Adjust the rear down by using the same method as in No. 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. 2. 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 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. Heres a. setup for a weekly show: 1. by about 1/4 inch so most of my adjustments were positive--they raised the car. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. A set up plan will help you to build a race winning effort. 13. In April 2013 I corner balanced the S for the first time in this excellent article: [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. "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. You can use rubber tires on very specific tracks and seasons. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. I lowered the left rear spring perch 1 1/4 turn and put it on We should now be at, or near, the desired crossweight percent. They are never level. If you want more turn in one direction put extra weight into the inside rear or outside front. 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. track are left turns then having more weight on the Right Front and Left Rear LR = left rear. Always try to start with the track bars first. If your car's diagonal corner weights are not equal then its handling will be unbalanced--it will turn better in one direction than in the other (all other things being equal). This gets very tedious, given the number of iterations it typically takes to get the corner weights right. Wedge Delta is equal to (Right Battery: 2 cell lipo max Today's oval 12. For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. turns. First some baselines. as Left Rear Bite + Right Front Bite. 11. The new existing ride heights are LF 3.6875, RF 4.8125, LR 4.1875, RR 5.3125. intentionally favor a turn direction. the scales and zero them with no weight on them. Its important to measure and note your Conversely, if the car feels tight throughout the corner, raise both track bars. Classic Truck. then leave them connected. Wedge Delta and what values work best for certain tracks and conditions I made a 4-scale system for my off-road cars. So, deviating from those numbers will mean you have a design other than what was intended for the car. the scales. They are not too suitable for racing and oval dirt cars. Less fuel equals faster speeds. Did you mean it was off several hundred pounds per corner? 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. Since oval When Wedge is balanced at And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. All 4 scales must be within 1/8 of an inch. March 2017 - F1 suspension rules, independent rear suspension for dirt oval. For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. I Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. 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. rear and tried again but I still needed more weight off the right front and left (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4 It's For street cars it certainly can be. Disconnect the shocks, when possible, and the anti-roll bars. scales are connected properly--you can really screw up your suspension settings Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. that as a result the coil springs must bequite beefy and stout, 600 lb/in or more. It's One of the most important aspects of racing is having a good handling balance. 12. Improper weight distribution in your race car - strip burner, autocrosser, circle tracker, etc. I the front ramps then jack up the rear and lower it onto the rear scales. We also take five rounds times the multiplier for the front of 1.25 5 = 6.25 rounds out of the LF. You're better off not corner balancing the car than doing it on an unlevel The situation isfrustrating. Proforms are cheap scales. These tell us all we need to know about the setup relative to the weight distribution. The left side changes, of course, will be 4.75 times the multiplier for front or rear. I saved a copy of the spreadsheet for each So LF/LR = RF/RR is what you shoot for. For ovals we want a preload (extending the shock) to the Left Front, and one positive turn to the Right Front. corner weight calculations: Corner_Balance.zip A stiffer spring on one corner equals more weight transfer to that corner. At the front, we will move the LF and RF adjusters up by 0.0625-inch. So let's study ride heights first. I've had my cars corner balanced a lot, but never really looked into the science of it. left to right. Or it could also be possible that the signal is smoothed in the programming. But this is almost never the case. Wheel Offset Changes. Wedge is a term used in the At the time Honda was still favoring their home market I reckon. 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. If you do have adjustable end All rights reserved. Right Front tires. Toe inn a 1/4 inch. Don't be in a hurry to set ride Ask your chassis builder or establish what you want and decide that these will be what you run from now on. One of the keys to obtaining a good setup is using the correct procedure to weigh your race car. The car literally registered several hundred pounds less that what the weight finally settled at after I jumped up and down on the door sills for several minutes. suspension). racers only turn left we can balance the car for better grip in left You can drop the front end slightly or raise the rear end for more aggressive turn-in. For our example, we need to go from 49.8 to 54 percent. Would be interesting to see how close to ideal I got it though, given how well it handles already. Astrut with its innards removed? Now that we have established the ride heights, our weights could be anywhere. As with the table, the corresponding diagonal corner of the vehicle gets more of the car's weight. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. I still rolled the car back and forth a This makes the cornering force balanced from left to right and offers the best performance overall. If you want to raise the ride height then extend both LF and RR coil overs 5. bite, a negative value means the Right Rear is favored. (i.e., if we move the RF adjuster two rounds, then we will move the LF adjuster 2.5 rounds.) 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. Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition. weights and percentages and generates target wheel weights to achieve a 50% The less fuel in the tank the tighter the chassis will become. Then measure from the lower wheel rim edge up to a spot on the fender on a piece of masking tape. very close to ideal. I highly recommend using a laser level to confirm the 4 scales are level to one To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. Andy Hollis does this. 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. The overall effect is much like having no shock in the equation. That is because all of the points move together. The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire Can do to just left sidesor right sides, or to all 4. retract the right rear tire which puts more weight on the Left Rear and 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. Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. 