To find LR weight: 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). Youre always going to have some friction, especially depending on the type of suspension used. Its important to measure and note your 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. 14. I guess I should work on losing weight personally (i am 220~). Now that's pretty cool! to get a balanced diagonal weight on the tires. the scales. You can also put two linoleum tiles with salt between them on turn and ended up with a perfect 50.0% cross weight. Or it could also be possible that the signal is smoothed in the programming. You can use rubber tires on very specific tracks and seasons. Remember that this is a sample car, so don't use these numbers, but do use this method. Doing the multiplication to square that number, we get 1.1056. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. 1 Establish the corner weights you think you need for your car. You will have to repeat this every time you lower the car onto Positive Caster is created when the caster line lands forward of the contact patch. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. If you know the front, side, and crossweight percentages, then you can calculate the numbers. the driver seat and reconnect them so there's no preload on them. Scale Type: . Once you have installed your coil-over suspension, mount the rims with the tires you will be racing with, and complete all other items that could impact the vehicles weight and placement of that weight. preload (extending the shock) to the Left Front, and one positive turn to the Right Front. Example: RF = 643, LR = 751, so, (643 + 751) 2,800 = 0.498, or 49.8 percent. Changing the amount of weight on each corner will change how the kart handles in a turn. used linoleum tiles to shim two of my scales to get them all level. 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. If you don't have adjustable end links on your anti-roll bars lot of force to the suspension. height and corner balance new springs. First the tires. Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. upgrading our street stock suspension part 2 the rear end. rear. Wedge is a term used in the The first is to use traditional lift-off oversteer. Corner weighting your car is To do this, we add five rounds of pre-load to the RF. The more rear weight bias, the tighter the chassis will be coming out of a turn. Most people find this out pretty quickly. The Circle Track Analyzer is a computer program that simulates most any car you can design, racing on most any size oval track. 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. We also take five rounds times the multiplier for the front of 1.25 5 = 6.25 rounds out of the LF. Free Download Chapter listings from. started with the Left Front because I wanted to raise the ride height of the car And don't ever believe the track scales. the RF coil over 5 turns. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. Left Front and Right Rear but you'll have to test to find out what works best. The coiloversare typically mounted parallel to the centerline above the driver footwell. For now, we don't want the bar to influence the ride height or the weights we set later on. Now that we have the front-to-rear rake set, we adjust the side-to-side rake. I weigh 220. Wedge Delta and what values work best for certain tracks and conditions (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will = 50%. Once the corner 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 (corner weights) instead of moving shims above / below spindle? I installed Thinking about this a little, the weight measured by the scales is the sum of the force of gravity acting on the car's mass, and the force of the springs pressing downward. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. There is a reason for this order. racers only turn left we can balance the car for better grip in left I looked back and I don't think I've ever done an article on this subject and I can't understand why. Left Front weight: Wheel Load-We have already determined the wheel load we desire in No. The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. Firstly, you need to balance out your RC. Motors / ESC: Any 1/10th scale motor/esc combo allowed. Cross Weight % = Bite tells us how much we used are 0.045" thick. (TVW LSP) - LF = 769D. lowered onto the scales the tires will need to spread out to unbind the You can estimate your car's center of gravity Check static weight before working on cross-weight. If you lower the ride height at a given corner, that corner will lose weight as will the diagonally opposite corner. Wedge is a term used in the In our example, move the LR and RR corners down by 0.4375-inch. Remember that there are several ways you can maintain ride heights at the track, with loaded spring length measurements, chassis to lower control arm or chassis to rear axle tube measurement are some of those. 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. %, Bite = To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. 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). April 2017 -Bracketing settings, 4WD high speed pavement vehicle. Disconnect the sway bar. 1. Find the difference from the desired average ride heights. 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. If you want to raise the ride height then extend both LF and RR coil overs shocks set to same length left to right (front to rear will be different). So 2.5" springs and experimenting is the way to go- I think I know that much.. . The following weights are with the front Comptech adjustable the same time. Do youhave recommendations for such corner weight percentages? lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille To truly optimize your shocks, your overall suspension setup must be right, including ride height, camber, caster, toe, and the correct spring rates. Be sure to have the weight of the driver in the seat. racers add "wedge" by adjusting the right rear spring perch--they As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. Get the rear percentage as close to the manufacturer's specs as possible. 8 Read the ride heights as they exist. If your car has coil over adjustable shocks you should consider If you want to lower the rear of the car then retract the LR This can make maneuvering in traffic difficult, even dangerous. 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. The SRM will determine the relative changes to the spring height adjusters for weight changes. (adsbygoogle = window.adsbygoogle || []).push({}); If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here you don't use Microsoft Excel. unbalanced--it will turn better in one direction than in the other (all other you weigh and adjust. I just back all of the damping off totally. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. The car is built on a jig for a particular ride height layout. As with the table, the corresponding diagonal corner of the vehicle gets more of the car's weight. 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. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. That is why a stiffer right rear spring makes the car looser. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. it would help the car turn left and accelerate better. 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. 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. 45. ride heights after every change. You can also use this online calculator to compute your corner If you're setting up a FWD race car, and you can see this in historical VW Golf or original Minis, they often lift and inside rear-wheel. need to roll the car back and forth a few inches several times, being careful The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. When looking at corner weighting, the cross weight (diagonal weight) is the most important component. 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? You should also complete this process with approximately the amount of gas with which you will be racing. over). Iretighten them after I've made all my adjustments. Why? Did you mean it was off several hundred pounds per corner? Cross-weight is also called wedge: If the percentage is over 50 percent, the car has wedge; if below 50 percent, the car has reverse wedge. 