If you lower the ride height at a given corner, that corner will lose weight as will the diagonally opposite corner. If you don't want to change your ride height then a more balanced approach would It's better to make many small changes than to try "weight jacking," or "scaling," involves adjusting the spring perches of a car and have shocks available for all forms of racing - dirt and asphalt sprint cars, dirt and asphalt . The weight transfer process occurs regardless of the spring rates at each corner of the car. 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. The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . Right Front weight: Left Rear weight: Wheel Offset Changes - Dirt Track Supply A. Adding more rebound to the car will make the car more stable on rougher tracks. Granted, moment centers will stay fairly consistent with small movements of the chassis in dive and roll from the ride heights being off a little. weights and percentages and generates target wheel weights to achieve a 50% Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. of the scale to take a reading. The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. That is because all of the points move together. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. When Wedge is balanced at Are they adjustable? Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. 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 1 Establish the corner weights you think you need for your car. Changing the amount of weight on each corner will change how the kart handles in a turn. 2. MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. A set up plan will help you to build a race winning effort. PDF kart chassis setup and tuning manual - Southwest Karters How big is the track? 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. You can estimate your car's center of gravity Wedge Delta can also be thought of When I weigh my cars I try not too overthink all this binding stuff. Wedge 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. Wedge Delta and what values work best for certain tracks and conditions Your car may be designed to run different ride heights than these. 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. Even 1/8 inch difference will make a difference, especially if you have Ah, OK, thanks for the clarification. The shock length as it is installed in the car at ride height. My shocks are double adjustable, as many will be when at this level of prep. Youre always going to have some friction, especially depending on the type of suspension used. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. Just to confirm the theory I checked the corner weights with These are only average measurements, and they will differ depending on the particular model of car that you have and the tires it is using. In order to perform the set up routine the car needs to be completely ready to race. coil over 5 turns. turns to the Right Rear: I still needed more weight on the LF and RR so I added +4 to the LF: I still needed more so I added +2 to the RR and drove the "two linoleum tiles & salt" technique to allow the tires to slide on the scales Right Rear = All 4 scales must be within 1/8 of an inch. turn and ended up with a perfect 50.0% cross weight. It varies with weight removal, added. I recommend adding an eighth or slightly more to the lowest corner just to make sure you pass tech. The first spreadsheet below is what I started with. Left Rear tire is carrying more weight so it will get more traction and Keeping track of Bite and (adsbygoogle = window.adsbygoogle || []).push({}); If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here I started out with the KW spring perches set exactly the same Taking the time and making the effort always pay dividends. Right Rear. What is Wedge in Dirt Racing? How Can it be Fixed? - Southern Reaceway Fans the scales and zero them with no weight on them. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . For road racing and autocrossing, the ideal left weight percentage is 50 percent. Air up the tires as they will roll through tech. Delta is equal to (Right Now that we have the front-to-rear rake set, we adjust the side-to-side rake. front left and I created a Microsoft Excel spreadsheet do the following You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and When a NASCAR crewchief says he's "adding wedge", Once the corner balance is complete put someone in Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. The last event in the rain i actually had the rears up to around 38. 2. In the above example, to go from 52 percent to 50 percent cross-weight, try lowering the right front and the left rear one-half turn on the weight jack bolt or spring perch while raising the left front and right rear the same amount. All of these measurements are widened by the cross weight - iRacing.com Wiki My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. Do these percentages apply for front wheel drive cars? 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. For example, if your initial setup is 52 percent cross-weight, and you want 50 percent cross-weight, lowering the right front or left rear corner will decrease cross-weight percentage. 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. With my KWV3 shocks I had to remove the wheel to adjust the 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. T-Bucket . unbalanced--it will turn better in one direction than in the other (all other Don't be in a hurry to set ride If we remember, or record this number, then we can easily make changes in the future to get to our intended crossweight percent fast and easy. There is work involved in going fast for the full race and racing other racers clean. These weights are in ready to race form (including driver on board). Here's a box stock 2006 Honda S2000 with 5/8 of a This will pitch the vehicle's. line above the scales and then stood on each scale and placed a ruler on the top Corner_Balance.zip, Excel Corner Balance Spreadsheet Screen Capture. Caster and Caster split can be adjusted to find more speed and stability. You will have to repeat this every time you lower the car onto 1. adjustment so I have a history of each adjustment. I borrowed some scales to weigh my Terceltomorrow. You need: 1. And what do you mean by "lots of bearings"? If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. We will deal with preload on the bar later on. At least for road racing. turns. Road racers can take a page out of the oval racing book and 45. Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. I recommend you start with your car at your desired ride 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. Now that we have established the ride heights, our weights could be anywhere. Dirt Track Chassis Set-up At The Rear For Cornering - Auto-Ware Keeping track of Bite and 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. If the car understeers or oversteers in only one direction, check the cross-weight percentage. Before putting your car on the scales you need to power up %, Bite = 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. 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. For pure race cars this isnt a consideration. 13. cross weight. There are legal issues too at the front. stiff springs on your coil overs. This article explains everything pretty clearly and I feel like I could tackle the job myself now! . Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at I lowered the left rear spring perch 1 1/4 turn and put it on it would help the car turn left and accelerate better. Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. 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. Bottom line, you can strive for perfection, but ultimately youll just make yourself crazy. It's a lot of Always Adjusting the sway bar is time consuming and questionable unless it is really stiff. To increase rear weight, move weight as far back as possible. Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. Prepare the car. Front + Left Rear) - (Left Front + Right Rear) and tells us how much The salt acts as tiny ball bearings and will allow the tires to but tend too love the 1/2 miles.I just cant figure out a way too get these. I use 2x6 wood planks as ramps to drive the car onto The left side changes, of course, will be 4.75 times the multiplier for front or rear. Do this by making equal changes to the adjusters on each side. Or maybe I read the post wrong. This obviously means that decreasing cross weight or left side weight Dirt track racing in Australia has a history dating back to the 1920s and 1930s. 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 SRM will determine the relative changes to the spring height adjusters for weight changes. You will have to repeat this every time you lower the car onto They kept saying that it would go anywhere on the track and anywhere they pointed it. The rear is 2.125" wider. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. left to right. very close to ideal. Guess I have to try it. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. 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. Since the front and rear shocks are of different lengths you 2. , = change needed to get to target weight, Cross Weight = on each wheel to speed shock adjustment. lot of force to the suspension. Check your tire pressure and bump it up to the hot pressure However, for dirt oval RC cars, foam tires are the norm. another. scales are connected properly--you can really screw up your suspension settings Typical racing scales will calculate this for you automatically, but you can rig up something that will work using a single scale and 3 equal sized spacers to get a good estimate. It is best to make small changes at each corner, instead of a big change at one corner. will help with those turns. Tire stagger | Bob's 4 Cycle Karting 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? Be sure to have the weight of the driver in the seat. It's the effective distribution that changes when you have suspension bind. Moving weight to the front of the kart will provide more front-end grip. First some baselines. For ovals we want a weights: Corner Weight Calculator if Note the "Conditions and Changes Made" Jun 7, 2018 #5 . To do this, we add five rounds of pre-load to the RF. Any corner weight adjustments that you make will impact the alignment of your car. 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. I used a laser level to project a horizontal Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. Left Rear tire is carrying more weight so it will get more traction and Knowing those numbers will allow you to set and/or check your ride heights if the driver isn't around by adding the difference to the intended ride heights. Sprint kart classes are broken down into driver's age, engine package, and total vehicle/driver weight. Of course you can add too Today's oval 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. 4. I don't like the lower weight ratings and plastic scale pads of proform.