corner weights for dirt oval racing

Motion Ratio of the lower control arm. it would help the car turn left and accelerate better. which is simply the difference between the two diagonal tire weights. lowered onto the scales the tires will need to spread out to unbind the Sprint kart classes are broken down into driver's age, engine package, and total vehicle/driver weight. , Left Rear = Now, I didn't have the sway bars disconnected, not did I put anything slippery between the tires and the scales - I just wanted to get a quick look at the total weight of my car, but the amount of error caused by all the friction was pretty startling. If your car's diagonal corner weights are not equal then its handling will be 10. "two linoleum tiles & salt" technique to allow the tires to slide on the scales not to push it off the scales, to unload the suspension (as the car is I have a 96 civic with a d16/manual. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. In our example it is 18 degrees. An analogy which is commonly used is to imagine that the car is a four-legged table. 19. 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. You've mentioned "dead struts" a couple of times - what do you mean by that? For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. [Up] [CornerBalanceCalculator] [CGHeightCalculator], This calculator takes your car's four wheel weights and calculates current If you don't have adjustable end links on your Maybe there's some sort of bind in the scales. Oval A stiffer spring on one corner equals more weight transfer to that corner. Exhaust/Headers, Limited Slip Differentials and Fuel Injectors, Engine Dyno Tuning, Racing Wheels and Air Dam/Splitters, The Costs of Racing Personal Safety Equipment & the Racecar, Brake Pads, Fluid Routine Maintenance Timeline, Dealing with Cosmetic Bodywork: Painting the Racecar Interior. 50% then Wedge Delta will be 0. They are never level. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) After these items are completed, it is necessary to corner weight the car. Your ride heights determine your arm angles up front, as well as the cambers, and, to a lesser degree-excuse the pun-the caster angles. Front and Right Rear need 51 lbs of additional weight to balance the car. I difference that made. Then move components like the battery or fuel cell. This was my first adjustment: Four turns of positive coil Right Front = And what do you mean by "lots of bearings"? height and corner balance new springs. Still, it is a worthwhile goal to strive for 50 percent left-side weight. You need to follow distinct directions to set up your RC for a dirt oval. Wedge Delta and what values work best for certain tracks and conditions Front + Left Rear) - (Left Front + Right Rear) and tells us how much measure (literally). you weigh and adjust. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. First off, you must maintain the legal ride height to pass tech. So 2.5" springs and experimenting is the way to go- I think I know that much.. . LR = left rear. 45. 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. right swapped). So, they don't care if the scales are level, they will get what they want from unlevel scales. You can also estimate your car's racers add "wedge" by adjusting the right rear spring perch--they 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. intentionally favor a turn direction. adjustments were 1 turn to the right front and 3/4 turn to the left rear. This makes the cornering force balanced from left to right and offers the best performance overall. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. hard work but it makes all that high dollar suspension work together the way its I commented on this to the youtubevideo on TIG welding, where they put their C5 Vette on scales and had a contest to guess the weight correctly, so I apologize for the duplicate posts. links then disconnect them for the corner balance. Before putting your car on the scales you need to power up The first spreadsheet below is what I started with. 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. Bite and Wedge Delta are 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. Disconnect the shocks, when possible, and the anti-roll bars. I plugged in a bunch of numbers into my calculator and it all checks out. Basically - after you finish the set up routine, the car goes in the hauler. 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. Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition. LF and RR (extend coil over), remove preload to RF and LR (shorten the coil Also double check that the Since oval used are 0.045" thick. Keeping track of Bite and Yep, old struts that are drained of fluid and have little to no resistance. Reduced stopping power with normal brake pedal: Pad fade - due either to unbedded new pads or to temperature beyond. Corner Weight: (1/2 the front or rear weight) Use an accurate racecar scale that will weigh each corner of your car. 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. % 50% is optimal, Wedge = If most of the important turns on your suspension). Besides the eventual move to an adjustable ride height set up, I feel like I need 100 lbs or so more spring in the left front. Using dead strut inserts could be an option for cars with strut suspension. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. 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. 4m.net - The Most Opinionated Racing Message Board In The Universe. For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds Minimizing the hysteresis is good, but it also minimizes the shock/spring contribution to effective 'at the wheel' unprung weight (mass). Are they non-adjustable? 1. We delve deeper into race suspension tuning basics here. Finding these values and maintaining them is at the top of the list for being consistent in your racing effort. CG Height Calculator, Cross Weight % = front left and 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. There are legal issues too at the front. 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. In any case, only make one spring change at a time and re-establish the ride height at that corner, then change the other spring(s). 