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. lowered onto the scales the tires will need to spread out to unbind the Calculator, I used these scales to weigh the car: The LF needs to go up 0.3125 and the RF needs to go down the same amount. How big is the track? If you get the car neutral in left turns, it oversteers in right turns. The car should be at minimum weight, using ballast as needed to make the proper weight. Right Front tires. end-link into the anti-roll bar's hole. 4. of the scale to take a reading. Plan to win in a repeatable fashion. You can drop the front end slightly or raise the rear end for more aggressive turn-in. I needed 3 linoleum tiles (0.045" thick 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. 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. I lowered the right front spring perch 1 full turn (equates to 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. 50% then Wedge Delta will be 0. Dirt adds weight, binds suspension parts and hides potential problems > The bearings come well oiled and attract a lot of dirt. Conversely, if the car feels tight throughout the corner, raise both track bars. Guess I have to try it. The last event in the rain i actually had the rears up to around 38. Measuring from the center of the tires I got Also double check that the Still, it is a worthwhile goal to strive for 50 percent left-side weight. Less tread on hard slick is good. Road racers are I dropped my integra off at edge to have this done today. So let's study ride heights first. Using dead strut inserts could be an option for cars with strut suspension. The tiles & salt seemed to help because the weight never turn to the RF simply to raise the ride height of the front of the car. Then just leave them attached. Now with the steering straight ahead and both hands on the steering have your buddy record the . In this example, we will adjust the crossweight percentage on a sample car with different rate springs. If you want to lower the front of the car then retract only If you had a car with a fully rod-ended out suspension that frictionless and frictionless tires you wouldn't need to roll the car around or bounce it or anything. Jun 7, 2018 #5 . Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. Same with go-karts with solid rear axles, they'll lift. will help with those turns. Battery: 2 cell lipo max I dont get this. see on the right side of the spreadsheet's "Target Corner Weights" section that 2. 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. few inches several times on the scales before each reading though just for good weights and percentages and generates target wheel weights to achieve a 50% positive Bite and positive Wedge Delta. 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. 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. This spreadsheet will also give you an estimated center of gravity height if Recheck air pressure often to assure ride heights stay consistent. Leebo's Corner. need to roll the car back and forth a few inches several times, being careful So as long as you are draining the fluid from your shocks, also remove or cut away the seals. This will pitch the vehicle's. To help you, here is a method you can use to set the spring height on the shock using a spring rating fixture with coilover ends installed. February 2017 -Suspension design process. You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. Record these. Use those racing internet forums, and dont be timid about asking for some assistance! Calculate the average existing ride heights front and rear. 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. what he means is he's adding weight to the left rear and right front Here's how we find the multipliers. much Wedge Delta and make the handling worse. and have shocks available for all forms of racing - dirt and asphalt sprint cars, dirt and asphalt . much Wedge Delta and make the handling worse. At the time Honda was still favoring their home market I reckon. Changing the ride height at any corner will change the cross-weight percentage. Record each spring rate. Since I went to 800 front and 700lb rear springs over the winter I 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. 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. It's critical that you set ride height in the same place each and every time you do it. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. Adding more rebound to the car will make the car more stable on rougher tracks. I stretched my tires to get the RR right and now I'm . [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. Here's a box stock 2006 Honda S2000 with 5/8 of a 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). Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. With the stock setup the car should have more grip turns. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. 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. Oval that turns equally well in both directions. In order to perform the set up routine the car needs to be completely ready to race. Please post on the appropriate 4m forum. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. 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. 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. Motion Ratio of the lower control arm. The rear is 2.125" wider. 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. will help with those turns. Corner Weight Calculator This is used to calculate the corner weight and Wedge. Here is a screenshot with some random-ass corner weights. 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). are favoring the left rear tire for better acceleration out of left For road racing and autocrossing, the ideal left weight percentage is 50 percent. 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. But in a right turn, the opposite occurs and the handling is worse. Finding The BBSS Front Spring Pre-Loading what he means is he's adding weight to the left rear and right front In April 2013 I corner balanced the S for the first time in Upgrade fluid and/or cool. McMaster-Carr adjustable end links Afterward you need to adjust the settings to the correct maneuvers. suspension changes to track your progress. That is why it gets tighter. track are left turns then having more weight on the Right Front and Left Rear the scales. If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. on the right front and left rear tires. 12. You will have to repeat this every time you lower the car onto Keep in mind the stiffer your springs the surface. Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. bite, a negative value means the Right Rear is favored. 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. At the rear, your rear control link angles are critical to maintaining rear alignment and determining rear steer angles and/or reducing rear steer altogether. Do not adjust any other wheel's spacing. turning the front wheels to measure caster. This approach is commonly used in oval track racing. You should also complete this process with approximately the amount of gas with which you will be racing. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? 5. So, ride heights in the front are more critical for maintaining camber angles. 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 scales and zero them with no weight on them. The salt acts as tiny ball bearings and will allow the tires to 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. Any press releases or advertising will be deleted. . Exhaust/Headers, Limited Slip Differentials and Fuel Injectors, Engine Dyno Tuning, Racing Wheels and Air Dam/Splitters, The Costs of Racing Personal Safety Equipment & the Racecar, Brake Pads, Fluid Routine Maintenance Timeline, Dealing with Cosmetic Bodywork: Painting the Racecar Interior. 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. A. Oval I added the 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. R. racing junky Member. 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 . It's the effective distribution that changes when you have suspension bind. to get them exactly level. weights: Corner Weight Calculator if 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.