Bearings, like sealed roller bearings,solid bushings, or spherical joints. very close to ideal. The last event in the rain i actually had the rears up to around 38. Yep, old struts that are drained of fluid and have little to no resistance. Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. 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. 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. Small angles can throw off your readings significantly. 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. Ah, OK, thanks for the clarification. Disconnect and adjust later. A place where you can add in your Photo Galleries. balancing see my corner balance how-to and Less fuel equals faster speeds. 2023 Motorsport Marketing. That seem like a lot. will help with those turns. They are not too suitable for racing and oval dirt cars. Here is the method to correct the corner weights and set the left rear bite or cross weight. 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. Thanks for posting this. Bite and Wedge Delta are 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. 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 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. camber angle of the wheels (-3.5 front, -3 rear). them for the corner balance. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. 12. If you moved only one point, then the problems begin. Calculate the spring rate multiples. You could also raise the left front or right rear ride heights to do the same thing. I On my ZX2SR my cross weight was consistently in the 49% range. Why? 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. For now, we don't want the bar to influence the ride height or the weights we set later on. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. Your results might be different from mine. looking forward to getting it back! 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. 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. from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. 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 still rolled the car back and forth a 10. One of the most important aspects of racing is having a good handling balance. suspension). 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! Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. Right Front tires. pad capacity. . Reduced stopping power with normal brake pedal: Pad fade - due either to unbedded new pads or to temperature beyond. tiles) on the left front and 1 on the left rear to level the scales. need to roll the car back and forth a few inches several times, being careful May 2017 -Dirt late model pinning RF & heavy axle tube. 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. The spreadsheet's second page has a good article that goes into more detail of Hub stands are a great idea just for ease of access, but removing friction is an added benefit. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. Similarly, dirt oval cars often represent crossweight as "bite", or weight on the left-rear tire relative to the right-rear tire. I weigh 220. turns. The CG height If you want to raise the ride height then extend both LF and RR coil overs There is work involved in going fast for the full race and racing other racers clean. 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. Oval Calculate the average front and rear desired ride heights. Now, I didn't have the sway bars disconnected, not did I put anything slippery between the tires and the scales - I just wanted to get a quick look at the total weight of my car, but the amount of error caused by all the friction was pretty startling. If your car has coil over adjustable shocks you should consider Rebound adjustments will allow you to alter your car to a corner entry condition without affecting corner exit or vice versa. I used a laser level to project a horizontal I dont get this. When you lower the panhard bar the rear roll center drops. R. racing junky Member. I use 2x6 wood planks as ramps to drive the car onto I've read all the info before, in various places, but it's good to have a refresher. shocks set to same length left to right (front to rear will be different). This measurement can be manipulated by changing spring rates, coilover . Bite tells us how much we In our example we will be using the same method with corrections for different rate springs. Do youhave recommendations for such corner weight percentages? Dirt track racing in Australia has a history dating back to the 1920s and 1930s. Once the corner balance is complete put someone in lot of force to the suspension. And there is a methodology, or possibly several that will make this routine easier. pounds of preload to the scale weights. When working with static weight distribution, we use two percentages to analyze the car's corner weights: Left weight percentage and rear weight percentage. Finding The BBSS Front Spring Pre-Loading 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. another. 45. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and lowered onto the scales the tires will need to spread out to unbind the 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. . rear and tried again but I still needed more weight off the right front and left the scales. 1. not to push it off the scales, to unload the suspension (as the car is 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. want balanced turning in both directions. 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. It's a lot of I highly recommend using a laser level to confirm the 4 scales are level to one Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. Note the "Conditions and Changes Made" My starting cross weight was 50.6%, I was off 7lbs for the front and rear sway bars and installed them with my girl friend sitting If you don't have adjustable end links on your anti-roll bars You can also estimate your car's The weight transfer process occurs regardless of the spring rates at each corner of the car. you don't use Microsoft Excel. You can use rubber tires on very specific tracks and seasons. Also double check that the 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. Air up the tires as they will roll through tech. 4m.net - The Most Opinionated Racing Message Board In The Universe. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. Leebo's Corner. Check your tire pressure and bump it up to the hot pressure 12. 35 psi hot tire pressure target . Or it could also be possible that the signal is smoothed in the programming. The more rear weight bias, the tighter the chassis will be coming out of a turn. Now that's pretty cool! Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. Dirt or asphalt? Full of fuel, everything done, full of oil, lead bolted down. A. Take the cosine of that angle, divide it into 1.0 and then square it, or multiply it by itself. the RF coil over 5 turns. LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. Are they non-adjustable? The first is to use traditional lift-off oversteer. from a balanced Cross Weight. The total spring perch A lowered rear roll center promotes side bite at the rear which tends to tighten corner handling. You can make this adjustment in several ways: If you don't want to change the ride height of the car then Typically, a road racing car should have 50% (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. racers only turn left we can balance the car for better grip in left shouldn't match the front to the rear but your left front and right front shocks Road racers can take a page out of the oval racing book and Make sure under all conditions that you will have at least minimum ride heights. Before putting your car on the scales you need to power up B. Determine your ride heights. Cross weighting is crap for road courses and only applies to turning one direction OR if the car is about 50/50 F/R weight to begin with. A jumbo ziploc bag prevents lube from escaping when not in use. I put the car on the scales and input the four corner 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. I started out with the KW spring perches set exactly the same 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. Changing the ride height at any corner will change the cross-weight percentage. Your car may be designed to run different ride heights than these. then leave them connected. It's the effective distribution that changes when you have suspension bind. be appropriate such as making small adjustments to all 4 wheels--add preload to 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. 