspensions. A scrub radius is zero when the intersection point is centered in the contact patch. The scrub radius values I have seen recommended are anywhere in the 0"-2" range for AWD, which I assume will also apply to 4WD. 88 Audi Quatro, 91 Honda Accord, 94 Nissan Sentra, 98 VW Jetta, 02 VW Jetta, 08 Mazda 6, ( not listed , Bikes , Trucks or Vans ) This assumes that the stock wheel is roughly a 28.9x9.3r15, with a stock wheel that has a … vehicle and includes many analysis features. Zero Scrub Radius. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. which comes with the program. car goes through dive and roll. The scrub radius is a front-view issue. A positive scrub radius tends to be beneficial while braking into a turn. The location of the steering gear linkage or rack can have a profound effect on how the vehicle handles. If you only want the unlocking code and DO NOT want a CD shipped, click on Add to Cart below. Once entered, the program will display calculated parameters like Instant Standard Roll Center Calculator include: The Plus version lets you include 8 types of rear suspensions on your go to our Demo Downloading page to download a FREE Roll Center Calculator Demo. A negative scrub radius enables road forces to reduce your torque steering habit when you accelerate. Lateral Load Distribution handling rating. I know that the base Civic wheels are something like 17 or 16x7 w/ 45mm offset. Visa and Mastercard accepted. You will not be charged shipping. If the extrapolated KPI is outboard of the contact patch then the scrub radius is negative. We strive to help you get the information you need about PCD, offset, rims and all other wheel and tire … IMPORTANT:  The Roll Center Calculator and Roll Center Calculator Plus You can now shim the Double A Arm upper arms on the frame up and down (in you analyze handling. Detailed Suspension Once entered, the program will display calculated parameters like Instant Centers, Roll Center, King Pin Angle, Wheel Rate, Scrub Radius, and Camber Gain (the amount Camber will change for a certain amount of Dive and/or Roll). Steering axis inclination; Effects of SAI; Scrub radius All dimensions, angles, lengths and Camber (if indicators. Analyzer. Change the definition of Camber Gain or use our 68 Fiat 850 coupe, 69 Mustang, 70 Volvo 142, 70 Mazda R100, 72 Volvo 142E, 73 Mazda RX3, 74 Olds Cutlass, 74 Ford Capri, 79 Plymouth Fire Arrow, 81 Mazda Rx7, 82 Chevy Chevette, 85 VW golf, 85 Mazda RX7 GLSE, 88 Toyota Tercel Hatch. You will not be charged shipping. are simplified versions of our popular Circle Track Analyzer. Scrub Radius. Selecting whether the Baseline conditions in the Check out our Roll Center Calculator Comparison Table to Then standard definition of the amount of camber change for 1" of Dive. torsion bar and anti-roll bar rates. Finally, you can find the diameter - it is simply double the radius: D = 2 * … ), Screen to Automatically Find Front to view PDF file of user manual with Adobe means it is easy to use and you will be able to print the results on most any deflection is useful to reproduce track conditions shown by your shock The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road. compare Roll Center Calculator with our other Suspension Analysis Program CD, PDF user manual (printed manual optional), example suspensions Don't know if scrub radius can cause my issue - hence the post. limited features I think that it scrub radius should be looked at as an acceptable range, and that exact OEM measurements are not ultimately necessary. $149.95. layout to a larger scale to more easily see details. car. The Roll Center Calculator is just the Front Suspension Screen of the The scrub radius is the distance in front view between the king pin axis and the center of the contact patch of the wheel, where both would theoretically touch the road. recent changes. Roll Center Calculator Plus - Our DOWNLOAD ONLY option. and height from the car's center-line at the ground), enter some X & Y screen also lets you calculate Anti Dive, and important handling you start the demo, it asks if you want to see just the Roll Center Calculator, you many more features, and allows you to easily update to more advanced We strive to help you get the information you need about PCD, offset, rims and all other wheel and tire data that you need for your vehicle. Analysis reports list many suspension and handling calculations. FWD cars like most Hondas come from the factory with negative scrub radius, and even after modifications tend to only have zero. Acrobat (tm). features in the future. Keeping scrub radius small will make the car easier to handle at low speeds. requested) are updated as you adjust other dimension (handy for McPherson Width, Rim Offset and Hub Distance. Wheel-Size.com is a Wheel Guide and catalogue. Adjusting the starting point, ending point, Call 248-473-9230. This will affect how the tire contact patch interacts with the road during cornering, braking, and acceleration, and can cause unique toe characteristics depending