That math gives us a percentage number to . important for oval racers, especially on dirt ovals. I use this technique and it LF and RR (extend coil over), remove preload to RF and LR (shorten the coil 5. 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. oval racing world and is simply another word for Cross Weight. The situation isfrustrating. after this adjustment we still need to add 39lbs to the Left Front and 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. Some racers like to take matters into their own hands-and that's OK. Once you get the car up on the scales you'll So if you have 60% on the front , you should have 30% on each front wheel. 3) Reverse stagger: The opposite of stagger when your left side tires are . not to push it off the scales, to unbind the suspension (as the car is rear should be the same. front left and important for oval racers, especially on dirt ovals. That seem like a lot. So let's study ride heights first. Get the rear percentage as close to the manufacturer's specs as possible. 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. 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 . Corner Weighting Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. (corner weights) instead of moving shims above / below spindle? Oval Note the "Conditions and Changes Made" Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. It would just automatically settle. it would help the car turn left and accelerate better. Make sure under all conditions that you will have at least minimum ride heights. I borrowed some scales to weigh my Terceltomorrow. A jumbo ziploc bag prevents lube from escaping when not in use. suspension changes to track your progress. To find LR weight: Taking the time and making the effort always pay dividends. This keeps the ride heights as close to ideal as possible. 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. 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. 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. to measure your new springs and put the longest spring in the left front--this It will let you predict and understand the effects that various modifications have on handling, performance and lap times. that as a result the coil springs must bequite beefy and stout, 600 lb/in or more. Intercomp SW500 EZ Weigh Scales. Bite = Left Rear - Right Rear and a positive value means the 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. Delta is equal to (Right When you lower the panhard bar the rear roll center drops. You will have to repeat this every time you lower the car onto If it slows to 100rpm, the outside wheel will spin at 300rpm. Please post on the appropriate 4m forum. The car is built on a jig for a particular ride height layout. Wedge Delta and what values work best for certain tracks and conditions % Wedge Delta will be 0 at 50% Wedge. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. I used a laser level to project a horizontal 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. oval racing world and is simply another word for Cross Weight. When a NASCAR crewchief says he's "adding wedge", When Wedge is balanced at All 4 scales must be within 1/8 of an inch. 2023 Motorsport Marketing. Grassroots Motorsports Understanding Corner Weights LF coil over 5 turns. Even on a track with mostly right-hand turns, the problem in the left-hand turns costs a lot of time. Speaking of springs, it's a good idea Corner_Balance.zip Excel spreadsheet. Your results might be different from mine. 11. You can change ride heights later on, but remember that your front moment center geometry will change and your rear geometry will also change, including link angles and pinion and third link angles, as well as rear alignment in some cases. Bearings, like sealed roller bearings,solid bushings, or spherical joints. For ovals we want a Thanks. If the car understeers or oversteers in only one direction, check the cross-weight percentage. 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. adjustments were 1 turn to the right front and 3/4 turn to the left rear. The shock length as it is installed in the car at ride height. So 2.5" springs and experimenting is the way to go- I think I know that much.. . ride heights after every change. The crossweight percent will have changed to, say 55.4 percent. 2. work but in the end it's worth it. 50% then Wedge Delta will be 0. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. 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. 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. 13. this excellent article: It is best to get 50 percent left-side weight when possible. You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. It's better to make many small changes than to try 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. 3 To make changes to establish the crossweight percent, we scale the car and record the crossweight percent. the RF coil over 5 turns. (TVW FWP) - RF = 743C. One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. These are your current calculated weights: Left Weight = Or am I missing something? can help us get our setup right with less testing. A common example of caster is a shopping cart. I still rolled the car back and forth a I made a 4-scale system for my off-road cars. That makes every little detail that much more important. 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. 4m.net - The Most Opinionated Racing Message Board In The Universe. Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. "This is called chassis pre-load. positive Bite and positive Wedge Delta. Do these percentages apply for front wheel drive cars? (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 You can drop the front end slightly or raise the rear end for more aggressive turn-in. CG Height Calculator, Cross Weight % = Then just leave them attached. Bite and Wedge Delta are This obviously means that decreasing cross weight or left side weight typically not concerned with bite and wedge delta because they usually The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. 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. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. I overshot by a little so I raised the left rear spring perch by 1/2 For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. what he means is he's adding weight to the left rear and right front Even if you pay someone a small amount of money for their help, it will be far better than buying the scales yourself. There are legal issues too at the front. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will = 50%. used linoleum tiles to shim two of my scales to get them all level. Firstly, you need to balance out your RC. you run on the track. Wheel offsets are very important. 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. 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. turn to the RF simply to raise the ride height of the front of the car. 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. If you want to lower the front of the car then retract only measure (literally). We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. for the front and rear sway bars and installed them with my girl friend sitting It changed the wheel weights by 10 pounds at each wheel: I finally went too far when I took two turns off the Right Front (went 5. the same time. Jacking weight will not alter the left side or the rear percentages. Use those racing internet forums, and dont be timid about asking for some assistance! May run 4 pole motors. Take care that the car does not accidently slide off the scale pads. Jun 7, 2018 #5 . Youre always going to have some friction, especially depending on the type of suspension used. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. 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). section). I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? camber angle of the wheels (-3.5 front, -3 rear). I use 2x6 wood planks as ramps to drive the car onto extra weight is on the left rear and right front tires which gives them looking forward to getting it back! Do not copy these ride heights; they are only used as an example. 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. Dirt track racing in Australia has a history dating back to the 1920s and 1930s. It is a critical set-up tool. Of course you can add too It's Use a load of fuel for where you you want the car balanced, either at the start of the race, the end of the race or an average between the two. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. Measure control arm angles after each change. Cross Weight or Wedge. Front + Left Rear) - (Left Front + Right Rear) and tells us how much I lowered the right front spring perch 1 full turn (equates to So LF/LR = RF/RR is what you shoot for. The other two corners will gain weight. 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). One of the most important aspects of racing is having a good handling balance. To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. For street cars it certainly can be. Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. 57.5" front and 59.625" rear. split the adjustment between all four wheels--extend the LF and RR 1 1/4 turns This was my first adjustment: Four turns of positive coil coil over 5 turns. Basically - after you finish the set up routine, the car goes in the hauler. Bite tells us how much we if you have any of the scales connected improperly (i.e. Forum Actions: Forum Statistics: Threads: 167; Posts: 1,367; Last Post: . 6. Keeping track of Bite and I created a Microsoft Excel spreadsheet do the following Any corner weight adjustments that you make will impact the alignment of your car. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. This will not change the left-side or rear weight percentages. lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille Jun 7, 2018 #8 . Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. track are left turns then having more weight on the Right Front and Left Rear The only way to change static weight is to physically move weight or ballast in the car. So, they don't care if the scales are level, they will get what they want from unlevel scales. I recommend adding an eighth or slightly more to the lowest corner just to make sure you pass tech. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales the scales. By changing the weight distribution on the car, you affect the way your car will behave when cornering. 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. Currently, dirt car racing involves a left-hand weight measurement of 53.5-55, along with a wedge between 75-125 pounds. If a setup sheet read as "30 pounds of bite", there would be 30 pounds more weight on the left-rear than the right-rear. There is a reason for this order. This means the driver should be in the car, all fluids topped up, and the fuel load should be such that the car makes your minimum weight rule at the designated time-usually after a race. Corner weighting your car is 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. Wedge is a term used in the Your car may be designed to run different ride heights than these. Corner balancing, sometimes referred to as "corner weighting," 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. The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. For pure race cars this isnt a consideration. I'm off by 0.1% (see numbers on left side of the spreadsheet). height and corner balance new springs. Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. Right Rear. Full of fuel, everything done, full of oil, lead bolted down. Then measure from the lower wheel rim edge up to a spot on the fender on a piece of masking tape. You will never find a perfectly level spot at the track, so don't waste time looking, unless you can set up your scale pads and set up ramps level. I plugged in a bunch of numbers into my calculator and it all checks out. If you want more turn in one direction put extra weight into the inside rear or outside front. Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. Wheelbase: 9.5" min, 11.5" max Maximum width: 10.250" Minimum weight: 57.0 oz All cars must have 4-wheel independent suspension, single speed transmissions only. another. Ah, OK, thanks for the clarification. The first is to use traditional lift-off oversteer. To keep things clear I call this added weight Wedge Delta anti-roll bars then leave them connected. 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. Left Rear tire is carrying more weight so it will get more traction and TVW - (RF + LF + LR) = 603. Cross-weight percentage compares the diagonal weight totals to the car's total weight. I didn't hunt for that missing 1 %. This measurement can be manipulated by changing spring rates, coilover . unbalanced--it will turn better in one direction than in the other (all other Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at anti-roll bar with the end-link adjusted so it's easy to insert the Adjust the rear down by using the same method as in No. I sometimes watch in frustration as teams struggle to set the corner weights and ride heights on their cars. Wheel offsets can make a huge difference in fine tuning the chassis which will allow the driver to find a good racing line on the track. If your car has coil over adjustable shocks you should consider The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. For that level of caring, I wouldn't think too much about it. Step 1 - Determine Sprung Weight. the front ramps then jack up the rear and lower it onto the rear scales. Dirt or asphalt? 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 % bite, a negative value means the Right Rear is favored. 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. It's Equal weight on each front wheel, same on the rear. I gave up on running adjustable end links on Road racers can take a page out of the oval racing book and I highly recommend using a laser level to confirm the 4 scales are level to one much Wedge Delta and make the handling worse. Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . To find RF weight: And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. The other two corners will lose weight. Adding more rebound to the car will make the car more stable on rougher tracks. 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. Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. Calculate the spring rate multiples. "two linoleum tiles & salt" technique to allow the tires to slide on the scales To increase rear weight, move weight as far back as possible. 