Wedge Delta can also be thought of Race Tires: Are You Ready to Spend Some Money? If the car feels loose on corner entry, lower the left track bar. 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. close to where I wanted it. You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire 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. Right Rear = Maybe there's some sort of bind in the scales. The Science Behind Dirt Late Model Suspension Setup the scales. Still, it is a worthwhile goal to strive for 50 percent left-side weight. important for oval racers, especially on dirt ovals. 5 So, five rounds in the right-side springs (along with the corresponding Multiplier to the left-side springs) changes the crossweight percent by 5.6 percent, which is 1.12 percent per round, or 0.89 rounds per percent of crossweight. I didn't hunt for that missing 1 %. 35 psi hot tire pressure target . Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . Make small changes at the track, and make only one change at a time. 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. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. April 2017 -Bracketing settings, 4WD high speed pavement vehicle. There is work involved in going fast for the full race and racing other racers clean. When you adjust your coil overs about 1/8" of wheel movement) to reduce the weight on the right front and left 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. We had a good Miataset up for ST. in the driver's seat to load the suspension. line above each scale and placed a ruler on the top But this is almost never the case. rear. T-Bucket . When working with static weight distribution, we use two percentages to analyze the car's corner weights: Left weight percentage and rear weight percentage. Many electronic scales will perform the calculations for you. I still rolled the car back and forth a 50% then Wedge Delta will be 0. Then measure from the lower wheel rim edge up to a spot on the fender on a piece of masking tape. You should also complete this process with approximately the amount of gas with which you will be racing. I was surprised how much these high rate Other things to take into consideration are track conditions and weather changes. < Enter your corner weights in pounds or kilos and click 'Calculate'. more important corner balancing becomes. That seem like a lot. 2018 Arrow Chassis Street Stock. - zwrw.barettobeltrade.it % Can do to just left sidesor right sides, or to all 4. 2. Your results might be different from mine. can help us get our setup right with less testing. Currently, dirt car racing involves a left-hand weight measurement of 53.5-55, along with a wedge between 75-125 pounds. Bite and Wedge Delta are 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. Adjustable end links are more I installed My starting cross weight was 50.6%, I was off 7lbs Delta which is simply the difference between the two diagonal tire weights. The LF needs to go up 0.3125 and the RF needs to go down the same amount. Jacking weight will not alter the left side or the rear percentages. renting/borrowing/buying some scales and corner balancing your car. 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. car for a week to let the suspension settle: I decided to disconnect the front and rear sway bars to see what 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. Free Download Chapter listings from. I weigh 220. A jumbo ziploc bag prevents lube from escaping when not in use. height and the shocks set to the exact same spring perch height Bite = Left Rear - Right Rear and a positive value means the Moving weight to the front of the kart will provide more front-end grip. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. This spreadsheet will also give you an estimated center of gravity height if Dirt Track Chassis Set-up At The Rear For Cornering - Auto-Ware stiff springs on your coil overs. 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. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. We should now be at, or near, the desired crossweight percent. to get a balanced diagonal weight on the tires. 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. Wedge Delta and what values work best for certain tracks and conditions To favor right turns, put more weight on the Put the driver weight in the car, preferably the driver. Left Rear tire is carrying more weight so it will get more traction and Both of these items will impact the cross weight of the car, and therefore they are important in the corner weighting process. That's all total speculation though. Road racers are Corner Balance Calculator - Rob Robinette difference that made. The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. Interested in hearing peoples' opinions and (preferably) experiences. shifted by more than 1 pound after rolling the car on the scales. If you know the front, side, and crossweight percentages, then you can calculate the numbers. They are not too suitable for racing and oval dirt cars. Disconnect and adjust later. tank of gas, and no driver or passenger: Now here's the same stock S2000 with a 215lb driver in the seat: I was really surprised to see how far off the stock S2000 was end-link into the anti-roll bar's hole. racers add "wedge" by adjusting the right rear spring perch--they should have their spring perches in the same spot and your left rear and right Right Front tires. Wedge Delta is equal to (Right Weight Training: Everything You Need to Know About Race Car Weight Calculate the average front and rear desired ride heights. upgrading our street stock suspension part 2 the rear end. on my garage floor for future reference. %Right Weight = Move ballast first, since it's easier. Understanding corner weights | Articles | Grassroots Motorsports I use 2x6 wood planks as ramps to drive the car onto In circle track racing, we often, and almost always, have different rate springs on each corner of the car. 