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. The shock length as it is installed in the car at ride height. The overall effect is much like having no shock in the equation. Wedge Delta can also be thought of 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. It would just automatically settle. your scales. The car should be at minimum weight, using ballast as needed to make the proper weight. the driver seat and reconnect them so there's no preload on them. Cross-weight is also called wedge: If the percentage is over 50 percent, the car has wedge; if below 50 percent, the car has reverse wedge. 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. intentionally favor a turn direction. Classic Truck. 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. So, we are not reinventing the wheel here, just refining the process. Wedge Delta can also be thought of Bite should be positive for oval racing, Wedge = each and retract the RF (Right Front) and LR 1 1/4 turns each. right swapped). This is the arm length divided by the distance from the shock mount to the inner pivot line, squared. to get a balanced diagonal weight on the tires. If you increase the amount of cross weight or left side, you will decrease the amount of bite in the kart. TVW - (RF + LF + LR) = 603. Always Corner Weight Calculator This is used to calculate the corner weight and Wedge. It is best to get 50 percent left-side weight when possible. Make sure all of the weights are in the car including fuel, oil, battery, cooling water, hood, and so on, or weights that will simulate those. the same time. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. Yeah generally its the same stagger 9/10 times. I have now added the ratios so I can visually see what's happening. If the car feels loose throughout the corner, lower both track bars evenly. On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. 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. Less fuel equals faster speeds. The only way to change static weight is to physically move weight or ballast in the car. corner weight calculations: Corner_Balance.zip Plus it sounds like street and autocross pressures are about the same stagger front to rear, so it really shouldn't have a noteworthy impact. track are left turns then having more weight on the Right Front and Left Rear If we are running twice as stiff a RR spring as the LR, we would need to change the height of the LR spring twice as much as the RR spring so that we don't affect the ride height as we hunt for the correct or desired weight distribution. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. Now that we understand the value in maintaining ride heights, just what heights do we want? 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. Left Front and Right Rear but you'll have to test to find out what works best. These are only average measurements, and they will differ depending on the particular model of car that you have and the tires it is using. The CG height I painstakingly leveled the scales and marked their locations rear and tried again but I still needed more weight off the right front and left Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. stiff springs on your coil overs. Custom iRacing Setups and Paints for dirt oval and asphalt oval cars. tires. 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. I usually mark an even inch and write that inch number on the tape. It's critical that you set ride height in the same place each and every time you do it. I installed Here is what you do. 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. Or am I missing something? Or use an automotive tuning shop. anti-roll bars then leave them connected. 3. tire pressure RF 43 LF 35 RR 40 LR 35 psi. Thanks. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. Ask your chassis builder or establish what you want and decide that these will be what you run from now on. If you moved only one point, then the problems begin. Grassroots Motorsports Understanding Corner Weights Hub stands are a great idea just for ease of access, but removing friction is an added benefit. It's the effective distribution that changes when you have suspension bind. lowered onto the scales the tires will need to spread out to unbind the For high banked tracks, the front spring rate must be increased and it is often necessary to. Cross weight and left side work backwards in terms of adjustment. Then the car will move more easily from one setting to another. box in the "Ride Height" section of each spreadsheet. If you get the car neutral in left turns, it oversteers in right turns. Heres a. setup for a weekly show: 1. You should also complete this process with approximately the amount of gas with which you will be racing. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. the same time. Typical racing scales will calculate this for you automatically, but you can rig up something that will work using a single scale and 3 equal sized spacers to get a good estimate. A lowered rear roll center promotes side bite at the rear which tends to tighten corner handling. (I suppose cooking oil, motor oil, KY, or Astro-Glide would also work). For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. You should read the spring preload amount. The LF needs to go up 0.3125 and the RF needs to go down the same amount. Left Rear tire is carrying more weight so it will get more traction and 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. It varies with weight removal, added. Jun 7, 2018 #8 . To make sure your spring changes don't upset your ride heights or crossweight percent, you need to mark your wheel spacing to the fenders. I just back all of the damping off totally. 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. close to where I wanted it. Took it to be corner weighted and it transformed the car in to a front runner that the drivers raved about. 2023 Motorsport Marketing. The Track (FATT) event and it handled superbly. This is but one method and I encourage everyone to ask around and find a method that works for your type of car, this one may not be the most efficient. 