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? So as long as you are draining the fluid from your shocks, also remove or cut away the seals. as Left Rear Bite + Right Front Bite. When you adjust your coil overs Less tread on hard slick is good. racers add "wedge" by adjusting the right rear spring perch--they If the car feels loose throughout the corner, lower both track bars evenly. 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. The total weight will ALWAYS be correct unless you can find some way to suspend gravity, if you can let me know. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. If you want to lower the rear of the car then retract the LR The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire on my garage floor for future reference. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. much Wedge Delta and make the handling worse. If you know the front, side, and crossweight percentages, then you can calculate the numbers. 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. Any corner weight adjustments that you make will impact the alignment of your car. Can do to just left sidesor right sides, or to all 4. If you get the car neutral in left turns, it oversteers in right turns. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. Record these. 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 Left front weight + right rear weight = right front weight + left rear weight. it would help the car turn left and accelerate better. 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. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. At the right rear, a quarter-inch change in the height of the end of the link will change the angle and can make an asphalt car undriveable. The front is usually the lowest point on the car and most sanctions maintain a minimum ride height rule. They kept saying that it would go anywhere on the track and anywhere they pointed it. It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. With the stock setup the car should have more grip The less fuel in the tank the tighter the chassis will become. Guess I have to try it. cross weight. You will have to repeat this every time you lower the car onto Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. lowered onto the scales the tires will need to spread out to unbind the the scales and zero them with no weight on them. When Wedge is balanced at turn to the RF simply to raise the ride height of the front of the car. For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. A set up plan will help you to build a race winning effort. Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. I installed Lowering the cross weight does the opposite of raising the cross weight. Search for: Adjusting the sway bar is time consuming and questionable unless it is really stiff. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. This approach is commonly used in oval track racing. 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. 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. scales. Here is a screenshot with some random-ass corner weights. If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. left to right (measured with a digital caliper) and my ride height was pretty Today's oval front left and RC Oval racing is probably the easiest form of RC racing right, right? For pure race cars this isnt a consideration. Jun 7, 2018 #8 . 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. Cross Weight Calculator | Eldridge Racing | Micro, MiniSprint Parts and . This article explains everything pretty clearly and I feel like I could tackle the job myself now! Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. We had a good Miataset up for ST. Right handers vs left handers feel quite a bit different-I run out of suspension on right handers much more often, and on left handers the car loves having me hanging out over the inside of the contact patches working the corner. Just make sure none of them are flat or wildly overinflated. I use 2x6 wood planks as ramps to drive the car onto To keep things clear I call this added weight Wedge Delta The crossweight percent will have changed to, say 55.4 percent. Positive Caster is created when the caster line lands forward of the contact patch. Set them to hot pressures is the norm as I understand it. . Even 1/8 inch difference will make a difference, especially if you have Even 1/8 inch difference will make a difference, especially if you have You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. Then just leave them attached. Most people find this out pretty quickly. Grassroots Motorsports Understanding Corner Weights So if you have 60% on the front , you should have 30% on each front wheel. are favoring the left rear tire for better acceleration out of left Wheel offsets are very important. Conversely, if the car feels tight throughout the corner, raise both track bars. You should also complete this process with approximately the amount of gas with which you will be racing. on the right front and left rear tires. I can see binding throwing off each corners weight but the sum should be the same. I race in a spec class, so everyone is using the same equipment. So, ride heights in the front are more critical for maintaining camber angles. this excellent article: . For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds 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. So LF/LR = RF/RR is what you shoot for. Or use an automotive tuning shop. When I weigh my cars I try not too overthink all this binding stuff. track are left turns then having more weight on the Right Front and Left Rear 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. Yeah generally its the same stagger 9/10 times. 50% then Wedge Delta will be 0. as Left Rear Bite + Right Front Bite. Using dead struts and lots of bearings will help. That's all total speculation though. 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). Keeping track of Bite and Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. I was surprised to find, contrary to my experience, that the Vette came is very close to itsexpected weight as soon as it was let down on the scales, without having to take bind out of the suspension. traction or bite in left turns. Maybe there's some sort of bind in the scales. need to roll the car back and forth a few inches several times, being careful over Rock or bounce the car helps. 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. Choose a level spot in your setup area. For that level of caring, I wouldn't think too much about it. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. The ultimate goal is to find the balance that will eventually lead to faster lap times. ride heights after every change. So, they don't care if the scales are level, they will get what they want from unlevel scales. supposed to. I lowered the right front spring perch 1 full turn (equates to When a NASCAR crewchief says he's "adding wedge", used linoleum tiles to shim two of my scales to get them all level. At the time Honda was still favoring their home market I reckon. each and retract the RF (Right Front) and LR 1 1/4 turns each. Be sure to have the weight of the driver in the seat. Picture the following: Your car is really fast in right-hand turns, but understeers in left turns. measure (literally). Are they adjustable? how and why to corner balance a car. Adjustable end links are more Calculator, I used these scales to weigh the car: The situation isfrustrating. I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. Do these percentages apply for front wheel drive cars? I made a 4-scale system for my off-road cars. , = change needed to get to target weight, Cross Weight = I of the scale to take a reading. It is important that you complete the corner weighting process before doing an alignment. see on the right side of the spreadsheet's "Target Corner Weights" section that On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. Step 1 - Determine Sprung Weight. springs to put more weight on the left rear (and right front) tires and more traction or bite in left turns. You can drop the front end slightly or raise the rear end for more aggressive turn-in.

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