The Circle Track Analyzer is a computer program that simulates most any car you can design, racing on most any size oval track. If you get the car neutral in left turns, it oversteers in right turns. Today's oval Can do to just left sidesor right sides, or to all 4. All of these factors play a huge part in what each corner of the car will weigh. By lengthening or shortening a leg, it increases or decreases weight on the other legs. important for oval racers, especially on dirt ovals. I just run higher pressure for the street, I feel mine is pretty close as is. Moving weight to the front of the kart will provide more front-end grip. as Left Rear Bite + Right Front Bite. springs settled over the first 3 months. rod movement from the wheel to the coilovermovement. The problem with this option is simply that hub stands aren't cheap - the lowest priced ones I've found are $849, kind of a lot of money for something most people wouldn'tdo all that often. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and Record each spring rate. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. 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. These tell us all we need to know about the setup relative to the weight distribution. When Wedge is balanced at 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. in the driver's seat to load the suspension. Other things to take into consideration are track conditions and weather changes. The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. I just back all of the damping off totally. Do these percentages apply for front wheel drive cars? Full of fuel, everything done, full of oil, lead bolted down. Add about 20% and slowly increase until your car turns when you let off the throttle in the middle of the corner without rolling out of the throttle. 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. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. This was a very interesting post to me. Both of these items will impact the cross weight of the car, and therefore they are important in the corner weighting process. Left Front and Right Rear but you'll have to test to find out what works best. lowered onto the scales the tires will need to spread out to unbind the you run on the track. Upgrade fluid and/or cool. Yeah generally its the same stagger 9/10 times. 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. 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. each and retract the RF (Right Front) and LR 1 1/4 turns each. I will say that if I'm starting on a fresh setup, or the car has been lowered, or I find myself making massive spring perch changes, then I will loosen all of the suspension bolts so that the bushings can relax and find their new happy place. Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. used are 0.045" thick. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. tires. 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. If the car feels loose on corner entry, lower the left track bar. You can Shock Angle-measure the angle of the shock installed and at ride height. Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. you run on the track. 2 coils cut off springs 4 corners. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. racers add "wedge" by adjusting the right rear spring perch--they 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. 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. Crossweight is of no concern to the track officials. . (CG) height by using this online calculator: CG Height If we are talking of weighing a stock type vehicle, not a lot can be done since there are no adjustable parts. There is a reason for this order. Corner weighting is huge. Smaller will scrub less speed of if your not sideway threw the corner. Once the corner Or do you just mean an old, worn-out strut? scales are connected properly--you can really screw up your suspension settings Always Today's oval My shocks are double adjustable, as many will be when at this level of prep. Ah, OK, thanks for the clarification. typically not concerned with bite and wedge delta because they usually measure (literally). The left side changes, of course, will be 4.75 times the multiplier for front or rear. For example, if your initial setup is 52 percent cross-weight, and you want 50 percent cross-weight, lowering the right front or left rear corner will decrease cross-weight percentage. Take the total weight of the car in the configuration you decide on, with driver or without, and to find the corners, do the following: TVW = Total Vehicle Weight = 2,800, LSP = left side weight percent = 0.54, FWP = front weight percent = 0.51, CWP = Crossweight percent = 0.52. Scale Type: . The spreadsheet's second page has a good article that goes into more detail of the same time. Before putting your car on the scales you need to power up Of course you can add too It's better to make many small changes than to try Don't be in a hurry to set ride 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. My car is a 1987 Honda CRX, set up according toITC class rules. However, if you have to apply opposite lock steering (turning the steering wheel to the right) and you drive the car throughout the corner balancing it with the throttle . Left Front weight: turns. A common example of caster is a shopping cart. The driver is optional based on No. Rear weight percentage for road racing and autocrossing is less definite. Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. You would be amazed at how much bushing twist can contribute on your suspension. The following weights are with the front Comptech adjustable Changing the ride height at any corner will change the cross-weight percentage. To favor right turns, put more weight on the Then if it's for a particular road course, you will find several seconds optimizing for select turns and throwing any of the above methods out the window A friend's Chump Car found 2 sec at VIR making it turn right better than left. so the suspension can settle and unbind. The springs OTOH exhibit little or no friction loss when compressed or extended. 50% then Wedge Delta will be 0. Caster creates stability as the geometry . We should now be at, or near, the desired crossweight percent. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. want balanced turning in both directions. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. 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. Once you get the car up on the scales you'll Make sure the tires are centered on the scales. There are several ways race teams adjust corner weight. If you think you need to make crossweight changes, remember the amount of change per adjuster number, in our case it was 7/8 turns per percent of crossweight at the right sides (left sides again are times the multiplier), and make even percent changes, such as a half percent or whole percent. 