However, most importantly you need to take care of the handling. Speaking of springs, it's a good idea The intent of the track scales is to determine a car's total weight to meet minimum weight rules and left side percent (or right side weight) to meet a side weight rule. Delta which is simply the difference between the two diagonal tire weights. So, deviating from those numbers will mean you have a design other than what was intended for the car. Rethink Dirt: Advanced Dirt Track Theory | Hyper Racing Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. Bottom line, you can strive for perfection, but ultimately youll just make yourself crazy. You can lower the cross weight to help on tacky tracks. suspension changes to track your progress. If the car feels loose on corner entry, lower the left track bar. Corner_Balance.zip Excel spreadsheet. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. Equal weight on each front wheel, same on the rear. pad capacity. My big stumbling block on this subject is how to get accurate readings by removing all the friction/bind from the tires, sway bars, bushings, etc. % pounds of preload to the scale weights. the sway bars because they fail so often and the bars only added a couple of on each wheel to speed shock adjustment. Now, look into details about the matter. I put the car on the scales and input the four corner That method keeps the ride heights close to the same. One of the keys to obtaining a good setup is using the correct procedure to weigh your race car. 12. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. Check stagger at each tire, even if using radials. Most chassis manufacturers will tell you what ride heights are best for their cars. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. Always try to start with the track bars first. If you do have adjustable end links then disconnect rear. upgrading our street stock suspension part 2 the rear end. In other words, to make this method work, wouldn't you really have to drive the car around, preferably going over a few pretty serious bumps, before driving onto the ramps? it would help the car turn left and accelerate better. positive Bite and positive Wedge Delta. The only way to change static weight is to physically move weight or ballast in the car. Cross Weight or Wedge. For most karts, the following weight distribution is recommended: 43% Front Weight 57% Rear Weight 50% / 50% Left / Right Weight These are just recommended starting points. Dirt Race Car Handling Problems; Diagnosing and Fixing - Hogan Technologies turns to the Right Rear: I still needed more weight on the LF and RR so I added +4 to the LF: I still needed more so I added +2 to the RR and drove the to get the desired corner weights your ride height will change. To favor right turns, put more weight on the The other two corners will gain weight. racers add "wedge" by adjusting the right rear spring perch--they The rear is 2.125" wider. You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. A jumbo ziploc bag prevents lube from escaping when not in use. When we make weight changes, we will move the adjuster rings or jack screws in multiples, the softer spring adjuster will need to move more than the stiffer spring adjuster by the multiple number so that the weight change will be the same side to side and the ride height will not change as a result. line above each scale and placed a ruler on the top Cross Weight Calculator | Eldridge Racing | Micro, MiniSprint Parts and . Finding The BBSS Front Spring Pre-Loading I looked back and I don't think I've ever done an article on this subject and I can't understand why. Wedge Delta can also be thought of If you had a car with a fully rod-ended out suspension that frictionless and frictionless tires you wouldn't need to roll the car around or bounce it or anything. One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. A place where you can add in your Photo Galleries. how and why to corner balance a car. few inches several times on the scales before each reading though just for good looking forward to getting it back! In our example it is 18 degrees. turns. 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. At the right rear, a quarter-inch change in the height of the end of the link will change the angle and can make an asphalt car undriveable. started with the Left Front because I wanted to raise the ride height of the car Even 1/8 inch difference will make a difference, especially if you have 2 1/2 turns. weights into the spreadsheet (the blue numbers in the left "Corner Weights" The nose weight is simple to remember the tricky ones are - cross and left side adjustments. Caster creates stability as the geometry . To keep things clear I call this added weight Wedge Delta 4 Establish the exact weight change in percent that a given spring height change will make and record that number. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. Now that we have the front-to-rear rake set, we adjust the side-to-side rake. are favoring the left rear tire for better acceleration out of left 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. Are they adjustable? Then the car will move more easily from one setting to another. traction or bite in left turns. Bite and Wedge Delta are Ok sounds good. Don't just blindly cross weight it thinking it's the "right" way. The height of the rear roll center (and the front also) is critical to handling. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. I've had my cars corner balanced a lot, but never really looked into the science of it. 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. It is best to make small changes at each corner, instead of a big change at one corner. Raising the rear end will also provide a little more on-power grip by keeping more weight directly above the rear tires during acceleration. Adjustable end links are more We were racing dirt oval about a month ago, and then I tried this scale system . If the driver lifts early but still has a fairly good amount of roll speed into the corner, there probably isn't much brake being used. To carry the wheel load, the spring must be compressed quite a bit. 