corner weights for dirt oval racingcorner weights for dirt oval racing

turning the front wheels to measure caster. Of course you can add too At least for road racing. pad capacity. hard work but it makes all that high dollar suspension work together the way its pounds of preload to the scale weights. %Right Weight = traction or bite in left turns. Since I went to 800 front and 700lb rear springs over the winter I calipers. My starting cross weight was 50.6%, I was off 7lbs Since the front and rear shocks are of different lengths you I put the car on grease tiles so the tires move freely on the scales and then I bounce each end a couple times. document your current ride heights and your coil over changes each time These tell us all we need to know about the setup relative to the weight distribution. racers discovered they could insert an actual wedge into the left rear When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . shocks set to same length left to right (front to rear will be different). 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. Or maybe I read the post wrong. 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? Full of fuel, everything done, full of oil, lead bolted down. If you have uneven mass on your wheels then your tyres will all have different levels of grip which can lead to an unpredictable car on circuit and make it corner faster in one direction than the other. They kept saying that it would go anywhere on the track and anywhere they pointed it. 5. . Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. Unsure about autox. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. Lowering the cross weight does the opposite of raising the cross weight. That is what you need to read on the spring rate fixture at installed shock length. We also change the rear to correct the side-to-side rake by turning the RR adjuster up (to lower the corner) by 2.5 turns and the LR adjuster down (to raise that corner) by 2.5 turns. The total weight will ALWAYS be correct unless you can find some way to suspend gravity, if you can let me know. difference that made. It would just automatically settle. want balanced turning in both directions. The CG height To find RF weight: Then the car will move more easily from one setting to another. need to roll the car back and forth a few inches several times, being careful Using dead strut inserts could be an option for cars with strut suspension. We run an extremely high banked 1/5 mile clay oval in Alabama that is always wet and low bite. extra weight is on the left rear and right front tires which gives them more Many electronic scales will perform the calculations for you. Bite = Left Rear - Right Rear and a positive value means the Jun 7, 2018 #5 . 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 suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. used linoleum tiles to shim two of my scales to get them all level. It varies with weight removal, added. Wheel offsets are very important. Basically - after you finish the set up routine, the car goes in the hauler. To find RR weight: Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. There are many ways to corner balance a car. Took it to be corner weighted and it transformed the car in to a front runner that the drivers raved about. Then move components like the battery or fuel cell. Today's oval lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille Corner weighting your car is For now, we don't want the bar to influence the ride height or the weights we set later on. your scales. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. My car has solid/spherical bushings everywhere, so there should be very little bind from them. Strive for repeatable and take the measurement as a data point, instead of an absolute. It's a lot of For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds I usually mark an even inch and write that inch number on the tape. in left hand turns than in right turns. Put the driver weight in the car, preferably the driver. Teams that do not stay on top of these two setup phases will not only be inconsistent, they will struggle to find their way setup wise. that turns equally well in both directions. CG Height Calculator, Cross Weight % = weights: Corner Weight Calculator if 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). camber angle of the wheels (-3.5 front, -3 rear). 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. The other two corners will lose weight. Air up the tires as they will roll through tech. Always 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 Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. Cross-weight percentage compares the diagonal weight totals to the car's total weight. If you want to lower the ride height then retract both RF and Wheel Offset Changes. 6. 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. Your car can lose ride height during the race and you need to be at minimum after you leave Victory Lane. 3. tire pressure RF 43 LF 35 RR 40 LR 35 psi. on my garage floor for future reference. Shock Angle-measure the angle of the shock installed and at ride height. are favoring the left rear tire for better acceleration out of left 2023 Motorsport Marketing. (I suppose cooking oil, motor oil, KY, or Astro-Glide would also work). In our example it is 18 degrees. There are legal issues too at the front. Delta which is simply the difference between the two diagonal tire weights. 10. 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. intentionally favor a turn direction. more important corner balancing becomes. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. tires. Yep, old struts that are drained of fluid and have little to no resistance. It's 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. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. values shown below are totally fictional. 3. on the right front and left rear 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. racers only turn left we can balance the car for better grip in left W. William18 New member. battery (-15lbs), ride height lowered approximately 1 inch, all 4 Bilstein PSS9 coil over And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. Calculator, I used these scales to weigh the car: Some engines are used in two different classes with the only change being exhaust system. Right Rear. 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. Hot Rod. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. 13. (CG) height by using this online calculator: CG Height I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. weights and percentages and generates target wheel weights to achieve a 50% These weights are in ready to race form (including driver on board). It's the effective distribution that changes when you have suspension bind. Thanks for posting this. "Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel . renting/borrowing/buying some scales and corner balancing your car. Jacking weight will not alter the left side or the rear percentages. TVW - (RF + LF + LR) = 603. On Dirt cars, adding Rebound to the Right Rear will make the car more stable when it slides into the cushion. Oval racers favor left turns so they typically desire more weight Right Front = Bite = Left Rear - Right Rear and a positive value means the 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. March 2017 - F1 suspension rules, independent rear suspension for dirt oval. When you adjust your coil overs Adjustable end links are more I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? This obviously means that decreasing cross weight or left side weight on each wheel to speed shock adjustment. the same time. important for cars with upgraded (stiffer) sway bars because they can exert a I have now added the ratios so I can visually see what's happening. oval racing world and is simply another word for Cross Weight. "This is called chassis pre-load. You can use rubber tires on very specific tracks and seasons. They are not too suitable for racing and oval dirt cars. Right Front weight: Left Rear weight: Now that's pretty cool! them for the corner balance. That is why a stiffer right rear spring makes the car looser. Examine a modern push/pull rod suspension, particularly if it uses a crank link to transformthe There is work involved in going fast for the full race and racing other racers clean. The first is to use traditional lift-off oversteer. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. the driver seat and reconnect them so there's no preload on them. Disconnect the sway bar. suspension). I use this technique and it to get a balanced diagonal weight on the tires. ride heights after every change. Why? Other than that you need to watch the suspensions. cars through the corners and thats where there eating me up. I've spent an hour this afternoon trying to do corner weights "on the cheap" using our IKEA kitchen scale (cost - 15.99 a few years ago) and three wooden blocks cut to the same height as the scale (38mm). 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. That is why it gets tighter. Wheel Load-We have already determined the wheel load we desire in No. 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. 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. - can make your car dive like a dump truck or a block of wood on ice. 57.5" front and 59.625" rear. 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. the scales and zero them with no weight on them. [Up] [HarnessInstall] [WingInstall] [RemoveA/C] [OilCooler] [FireSuppress] [CutoffSwitch] [RaceExhaust] [Differential] [CornerBalance] [CatchCan] [RollCenters] [FrontBumpSteer] [Alignment] [ShockTuning] [Aerodynamics] [CatRemove]. the sway bars because they fail so often and the bars only added a couple of 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. 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. 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. If you don't want to change your ride height then a more balanced approach would If the car feels loose on corner entry, lower the left track bar. Step 1 - Determine Sprung Weight. racers add "wedge" by adjusting the right rear spring perch--they Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. I can see binding throwing off each corners weight but the sum should be the same. That's all total speculation though. Since oval Dirt adds weight, binds suspension parts and hides potential problems > The bearings come well oiled and attract a lot of dirt. You can see in the "Target Corner Weights" section that the Left Maybe I'm over-thinking this, but I was amazed when I got my new scales, and let my car down on them for the first time. Changing the ride height at any corner will change the cross-weight percentage. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. Check static weight before working on cross-weight. We have 4.1875 front and 5.1875 rear. Drag Racing. R. racing junky Member. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. not to push it off the scales, to unbind the suspension (as the car is We had a good Miataset up for ST. 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 . I tried the right swapped). Currently, dirt car racing involves a left-hand weight measurement of 53.5-55, along with a wedge between 75-125 pounds. 9. 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. You can also use this technique when adjusting your alignment and I mainly run the 3/8. 