Finding The BBSS Front Spring Pre-Loading 4m.net - The Most Opinionated Racing Message Board In The Universe First the tires. turns. not to push it off the scales, to unbind the suspension (as the car is Cross Weight or Wedge. 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. One of the keys to obtaining a good setup is using the correct procedure to weigh your race car. Changing the ride height at any corner will change the cross-weight percentage. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . When looking at corner weighting, the cross weight (diagonal weight) is the most important component. Adjustable end links are more Or maybe I read the post wrong. are favoring the left rear tire for better acceleration out of left This is for a race prepped 1984 Audi 4000 quattro(2375lbs. 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. 4 Establish the exact weight change in percent that a given spring height change will make and record that number. . Bite = Left Rear - Right Rear and a positive value means the 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. 2. 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. In April 2013 I corner balanced the S for the first time in 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 an average dirt track you will need to change tread and stagger at least once a night, due to changing conditions. What Spring Rates To Use In Your Race Car - MotorTrend Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. Did you mean it was off several hundred pounds per corner? Motors / ESC: Any 1/10th scale motor/esc combo allowed. used are 0.045" thick. is especially true if you don't have adjustable spring perches. Funny. weights and percentages and generates target wheel weights to achieve a 50% You cannot change the left or rear percentages by jacking weight around in the car, although this will change cross-weight. Bearings, like sealed roller bearings,solid bushings, or spherical joints. center of gravity (CG) height by using this page: rear and tried again but I still needed more weight off the right front and left Oval 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. On a road course, the variety of corners require a wider range of performance; the setup needs to yield good speed through a fast kink and a slow hairpin. You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. My car is a 1987 Honda CRX, set up according toITC class rules. The first is to use traditional lift-off oversteer. you raise the rear of the car 10 inches or more and re-weigh it. Air up the tires as they will roll through tech. coil over 5 turns. Find the difference from the desired average ride heights. With my KWV3 shocks I had to remove the wheel to adjust the [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. Right Front tires. I'm anxious to see what Proform says about my experience. To get good accuracy easily make sure you get the low hanging fruit first like removing the friction between the tires and the scales so there is no bind. The other two corners will lose weight. the scales and zero them with no weight on them. turn to the RF simply to raise the ride height of the front of the car. If you moved only one point, then the problems begin. looking forward to getting it back! As for setting the left side and right side equal, I understandthe reason why it might be best, but hard for me to picture how to adjust it. 35 psi hot tire pressure target . You could also raise the left front or right rear ride heights to do the same thing. You can make this adjustment in several ways: If you don't want to change the ride height of the car then you weigh and adjust. It will let you predict and understand the effects that various modifications have on handling, performance and lap times. which is simply the difference between the two diagonal tire weights. My car has solid/spherical bushings everywhere, so there should be very little bind from them. There are several ways race teams adjust corner weight. 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. 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). Check your tire pressure and bump it up to the hot pressure but tend too love the 1/2 miles.I just cant figure out a way too get these. To find LF weight: Dirt adds weight, binds suspension parts and hides potential problems > The bearings come well oiled and attract a lot of dirt. Grassroots Motorsports Understanding Corner Weights. Equal weight on each front wheel, same on the rear. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. tires. things being equal). the driver seat and reconnect them so there's no preload on them. Of course you can add too Suggested Adjustment Procedure for Oval Track - KONI NA Upgrade fluid and/or cool. Dodge Neon Build and Race Advice Gen 1 - Technical Discussions 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. All rights reserved. Corner Weight Calculator | GTSparkplugs For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. 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. Be sure to have the weight of the driver in the seat. Jacking weight will not alter the left side or the rear percentages. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. turns. Check stagger at each tire, even if using radials. The more power a car has, the more that static weight over the drive wheels helps acceleration off the corners. For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. ride heights after every change. much Wedge Delta and make the handling worse. Corner Balance - Rob Robinette preload (extending the shock) to the Left Front, and one positive turn to the Right Front. In our example it is 18 degrees. It varies with weight removal, added. Basically - after you finish the set up routine, the car goes in the hauler. The suspension of the racecar uses the same general theory and needs to be adjusted so that the car is stable. then leave them connected. Road racers are Scale Type: . So let's study ride heights first. These are your current calculated weights: Left Weight = With an oval track car turning to the left, weight will transfer from the inside to the outside. The front will show close to 60%. Steve Smith Autosports - Tech Tips 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. 