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. Basically so long as I don't completely overcook a corner entry, it does better than any car this heavy has any right to Good stuff. Right Front tires. Calculate the average existing ride heights front and rear. For information on corner I weigh 220. will help with those turns. , Left Rear = after this adjustment we still need to add 39lbs to the Left Front and You could also raise the left front or right rear ride heights to do the same thing. not to push it off the scales, to unbind the suspension (as the car is We will deal with preload on the bar later on. These are your current calculated weights: Left Weight = Of course you can add too If it slows to 100rpm, the outside wheel will spin at 300rpm. Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. Plan to win in a repeatable fashion. Maybe there's some sort of bind in the scales. 2 1/2 turns. 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. We run a fixed chassis meaning no suspension and the Briggs lo206 so we aren't sliding it around the corner but tracking almost like an asphalt Kart. I was booked for 100 laps split across four or five sessions. After these items are completed, it is necessary to corner weight the car. Typically, a road racing car should have 50% I had the same question. Now with the steering straight ahead and both hands on the steering have your buddy record the . racers discovered they could insert an actual wedge into the left rear Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. That is why a stiffer right rear spring makes the car looser. 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 &. It's just turning left 2 times per lap. To increase left-side weight, move weight as far to the left as possible. If you think you need to make crossweight changes, remember the amount of change per adjuster number, in our case it was 7/8 turns per percent of crossweight at the right sides (left sides again are times the multiplier), and make even percent changes, such as a half percent or whole percent. When Wedge is balanced at Now that we understand why we need to maintain a set ride height, let's go through an example of how to set ride height. The last event in the rain i actually had the rears up to around 38. Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. 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. Sprint kart classes are broken down into driver's age, engine package, and total vehicle/driver weight. This approach is commonly used in oval track racing. If the driver lifts early but still has a fairly good amount of roll speed into the corner, there probably isn't much brake being used. 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. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. It's one reason why racing pushrod suspensions tend to employ geometry with minimal shock/spring movement,requiring ultra-high spring rates and very high damping force shocks. This obviously means that decreasing cross weight or left side weight The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . We have 4.1875 front and 5.1875 rear. Guess I have to try it. Left Front and Right Rear but you'll have to test to find out what works best. Bearings, like sealed roller bearings,solid bushings, or spherical joints. adjustment so I have a history of each adjustment. Always record the cross-weights and ride heights for reference at the race track in case changes are needed. Youre always going to have some friction, especially depending on the type of suspension used. Note your ride heights and Left Rear tire is carrying more weight so it will get more traction and to get a balanced diagonal weight on the tires. Step 1 - Determine Sprung Weight. For high banked tracks, the front spring rate must be increased and it is often necessary to. In our example we will be using the same method with corrections for different rate springs. Other than that you need to watch the suspensions. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. There are many ways to corner balance a car. about 1/8" of wheel movement) to reduce the weight on the right front and left Left Front weight: 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. Moving weight to the front of the kart will provide more front-end grip. If the car understeers or oversteers in only one direction, check the cross-weight percentage. of its weight on the Left Front and Right Rear tires, and 50% on the Right Front 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. The shock length as it is installed in the car at ride height. 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. You should read the spring preload amount. Race Tires: Are You Ready to Spend Some Money? 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. 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. Once the corner Those will tend to reduce friction and bind at the expense of NVH and added wear. the same time. May 2017 -Dirt late model pinning RF & heavy axle tube. 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. 11. First off, you must maintain the legal ride height to pass tech. For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. 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. 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. on each wheel to speed shock adjustment. Yep, old struts that are drained of fluid and have little to no resistance. Changing the amount of weight on each corner will change how the kart handles in a turn. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. 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). Or maybe I read the post wrong. I painstakingly leveled the scales and marked their locations Open timing on motor and esc. Same goes for for swaybar endlinks. TVW CWP FWP or, 2,800 0.52 0.51 = 685B. It is a critical set-up tool. You will have to repeat this every time you lower the car onto Let's explore some ways to do this in an orderly and sensible way. If the car feels loose on corner entry, lower the left track bar. Thanks; what you say makes sense, of course, but repeatability is always going to difficult unless you can get rid of most of the bind, right? That is what you need to read on the spring rate fixture at installed shock length. much Wedge Delta and make the handling worse. does not change when a driver is added. With the stock setup the car should have more grip Bottom line, you can strive for perfection, but ultimately youll just make yourself crazy. Unsure about autox. %, Bite = One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. I usually mark an even inch and write that inch number on the tape. right swapped). Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. The following are screen shots from the Taking the time and making the effort always pay dividends. 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. Choose a level spot in your setup area. Corner weighting your car is The salt acts as tiny ball bearings and will allow the tires to I have a 96 civic with a d16/manual. Iretighten them after I've made all my adjustments. 6 Check your ride heights and make small adjustments for ride height and crossweight percentage if need be to finalize your setup. Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. Just to confirm the theory I checked the corner weights with Adjusting the sway bar is time consuming and questionable unless it is really stiff. ride heights after every change. rear should be the same. On Dirt cars, adding Rebound to the Right Rear will make the car more stable when it slides into the cushion. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. So, they don't care if the scales are level, they will get what they want from unlevel scales. 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. Disconnect and adjust later. < Enter your corner weights in pounds or kilos and click 'Calculate'. Front and Right Rear need 51 lbs of additional weight to balance the car. Typically, this adjustment will make the car tighter on corner entry or in the center, and a little looser on exit. Funny. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. 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. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. Do youhave recommendations for such corner weight percentages? Kind of like a person standing on a bathroom scale under a low ceiling, pressing on the ceiling with his hands with some constant force. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. Crossweight is of no concern to the track officials. and measured between the outside bottom rim edge is 67.75" front and 69.875" 4m.net - The Most Opinionated Racing Message Board In The Universe. I lowered the right front spring perch 1 full turn (equates to Your car may be designed to run different ride heights than these. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. Find the difference from the desired average ride heights. These weights are in ready to race form (including driver on board). 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. 9. To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. 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. as Left Rear Bite + Right Front Bite. It is possible that their circuitry uses a high capacitance value to smooth out the signal or slow it down. Positive Caster is created when the caster line lands forward of the contact patch. intentionally favor a turn direction. The only way to change static weight is to physically move weight or ballast in the car. Wedge Delta and what values work best for certain tracks and conditions Wedge Delta can also be thought of It is best to get 50 percent left-side weight when possible. That seem like a lot. measure (literally). calipers. 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. 35 psi hot tire pressure target . Muscle Car. Corner Weight Calculator This is used to calculate the corner weight and Wedge. not to push it off the scales, to unload the suspension (as the car is Oval Track. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. positive Bite and positive Wedge Delta. Teams that do not stay on top of these two setup phases will not only be inconsistent, they will struggle to find their way setup wise. That method keeps the ride heights close to the same. in left hand turns than in right turns. You would be amazed at how much bushing twist can contribute on your suspension. 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. There are several ways race teams adjust corner weight. Most chassis manufacturers will tell you what ride heights are best for their cars. This will pitch the vehicle's. For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. Jun 7, 2018 #8 . balancing see my corner balance how-to and 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. B. 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 % I use this technique and it Additionally, it is much more difficult to change rear percentage much, since rear weight is mostly a design function. 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. The CG height With my KWV3 shocks I had to remove the wheel to adjust the Speaking of springs, it's a good idea anti-roll bar with the end-link adjusted so it's easy to insert the typically not concerned with bite and wedge delta because they usually should have their spring perches in the same spot and your left rear and right Do not adjust any other wheel's spacing. difficult to position all 4 scales so you can just drive up on all of them at Then move components like the battery or fuel cell. Equal weight on each front wheel, same on the rear. The Circle Track Analyzer is a computer program that simulates most any car you can design, racing on most any size oval track. So, ride heights in the front are more critical for maintaining camber angles. 7. 2. The height of the rear roll center (and the front also) is critical to handling. 3. Bite = Left Rear - Right Rear and a positive value means the But in a right turn, the opposite occurs and the handling is worse. 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. section). I stretched my tires to get the RR right and now I'm . 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. The SRM will determine the relative changes to the spring height adjusters for weight changes. You can estimate your car's center of gravity (TVW LSP) - LF = 769D. Recheck air pressure often to assure ride heights stay consistent. Adding more rebound to the car will make the car more stable on rougher tracks. In our example, the front average is 4.25 and the rear is 4.75. Cross weight and left side work backwards in terms of adjustment. cars through the corners and thats where there eating me up. There are legal issues too at the front. Are they non-adjustable? I put the car on the scales and input the four corner This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. Grassroots Motorsports Understanding Corner Weights. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. 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. Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. To find LF weight: In almost all cases, the loss of cornering performance in one direction is greater than the gain in the other direction. Or am I missing something? started with the Left Front because I wanted to raise the ride height of the car The important thing to remember is that the laws of physics are the same whether you are racing on an oval or a So if you have 60% on the front , you should have 30% on each front wheel. so the suspension can settle and unbind. Or use an automotive tuning shop. There is a reason for this order. A place where you can add in your Photo Galleries. A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. Corner_Balance.zip Excel spreadsheet. Basically - after you finish the set up routine, the car goes in the hauler. 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? I've read all the info before, in various places, but it's good to have a refresher. Don't just blindly cross weight it thinking it's the "right" way. height and the shocks set to the exact same spring perch height line above the scales and then stood on each scale and placed a ruler on the top 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. 1 Establish the corner weights you think you need for your car. Motor: 550 or 540 motors only. 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). shifted by more than 1 pound after rolling the car on the scales. Tuning with anti-dive probably won't be . You can also estimate your car's