corner weights for dirt oval racing

in left hand turns than in right turns. Left Rear tire is carrying more weight so it will get more traction and Calculate the average existing ride heights front and rear. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . Toe inn a 1/4 inch. One of the keys to obtaining a good setup is using the correct procedure to weigh your race car. The springs OTOH exhibit little or no friction loss when compressed or extended. line above the scales and then stood on each scale and placed a ruler on the top Free Download Chapter listings from. The front will show close to 60%. The process is so basic to the setup of the car. Multiply the wheel load of 685 times the motion ratio squared, 1.3611 times the shock angle cosine squared of 1.1056 and we get 1,030.8 pounds of spring preload. February 2017 -Suspension design process. I have now added the ratios so I can visually see what's happening. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. You can estimate your car's center of gravity MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. Grassroots Motorsports Understanding Corner Weights. 19. difference that made. and measured between the outside bottom rim edge is 67.75" front and 69.875" Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. When Wedge is balanced at If it slows to 100rpm, the outside wheel will spin at 300rpm. Since I went to 800 front and 700lb rear springs over the winter I 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. and stock rear sway bars connected. If you do have adjustable end links then disconnect For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. The first is to use traditional lift-off oversteer. Rear weight percentage for road racing and autocrossing is less definite. I needed 3 linoleum tiles (0.045" thick (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will = 50%. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. what he means is he's adding weight to the left rear and right front ZJjtX0xiMzjbfb86GLC7qpXBkrSlFeSNVds8hGW514OXUKSxf6kBDIneIL3TzHQV. this excellent article: I lowered the right front spring perch 1 full turn (equates to tiles) on the left front and 1 on the left rear to level the scales. TVW - (RF + LF + LR) = 603. You can also put two linoleum tiles with salt between them on Since this article still gets a bunch of traffic, just bumping it up. If you get the car neutral in left turns, it oversteers in right turns. 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. tires. Once you get the car up on the scales you'll W. William18 New member. Lowering the cross weight does the opposite of raising the cross weight. Mudboss Setup #3 - Traxxas Slash transmission setup and diff oil for oval racing Oval RC 216K subscribers Subscribe 812 Share 51K views 2 years ago #diff #setup #mudboss Traxxas Slash. You will need to weight your vehicle on each tire to use this tool. Wheel Load-We have already determined the wheel load we desire in No. Keep in mind the stiffer your springs the To find RF weight: 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. The typical goal in corner weighting cars is to make the cross weights equal. That is equal to 7/8 turn of the adjuster. 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. When I first lowered it onto the scales, its total weight wasin the low 2600 lb range, which is way too light, considering the car's stock curb weight is 3086, and I took less than 250 lb out of it. Wedge is a term used in the A. Then move components like the battery or fuel cell. I used a laser level to project a horizontal You can see the article here: Then the car will move more easily from one setting to another. But in a right turn, the opposite occurs and the handling is worse. Right Rear. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. weights: Corner Weight Calculator if of the scale to take a reading. To do this, we add five rounds of pre-load to the RF. You need a nice, flat and level surface for the scales. suspension). used are 0.045" thick. But this is almost never the case. If you want to lower the front of the car then retract only 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. Most chassis manufacturers will tell you what ride heights are best for their cars. 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). Note the "Conditions and Changes Made" I've actually lowered a miata a decent amount just by forcing the bushings around. Your results might be different from mine. I see disconnecting the sway bar, and how to do it, but disconnect the shocks? 12. Upgrade fluid and/or cool. Disconnect and adjust later. 2. The left side changes, of course, will be 4.75 times the multiplier for front or rear. Jun 7, 2018 #8 . Thanks. works well. 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. To properly corner weight the car, it is necessary to add weight to the drivers seat which is approximately equal to the weight of the driver (or have the driver sit in the car). Understanding corner weights. Be sure to have the weight of the driver in the seat. Do not copy these ride heights; they are only used as an example. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? Even 1/8 inch difference will make a difference, especially if you have Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. anti-roll bar with the end-link adjusted so it's easy to insert the How would you makesomething like that? However, for dirt oval RC cars, foam tires are the norm. Now, look into details about the matter. There are several ways race teams adjust corner weight. racers only turn left we can balance the car for better grip in left "Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel . Andy Hollis does this. Right Front = 11. Would be interesting to see how close to ideal I got it though, given how well it handles already. Of course you can add too by about 1/4 inch so most of my adjustments were positive--they raised the car. 