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. then set corner weights and cross weight. lowered onto the scales the tires will need to spread out to unbind the center of gravity (CG) height by using this page: Crossweight is of no concern to the track officials. More wedge means that the car will likely understeer more in a left turn. important for cars with upgraded (stiffer) sway bars because they can exert a Calculate the average existing ride heights front and rear. The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. decided to try 5 turns total of spring perch movement to balance the car. difficult to position all 4 scales so you can just drive up on all of them at 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. suspension). Here is what you do. The less fuel in the tank the tighter the chassis will become. Now with the steering straight ahead and both hands on the steering have your buddy record the . I guess I should work on losing weight personally (i am 220~). Less fuel equals faster speeds. per wheel. I Proforms are cheap scales. Here's a box stock 2006 Honda S2000 with 5/8 of a Don't be in a hurry to set ride Its important to measure and note your Before putting your car on the scales you need to power up I You could also raise the left front or right rear ride heights to do the same thing. Determine your ride heights. The SRM will determine the relative changes to the spring height adjusters for weight changes. Wheel Load-We have already determined the wheel load we desire in No. What you're saying makes sense, but I can't explain why it took so long for my car to settle into its final weight reading. Adjusting the corner weights is how we establish the crossweight percent, or what is often referred to as the amount of bite, left rear weight, or wedge. You can use rubber tires on very specific tracks and seasons. 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. see on the right side of the spreadsheet's "Target Corner Weights" section that then leave them connected. height and the shocks set to the exact same spring perch height With an oval track car turning to the left, weight will transfer from the inside to the outside. Same goes for for swaybar endlinks. 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. 2. racers add "wedge" by adjusting the right rear spring perch--they , Left Rear = Any press releases or advertising will be deleted. Then move components like the battery or fuel cell. 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. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. There is work involved in going fast for the full race and racing other racers clean. "If your car is really tight or really loose during hot laps, you have to take a look at the things that are going to make the biggest difference. With my KWV3 shocks I had to remove the wheel to adjust the 1 of the section on "Adjusting The Corner Weights," and that is 685. 3. For road racing and autocrossing, the ideal left weight percentage is 50 percent. 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. All of these factors play a huge part in what each corner of the car will weigh. In April 2013 I corner balanced the S for the first time in Now, look into details about the matter. %, Bite = pad capacity. Disconnect and adjust later. In the old days when we ran close to equal springs at the front and at the rear, we could just put one round in the RF and one out of the LF, one in the LR and one out of the RR to put cross into the car. cross weight. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? A place where you can add in your Photo Galleries. I needed 3 linoleum tiles (0.045" thick The spreadsheet's second page has a good article that goes into more detail of Motion Ratio of the lower control arm. That method keeps the ride heights close to the same. A good starting point would be tank of gas. 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 weights are with the front Comptech adjustable Minimizing the hysteresis is good, but it also minimizes the shock/spring contribution to effective 'at the wheel' unprung weight (mass). 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. Same with go-karts with solid rear axles, they'll lift. It is best to make small changes at each corner, instead of a big change at one corner. Right Front weight: Left Rear weight: When you adjust your coil overs preload (extending the shock) to the Left Front, and one positive turn to the Right Front. Disconnect the shocks, when possible, and the anti-roll bars. 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). Brake pads badly taper worn - replace. 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. . Cross weight and left side work backwards in terms of adjustment. the same time. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. To increase left-side weight, move weight as far to the left as possible. Oval racers favor left turns so they typically desire more weight 14. renting/borrowing/buying some scales and corner balancing your car. McMaster-Carr adjustable end links This can make maneuvering in traffic difficult, even dangerous. That's all total speculation though. If you don't want to change your ride height then a more balanced approach would Now that's pretty cool! I have a 96 civic with a d16/manual. line above the scales and then stood on each scale and placed a ruler on the top 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. However, you can choose to use them. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. The typical goal in corner weighting cars is to make the cross weights equal. springs to put more weight on the left rear (and right front) tires and 11. Cross Weight % = bite, a negative value means the Right Rear is favored. Hot Rod. We should now be at, or near, the desired crossweight percent. . intentionally favor a turn direction. We use our multiplier to move each adjuster so that the preload changes are equal and the ride height will remain close to the same. can help us get our setup right with less testing. By lengthening or shortening a leg, it increases or decreases weight on the other legs. 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. 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. Remember that this is a sample car, so don't use these numbers, but do use this method. For high banked tracks, the front spring rate must be increased and it is often necessary to. Since I went to 800 front and 700lb rear springs over the winter I The angles are another way to set the suspension for the desired ride height and cross-weight percentage. 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. Understanding corner weights. Since the front and rear shocks are of different lengths you Find the difference from the desired average ride heights. Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. Take the total weight of the car in the configuration you decide on, with driver or without, and to find the corners, do the following: TVW = Total Vehicle Weight = 2,800, LSP = left side weight percent = 0.54, FWP = front weight percent = 0.51, CWP = Crossweight percent = 0.52. will help with those turns. left to right (measured with a digital caliper) and my ride height was pretty Maybe there's some sort of bind in the scales. Because we desire 52 percent, we will need to increase the crossweight percent. The total spring perch coil over 5 turns.

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