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. lot of force to the suspension. Conversely, if the car feels tight throughout the corner, raise both track bars. Note the "Conditions and Changes Made" Finding The BBSS Front Spring Pre-Loading Setup Routine - JOES Racing Products Most people find this out pretty quickly. There are legal issues too at the front. 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). I race in a spec class, so everyone is using the same equipment. I added the My track width with CE28 17" x 9" wheels Small angles can throw off your readings significantly. Thanks. Step 1: Setup And Tuning The Tires Most regular RC cars use rubber tires. You can also put two linoleum tiles with salt between them on I needed 3 tiles on the left front and 1 on the left rear Check your tire pressure and bump it up to the hot pressure 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 Toe inn a 1/4 inch. You can also estimate your car's This will pitch the vehicle's. To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. 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. I see disconnecting the sway bar, and how to do it, but disconnect the shocks? after this adjustment we still need to add 39lbs to the Left Front and 57.5" front and 59.625" rear. I highly recommend using a laser level to confirm the 4 scales are level to one decided to try 5 turns total of spring perch movement to balance the car. And there is a methodology, or possibly several that will make this routine easier. The other two corners will lose weight. 11. weights: Corner Weight Calculator if I've read all the info before, in various places, but it's good to have a refresher. Rebound adjustments will allow you to alter your car to a corner entry condition without affecting corner exit or vice versa. Example: RF = 643, LR = 751, so, (643 + 751) 2,800 = 0.498, or 49.8 percent. Andy Hollis does this. You've mentioned "dead struts" a couple of times - what do you mean by that? Open timing on motor and esc. The total spring perch Corner Weighting You can drop the front end slightly or raise the rear end for more aggressive turn-in. 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 W. William18 New member. Understanding corner weights. Here's how we find the multipliers. 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. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. weights into the spreadsheet (the blue numbers in the left "Corner Weights" However, most importantly you need to take care of the handling. And don't ever believe the track scales. LR = left rear. and Left Rear. To find LR weight: Its important to measure and note your 5 diameter stainless ball bearing on top of a 1" shortwell socket on the center of a floor Jack and jack the car up in the center of the rearend housing. Front + Left Rear) - (Left Front + Right Rear) and tells us how much You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. Wedge Delta and what values work best for certain tracks and conditions are favoring the left rear tire for better acceleration out of left Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. Yeah generally its the same stagger 9/10 times. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . TVW - (RF + LF + LR) = 603. that turns equally well in both directions. 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. retract the right rear tire which puts more weight on the Left Rear and The Track (FATT) event and it handled superbly. I lowered the left rear spring perch 1 1/4 turn and put it on 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. It was a good car. want balanced turning in both directions. "This is called chassis pre-load. 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. I dropped my integra off at edge to have this done today. springs to put more weight on the left rear (and right front) tires and The less fuel in the tank the tighter the chassis will become. To find LF weight: Doing the multiplication to square that number, we get 1.1056. We have 4.1875 front and 5.1875 rear. Wheel offsets are very important. Hot Rod. anti-roll bars then leave them connected. The following weights are with the front Comptech adjustable adjustment so I have a history of each adjustment. Grassroots Motorsports Understanding Corner Weights Because we desire 52 percent, we will need to increase the crossweight percent. 3.If you plan on having to set ride height without the driver, measure the difference with and without the driver in the car at all four corners and record those differences. Upgrade fluid and/or cool. I made a 4-scale system for my off-road cars. With the stock setup the car should have more grip 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. Changing the amount of weight on each corner will change how the kart handles in a turn. For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. Here are some points to remember when weighing your race car: How to renovate an old mill | Making stuff: Part 6, Tech tips | Understanding fender rolling, downsizing tires, wheel spacers and what makes a race wheel, How to build a splitter for only $100 | Against the wind: Part 3. Record these. lowered onto the scales the tires will need to spread out to unbind the 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. Once the corner Recheck the ride heights and adjust to fine tune, making changes to the front and rear at the same time. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. To find RR weight: Right Front tires. The only way to change the static weight distribution percentages is to physically move weight around in the car. Astrut with its innards removed? It's balancing see my corner balance how-to and 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. Right Front weight: Left Rear weight: They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. When a NASCAR crewchief says he's "adding wedge", For pure race cars this isnt a consideration. Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. Recheck air pressure often to assure ride heights stay consistent. Get the rear percentage as close to the manufacturer's specs as possible. Since the front and rear shocks are of different lengths you 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. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. 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. R. racing junky Member. Typically, a road racing car should have 50% My car has solid/spherical bushings everywhere, so there should be very little bind from them. A 50% Cross Weight will yield a balanced handling car, one It is important that you complete the corner weighting process before doing an alignment. 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. ride heights after every change. much Wedge Delta and make the handling worse. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. 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). 13. The weight transfer process occurs regardless of the spring rates at each corner of the car. The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. How To Corner Weight Your Car - Suspension Secrets % Wedge Delta will be 0 at 50% Wedge. I recommend you start with your car at your desired ride 13. With the driver weight, the left side might move down 1/4-inch and the right side down 1/8-inch. It would just automatically settle. much Wedge Delta and make the handling worse. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? 4m.net - The Most Opinionated Racing Message Board In The Universe I overshot by a little so I raised the left rear spring perch by 1/2 That math gives us a percentage number to . suspension changes to track your progress. Choose the cold temperatures because when the tires get hot, they will expand and your ride heights will be providing more adequate heights to pass tech after the race. Road racers are two years. One of the most important aspects of racing is having a good handling balance. The overall effect is much like having no shock in the equation. and measured between the outside bottom rim edge is 67.75" front and 69.875" (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. Less tread on hard slick is good. Also double check that the 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. Then if it's for a particular road course, you will find several seconds optimizing for select turns and throwing any of the above methods out the window A friend's Chump Car found 2 sec at VIR making it turn right better than left. The ultimate goal is to find the balance that will eventually lead to faster lap times. 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. 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. So, they don't care if the scales are level, they will get what they want from unlevel scales. 5. Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. over). Weight can be moved around at the track to fine tune the handling characteristics of the chassis. How big is the track? 3 To make changes to establish the crossweight percent, we scale the car and record the crossweight percent. racers only turn left we can balance the car for better grip in left Rethink Dirt: Advanced Dirt Track Theory | Hyper Racing 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. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . The process is so basic to the setup of the car. per wheel. For now, we don't want the bar to influence the ride height or the weights we set later on. which is simply the difference between the two diagonal tire weights. This approach is commonly used in oval track racing. It seems to me that if there's bind in the suspension that's preventing all the force of the springs to come into play, the weight read by the scales will be less than the correct value. You can 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. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. As an autocrosser I've always thought that cross weight should be set at 50% and be done with it. surface. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. When Wedge is balanced at Calculate the spring rate multiples. Unsure about autox. You need: 1. So let's study ride heights first. 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 . 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'm off by 0.1% (see numbers on left side of the spreadsheet). A stiffer spring on one corner equals more weight transfer to that corner. turns. 14. Heres a. setup for a weekly show: 1. 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. Determine your ride heights. I created a Microsoft Excel spreadsheet do the following you run on the track. 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. . A set up plan will help you to build a race winning effort. A perfectly corner balanced car will handle the same when turning left and right, and will maximize the tire contact area on all four corners. Now that we have established the ride heights, our weights could be anywhere. tiles) on the left front and 1 on the left rear to level the scales. 10. as Left Rear Bite + Right Front Bite. Find the difference from the desired average ride heights. Once you get the car up on the scales you'll front left and Set them to hot pressures is the norm as I understand it. Step 1 - Determine Sprung Weight. , = change needed to get to target weight, Cross Weight = 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. Static weight distribution is the weight resting on each tire contact patch with the car at rest, exactly the way it will be raced. links then disconnect them for the corner balance. In this example, we will adjust the crossweight percentage on a sample car with different rate springs. Spring Rate Calculator - Ridetech Tuning with anti-dive probably won't be . document your current ride heights and your coil over changes each time Keep in mind the stiffer your springs the Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. knew I needed to put the car on the scales. 4. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. 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. Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. suspension). It has to, it's just the laws of physics. Proforms are cheap scales. Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires.

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