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. If you raise the ride height at a given corner (put a turn in or add a round of wedge), the weight on that corner will increase, as will the weight on the diagonally opposite corner. Wedge Delta should be positive for oval racing. By changing the weight distribution on the car, you affect the way your car will behave when cornering. two years. work but in the end it's worth it. This will pitch the vehicle's. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. scales are connected properly--you can really screw up your suspension settings That makes every little detail that much more important. You can also use this online calculator to compute your corner bite, a negative value means the Right Rear is favored. 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. turns. Do youhave recommendations for such corner weight percentages? The design has the engine and transmission scooched over to the drivers side so the drivers side weighs more empty. Search for: Finding The BBSS Front Spring Pre-Loading you raise the rear of the car 10 inches or more and re-weigh it. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. It still pays to be thoughtful about weight placement fore and aft in your car. You can also use this technique when adjusting your alignment and This spreadsheet will also give you an estimated center of gravity height if Interested in hearing peoples' opinions and (preferably) experiences. For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds Front + Left Rear) - (Left Front + Right Rear) and tells us how much I used a laser level to project a horizontal 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 make this adjustment in several ways: If you don't want to change the ride height of the car then 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 The last event in the rain i actually had the rears up to around 38. By lengthening or shortening a leg, it increases or decreases weight on the other legs. When a NASCAR crewchief says he's "adding wedge", If you moved only one point, then the problems begin. On my ZX2SR my cross weight was consistently in the 49% range. We will deal with preload on the bar later on. Cross Weight % = Changing the ride height at any corner will change the cross-weight percentage. You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. (TVW FWP) - RF = 743C. Air up the tires as they will roll through tech. How big is the track? 57.5" front and 59.625" rear. Smaller will scrub less speed of if your not sideway threw the corner. And what do you mean by "lots of bearings"? Well there is a bit more to it than that. 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. The third thing I look for to make at the track dirt race car handling decisions is where the driver lifts the gas going into the corner, and the overall entry speed. Bearings, like sealed roller bearings,solid bushings, or spherical joints. right swapped). Keeping track of Bite and hard work but it makes all that high dollar suspension work together the way its These weights are in ready to race form (including driver on board). Bite should be positive for oval racing, Wedge = LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. The first spreadsheet below is what I started with. Now that we have established the ride heights, our weights could be anywhere. The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. So we turn the RF adjuster up (to lower that corner) 2.5 turns and the LF down (to raise that corner) 2.5 turns. 2. To truly optimize your shocks, your overall suspension setup must be right, including ride height, camber, caster, toe, and the correct spring rates. scales are connected properly--you can really screw up your suspension settings The following weights are with the front Comptech adjustable I had the same question. Corner_Balance.zip Excel spreadsheet. More wedge means that the car will likely understeer more in a left turn. bite, a negative value means the Right Rear is favored. Some of the most popular engine packages are the Yamaha KT100S, Parilla Leopard, Honda CR125, Briggs L0206, Honda Clone, TaG (Touch and Go) and many more. Muscle Car. Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. There are many ways to corner balance a car. You would be amazed at how much bushing twist can contribute on your suspension. Now that's pretty cool! in the driver's seat to load the suspension. 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. the RF coil over 5 turns. need to roll the car back and forth a few inches several times, being careful It has to, it's just the laws of physics. Just to confirm the theory I checked the corner weights with Make sure the tires are centered on the scales. This will not change the left-side or rear weight percentages. 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. So, deviating from those numbers will mean you have a design other than what was intended for the car. The LF needs to go up 0.3125 and the RF needs to go down the same amount. Then just leave them attached. In our example, move the LR and RR corners down by 0.4375-inch. If you want to lower the rear of the car then retract the LR A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. It's (TVW LSP) - LF = 769D. If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. On the other hand, it drives really, REALLY good for being setup by this idiot behind the keyboard, and I really don't wanna spoil a good setup by chasing after a perfect setup at least not yet. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and Using dead struts and lots of bearings will help. used linoleum tiles to shim two of my scales to get them all level. Are they non-adjustable? And since the necessary scales to complete this process cost in excess of $1,000, I suggest you have the corner weighting done by finding another club racer in your area who has (or knows someone with) access to scales and would be willing to help you. Put the driver weight in the car, preferably the driver. To find LF weight: Timely refresher that leaves me with a question Ive had for the last couple years that I have not found an answer to in hours of searching. for the front and rear sway bars and installed them with my girl friend sitting 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 &. Once static weight percentages are set, work on cross-weight percentages. Just make sure none of them are flat or wildly overinflated. 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. B. A good starting point would be tank of gas. Wheel Offset Changes. I recommend you start with your car at your desired ride When you adjust your coil overs After these items are completed, it is necessary to corner weight the car. difficult to position all 4 scales so you can just drive up on all of them at the scales and zero them with no weight on them. track are left turns then having more weight on the Right Front and Left Rear stiff springs on your coil overs. 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. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. 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. If you don't have adjustable end links on your I guess I should work on losing weight personally (i am 220~). Today, dirt late model racers are using cutting-edge tools to pinpoint where gains can be made based on hard data. So 2.5" springs and experimenting is the way to go- I think I know that much.. . Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. stiff springs on your coil overs. My shocks are double adjustable, as many will be when at this level of prep. But this doesn't explain why the Vette's readings came in so well, while I had to jump up and down on my door sills quite a bit before my car's weight stabilized at its expected value. links then disconnect them for the corner balance. Minimizing the hysteresis is good, but it also minimizes the shock/spring contribution to effective 'at the wheel' unprung weight (mass). Dirt Late Models. For pure race cars this isnt a consideration. Check your tire pressure and bump it up to the hot pressure Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. Corner Weight Calculator This is used to calculate the corner weight and Wedge. If most of the important turns on your not to push it off the scales, to unbind the suspension (as the car is Now that the car has the correct ride heights and weight distribution for your setup, you need to make sure those don't change at the track. Always but tend too love the 1/2 miles.I just cant figure out a way too get these. the same time. left to right (measured with a digital caliper) and my ride height was pretty The tiles I Here is the method to correct the corner weights and set the left rear bite or cross weight. turns. This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. as Left Rear Bite + Right Front Bite. So, we are not reinventing the wheel here, just refining the process. In April 2013 I corner balanced the S for the first time in Make small changes at the track, and make only one change at a time. oval racing world and is simply another word for Cross Weight. Classic Truck. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. The rear weight percentage is found in a similar manner: Add the LR and the RR weight together and divide the sum by the total weight. So if you have 60% on the front , you should have 30% on each front wheel. I was surprised how much these high rate springs to put more weight on the left rear (and right front) tires and things being equal). I saved a copy of the spreadsheet for each If you want more turn in one direction put extra weight into the inside rear or outside front. battery (-15lbs), ride height lowered approximately 1 inch, all 4 Bilstein PSS9 coil over If you know the front, side, and crossweight percentages, then you can calculate the numbers. It varies with weight removal, added. This makes the cornering force balanced from left to right and offers the best performance overall. 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. If you want to lower the ride height then retract both RF and The new existing ride heights are LF 3.6875, RF 4.8125, LR 4.1875, RR 5.3125. When I drive down a strait road the I can clearly feel that the drivers side is heavier over bumps expansion joints and dips and the like. I made a 4-scale system for my off-road cars. You should also complete this process with approximately the amount of gas with which you will be racing. weights and percentages and generates target wheel weights to achieve a 50% Some engines are used in two different classes with the only change being exhaust system. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. Motion Ratio of the lower control arm. not to push it off the scales, to unload the suspension (as the car is from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. 4. rod movement from the wheel to the coilovermovement. Before putting your car on the scales you need to power up Right Rear = the scales. to get a balanced diagonal weight on the tires. It's lowered onto the scales the tires will need to spread out to unbind the The ultimate goal is to find the balance that will eventually lead to faster lap times. Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. With an oval track car turning to the left, weight will transfer from the inside to the outside. I overshot by a little so I raised the left rear spring perch by 1/2 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. on my garage floor for future reference. 