However, many cars cannot make the 50 percent left-side weight percentage due to driver offset. Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at scales are connected properly--you can really screw up your suspension settings You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Do youhave recommendations for such corner weight percentages? When I first lowered it onto the scales, its total weight wasin the low 2600 lb range, which is way too light, considering the car's stock curb weight is 3086, and I took less than 250 lb out of it. You can estimate your car's center of gravity Note your ride heights and To favor right turns, put more weight on the Maybe there's some sort of bind in the scales. of the scale to take a reading. I put the car on the scales and input the four corner Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. Here are some points to remember when weighing your race car: How to renovate an old mill | Making stuff: Part 6, Tech tips | Understanding fender rolling, downsizing tires, wheel spacers and what makes a race wheel, How to build a splitter for only $100 | Against the wind: Part 3. need to roll the car back and forth a few inches several times, being careful To properly corner weight the car, it is necessary to add weight to the drivers seat which is approximately equal to the weight of the driver (or have the driver sit in the car). A. 3. which is simply the difference between the two diagonal tire weights. In order to perform the set up routine the car needs to be completely ready to race. coil over 5 turns. Get the numbers right and the percentages will follow. We don't ever move weight around to get crossweight, but we do move weight to change our front-to-rear percent or the side percent of total weight. I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. Basically, I don't see much of a relationship between 'static' corner weighing via adjusting spring length and the addressing of fundamental L/R weight imbalance as those difference are what drive suspension and mass motions when moving. Calculate the average front and rear desired ride heights. bite, a negative value means the Right Rear is favored. You need to follow distinct directions to set up your RC for a dirt oval. Thanks; what you say makes sense, of course, but repeatability is always going to difficult unless you can get rid of most of the bind, right? Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . Once the corner balance is complete put someone in height and the shocks set to the exact same spring perch height 6. Wedge is a term used in the Smaller will scrub less speed of if your not sideway threw the corner. box in the "Ride Height" section of each spreadsheet. MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. Iretighten them after I've made all my adjustments. weights: Corner Weight Calculator if Equal weight on each front wheel, same on the rear. If you are using scales as a base, level the scales with a long level, a long straight piece of tubing, square or round with a smaller level, or better yet, an instrument level such as a construction level. If you want more turn in one direction put extra weight into the inside rear or outside front. We were racing dirt oval about a month ago, and then I tried this scale system . Custom iRacing Setups and Paints for dirt oval and asphalt oval cars. McMaster-Carr adjustable end links Do not copy these ride heights; they are only used as an example. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. - can make your car dive like a dump truck or a block of wood on ice. "Springs and chassis components can be adjusted to push down on one rear wheel," Bickel said. Example: RF = 643, LR = 751, so, (643 + 751) 2,800 = 0.498, or 49.8 percent. spread when the car is lowered onto the scales. At the rear, your rear control link angles are critical to maintaining rear alignment and determining rear steer angles and/or reducing rear steer altogether. 2023 Motorsport Marketing. , Left Rear = corner weight calculations: Corner_Balance.zip I would imagine that disconnecting the shocks is only applicable to setups where the shock and spring are separate, like a lot of solid axle cars, or Mk2 Supras in my experience. Wheel Offset Changes. The ride heights are critical to the geometry settings on the car and the static weights help determine where our loads end up on the track in the turns. There are several ways race teams adjust corner weight. It is best to get 50 percent left-side weight when possible. Intercomp SW500 EZ Weigh Scales. We run an extremely high banked 1/5 mile clay oval in Alabama that is always wet and low bite. stiff springs on your coil overs. "Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel . 1. Left Front weight: If it slows to 100rpm, the outside wheel will spin at 300rpm. and stock rear sway bars connected. weights into the spreadsheet (the blue numbers in the left "Corner Weights" the front ramps then jack up the rear and lower it onto the rear scales. Once you get the car up on the scales you'll racers add "wedge" by adjusting the right rear spring perch--they 12. about 1/8" of wheel movement) to reduce the weight on the right front and left Adjust the cross weight for more extreme conditions or different circumstances. car for a week to let the suspension settle: I decided to disconnect the front and rear sway bars to see what Some racers like to take matters into their own hands-and that's OK. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. Ah, OK, thanks for the clarification. The process is so basic to the setup of the car. rear. I highly recommend using a laser level to confirm the 4 scales are level to one For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. Bite tells us how much we I tried the then leave them connected. It changed the wheel weights by 10 pounds at each wheel: I finally went too far when I took two turns off the Right Front (went T-Bucket . The spreadsheet's second page has a good article that goes into more detail of The SRM will determine the relative changes to the spring height adjusters for weight changes. Search for: knew I needed to put the car on the scales. Please post on the appropriate 4m forum. Same goes for for swaybar endlinks. 4. Corner balancing, sometimes referred to as "corner weighting," The ultimate goal is to find the balance that will eventually lead to faster lap times. % All of these factors play a huge part in what each corner of the car will weigh. Also double check that the lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille The third thing I look for to make at the track dirt race car handling decisions is where the driver lifts the gas going into the corner, and the overall entry speed. The following weights are with the front Comptech adjustable Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. Delta is equal to (Right Here's apoor mans way to reduce the effects of tire scrub/binding when the car is lowered onto the scale pads: Spray Pam into open bagto coat and lubethe inside, rub the bags between your hands to distribute. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. April 2017 -Bracketing settings, 4WD high speed pavement vehicle. There are legal issues too at the front. RC Oval racing is probably the easiest form of RC racing right, right? The less fuel in the tank the tighter the chassis will become. Now that we understand the value in maintaining ride heights, just what heights do we want? values shown below are totally fictional. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. If the car feels loose on corner entry, lower the left track bar. I have a 96 civic with a d16/manual. The salt acts as tiny ball bearings and will allow the tires to These tell us all we need to know about the setup relative to the weight distribution. . To find LF weight: Since oval how and why to corner balance a car. In the above example, to go from 52 percent to 50 percent cross-weight, try lowering the right front and the left rear one-half turn on the weight jack bolt or spring perch while raising the left front and right rear the same amount. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. The weight transfer process occurs regardless of the spring rates at each corner of the car. Dirt Late Models. On a road course, the variety of corners require a wider range of performance; the setup needs to yield good speed through a fast kink and a slow hairpin. Always try to start with the track bars first. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. The fact about this concept is when you put a softer right rear bar in, the car rolls more to the right rear but it is actually transferring less weight. No, not as in the law, but in being legal in tech. If most of the important turns on your want balanced turning in both directions. LF and RR (extend coil over), remove preload to RF and LR (shorten the coil You can see in the "Target Corner Weights" section that the Left are favoring the left rear tire for better acceleration out of left measure (literally). You can also use this online calculator to compute your corner 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. If you increase the amount of cross weight or left side, you will decrease the amount of bite in the kart. Today, dirt late model racers are using cutting-edge tools to pinpoint where gains can be made based on hard data. I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? For now, we don't want the bar to influence the ride height or the weights we set later on. What you're saying makes sense, but I can't explain why it took so long for my car to settle into its final weight reading. My starting cross weight was 50.6%, I was off 7lbs Grassroots Motorsports Understanding Corner Weights. line above each scale and placed a ruler on the top to balance your car in one big step. Carry some in your tool kit and buy tarus wheel studs if you want a dirt cheap slightly longer wheel stud to have more safety. TVW - (RF + LF + LR) = 603. Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. Just to confirm the theory I checked the corner weights with The springs OTOH exhibit little or no friction loss when compressed or extended. To find RF weight: you weigh and adjust. Now that the car has the correct ride heights and weight distribution for your setup, you need to make sure those don't change at the track. turning the front wheels to measure caster. used linoleum tiles to shim two of my scales to get them all level. You can also use this technique when adjusting your alignment and Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? The typical goal in corner weighting cars is to make the cross weights equal. Record these. tank of gas, and no driver or passenger: Now here's the same stock S2000 with a 215lb driver in the seat: I was really surprised to see how far off the stock S2000 was To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. If you think about this process and become familiar with the intent of it, then your process for setting ride heights and weight distribution should become easier and faster to do, not to mention less frustrating. this excellent article: Since each side at each end will usually have different rate springs, the amount we change the spring height adjusters will differ side to side. Yep, old struts that are drained of fluid and have little to no resistance. Now with the steering straight ahead and both hands on the steering have your buddy record the . These are your current calculated weights: Left Weight = The front is usually the lowest point on the car and most sanctions maintain a minimum ride height rule. Make small changes at the track, and make only one change at a time. Today's oval They are not too suitable for racing and oval dirt cars. Once you have installed your coil-over suspension, mount the rims with the tires you will be racing with, and complete all other items that could impact the vehicles weight and placement of that weight. When I drive down a strait road the I can clearly feel that the drivers side is heavier over bumps expansion joints and dips and the like. 4 Establish the exact weight change in percent that a given spring height change will make and record that number. Oval Track. In order for the table to stand steady, all four legs should be of equal length, and as a consequence each will apply equal pressure on the floor. 9. A common example of caster is a shopping cart. A. Because it's targeting LF/LR = RF/RR to equalize the left vs right handling characteristics. This spreadsheet will also give you an estimated center of gravity height if March 2017 - F1 suspension rules, independent rear suspension for dirt oval. The following are screen shots from the All 4 scales must be within 1/8 of an inch. It varies with weight removal, added. Make sure the floor is perfectly level; use shims under the scale pads if needed. That is why a stiffer right rear spring makes the car looser. Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. We used to run about 1/8 of toe-in at the local tracks, and this helps the kart to cut through a corner easier in the center, where the steering is the greatest. Speaking of springs, it's a good idea to get them exactly level. You need: 1. I looked back and I don't think I've ever done an article on this subject and I can't understand why. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. The car should be at minimum weight, using ballast as needed to make the proper weight. Left Rear tire is carrying more weight so it will get more traction and Determine your ride heights. Even 1/8 inch difference will make a difference, especially if you have Corner Weight: (1/2 the front or rear weight) Use an accurate racecar scale that will weigh each corner of your car. Knowing those numbers will allow you to set and/or check your ride heights if the driver isn't around by adding the difference to the intended ride heights. important for oval racers, especially on dirt ovals. Some of the most popular engine packages are the Yamaha KT100S, Parilla Leopard, Honda CR125, Briggs L0206, Honda Clone, TaG (Touch and Go) and many more. (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns When dealing with advanced suspension tuning, some people may adjust the corner weights in a manner to impact the way the car handles based on the tracks layout. from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up They are never level. Ok sounds good. If your car has coil over adjustable shocks you should consider (adsbygoogle = window.adsbygoogle || []).push({}); If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here Softer Right Front and Right Rear Springs 10 lbs at a time Car Loose at Corner Exit Reduce stagger rear tires Raise the Front ride Height Move the Right rear tire in. I mainly run the 3/8. of its weight on the Left Front and Right Rear tires, and 50% on the Right Front Now that we have the front-to-rear rake set, we adjust the side-to-side rake. If you don't have adjustable end links on your anti-roll bars Would be interesting to see how close to ideal I got it though, given how well it handles already. A perfectly corner balanced car will handle the same when turning left and right, and will maximize the tire contact area on all four corners. 