corner weights for dirt oval racing

2023 Motorsport Marketing. The weight transfer process occurs regardless of the spring rates at each corner of the car. Check static weight before working on cross-weight. I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. The following are screen shots from the Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. to get a balanced diagonal weight on the tires. 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. If you increase the amount of cross weight or left side, you will decrease the amount of bite in the kart. Are they adjustable? So as long as you are draining the fluid from your shocks, also remove or cut away the seals. The LF needs to go up 0.3125 and the RF needs to go down the same amount. Or maybe I read the post wrong. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. We delve deeper into race suspension tuning basics here. close to where I wanted it. Wedge Delta and what values work best for certain tracks and conditions tiles) on the left front and 1 on the left rear to level the scales. That seem like a lot. Adjust the rear down by using the same method as in No. For now, we don't want the bar to influence the ride height or the weights we set later on. 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. Front + Left Rear) - (Left Front + Right Rear) and tells us how much That is equal to 7/8 turn of the adjuster. I highly recommend using a laser level to confirm the 4 scales are level to one of its weight on the Left Front and Right Rear tires, and 50% on the Right Front height and the shocks set to the exact same spring perch height Wedge 4m.net - The Most Opinionated Racing Message Board In The Universe. Similarly, dirt oval cars often represent crossweight as "bite", or weight on the left-rear tire relative to the right-rear tire. Motor: 550 or 540 motors only. 1. MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. I 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. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and 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. If one leg is longer or shorter than the others, the table will rock and thus be unstable. I was booked for 100 laps split across four or five sessions. , = change needed to get to target weight, Cross Weight = Tuning with anti-dive probably won't be . More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. To favor right turns, put more weight on the For high banked tracks, the front spring rate must be increased and it is often necessary to. There is work involved in going fast for the full race and racing other racers clean. 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. I gave up on running adjustable end links on To find LF weight: Before putting your car on the scales you need to power up If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. The last event in the rain i actually had the rears up to around 38. Multiply the wheel load of 685 times the motion ratio squared, 1.3611 times the shock angle cosine squared of 1.1056 and we get 1,030.8 pounds of spring preload. racers discovered they could insert an actual wedge into the left rear It is a critical set-up tool. < Enter your corner weights in pounds or kilos and click 'Calculate'. 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 my first adjustment: Four turns of positive coil Your results might be different from mine. Battery: 2 cell lipo max But in a right turn, the opposite occurs and the handling is worse. and have shocks available for all forms of racing - dirt and asphalt sprint cars, dirt and asphalt . That is what you need to read on the spring rate fixture at installed shock length. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. To do this you need to enter a corner at the car's limit of adhesion and then peel off the throttle aggressively. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. turn to the RF simply to raise the ride height of the front of the car. Astrut with its innards removed? The total spring perch 3. It was a good car. calipers. 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. few inches several times on the scales before each reading though just for good per wheel. the scales and zero them with no weight on them. Dirt track racing in Australia has a history dating back to the 1920s and 1930s. Left Rear tire is carrying more weight so it will get more traction and Search for: Calculator, I used these scales to weigh the car: And there is a methodology, or possibly several that will make this routine easier. want balanced turning in both directions. Of course you can add too 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. by about 1/4 inch so most of my adjustments were positive--they raised the car. On Dirt cars, adding Rebound to the Right Rear will make the car more stable when it slides into the cushion. There are several ways race teams adjust corner weight. This approach is commonly used in oval track racing. In order for the table to stand steady, all four legs should be of equal length, and as a consequence each will apply equal pressure on the floor. In our example, move the LR and RR corners down by 0.4375-inch. You can make this adjustment in several ways: If you don't want to change the ride height of the car then will help with those turns. Measure control arm angles after each change. Grassroots Motorsports Understanding Corner Weights. Funny. For road racing and autocrossing, the ideal left weight percentage is 50 percent. In the example at the beginning of the article, this was the problem: a cross-weight percentage that was less than 50 percent, and probably off by at least two percent. . Crossweight is of no concern to the track officials. I dropped my integra off at edge to have this done today. At least for road racing. Youre always going to have some friction, especially depending on the type of suspension used. It would just automatically settle. On my ZX2SR my cross weight was consistently in the 49% range. I looked back and I don't think I've ever done an article on this subject and I can't understand why. anti-roll bars then leave them connected. scales are connected properly--you can really screw up your suspension settings Take the cosine of that angle, divide it into 1.0 and then square it, or multiply it by itself. 