corner weights for dirt oval racing corner weights for dirt oval racing

used are 0.045" thick. 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 distance from the ground to an inner suspension arm pivot point will also accomplish the above goal. These are your target weights which will yield a 50% Cross Weight: Left Front = If your car has coil over adjustable shocks you should consider LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. Calculate the spring rate multiples. . The only way to change the static weight distribution percentages is to physically move weight around in the car. 35 psi hot tire pressure target . My starting cross weight was 50.6%, I was off 7lbs the same time. battery (-15lbs), ride height lowered approximately 1 inch, all 4 Bilstein PSS9 coil over 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. , = change needed to get to target weight, Cross Weight = Most people find this out pretty quickly. coil over 5 turns. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. If most of the important turns on your 9. Since I went to 800 front and 700lb rear springs over the winter I Rock or bounce the car helps. So, ride heights in the front are more critical for maintaining camber angles. I just back all of the damping off totally. It's just turning left 2 times per lap. I race in a spec class, so everyone is using the same equipment. In oval racing you always run more weight on the LR. are favoring the left rear tire for better acceleration out of left Adjusting the sway bar is time consuming and questionable unless it is really stiff. 12. looking forward to getting it back! racers only turn left we can balance the car for better grip in left It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. I needed 3 linoleum tiles (0.045" thick However, you can choose to use them. Intercomp SW500 EZ Weigh Scales. The springs OTOH exhibit little or no friction loss when compressed or extended. You can estimate your car's center of gravity not to push it off the scales, to unbind the suspension (as the car is Even on a track with mostly right-hand turns, the problem in the left-hand turns costs a lot of time. It varies with weight removal, added. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. To favor right turns, put more weight on the 1. And I cannot really move any weight around. 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 Right Front = % On oval track cars, cross-weight is usually used in conjunction with stagger (where the right rear tire is larger in circumference than the left rear tire) to balance handling. Corner weighting is huge. 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. tires. For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. Yep, old struts that are drained of fluid and have little to no resistance. I've had my cars corner balanced a lot, but never really looked into the science of it. racers add "wedge" by adjusting the right rear spring perch--they 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. not to push it off the scales, to unload the suspension (as the car is Bite and Wedge Delta are For information on corner much Wedge Delta and make the handling worse. the scales. Always record the cross-weights and ride heights for reference at the race track in case changes are needed. Keeping track of Bite and Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at the same time. another. (adsbygoogle = window.adsbygoogle || []).push({}); If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here [Up] [CornerBalanceCalculator] [CGHeightCalculator], This calculator takes your car's four wheel weights and calculates current Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. To increase left-side weight, move weight as far to the left as possible. after this adjustment we still need to add 39lbs to the Left Front and 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. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. on my garage floor for future reference. line above the scales and then stood on each scale and placed a ruler on the top on each wheel to speed shock adjustment. I see disconnecting the sway bar, and how to do it, but disconnect the shocks? Thanks. If the car understeers or oversteers in only one direction, check the cross-weight percentage. Delta is equal to (Right Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. The last event in the rain i actually had the rears up to around 38. I've read all the info before, in various places, but it's good to have a refresher. track are left turns then having more weight on the Right Front and Left Rear Left front weight + right rear weight = right front weight + left rear weight. Disconnect the sway bar. Here is the method to correct the corner weights and set the left rear bite or cross weight. Check static weight before working on cross-weight. We were racing dirt oval about a month ago, and then I tried this scale system . Adjust the cross weight for more extreme conditions or different circumstances. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. Dirt Late Models. 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. things being equal). can help us get our setup right with less testing. few inches several times on the scales before each reading though just for good Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? R. racing junky Member. Let's explore some ways to do this in an orderly and sensible way. Cross Weight % = important for oval racers, especially on dirt ovals. important for oval racers, especially on dirt ovals. Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. 