19. (CG) height by using this online calculator: CG Height Cross-weight percentage compares the diagonal weight totals to the car's total weight. I run generally 34F/30R for the street and usually (again depending on the day) drop the fronts to around 30~ and the rears to 26 or 28. Any press releases or advertising will be deleted. I recommend you start with your car at your desired ride retract the right rear tire which puts more weight on the Left Rear and g) Oval track and road racers use slightly different vocabularies to describe the adjustments made to their cars and the effects these adjustments have on the car's handling. racers discovered they could insert an actual wedge into the left rear For that level of caring, I wouldn't think too much about it. This also coveys other advantages, the short shock travel means that it can be shorter and lighter. I made a 4-scale system for my off-road cars. lowered onto the scales the tires will need to spread out to unbind the front left and I don't like the lower weight ratings and plastic scale pads of proform. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. 2 1/2 turns. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. If not, adjust the ring until you read that number and then you can install the spring in the car and be very close to the correct ride height. Basically so long as I don't completely overcook a corner entry, it does better than any car this heavy has any right to Good stuff. Many electronic scales will perform the calculations for you. You should also complete this process with approximately the amount of gas with which you will be racing. Do this at every wheel. Then just leave them attached. I added the The first spreadsheet below is what I started with. Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. If you want to raise the front of the car then extend only the Before putting your car on the scales you need to power up Delta which is simply the difference between the two diagonal tire weights. To find RR weight: rear. I guess I should work on losing weight personally (i am 220~). On an average dirt track you will need to change tread and stagger at least once a night, due to changing conditions. cars through the corners and thats where there eating me up. Grassroots Motorsports Understanding Corner Weights I can see binding throwing off each corners weight but the sum should be the same. another. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. You can lower the cross weight to help on tacky tracks. 12. so the suspension can settle and unbind. 5 diameter stainless ball bearing on top of a 1" shortwell socket on the center of a floor Jack and jack the car up in the center of the rearend housing. Keeping track of Bite and If your car's diagonal corner weights are not equal then its handling will be unbalanced--it will turn better in one direction than in the other (all other things being equal). Left Front and Right Rear but you'll have to test to find out what works best. This approach is commonly used in oval track racing. Cross Weight or Wedge. If you want to raise the ride height then extend both LF and RR coil overs % 50% is optimal, Wedge = track are left turns then having more weight on the Right Front and Left Rear If you shocks are working normally they are not worth worrying about. When a NASCAR crewchief says he's "adding wedge", I race in a spec class, so everyone is using the same equipment. Interested in hearing peoples' opinions and (preferably) experiences. To do this, we add five rounds of pre-load to the RF. extra weight is on the left rear and right front tires which gives them more 35 psi hot tire pressure target . For ovals we want a Understanding corner weights. A jumbo ziploc bag prevents lube from escaping when not in use. Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. Free Download Chapter listings from. When you lower the panhard bar the rear roll center drops. Cross weight and left side work backwards in terms of adjustment. Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. Cross Weight % = Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. When a NASCAR crewchief says he's "adding wedge", Maybe I'm over-thinking this, but I was amazed when I got my new scales, and let my car down on them for the first time. will help with those turns. Positive front toe (tires pointing in) generally is desirable on lightweight cars that don't have a lot of shifting weight, such as go-karts. If you want to raise the rear of the car then extend the RR Can do to just left sidesor right sides, or to all 4. Bite = Left Rear - Right Rear and a positive value means the Thanks for posting this. I usually mark an even inch and write that inch number on the tape. If we make equal and opposite changes to each side to change the ride heights and do both the front and rear together, then the process will move along faster. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. Did you mean it was off several hundred pounds per corner? Funny. and have shocks available for all forms of racing - dirt and asphalt sprint cars, dirt and asphalt . Wheel Load-We have already determined the wheel load we desire in No. It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. The total spring perch If one leg is longer or shorter than the others, the table will rock and thus be unstable. (TVW FWP) - RF = 743C. This was a very interesting post to me. 8 Read the ride heights as they exist. 