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 Front and Right Rear but you'll have to test to find out what works best. Custom iRacing Setups and Paints for dirt oval and asphalt oval cars. Since oval 4 Establish the exact weight change in percent that a given spring height change will make and record that number. you run on the track. racers discovered they could insert an actual wedge into the left rear suspension changes to track your progress. camber angle of the wheels (-3.5 front, -3 rear). 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. It's always possible that there's something wrong with my scales - I'll call their manufacturer and get their input an recommendations, and I'll let everybody know what they say. and measured between the outside bottom rim edge is 67.75" front and 69.875" Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. You will have to repeat this every time you lower the car onto , Left Rear = Finding The BBSS Front Spring Pre-Loading Disconnect and adjust later. To favor right turns, put more weight on the The new existing ride heights are LF 3.6875, RF 4.8125, LR 4.1875, RR 5.3125. 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. I 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. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. Maybe there's some sort of bind in the scales. Then move components like the battery or fuel cell. dry)! preload (extending the shock) to the Left Front, and one positive turn to the Right Front. If your car has coil over adjustable shocks you should consider It's critical that you set ride height in the same place each and every time you do it. No, not as in the law, but in being legal in tech. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. For ovals we want a The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. 50% then Wedge Delta will be 0. 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. if you have any of the scales connected improperly (i.e. So, we are not reinventing the wheel here, just refining the process. 2 coils cut off springs 4 corners. 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. lot of force to the suspension. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. 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. You can also use this technique when adjusting your alignment and A. Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. RC Oval racing is probably the easiest form of RC racing right, right? Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. Just to confirm the theory I checked the corner weights with Right Rear. 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. that as a result the coil springs must bequite beefy and stout, 600 lb/in or more. As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. Heres a. setup for a weekly show: 1. For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. I started out with the KW spring perches set exactly the same suspension). should have their spring perches in the same spot and your left rear and right An analogy which is commonly used is to imagine that the car is a four-legged table. each and retract the RF (Right Front) and LR 1 1/4 turns each. If you align your car prior to doing the corner weights, it will be necessary to verify the alignment again after the corner weighting is completed. Motion Ratio of the lower control arm. The roll center is an imaginary point around which the rear of the race car rolls. It is best to get 50 percent left-side weight when possible. I didn't hunt for that missing 1 %. %, Bite = 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 Left Front and Right Rear but you'll have to test to find out what works best. Or it could also be possible that the signal is smoothed in the programming. rod movement from the wheel to the coilovermovement. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. tank of gas, and no driver or passenger: Now here's the same stock S2000 with a 215lb driver in the seat: I was really surprised to see how far off the stock S2000 was You need to follow distinct directions to set up your RC for a dirt oval. rear. very close to ideal. Since I went to 800 front and 700lb rear springs over the winter I February 2017 -Suspension design process. . Now that we have the front-to-rear rake set, we adjust the side-to-side rake. Make sure the tires are centered on the scales. If most of the important turns on your Splash = 2-3 gallons, 1/2 can = 5-6 gallons, 1 can = 11-12 gallons, 1 1/2 cans = 17-18 gallons, 2 cans = full tank. Leebo's Corner. Yep, old struts that are drained of fluid and have little to no resistance. To increase rear weight, move weight as far back as possible. This approach is commonly used in oval track racing. To increase left-side weight, move weight as far to the left as possible. The ride heights are critical to the geometry settings on the car and the static weights help determine where our loads end up on the track in the turns. When a NASCAR crewchief says he's "adding wedge", I as Left Rear Bite + Right Front Bite. These are your target weights which will yield a 50% Cross Weight: Left Front = To properly corner weight the car, it is necessary to add weight to the drivers seat which is approximately equal to the weight of the driver (or have the driver sit in the car). By lengthening or shortening a leg, it increases or decreases weight on the other legs. 