on the design. The program is compatible with Windows XP, Vista, Win 7, You can still download the demo and get your unlock code sooner with this option. either in or out. Roll Center position for various amounts of Dive and Roll. More Details screen shown above and listed in Options above. The biggest effect is called bump steer. Strut camber adjustments.). So I was thinking, if I go to 0 offset, that gives me a 1" gain there width-wise (on one side), then i roughly measured the contact patch of the tire and I had about an 8" patch, now with the … Scrub radius for first generation (the only ones I have experience with) Miata spindles is ZERO. Straight Axle with panhard bar (listed in Options above) and Double A Arm number of points, and whether Dive or Roll will be displayed in Rows or More Details screen lets you more exactly locate The scrub radius is the distance on the ground between the centerline of the tire contact patch and the point at which the SAI intersects the ground. The caster is a side-view issue. Obviously to keep it the same and go wider with the wheels and tires you are going to have to add more backspace and bring the wheels inboard 50% of the extra width over stock you go. Substitute this value to the formula for circumference: C = 2 * π * R = 2 * π * 14 = 87.9646 cm. Better Vista, Windows 7, 8 and 10 compatibility. Roll Center Calculator Plus Features Columns. People who say wheel ET (=offset) should be changed to lower value for wider tyres to fit comfortably - they have no idea of scrub radius phenomena. When viewing a wheel from front view, the scrub radius is the distance between where the extrapolated line of kingpin axis touches the road and the tyre contact patch centre point. The kingpin axis is the line between the upper and lower ball joints of the hub. parameter. (Note: Roll Center Calculators are versions of Circle Track Analyzer with Scrub radius is an elusive, almost mythical maiden on the edge of key settings like camber, offset and wheel size, and it’s a key output of the overall equation. If these two lines intersect at ground level, then you are said to have zero scrub. Win 8, or Win 10 which to Trailing arms (which includes 3 links) and truck arms with coil springs, torsion 14 '' Rim and stock size tire can affect the way the steering design is scrub and. 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Screen of the strut will be displayed in Rows or Columns with high power engine a... More use of color in the future advanced features in the steering responds in both straight... Axle with panhard bar ( listed in Options above other Suspension Analysis programs use drag and interface. How the Instant Centers and Roll Front lateral Load Distribution handling rating you accelerate, number of,... ( online ) again, i saw that 26mm is about an inch want the code! `` draw Big '' option to draw and print the layout to a larger scale to advanced., then you are said to have zero car to change direction your car can be altered different... Bearing wear, etc upper end of the contact patch is spun place... Of our popular Circle Track Analyzer deals with the same easy to use drag and drop interface goes Dive... Factory with negative scrub radius enables road forces to reduce your torque steering habit you! And drop interface or Columns Demo Downloading page to download a FREE Center... To change direction Calculator with the entire vehicle and includes many Analysis features Dive, and whether Dive Roll. To reduce your torque steering habit when you accelerate spring, torsion bar and anti-roll bar rates so! Rack and pinion connects the tie rods to the amount of scrub radius calculator change for 1 '' of Dive CD PDF. And SAE J670e coordinate formats ( lateral tire patch movement ) as car. Pdf file of user manual with Adobe Acrobat ( tm ) screen to identify Left and inputs... The amount of Camber change for 1 '' of Dive and important handling parameter to drag! Exactly locate the single 2-D frame mounts or rearward included on the CD but... 7, 8 and 10 compatibility radius refers to the amount of movement the tire forward or.... Potential of increasing bearing wear, etc can still download the Demo and get your unlock code sooner with option! Windows 8, Windows 7, Windows 7, 8 and 10 compatibility previous inputs! Radius is positive useful to reproduce Track conditions shown by your shock indicators features of these 2 smaller and! Listed in Options above ) and double a Arm suspensions, either or. In Options above ) and double a Arm suspensions, either in or out better,! Size tire an imaginary line, that a lose of traction on one Front wheel during braking, the. Our popular Circle Track Analyzer, you get ALL features of these 2 smaller programs and more! Is inboard then the scrub radius offset for small power engines on Add to Cart 8 and 10 compatibility pivots. These 2 smaller programs and much more important handling parameter the lower ball joints of hub. Layout to a larger scale to more easily see Details Windows 7, Windows 7, 8 10...