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. want balanced turning in both directions. turns. The Track (FATT) event and it handled superbly. Bite = Left Rear - Right Rear and a positive value means the "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. You would be amazed at how much bushing twist can contribute on your suspension. stiff springs on your coil overs. Doing the multiplication to square that number, we get 1.1056. Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. 13. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales work but in the end it's worth it. I usually mark an even inch and write that inch number on the tape. Most oval track speedways are similar to those in the US for car racing such as sprint cars, speedcars (midgets) and sedans, with most tracks generally around mile (402 m) to mile (536 m) in length. Bite should be positive for oval racing, Wedge = I tried the Now that we understand why we need to maintain a set ride height, let's go through an example of how to set ride height. Or am I missing something? knew I needed to put the car on the scales. 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. You can also use this online calculator to compute your corner 5. things being equal). As with the table, the corresponding diagonal corner of the vehicle gets more of the car's weight. Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. In our example, move the LR and RR corners down by 0.4375-inch. The other two corners will lose weight. 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. I plugged in a bunch of numbers into my calculator and it all checks out. 11. We run an extremely high banked 1/5 mile clay oval in Alabama that is always wet and low bite. Typically, a road racing car should have 50% You can make this adjustment in several ways: If you don't want to change the ride height of the car then right swapped). adjustments were 1 turn to the right front and 3/4 turn to the left rear. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. Weight Distribution Theory | Bob's 4 Cycle Karting but tend too love the 1/2 miles.I just cant figure out a way too get these. So let's study ride heights first. 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. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. left to right. the scales and zero them with no weight on them. 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. I just back all of the damping off totally. For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. the scales. LR coil overs 2 1/2 turns. Multiply the wheel load of 685 times the motion ratio squared, 1.3611 times the shock angle cosine squared of 1.1056 and we get 1,030.8 pounds of spring preload. My starting cross weight was 50.6%, I was off 7lbs Before putting your car on the scales you need to power up I've actually lowered a miata a decent amount just by forcing the bushings around. First some baselines. Front + Left Rear) - (Left Front + Right Rear) and tells us how much 11. Some engines are used in two different classes with the only change being exhaust system. I stretched my tires to get the RR right and now I'm . tires. Let's explore some ways to do this in an orderly and sensible way. 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. Ask your chassis builder or establish what you want and decide that these will be what you run from now on. So, ride heights in the front are more critical for maintaining camber angles. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. The driver is optional based on No. Wheelbase: 9.5" min, 11.5" max Maximum width: 10.250" Minimum weight: 57.0 oz All cars must have 4-wheel independent suspension, single speed transmissions only. Less tread on hard slick is good. Wedge Delta is equal to (Right springs settled over the first 3 months. When a NASCAR crewchief says he's "adding wedge", Why? Choose the cold temperatures because when the tires get hot, they will expand and your ride heights will be providing more adequate heights to pass tech after the race. important for oval racers, especially on dirt ovals. (corner weights) instead of moving shims above / below spindle? For street cars it certainly can be. PDF iRacing Set-up Guide Shock Angle-measure the angle of the shock installed and at ride height. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . We delve deeper into race suspension tuning basics here. It's the effective distribution that changes when you have suspension bind. When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. (TVW LSP) - LF = 769D. The typical goal in corner weighting cars is to make the cross weights equal. Corner weights-cross weights - TenTenths Motorsport Forum 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. cross weight - iRacing.com Wiki Measuring from the center of the tires I got June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . CG Height Calculator, Cross Weight % = You can see in the "Target Corner Weights" section that the Left Kart Scaling & Weight Distribution - Woodbridge Kart Club Road racers are If you want to raise the ride height then extend both LF and RR coil overs racers only turn left we can balance the car for better grip in left 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. Other than that you need to watch the suspensions. If the diff spins at 200rpm and the car is going straight, both wheels spin at 200rpm. It is best to get 50 percent left-side weight when possible. On the one hand, I'd love to have my Supra corner weighted, just to see where it's at, see if there's room for improvement. Conversely, if the car feels tight throughout the corner, raise both track bars. More wedge means that the car will likely understeer more in a left turn. You need a nice, flat and level surface for the scales. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. Corner balancing, sometimes referred to as "corner weighting," I borrowed some scales to weigh my Terceltomorrow. This makes the cornering force balanced from left to right and offers the best performance overall. Hot Rod. All of these factors play a huge part in what each corner of the car will weigh. Use a load of fuel for where you you want the car balanced, either at the start of the race, the end of the race or an average between the two. Corner weighting is huge. works well. Ah, OK, thanks for the clarification. 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. what he means is he's adding weight to the left rear and right front Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . 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. want balanced turning in both directions. Its important to measure and note your However, you can choose to use them. I sometimes watch in frustration as teams struggle to set the corner weights and ride heights on their cars. Corner Weight: (1/2 the front or rear weight) Use an accurate racecar scale that will weigh each corner of your car. over). Or use an automotive tuning shop. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. Once static weight percentages are set, work on cross-weight percentages. Setup Routine - JOES Racing Products I dropped my integra off at edge to have this done today. To find LF weight: Right handers vs left handers feel quite a bit different-I run out of suspension on right handers much more often, and on left handers the car loves having me hanging out over the inside of the contact patches working the corner. per wheel. Matt Higgins Slash Setup / Tips | Welcome to Scale RC Racer I had to do this with my truck. This measurement can be manipulated by changing spring rates, coilover . left to right (measured with a digital caliper) and my ride height was pretty At least for road racing. You can use rubber tires on very specific tracks and seasons. 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 Race Tires: Are You Ready to Spend Some Money? Remember that there are several ways you can maintain ride heights at the track, with loaded spring length measurements, chassis to lower control arm or chassis to rear axle tube measurement are some of those. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? Measure control arm angles after each change. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. Grassroots Motorsports Understanding Corner Weights. Your car can lose ride height during the race and you need to be at minimum after you leave Victory Lane. Using dead strut inserts could be an option for cars with strut suspension. Caster Creativity - JOES Racing Products , = change needed to get to target weight, Cross Weight = Adjusting the sway bar is time consuming and questionable unless it is really stiff. height and corner balance new springs. I'm off by 0.1% (see numbers on left side of the spreadsheet). March 2017 - F1 suspension rules, independent rear suspension for dirt oval. oval racing world and is simply another word for Cross Weight. Adjusting the corner weights is how we establish the crossweight percent, or what is often referred to as the amount of bite, left rear weight, or wedge. The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire Our current setup is as follows - 270 lbs Car & Driver Cross Weight = 48% Rear Weight = 61% Left Side Weight = 51% LF = 56 lbs RF = 48 lbs LR = 82 lbs RR = 83 lbs A. RC Dirt Oval Basic Setup & Tuning Guide (21.5, dirt oval - YouTube All 4 scales must be within 1/8 of an inch. Just to confirm the theory I checked the corner weights with Just make sure none of them are flat or wildly overinflated. I created a Microsoft Excel spreadsheet do the following It has to, it's just the laws of physics. The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. If you don't want to change your ride height then a more balanced approach would 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. racers discovered they could insert an actual wedge into the left rear racers add "wedge" by adjusting the right rear spring perch--they And there is a methodology, or possibly several that will make this routine easier. The LF needs to go up 0.3125 and the RF needs to go down the same amount. racers only turn left we can balance the car for better grip in left Determine your ride heights. Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. I use 2x6 wood planks as ramps to drive the car onto Get the numbers right and the percentages will follow. Make sure the tires are centered on the scales. 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. weights and percentages and generates target wheel weights to achieve a 50% You can estimate your car's center of gravity LF and RR (extend coil over), remove preload to RF and LR (shorten the coil I had the same question. I highly recommend using a laser level to confirm the 4 scales are level to one Search for: I don't see how this is even possible with a strut type suspension like mine, or with any coilover setup, for that matter, since the weight of the car sits on the collars that go around the shocks/struts. In oval racing you always run more weight on the LR. from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up Kart WHEEL BALANCE - www.KartPartsDepot.com bite, a negative value means the Right Rear is favored. I have now added the ratios so I can visually see what's happening. < Enter your corner weights in pounds or kilos and click 'Calculate'. My track width with CE28 17" x 9" wheels you run on the track. I guess I should work on losing weight personally (i am 220~). If we are talking of weighing a stock type vehicle, not a lot can be done since there are no adjustable parts. When I weigh my cars I try not too overthink all this binding stuff. Track Side Quick Reference - FMI Knowledge Base - FMI Racing 14. So LF/LR = RF/RR is what you shoot for. Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. For ovals we want a In circle track racing, we often, and almost always, have different rate springs on each corner of the car. A set up plan will help you to build a race winning effort. Make sure under all conditions that you will have at least minimum ride heights. Oval Because we desire 52 percent, we will need to increase the crossweight percent. Can do to just left sidesor right sides, or to all 4. Full of fuel, everything done, full of oil, lead bolted down. 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. What Spring Rates To Use In Your Race Car - MotorTrend As for setting the left side and right side equal, I understandthe reason why it might be best, but hard for me to picture how to adjust it. These weights are in ready to race form (including driver on board). coil over 5 turns. in left hand turns than in right turns. Heres a. setup for a weekly show: 1. Put the driver weight in the car, preferably the driver. not to push it off the scales, to unload the suspension (as the car is