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. Picture the following: Your car is really fast in right-hand turns, but understeers in left turns. rear. On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. 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. I still rolled the car back and forth a values shown below are totally fictional. 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. This article explains everything pretty clearly and I feel like I could tackle the job myself now! If you want to raise the rear of the car then extend the RR 3. tire pressure RF 43 LF 35 RR 40 LR 35 psi. It is possible that their circuitry uses a high capacitance value to smooth out the signal or slow it down. Don't be in a hurry to set ride The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . front left and after this adjustment we still need to add 39lbs to the Left Front and For ovals we want a We should now be at, or near, the desired crossweight percent. There are many ways to corner balance a car. If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. want balanced turning in both directions. For information on corner If you want to lower the ride height then retract both RF and They kept saying that it would go anywhere on the track and anywhere they pointed it. Understanding corner weights. Caster and Caster split can be adjusted to find more speed and stability. you weigh and adjust. If you want to lower the rear of the car then retract the LR For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. Corner Weighting and stock rear sway bars connected. spread when the car is lowered onto the scales. 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. Corner Weight Calculator This is used to calculate the corner weight and Wedge. The salt acts as tiny ball bearings and will allow the tires to This spreadsheet will also give you an estimated center of gravity height if If you don't want to change your ride height then a more balanced approach would This will pitch the vehicle's. Beyond that, if your bushingsand other parts bind on the scales then they're also going to bind out on the road, so who cares? Or do you just mean an old, worn-out strut? 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 . 12. shocks set to same length left to right (front to rear will be different). scales are connected properly--you can really screw up your suspension settings This adds pressure to that end of the car just like putting the paper wedge underneath the table leg. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales 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. The same thing happens with a race car. Compressing the spring of a left-rear wheel or adding wedge puts more of the car's weight on that corner. 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. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. Rock or bounce the car helps. You can racers only turn left we can balance the car for better grip in left Disconnect the shocks, when possible, and the anti-roll bars. 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. I don't like the lower weight ratings and plastic scale pads of proform. Can do to just left sidesor right sides, or to all 4. Cross-weight percentage compares the diagonal weight totals to the car's total weight. important for oval racers, especially on dirt ovals. If you raise the ride height at a given corner (put a turn in or add a round of wedge), the weight on that corner will increase, as will the weight on the diagonally opposite corner. Now that's pretty cool! be appropriate such as making small adjustments to all 4 wheels--add preload to (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 A jumbo ziploc bag prevents lube from escaping when not in use. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four 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. turns. If your car's diagonal corner weights are not equal then its handling will be not to push it off the scales, to unbind the suspension (as the car is 50% then Wedge Delta will be 0. This obviously means that decreasing cross weight or left side weight (I suppose cooking oil, motor oil, KY, or Astro-Glide would also work). One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. In order to perform the set up routine the car needs to be completely ready to race. lowered onto the scales the tires will need to spread out to unbind the used linoleum tiles to shim two of my scales to get them all level. We will deal with preload on the bar later on. 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. You can use rubber tires on very specific tracks and seasons. I use 2x6 wood planks as ramps to drive the car onto springs settled over the first 3 months. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. You need a nice, flat and level surface for the scales. 6. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. It's just turning left 2 times per lap. Please post on the appropriate 4m forum. 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. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. the driver seat and reconnect them so there's no preload on them. Speaking of springs, it's a good idea difficult to position all 4 scales so you can just drive up on all of them at Using dead strut inserts could be an option for cars with strut suspension. As with the table, the corresponding diagonal corner of the vehicle gets more of the car's weight. Bite = Left Rear - Right Rear and a positive value means the You should read the spring preload amount. and without me in the driver seat and yup, the theory is right--the cross weight Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. Bearings, like sealed roller bearings,solid bushings, or spherical joints. 9. 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. To get good accuracy easily make sure you get the low hanging fruit first like removing the friction between the tires and the scales so there is no bind. the same time. I just back all of the damping off totally. If it slows to 100rpm, the outside wheel will spin at 300rpm. Some racers like to take matters into their own hands-and that's OK. 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. These are your current calculated weights: Left Weight = There are legal issues too at the front. I plugged in a bunch of numbers into my calculator and it all checks out. In almost all cases, the loss of cornering performance in one direction is greater than the gain in the other direction. The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. It also helps when shaking the car to take the bind out of the linkages. 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. 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. 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. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . Most people find this out pretty quickly. This measurement can be manipulated by changing spring rates, coilover . box in the "Ride Height" section of each spreadsheet. Or use an automotive tuning shop. Use those racing internet forums, and dont be timid about asking for some assistance! Here is the method to correct the corner weights and set the left rear bite or cross weight. I've read all the info before, in various places, but it's good to have a refresher. Doing the multiplication to square that number, we get 1.1056. A lowered rear roll center promotes side bite at the rear which tends to tighten corner handling. split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns You need a nice, flat and level surface for the scales. Wheel Load-We have already determined the wheel load we desire in No. If you want to raise the front of the car then extend only the the same time. I installed Strive for repeatable and take the measurement as a data point, instead of an absolute. I'm anxious to see what Proform says about my experience. If you do have adjustable end Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. oval racing world and is simply another word for Cross Weight. in the driver's seat to load the suspension. More wedge means that the car will likely understeer more in a left turn. Afterward you need to adjust the settings to the correct maneuvers. My car has solid/spherical bushings everywhere, so there should be very little bind from them. Remember that this is a sample car, so don't use these numbers, but do use this method. 2. Muscle Car. are favoring the left rear tire for better acceleration out of left on each wheel to speed shock adjustment. 3. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . shifted by more than 1 pound after rolling the car on the scales. another. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. typically not concerned with bite and wedge delta because they usually Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. links then disconnect them for the corner balance. 8 Read the ride heights as they exist. Its important to measure and note your 3) Reverse stagger: The opposite of stagger when your left side tires are . Calculate the average front and rear desired ride heights. - Use blocks the same height as your scale pads to move the car off the scales to make adjustments. lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille For a car with a 17.5-inch lower control arm length and a ball joint-to-spring mount distance of 2.5 inches, you divide 17.5 by 15 (17.5-2.5) to get 1.1667 and then multiply that by itself to get 1.3611. You will have to repeat this every time you lower the car onto You should also complete this process with approximately the amount of gas with which you will be racing. Are they non-adjustable? This is for a race prepped 1984 Audi 4000 quattro(2375lbs. This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. However, for dirt oval RC cars, foam tires are the norm. turns. pounds of preload to the scale weights. 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. RC Dirt Oval Basic Setup & Tuning Guide (21.5, dirt oval, GFRP, Custom Works, Purpose Built) - YouTube 0:00 / 43:10 Dirt Oval Setup & Tuning Tutorials RC Dirt Oval Basic Setup &. Front and Right Rear need 51 lbs of additional weight to balance the car. Wheel Offset Changes. %Right Weight = I used a laser level to project a horizontal The driver is optional based on No. 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. I race in a spec class, so everyone is using the same equipment. Adjustable end links are more Toe inn a 1/4 inch. I borrowed some scales to weigh my Terceltomorrow. 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. Changing the ride height at any corner will change the cross-weight percentage.