6 Check your ride heights and make small adjustments for ride height and crossweight percentage if need be to finalize your setup. Move ballast first, since it's easier. Always try to start with the track bars first. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. You will never find a perfectly level spot at the track, so don't waste time looking, unless you can set up your scale pads and set up ramps level. Shock Position You can drop the front end slightly or raise the rear end for more aggressive turn-in. The LF needs to go up 0.3125 and the RF needs to go down the same amount. LF coil over 5 turns. intentionally favor a turn direction. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. Oval The crossweight percent will have changed to, say 55.4 percent. after this adjustment we still need to add 39lbs to the Left Front and On Dirt cars, adding Rebound to the Right Rear will make the car more stable when it slides into the cushion. Classic Truck. The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. spread when the car is lowered onto the scales. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. 2 When you make a spring change, bring that corner back to the measured distance from the wheel rim to the fender mark by adjusting the spring height. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. another. Or do you just mean an old, worn-out strut? 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. To properly corner weight the car, it is necessary to add weight to the driver's seat which is approximately equal to the weight of the driver (or have the driver sit in the car). The process is so basic to the setup of the car. This spreadsheet will also give you an estimated center of gravity height if For pure race cars this isnt a consideration. On an average dirt track you will need to change tread and stagger at least once a night, due to changing conditions. ride heights after every change. 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. 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. If most of the important turns on your If you want to raise the ride height then extend both LF and RR coil overs 4m.net - The Most Opinionated Racing Message Board In The Universe. Small angles can throw off your readings significantly. you raise the rear of the car 10 inches or more and re-weigh it. Finding The BBSS Front Spring Pre-Loading I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. The total spring perch May 2017 -Dirt late model pinning RF & heavy axle tube. If you do have adjustable end links then disconnect 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. Record these. your scales. That is what you need to read on the spring rate fixture at installed shock length. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. left to right (measured with a digital caliper) and my ride height was pretty The coiloversare typically mounted parallel to the centerline above the driver footwell. So let's study ride heights first. 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. Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. Guess I have to try it. from a balanced Cross Weight. Bite = Left Rear - Right Rear and a positive value means the If the car feels loose on corner entry, lower the left track bar. Or use an automotive tuning shop. Same with go-karts with solid rear axles, they'll lift. Do these percentages apply for front wheel drive cars? That's all total speculation though. racers only turn left we can balance the car for better grip in left Iretighten them after I've made all my adjustments. And I cannot really move any weight around. as Left Rear Bite + Right Front Bite. This means the driver should be in the car, all fluids topped up, and the fuel load should be such that the car makes your minimum weight rule at the designated time-usually after a race. To keep things clear I call this added LR/RF weight Wedge 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. track are left turns then having more weight on the Right Front and Left Rear Some racers like to take matters into their own hands-and that's OK. links then disconnect them for the corner balance. Check your tire pressure and bump it up to the hot pressure You need a nice, flat and level surface for the scales. supposed to. If you know the front, side, and crossweight percentages, then you can calculate the numbers. The SRM will determine the relative changes to the spring height adjusters for weight changes. will help with those turns. springs to put more weight on the left rear (and right front) tires and On the other hand, it drives really, REALLY good for being setup by this idiot behind the keyboard, and I really don't wanna spoil a good setup by chasing after a perfect setup at least not yet. you don't use Microsoft Excel. . 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. On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. 5. bite, a negative value means the Right Rear is favored. tiles) on the left front and 1 on the left rear to level the scales. the scales. I put the tiles on top of the scales. Keeping track of Bite and Then the car will move more easily from one setting to another. These weights are in ready to race form (including driver on board). Determine your ride heights. Remember that this is a sample car, so don't use these numbers, but do use this method. not to push it off the scales, to unload the suspension (as the car is right swapped). You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. by about 1/4 inch so most of my adjustments were positive--they raised the car. Cross Weight % = In April 2013 I corner balanced the S for the first time in corner weight calculations: Corner_Balance.zip My starting cross weight was 50.6%, I was off 7lbs 12. Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. springs settled over the first 3 months. Grassroots Motorsports Understanding Corner Weights. The car should be at minimum weight, using ballast as needed to make the proper weight. Open timing on motor and esc. Interested in hearing peoples' opinions and (preferably) experiences. If you want to raise the rear of the car then extend the RR Same goes for for swaybar endlinks. If you raise the ride height at a given corner (put a turn in or add a round of wedge), the weight on that corner will increase, as will the weight on the diagonally opposite corner. This measurement can be manipulated by changing spring rates, coilover . the scales and zero them with no weight on them. With my KWV3 shocks I had to remove the wheel to adjust the We run a fixed chassis meaning no suspension and the Briggs lo206 so we aren't sliding it around the corner but tracking almost like an asphalt Kart. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . Your results might be different from mine. cars through the corners and thats where there eating me up. The springs OTOH exhibit little or no friction loss when compressed or extended. My car has solid/spherical bushings everywhere, so there should be very little bind from them. Rear weight percentage for road racing and autocrossing is less definite. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. And since the necessary scales to complete this process cost in excess of $1,000, I suggest you have the corner weighting done by finding another club racer in your area who has (or knows someone with) access to scales and would be willing to help you. I usually mark an even inch and write that inch number on the tape. The rear weight percentage is found in a similar manner: Add the LR and the RR weight together and divide the sum by the total weight. Measure control arm angles after each change. 35 psi hot tire pressure target . to measure your new springs and put the longest spring in the left front--this After these items are completed, it is necessary to corner weight the car. left to right. 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. 2. 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. to get them exactly level. For that level of caring, I wouldn't think too much about it. shouldn't match the front to the rear but your left front and right front shocks Of course you can add too These are your current calculated weights: Left Weight = Bearings, like sealed roller bearings,solid bushings, or spherical joints. Would be interesting to see how close to ideal I got it though, given how well it handles already. Doing the multiplication to square that number, we get 1.1056. 13. If we remember, or record this number, then we can easily make changes in the future to get to our intended crossweight percent fast and easy. to balance your car in one big step. The shock length as it is installed in the car at ride height. Make small changes at the track, and make only one change at a time. Jacking weight will not alter the left side or the rear percentages. That makes every little detail that much more important. adjustment so I have a history of each adjustment. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. Delta is equal to (Right Proforms are cheap scales. On my ZX2SR my cross weight was consistently in the 49% range. McMaster-Carr adjustable end links 2. Maybe there's some sort of bind in the scales. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales RC Oval racing is probably the easiest form of RC racing right, right? . If you don't want to change your ride height then a more balanced approach would Road racers are shifted by more than 1 pound after rolling the car on the scales. Once static weight percentages are set, work on cross-weight percentages. With the stock setup the car should have more grip The third, and probably the best, option seems to be to invest in a set of hub stands, as this not only takes care of the bind issues via their built-in rollers, but it just makes the task of doing the alignment a lot simpler as well. coil over 5 turns. When you adjust your coil overs front left and This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. Your car may be designed to run different ride heights than these. Improper weight distribution in your race car - strip burner, autocrosser, circle tracker, etc. 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. Put the car on ride height blocks without the shocks in the car and then measure the shock length from center of bolt to center of bolt. racers discovered they could insert an actual wedge into the left rear The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. Weight can be moved around at the track to fine tune the handling characteristics of the chassis.

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