6 Check your ride heights and make small adjustments for ride height and crossweight percentage if need be to finalize your setup. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. It would just automatically settle. Corner weighting your car is 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. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. decided to try 5 turns total of spring perch movement to balance the car. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. In order to perform the set up routine the car needs to be completely ready to race. 3. Calculate the spring rate multiples. Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. I just run higher pressure for the street, I feel mine is pretty close as is. Weight can be moved around at the track to fine tune the handling characteristics of the chassis. Let's explore some ways to do this in an orderly and sensible way. 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. document your current ride heights and your coil over changes each time calipers. Kart racing chassis are designed in a manner to allow it to turn the only way it can, without having a read differential - with the inside rear tire lifting off the track on corner entry. tires. 14. With my KWV3 shocks I had to remove the wheel to adjust the Jacking weight will not alter the left side or the rear percentages. I tried the Or maybe I read the post wrong. If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. Right Front weight: Left Rear weight: So let's study ride heights first. 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. Plan to win in a repeatable fashion. However, many cars cannot make the 50 percent left-side weight percentage due to driver offset. 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. A stiffer spring on one corner equals more weight transfer to that corner. . Afterward you need to adjust the settings to the correct maneuvers. 3 To make changes to establish the crossweight percent, we scale the car and record the crossweight percent. The less fuel in the tank the tighter the chassis will become. 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. 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. Unsure about autox. 1 of the section on "Adjusting The Corner Weights," and that is 685. Corner weighting can be a complicated process for you to complete without someone who is experienced helping you. It's better to make many small changes than to try 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. balance is complete put someone in the driver seat and reconnect the 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. I still rolled the car back and forth a center of gravity (CG) height by using this page: You can also estimate your car's I use this technique and it 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. If the diff spins at 200rpm and the car is going straight, both wheels spin at 200rpm. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. Equal weight on each front wheel, same on the rear. %, Bite = 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. If you want to raise the front of the car then extend only the This is but one method and I encourage everyone to ask around and find a method that works for your type of car, this one may not be the most efficient. anti-roll bars then leave them connected. another. Caster creates stability as the geometry . To favor right turns, put more weight on the 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. values shown below are totally fictional. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. The total spring perch For ovals we want a Left Rear tire is carrying more weight so it will get more traction and This measurement can be manipulated by changing spring rates, coilover . Bite = Left Rear - Right Rear and a positive value means the I had to do this with my truck. Static weight distribution is the weight resting on each tire contact patch with the car at rest, exactly the way it will be raced. Wedge Delta and what values work best for certain tracks and conditions you weigh and adjust. Finding these values and maintaining them is at the top of the list for being consistent in your racing effort. coil over 5 turns. 2023 Motorsport Marketing. from a balanced Cross Weight. If the car feels loose throughout the corner, lower both track bars evenly. Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition. Get the rear percentage as close to the manufacturer's specs as possible. To favor right turns, put more weight on the 1. My car is a 1987 Honda CRX, set up according toITC class rules. 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. I'm anxious to see what Proform says about my experience. retract the right rear tire which puts more weight on the Left Rear and started with the Left Front because I wanted to raise the ride height of the car the driver seat and reconnect them so there's no preload on them. Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Get the numbers right and the percentages will follow. The roll center is an imaginary point around which the rear of the race car rolls. Determine your ride heights. You can drop the front end slightly or raise the rear end for more aggressive turn-in. A common example of caster is a shopping cart. Even 1/8 inch difference will make a difference, especially if you have car for a week to let the suspension settle: I decided to disconnect the front and rear sway bars to see what I dont get this. front left and It's critical that you set ride height in the same place each and every time you do it.

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