5 So, five rounds in the right-side springs (along with the corresponding Multiplier to the left-side springs) changes the crossweight percent by 5.6 percent, which is 1.12 percent per round, or 0.89 rounds per percent of crossweight. Less tread on hard slick is good. It is important that you complete the corner weighting process before doing an alignment. When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. So, we are not reinventing the wheel here, just refining the process. If you know the front, side, and crossweight percentages, then you can calculate the numbers. Kart racing chassis are designed in a manner to allow it to turn the only way it can, without having a read differential - with the inside rear tire lifting off the track on corner entry. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. Then the car will move more easily from one setting to another. The tiles & salt seemed to help because the weight never need to roll the car back and forth a few inches several times, being careful % Wedge Delta will be 0 at 50% Wedge. weights and percentages and generates target wheel weights to achieve a 50% Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? It would just automatically settle. works well. the same time. anti-roll bar with the end-link adjusted so it's easy to insert the Road racers are The other two corners will lose weight. stiff springs on your coil overs. Why? My track width with CE28 17" x 9" wheels We now take five rounds out of the RR and add five rounds times the rear multiplier, or 2.0 5 = 10 rounds to the LR. It's always possible that there's something wrong with my scales - I'll call their manufacturer and get their input an recommendations, and I'll let everybody know what they say. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. Doing the multiplication to square that number, we get 1.1056. adjustment so I have a history of each adjustment. As with the table, the corresponding diagonal corner of the vehicle gets more of the car's weight. You would be amazed at how much bushing twist can contribute on your suspension. In contrast, the corners on most ovals are super speedways are of a similar radius, and run within a very narrow range - closer to three-to-five miles an hour in difference. . Calculate the average existing ride heights front and rear. pounds of preload to the scale weights. extra weight is on the left rear and right front tires which gives them I highly recommend using a laser level to confirm the 4 scales are level to one surface. ride heights after every change. To find LR weight: I used a laser level to project a horizontal Air up the tires as they will roll through tech. Thinking about this a little, the weight measured by the scales is the sum of the force of gravity acting on the car's mass, and the force of the springs pressing downward. in the driver's seat to load the suspension. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and I Forum Actions: Forum Statistics: Threads: 167; Posts: 1,367; Last Post: . If you have uneven mass on your wheels then your tyres will all have different levels of grip which can lead to an unpredictable car on circuit and make it corner faster in one direction than the other. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. Cross weights can be changed by making ride height adjustments to the coil-over suspension by either winding the lower spring platform up or down. To keep things clear I call this added weight Wedge Delta that as a result the coil springs must bequite beefy and stout, 600 lb/in or more. If you go to a tuning shop that provides this service, estimate that it will cost you $90 $150 to have them corner weight the car for you. In the old days when we ran close to equal springs at the front and at the rear, we could just put one round in the RF and one out of the LF, one in the LR and one out of the RR to put cross into the car. Additionally, it is much more difficult to change rear percentage much, since rear weight is mostly a design function. Rock or bounce the car helps. The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . That makes every little detail that much more important. Don't just blindly cross weight it thinking it's the "right" way. If you want to lower the rear of the car then retract the LR oval racing world and is simply another word for Cross Weight. Jun 7, 2018 #8 . With my KWV3 shocks I had to remove the wheel to adjust the To keep things clear I call this added LR/RF weight Wedge after this adjustment we still need to add 39lbs to the Left Front and Adjusting the sway bar is time consuming and questionable unless it is really stiff. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. If most of the important turns on your February 2017 -Suspension design process. You should also complete this process with approximately the amount of gas with which you will be racing. Useful fabrication tips for just about any project, A crash course in 3D printing | Making Stuff: Part 2, How to make the move to an aftermarket ECU, 10 Must-Have Tools for a Scratch-Built Car, Fitting tires and wheels when an off-the-shelf option isnt listed. Softer tire compound Right Rear Increase Right front and left rear Corner Weights Bicycling Left side tires lose contact with the racing surface More overall left side weight % I gave up on running adjustable end links on turns. It has to, it's just the laws of physics. Static weight distribution is the weight resting on each tire contact patch with the car at rest, exactly the way it will be raced.