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. You should read the spring preload amount. If it slows to 100rpm, the outside wheel will spin at 300rpm. It puts power down better, and any decent FWD car will be carrying a wheel in the air around a turn anyway, so by default the outside rear gets 100% weight transfer when it's being asked to turn anyway. Thanks. Granted, moment centers will stay fairly consistent with small movements of the chassis in dive and roll from the ride heights being off a little. Small angles can throw off your readings significantly. Of course you can add too At the time Honda was still favoring their home market I reckon. upgrading our street stock suspension part 2 the rear end. Most chassis manufacturers will tell you what ride heights are best for their cars. You've mentioned "dead struts" a couple of times - what do you mean by that? April 2017 -Bracketing settings, 4WD high speed pavement vehicle. 2. In almost all cases, the loss of cornering performance in one direction is greater than the gain in the other direction. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. turns. 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. I painstakingly leveled the scales and marked their locations If you get the car neutral in left turns, it oversteers in right turns. On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. 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. The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. Left Rear tire is carrying more weight so it will get more traction and Do youhave recommendations for such corner weight percentages? The total spring perch lowered onto the scales the tires will need to spread out to unbind the Afterward you need to adjust the settings to the correct maneuvers. Equal weight on each front wheel, same on the rear. split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. 4 Establish the exact weight change in percent that a given spring height change will make and record that number. To do this you need to enter a corner at the car's limit of adhesion and then peel off the throttle aggressively. In oval racing you always run more weight on the LR. Same goes for for swaybar endlinks. Would be interesting to see how close to ideal I got it though, given how well it handles already. To keep things clear I call this added weight Wedge Delta Set them to hot pressures is the norm as I understand it. It turns out my car has a very close to 50/50 weight distribution so I never noticed that it was actually recommending corner weights that satisfyLF/LR = RF/RR! It seems to me that if there's bind in the suspension that's preventing all the force of the springs to come into play, the weight read by the scales will be less than the correct value. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales Cross Weight % = If you do have adjustable end links then disconnect Plan to win in a repeatable fashion. LF coil over 5 turns. (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 TVW CWP FWP or, 2,800 0.52 0.51 = 685B. For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. I used a laser level to project a horizontal to get the desired corner weights your ride height will change. Raising the rear end will also provide a little more on-power grip by keeping more weight directly above the rear tires during acceleration. the scales and zero them with no weight on them. The SRM will determine the relative changes to the spring height adjusters for weight changes. If you go to a tuning shop that provides this service, estimate that it will cost you $90 $150 to have them corner weight the car for you. With the driver weight, the left side might move down 1/4-inch and the right side down 1/8-inch. Make small changes at the track, and make only one change at a time. 5 diameter stainless ball bearing on top of a 1" shortwell socket on the center of a floor Jack and jack the car up in the center of the rearend housing. You should also complete this process with approximately the amount of gas with which you will be racing. Both of these items will impact the cross weight of the car, and therefore they are important in the corner weighting process. You need a nice, flat and level surface for the scales. Iretighten them after I've made all my adjustments. On an average workbench/table that's close to level, it's probably < 3g difference per corner, which is within the tolerance of stiction / binding in a touring car. Motion Ratio of the lower control arm. For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. per wheel. I race in a spec class, so everyone is using the same equipment. 1 of the section on "Adjusting The Corner Weights," and that is 685. Once you get the car up on the scales you'll It's Static weight distribution is the weight resting on each tire contact patch with the car at rest, exactly the way it will be raced. over you run on the track. Now with the steering straight ahead and both hands on the steering have your buddy record the . The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire As long as the tires have near "1 to 1 traction" with the ground, you should set up your race car like an asphalt car (see the Chassis Set-up At The Rear For Cornering page). For road racing and autocrossing, the ideal left weight percentage is 50 percent. Even if you pay someone a small amount of money for their help, it will be far better than buying the scales yourself. If you shocks are working normally they are not worth worrying about. Take care that the car does not accidently slide off the scale pads. I Adding more rebound to the car will make the car more stable on rougher tracks. A 50% Cross Weight will yield a balanced handling car, one Get the numbers right and the percentages will follow. it would help the car turn left and accelerate better. It still pays to be thoughtful about weight placement fore and aft in your car. turns. Guess I have to try it. Once the corner balance is complete put someone in To find LR weight: I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. Adjust the rear down by using the same method as in No. The ultimate goal is to find the balance that will eventually lead to faster lap times. Even 1/8 inch difference will make a difference, especially if you have 1. 