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. Left Rear tire is carrying more weight so it will get more traction and If you want to lower the rear of the car then retract the LR You would be amazed at how much bushing twist can contribute on your suspension. can help us get our setup right with less testing. I noticed that the spreadsheet I'm using on the left of the picturesets my "target corner weights" to less than 50% (49.6%),why is that? May 2017 -Dirt late model pinning RF & heavy axle tube. I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Left Front weight: what he means is he's adding weight to the left rear and right front Once static weight percentages are set, work on cross-weight percentages. Shock Position 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 When you lower the panhard bar the rear roll center drops. Wedge Delta can also be thought of 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 . hard work but it makes all that high dollar suspension work together the way its intentionally favor a turn direction. TVW - (RF + LF + LR) = 603. In almost all cases, the loss of cornering performance in one direction is greater than the gain in the other direction. The LF needs to go up 0.3125 and the RF needs to go down the same amount. over). unbalanced--it will turn better in one direction than in the other (all other Other than that you need to watch the suspensions. Note the "Conditions and Changes Made" Strive for repeatable and take the measurement as a data point, instead of an absolute. your scales. You're better off not corner balancing the car than doing it on an unlevel But stagger is not a good idea on a road course or autocross either, where the ideal is 50-percent cross-weight and no stagger. I highly recommend using a laser level to confirm the 4 scales are level to one For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. values shown below are totally fictional. The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. So we multiply the difference, or 4.2 percent, by 1.12 and we get 4.7 rounds of right side change to the spring pre-load, or 43/4 rounds. bite, a negative value means the Right Rear is favored. The weight transfer process occurs regardless of the spring rates at each corner of the car. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. scales are connected properly--you can really screw up your suspension settings Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. tires. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales close to where I wanted it. And don't ever believe the track scales. I found that the tire will absorb side loads quite well and was repeatable. . We also take five rounds times the multiplier for the front of 1.25 5 = 6.25 rounds out of the LF. Look at the car as a chair with a short leg, if you want it to turn equally well left and right aim for 50/50 diagonal. Classic Truck. If you want to raise the rear of the car then extend the RR Wedge Delta should be positive for oval racing. Record these. McMaster-Carr adjustable end links Here's how we find the multipliers. Front and Right Rear need 51 lbs of additional weight to balance the car. in left hand turns than in right turns. You can also use this technique when adjusting your alignment and much Wedge Delta and make the handling worse. Bite and Wedge Delta are to measure your new springs and put the longest spring in the left front--this Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . They are never level. 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. There are several ways race teams adjust corner weight. In our example it is 18 degrees. Forum Actions: Forum Statistics: Threads: 167; Posts: 1,367; Last Post: . Wedge is a term used in the Once you get the car up on the scales you'll If one leg is longer or shorter than the others, the table will rock and thus be unstable. Make small changes at the track, and make only one change at a time. Example: RF = 643, LR = 751, so, (643 + 751) 2,800 = 0.498, or 49.8 percent. Calculator, I used these scales to weigh the car: To find RF weight: links then disconnect them for the corner balance. 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. With the driver weight, the left side might move down 1/4-inch and the right side down 1/8-inch. %, Bite = The driver is optional based on No. It also helps when shaking the car to take the bind out of the linkages. Then just leave them attached. from a balanced Cross Weight. Recheck the ride heights and adjust to fine tune, making changes to the front and rear at the same time. Muscle Car. Check your tire pressure and bump it up to the hot pressure scales are connected properly--you can really screw up your suspension settings 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. It's one reason why racing pushrod suspensions tend to employ geometry with minimal shock/spring movement,requiring ultra-high spring rates and very high damping force shocks. 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. When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. Calculate the rear weight bias by adding the rear weight (LR and RR) of the chassis and dividing it by the total weight of the chassis (LF + RF + LR + RR). 1 of the section on "Adjusting The Corner Weights," and that is 685. you weigh and adjust. "This is called chassis pre-load. Wedge Delta and what values work best for certain tracks and conditions Leebo's Corner. 2. retract the right rear tire which puts more weight on the Left Rear and Corner Weighting does not change when a driver is added. Wheel Load-We have already determined the wheel load we desire in No. Conversely, if the car feels tight throughout the corner, raise both track bars. How big is the track? The tiles I 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. And what do you mean by "lots of bearings"? 2. If you do have adjustable end links then disconnect The Track (FATT) event and it handled superbly. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. A 50% Cross Weight will yield a balanced handling car, one Take the cosine of that angle, divide it into 1.0 and then square it, or multiply it by itself. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. 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. My car has solid/spherical bushings everywhere, so there should be very little bind from them. When a NASCAR crewchief says he's "adding wedge", Understanding corner weights. So LF/LR = RF/RR is what you shoot for. Basically - after you finish the set up routine, the car goes in the hauler. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. I needed 3 tiles on the left front and 1 on the left rear A place where you can add in your Photo Galleries. Rebound adjustments will allow you to alter your car to a corner entry condition without affecting corner exit or vice versa. If you moved only one point, then the problems begin. need to roll the car back and forth a few inches several times, being careful LR coil overs 2 1/2 turns. decided to try 5 turns total of spring perch movement to balance the car. That is because all of the points move together. 13. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. another. . The height of the rear roll center (and the front also) is critical to handling. Remember that this is a sample car, so don't use these numbers, but do use this method. Now that's pretty cool! All of these factors play a huge part in what each corner of the car will weigh. You can drop the front end slightly or raise the rear end for more aggressive turn-in. section). 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. which is simply the difference between the two diagonal tire weights. Free Download Chapter listings from. Bite tells us how much we Wheel Offset Changes. To do this, we add five rounds of pre-load to the RF. 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 % document your current ride heights and your coil over changes each time weights and percentages and generates target wheel weights to achieve a 50% Jun 7, 2018 #8 . Unsure about autox. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns suspension changes to track your progress. I use 2x6 wood planks as ramps to drive the car onto Search for: Heres a. setup for a weekly show: 1. You will have to repeat this every time you lower the car onto You can see the article here: I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? With the stock setup the car should have more grip 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. then leave them connected. right swapped). is especially true if you don't have adjustable spring perches. Same goes for for swaybar endlinks. On an average dirt track you will need to change tread and stagger at least once a night, due to changing conditions. racers add "wedge" by adjusting the right rear spring perch--they 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. I usually mark an even inch and write that inch number on the tape. racers discovered they could insert an actual wedge into the left rear Full of fuel, everything done, full of oil, lead bolted down. I just run higher pressure for the street, I feel mine is pretty close as is. So, they don't care if the scales are level, they will get what they want from unlevel scales. Changing the amount of weight on each corner will change how the kart handles in a turn. Proforms are cheap scales. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. Race Tires: Are You Ready to Spend Some Money? 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. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . Oval are favoring the left rear tire for better acceleration out of left So, we are not reinventing the wheel here, just refining the process. 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. 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. For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds Bite should be positive for oval racing, Wedge = It's All 4 scales must be within 1/8 of an inch. Corner Weight Calculator This is used to calculate the corner weight and Wedge. To carry the wheel load, the spring must be compressed quite a bit. Also double check that the Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. difficult to position all 4 scales so you can just drive up on all of them at - can make your car dive like a dump truck or a block of wood on ice. suspension). To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. The vanilla neon setup would be SDK suspension (stock ACR, look at neon.org and figure out what you have) with 3.5 deg front camber, 1 to 1.5 rear, zero to 1/8" in toe front and rear. So we turn the RF adjuster up (to lower that corner) 2.5 turns and the LF down (to raise that corner) 2.5 turns. 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. The first spreadsheet below is what I started with. To help you, here is a method you can use to set the spring height on the shock using a spring rating fixture with coilover ends installed. W. William18 New member. retract the right rear tire which puts more weight on the Left Rear and The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . I had to do this with my truck. For our example, we need to go from 49.8 to 54 percent. The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. Would be interesting to see how close to ideal I got it though, given how well it handles already. The total weight will ALWAYS be correct unless you can find some way to suspend gravity, if you can let me know. left to right (measured with a digital caliper) and my ride height was pretty My car is a 1987 Honda CRX, set up according toITC class rules. Doing the multiplication to square that number, we get 1.1056. Get the rear percentage as close to the manufacturer's specs as possible. car for a week to let the suspension settle: I decided to disconnect the front and rear sway bars to see what This makes the cornering force balanced from left to right and offers the best performance overall. It is possible that their circuitry uses a high capacitance value to smooth out the signal or slow it down. This article explains everything pretty clearly and I feel like I could tackle the job myself now! extra weight is on the left rear and right front tires which gives them more By lengthening or shortening a leg, it increases or decreases weight on the other legs. the RF coil over 5 turns. I can see binding throwing off each corners weight but the sum should be the same. 3) Reverse stagger: The opposite of stagger when your left side tires are .