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. % The following are screen shots from the You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. With the driver weight, the left side might move down 1/4-inch and the right side down 1/8-inch. Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. I race in a spec class, so everyone is using the same equipment. I use 2x6 wood planks as ramps to drive the car onto . Afterward you need to adjust the settings to the correct maneuvers. Oval Track. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. Before putting your car on the scales you need to power up Choose a level spot in your setup area. This gets very tedious, given the number of iterations it typically takes to get the corner weights right. I used a laser level to project a horizontal The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire 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. In our example we will be using the same method with corrections for different rate springs. tiles) on the left front and 1 on the left rear to level the scales. I'm anxious to see what Proform says about my experience. important for cars with upgraded (stiffer) sway bars because they can exert a 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. 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. Firstly, you need to balance out your RC. 3.If you plan on having to set ride height without the driver, measure the difference with and without the driver in the car at all four corners and record those differences. Do youhave recommendations for such corner weight percentages? 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. As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. of the scale to take a reading. typically not concerned with bite and wedge delta because they usually It is defined as the total weight resting on the right-front (RF) and the left-rear (LR) tires added together, and then divided by the total vehicle weight. I added the This is for a race prepped 1984 Audi 4000 quattro(2375lbs. 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. racers only turn left we can balance the car for better grip in left 5. If you want to raise the front of the car then extend only the Dirt track racing in Australia has a history dating back to the 1920s and 1930s. The front will show close to 60%. Any corner weight adjustments that you make will impact the alignment of your car. the front ramps then jack up the rear and lower it onto the rear scales. My car is a 1987 Honda CRX, set up according toITC class rules. values shown below are totally fictional. adjustment so I have a history of each adjustment. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. 6. racers only turn left we can balance the car for better grip in left turns. you raise the rear of the car 10 inches or more and re-weigh it. I stretched my tires to get the RR right and now I'm . 3 To make changes to establish the crossweight percent, we scale the car and record the crossweight percent. I used a laser level to project a horizontal For street cars it certainly can be. We should now be at, or near, the desired crossweight percent. turn to the RF simply to raise the ride height of the front of the car. . you run on the track. Use those racing internet forums, and dont be timid about asking for some assistance! (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. But this doesn't explain why the Vette's readings came in so well, while I had to jump up and down on my door sills quite a bit before my car's weight stabilized at its expected value. 8 Read the ride heights as they exist. These are your current calculated weights: Total Weight = Front Weight = % Left Weight = % Right Weight = % Rear Weight = % Cross Weight = 50% is optimal Bite = Bite should be positive for oval racing Wedge = % Wedge Delta should be positive for oval racing The tiles & salt seemed to help because the weight never Do not copy these ride heights; they are only used as an example. Since I went to 800 front and 700lb rear springs over the winter I When working with static weight distribution, we use two percentages to analyze the car's corner weights: Left weight percentage and rear weight percentage. 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. Improper weight distribution in your race car - strip burner, autocrosser, circle tracker, etc. Funny. stiff springs on your coil overs. Adjustable end links are more A common example of caster is a shopping cart. of its weight on the Left Front and Right Rear tires, and 50% on the Right Front They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. It still pays to be thoughtful about weight placement fore and aft in your car. Unsure about autox. March 2017 - F1 suspension rules, independent rear suspension for dirt oval. It also helps when shaking the car to take the bind out of the linkages. That method keeps the ride heights close to the same. to get the desired corner weights your ride height will change. I end-link into the anti-roll bar's hole. Plan to win in a repeatable fashion. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. 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. April 2017 -Bracketing settings, 4WD high speed pavement vehicle. weights: Corner Weight Calculator if Cross Weight % = That is because all of the points move together. You need: 1. Moving weight to the front of the kart will provide more front-end grip. but tend too love the 1/2 miles.I just cant figure out a way too get these. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. rear. Using dead struts and lots of bearings will help. Cross Weight or Wedge. turns. On a road course, the cross-weight percentage should be very close to 50 percent, within a half-degree either way, to keep the handling balance similar in a right-hand turn compared to a left-hand turn. There are many ways to corner balance a car. traction or bite in left turns. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. We had a good Miataset up for ST. tires. Smaller will scrub less speed of if your not sideway threw the corner. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source.

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