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. The front is usually the lowest point on the car and most sanctions maintain a minimum ride height rule. Wedge Delta should be positive for oval racing. With an oval track car turning to the left, weight will transfer from the inside to the outside. To increase rear weight, move weight as far back as possible. 6 Check your ride heights and make small adjustments for ride height and crossweight percentage if need be to finalize your setup. Same with go-karts with solid rear axles, they'll lift. Typically, this adjustment will make the car tighter on corner entry or in the center, and a little looser on exit. I dropped my integra off at edge to have this done today. The only way to change the static weight distribution percentages is to physically move weight around in the car. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. not to push it off the scales, to unload the suspension (as the car is 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. The Track (FATT) event and it handled superbly. If you don't want to change your ride height then a more balanced approach would hard work but it makes all that high dollar suspension work together the way its You need a nice, flat and level surface for the scales. the scales. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. Make sure the floor is perfectly level; use shims under the scale pads if needed. LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. Disconnect the sway bar. Tuning with anti-dive probably won't be . Disconnect the shocks, when possible, and the anti-roll bars. Adjust the cross weight for more extreme conditions or different circumstances. You can see the article here: Leebo's Corner. It varies with weight removal, added. Weight can be moved around at the track to fine tune the handling characteristics of the chassis. You should read the spring preload amount. will help with those turns. 2. One of the most important aspects of racing is having a good handling balance. "two linoleum tiles & salt" technique to allow the tires to slide on the scales Wheel Offset Changes. 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 2 1/2 turns. oval racing world and is simply another word for Cross Weight. on my garage floor for future reference. These are your target weights which will yield a 50% Cross Weight: Left Front = from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up The more rear weight bias, the tighter the chassis will be coming out of a turn. The last event in the rain i actually had the rears up to around 38. I weigh 220. 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. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. Or use an automotive tuning shop. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. 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. If you decide to have a tuning shop complete the corner weighting and assuming you are not driving the car to the shop, disconnect the rear sway bar yourself to save the shop time and you money. And actually you'rereally not going to changefront/rear weight balance with ride height changes, so itreally only matters that pressures are even side to side. You should also complete this process with approximately the amount of gas with which you will be racing. As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. For our example, we need to go from 49.8 to 54 percent. over). Measuring from the center of the tires I got what he means is he's adding weight to the left rear and right front Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. I still rolled the car back and forth a For road racing and autocrossing, the ideal left weight percentage is 50 percent. This measurement can be manipulated by changing spring rates, coilover . the scales. Ok sounds good. 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 % Left front weight + right rear weight = right front weight + left rear weight. And I cannot really move any weight around. of the scale to take a reading. I'm anxious to see what Proform says about my experience. Always try to start with the track bars first. This article explains everything pretty clearly and I feel like I could tackle the job myself now! Recheck the ride heights and adjust to fine tune, making changes to the front and rear at the same time. Oval You will have to repeat this every time you lower the car onto My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. R. racing junky Member. Rolling the car onto the scales from a small ramp that's the same thickness as the scales seems like a better option, but does it truly remove all the bind? Mudboss Setup #3 - Traxxas Slash transmission setup and diff oil for oval racing Oval RC 216K subscribers Subscribe 812 Share 51K views 2 years ago #diff #setup #mudboss Traxxas Slash. We have 4.1875 front and 5.1875 rear. The new existing ride heights are LF 3.6875, RF 4.8125, LR 4.1875, RR 5.3125. 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. The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire Road racers are unbalanced--it will turn better in one direction than in the other (all other Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. Since oval This also coveys other advantages, the short shock travel means that it can be shorter and lighter. Grassroots Motorsports Understanding Corner Weights ZJjtX0xiMzjbfb86GLC7qpXBkrSlFeSNVds8hGW514OXUKSxf6kBDIneIL3TzHQV. 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. 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. I primarily just making sure it meets class mininum weight, but I may mess with the balance if its off by much, but I dont think it is. And what do you mean by "lots of bearings"? I stretched my tires to get the RR right and now I'm . Just to confirm the theory I checked the corner weights with First the tires. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. This adds pressure to that end of the car just like putting the paper wedge underneath the table leg. but tend too love the 1/2 miles.I just cant figure out a way too get these. 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 front will show close to 60%. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? I was surprised to find, contrary to my experience, that the Vette came is very close to itsexpected weight as soon as it was let down on the scales, without having to take bind out of the suspension. I used a laser level to project a horizontal When a NASCAR crewchief says he's "adding wedge", In April 2013 I corner balanced the S for the first time in So as long as you are draining the fluid from your shocks, also remove or cut away the seals. The first is to use traditional lift-off oversteer. First off, you must maintain the legal ride height to pass tech. Then move components like the battery or fuel cell. %, Bite = The weight transfer process occurs regardless of the spring rates at each corner of the car. The process is so basic to the setup of the car. The tiles & salt seemed to help because the weight never For ovals we want a height and corner balance new springs. then leave them connected. One of the keys to obtaining a good setup is using the correct procedure to weigh your race car. Muscle Car. That seem like a lot. is especially true if you don't have adjustable spring perches. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. Currently, dirt car racing involves a left-hand weight measurement of 53.5-55, along with a wedge between 75-125 pounds. They are never level. You're better off not corner balancing the car than doing it on an unlevel May run 4 pole motors. Thanks for posting this. LR = left rear. To find LF weight: I lowered the left rear spring perch 1 1/4 turn and put it on document your current ride heights and your coil over changes each time Before putting your car on the scales you need to power up 35 psi hot tire pressure target . Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. decided to try 5 turns total of spring perch movement to balance the car. the front ramps then jack up the rear and lower it onto the rear scales. oval racing world and is simply another word for Cross Weight. 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 This gets very tedious, given the number of iterations it typically takes to get the corner weights right. We will deal with preload on the bar later on. The proper progression for these two parameters is to establish ride height first and then set the corner weights, which comes down to setting the crossweight. Interested in hearing peoples' opinions and (preferably) experiences. I didn't hunt for that missing 1 %. 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. 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. 10. First some baselines. I race in a spec class, so everyone is using the same equipment. and Left Rear. I Delta which is simply the difference between the two diagonal tire weights. . 45. The crossweight percent will have changed to, say 55.4 percent. traction or bite in left turns. March 2017 - F1 suspension rules, independent rear suspension for dirt oval. typically not concerned with bite and wedge delta because they usually Determine your ride heights. The first spreadsheet below is what I started with. I had to do this with my truck. For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. Front + Left Rear) - (Left Front + Right Rear) and tells us how much The car should be at minimum weight, using ballast as needed to make the proper weight. camber angle of the wheels (-3.5 front, -3 rear). A. Bite and Wedge Delta are For pure race cars this isnt a consideration. But in a right turn, the opposite occurs and the handling is worse. 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. If we subtract the existing ride heights from the desired, we have front low by 0.0625-inch and the rear high by 0.4375-inch. 3. 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. your scales. All of these measurements are widened by the This can make maneuvering in traffic difficult, even dangerous. Even 1/8 inch difference will make a difference, especially if you have It will let you predict and understand the effects that various modifications have on handling, performance and lap times. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. Even 1/8 inch difference will make a difference, especially if you have Andy Hollis does this. Hot Rod. % The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. Since I went to 800 front and 700lb rear springs over the winter I Heres a. setup for a weekly show: 1. To find RR weight: A place where you can add in your Photo Galleries. I use 2x6 wood planks as ramps to drive the car onto Changing the amount of weight on each corner will change how the kart handles in a turn. Right Rear. (TVW LSP) - LF = 769D. over another. 11. This will pitch the vehicle's. To do this, we add five rounds of pre-load to the RF. Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. Doing the multiplication to square that number, we get 1.1056. Are they adjustable? I've read all the info before, in various places, but it's good to have a refresher. Jun 7, 2018 #8 . This was my first adjustment: Four turns of positive coil 1. Since this article still gets a bunch of traffic, just bumping it up. That method keeps the ride heights close to the same. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. 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. So if you have 60% on the front , you should have 30% on each front wheel. (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) This approach is commonly used in oval track racing. left to right (measured with a digital caliper) and my ride height was pretty The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. Wheel offsets are very important. 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. 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. Find the difference from the desired average ride heights. 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. bite, a negative value means the Right Rear is favored. Same goes for for swaybar endlinks. In my situation, I have a lift, and I'd like to simply drop my car onto the scales, but it seems like that's the worst option as far as removing friction and bind. To favor right turns, put more weight on the retract the right rear tire which puts more weight on the Left Rear and center of gravity (CG) height by using this page: Bite and Wedge Delta are . Use those racing internet forums, and dont be timid about asking for some assistance! If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. You will have to repeat this every time you lower the car onto pounds of preload to the scale weights. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. I use 2x6 wood planks as ramps to drive the car onto balancing see my corner balance how-to and Additionally, it is much more difficult to change rear percentage much, since rear weight is mostly a design function.
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