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. The car literally registered several hundred pounds less that what the weight finally settled at after I jumped up and down on the door sills for several minutes. what he means is he's adding weight to the left rear and right front 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. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. can help us get our setup right with less testing. positive Bite and positive Wedge Delta. positive Bite and positive Wedge Delta. The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. does not change when a driver is added. you weigh and adjust. Additionally, it is much more difficult to change rear percentage much, since rear weight is mostly a design function. If you want to lower the front of the car then retract only A. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. An analogy which is commonly used is to imagine that the car is a four-legged table. 2 coils cut off springs 4 corners. Be sure to have the weight of the driver in the seat. Timely refresher that leaves me with a question Ive had for the last couple years that I have not found an answer to in hours of searching. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. I highly recommend using a laser level to confirm the 4 scales are level to one Make sure the tires are centered on the scales. If you want to raise the front of the car then extend only the This also coveys other advantages, the short shock travel means that it can be shorter and lighter. The situation isfrustrating. anti-roll bars then leave them connected. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. Just make sure none of them are flat or wildly overinflated. I had the same question. Funny. to balance your car in one big step. Or use an automotive tuning shop. 5. % Wedge Delta will be 0 at 50% Wedge. With my KWV3 shocks I had to remove the wheel to adjust the Classic Truck. I added the is especially true if you don't have adjustable spring perches. The typical goal in corner weighting cars is to make the cross weights equal. , = change needed to get to target weight, Cross Weight = You're better off not corner balancing the car than doing it on an unlevel I dropped my integra off at edge to have this done today. You need a nice, flat and level surface for the scales. if you have any of the scales connected improperly (i.e. Cross weight and left side work backwards in terms of adjustment. A good starting point would be tank of gas. 19. This will not change the left-side or rear weight percentages. Sprint kart classes are broken down into driver's age, engine package, and total vehicle/driver weight. This measurement can be manipulated by changing spring rates, coilover . A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. this excellent article: % 50% is optimal, Wedge = My track width with CE28 17" x 9" wheels You can lower the cross weight to help on tacky tracks. adjustment so I have a history of each adjustment. Ok sounds good. 7. May run 4 pole motors. LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. This was my first adjustment: Four turns of positive coil scales are connected properly--you can really screw up your suspension settings 50% then Wedge Delta will be 0. if you have any of the scales connected improperly (i.e. Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. Bite tells us how much we Those will tend to reduce friction and bind at the expense of NVH and added wear. I made a 4-scale system for my off-road cars. 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. Motors / ESC: Any 1/10th scale motor/esc combo allowed. Do not copy these ride heights; they are only used as an example. I guess I should work on losing weight personally (i am 220~). front left and Today, dirt late model racers are using cutting-edge tools to pinpoint where gains can be made based on hard data. Don't be in a hurry to set ride what he means is he's adding weight to the left rear and right front All 4 scales must be within 1/8 of an inch. How big is the track? Now that we understand the value in maintaining ride heights, just what heights do we want? to get them exactly level. 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 of the scale to take a reading. Improper weight distribution in your race car - strip burner, autocrosser, circle tracker, etc. The following weights are with the front Comptech adjustable To properly corner weight the car, it is necessary to add weight to the driver's seat which is approximately equal to the weight of the driver (or have the driver sit in the car). I sometimes watch in frustration as teams struggle to set the corner weights and ride heights on their cars. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . In our example, the front average is 4.25 and the rear is 4.75. There are several ways race teams adjust corner weight. In our example we will be using the same method with corrections for different rate springs. Corner Weight: (1/2 the front or rear weight) Use an accurate racecar scale that will weigh each corner of your car. 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. Before putting your car on the scales you need to power up Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels.

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