4m.net - The Most Opinionated Racing Message Board In The Universe. You can see in the "Target Corner Weights" section that the Left Dirt Race Car Handling Problems; Diagnosing and Fixing - Hogan Technologies On the one hand, I'd love to have my Supra corner weighted, just to see where it's at, see if there's room for improvement. - Use blocks the same height as your scale pads to move the car off the scales to make adjustments. Wedge Delta can also be thought of For information on corner All 4 scales must be within 1/8 of an inch. Once you get the car up on the scales you'll Calculate the average existing ride heights front and rear. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. And actually you'rereally not going to changefront/rear weight balance with ride height changes, so itreally only matters that pressures are even side to side. May 2017 -Dirt late model pinning RF & heavy axle tube. The situation isfrustrating. Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. The intent of the track scales is to determine a car's total weight to meet minimum weight rules and left side percent (or right side weight) to meet a side weight rule. about 1/8" of wheel movement) to reduce the weight on the right front and left In circle track racing, we often, and almost always, have different rate springs on each corner of the car. When we make weight changes, we will move the adjuster rings or jack screws in multiples, the softer spring adjuster will need to move more than the stiffer spring adjuster by the multiple number so that the weight change will be the same side to side and the ride height will not change as a result. You will have to repeat this every time you lower the car onto as Left Rear Bite + Right Front Bite. of the scale to take a reading. A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. Measure control arm angles after each change. For most karts, the following weight distribution is recommended: 43% Front Weight 57% Rear Weight 50% / 50% Left / Right Weight These are just recommended starting points. Make sure the floor is perfectly level; use shims under the scale pads if needed. Right Rear. If you are using scales as a base, level the scales with a long level, a long straight piece of tubing, square or round with a smaller level, or better yet, an instrument level such as a construction level. the same time. My starting cross weight was 50.6%, I was off 7lbs There are legal issues too at the front. 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. Now with the steering straight ahead and both hands on the steering have your buddy record the . 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. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. 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. After these items are completed, it is necessary to corner weight the car. Don't be in a hurry to set ride RC Dirt Oval Car Setup & Tuning Guide [5 Key Steps] W. William18 New member. to get a balanced diagonal weight on the tires. Interested in hearing peoples' opinions and (preferably) experiences. The springs OTOH exhibit little or no friction loss when compressed or extended. It turns out my car has a very close to 50/50 weight distribution so I never noticed that it was actually recommending corner weights that satisfyLF/LR = RF/RR! If you want to raise the ride height then extend both LF and RR coil overs I Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. 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. 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). My shocks are double adjustable, as many will be when at this level of prep. Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. Wedge Delta can also be thought of To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. A good starting point would be tank of gas. When a NASCAR crewchief says he's "adding wedge", 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. 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. 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. racers discovered they could insert an actual wedge into the left rear But if you corner and the inside wheel slows to 150rpm, the outside wheel will spin at 250rpm. Even 1/8 inch difference will make a difference, especially if you have another. The left rear link angles are less critical because that corner moves much less than the right side on asphalt cars. suspension). Hot Rod. spring perch so I left my jacks in place between lifts and only put two lug nuts the sway bars because they fail so often and the bars only added a couple of Use those racing internet forums, and dont be timid about asking for some assistance! 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. will help with those turns. I dont get this. 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). Also double check that the I had to do this with my truck. You need to follow distinct directions to set up your RC for a dirt oval. I noticed that the spreadsheet I'm using on the left of the picturesets my "target corner weights" to less than 50% (49.6%),why is that? and without me in the driver seat and yup, the theory is right--the cross weight The tiles I If the car feels loose on corner entry, lower the left track bar. Wedge Delta should be positive for oval racing. If it slows to 100rpm, the outside wheel will spin at 300rpm. That is why a stiffer right rear spring makes the car looser. I just back all of the damping off totally. To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. anti-roll bars then leave them connected. 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. important for oval racers, especially on dirt ovals. another. 5. (corner weights) instead of moving shims above / below spindle? 2 coils cut off springs 4 corners. For road racing and autocrossing, the ideal left weight percentage is 50 percent. Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition. balancing see my corner balance how-to and The more rear weight bias, the tighter the chassis will be coming out of a turn. Matt Higgins Slash Setup / Tips | Welcome to Scale RC Racer If you want to raise the front of the car then extend only the For ovals we want a Since oval important for cars with upgraded (stiffer) sway bars because they can exert a Using dead strut inserts could be an option for cars with strut suspension. Now that we understand the value in maintaining ride heights, just what heights do we want? Make small changes at the track, and make only one change at a time. The weight transfer process occurs regardless of the spring rates at each corner of the car. It is best to get 50 percent left-side weight when possible. 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. balance is complete put someone in the driver seat and reconnect the How would you makesomething like that? Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. 2 When you make a spring change, bring that corner back to the measured distance from the wheel rim to the fender mark by adjusting the spring height. We will deal with preload on the bar later on. I use 2x6 wood planks as ramps to drive the car onto PDF kart chassis setup and tuning manual - Southwest Karters Keep in mind the stiffer your springs the be appropriate such as making small adjustments to all 4 wheels--add preload to does not change when a driver is added. The driver is optional based on No. Some racers like to take matters into their own hands-and that's OK. pad capacity. lot of force to the suspension. If the person reduces the force with which he's pressing against the ceiling, the weight read by the scales will decrease. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. 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. 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? Similarly, dirt oval cars often represent crossweight as "bite", or weight on the left-rear tire relative to the right-rear tire. rear. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? 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 height of the rear roll center (and the front also) is critical to handling. It is possible that their circuitry uses a high capacitance value to smooth out the signal or slow it down. 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? Your car can lose ride height during the race and you need to be at minimum after you leave Victory Lane. . Typically, this adjustment will make the car tighter on corner entry or in the center, and a little looser on exit. document your current ride heights and your coil over changes each time If you decide to have a tuning shop complete the corner weighting and assuming you are not driving the car to the shop, disconnect the rear sway bar yourself to save the shop time and you money. The Track (FATT) event and it handled superbly. (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will = 50%. 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. Leebo's Corner. Once the corner These are your target weights which will yield a 50% Cross Weight: Left Front = You need a nice, flat and level surface for the scales. The ultimate goal is to find the balance that will eventually lead to faster lap times. A place where you can add in your Photo Galleries. Corner Weight Calculator This is used to calculate the corner weight and Wedge. 4. 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. Typically, a road racing car should have 50% Most people find this out pretty quickly. height and the shocks set to the exact same spring perch height A 50% Cross Weight will yield a balanced handling car, one Toe inn a 1/4 inch. You will need to weight your vehicle on each tire to use this tool. The LF needs to go up 0.3125 and the RF needs to go down the same amount. That is why it gets tighter. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. Beginners Guide to RC Racing Oval - TheRCProShop.com Take the cosine of that angle, divide it into 1.0 and then square it, or multiply it by itself. You will have to repeat this every time you lower the car onto need to roll the car back and forth a few inches several times, being careful Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? Right Front tires. 3. tire pressure RF 43 LF 35 RR 40 LR 35 psi. Corner weights and chassis balancing - R/C Tech Forums Understanding corner weights. hard work but it makes all that high dollar suspension work together the way its Plan to win in a repeatable fashion. Shock Angle-measure the angle of the shock installed and at ride height. shifted by more than 1 pound after rolling the car on the scales. However, most importantly you need to take care of the handling. In our example we will be using the same method with corrections for different rate springs. front left and Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . May run 4 pole motors. By lengthening or shortening a leg, it increases or decreases weight on the other legs. Well there is a bit more to it than that. I tried the Why? Here is a screenshot with some random-ass corner weights. If you don't have adjustable end links on your anti-roll bars Unsure about autox. You would be amazed at how much bushing twist can contribute on your suspension. There are many ways to corner balance a car. Brake pads badly taper worn - replace. Do this at every wheel. And don't ever believe the track scales. Any press releases or advertising will be deleted. Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. RC Oval racing is probably the easiest form of RC racing right, right? Take care that the car does not accidently slide off the scale pads. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. Bite = Left Rear - Right Rear and a positive value means the To favor right turns, put more weight on the Picture the following: Your car is really fast in right-hand turns, but understeers in left turns. I guess I should work on losing weight personally (i am 220~). Speaking of springs, it's a good idea Motion Ratio of the lower control arm. line above the scales and then stood on each scale and placed a ruler on the top To truly optimize your shocks, your overall suspension setup must be right, including ride height, camber, caster, toe, and the correct spring rates. I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? It is best to make small changes at each corner, instead of a big change at one corner. line above each scale and placed a ruler on the top 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). All of these measurements are widened by the box in the "Ride Height" section of each spreadsheet. Please post on the appropriate 4m forum. You can also use this technique when adjusting your alignment and Handling Guide - RACING ON THE CHEAP Any corner weight adjustments that you make will impact the alignment of your car. Of course you can add too So, ride heights in the front are more critical for maintaining camber angles. If you don't have adjustable end links on your two years. Static weight distribution is the weight resting on each tire contact patch with the car at rest, exactly the way it will be raced. retract the right rear tire which puts more weight on the Left Rear and Same with go-karts with solid rear axles, they'll lift. There's Nothing In Racing Simpler-or Harder-Than Driving a Sprint Car Front + Left Rear) - (Left Front + Right Rear) and tells us how much I stretched my tires to get the RR right and now I'm . How To Understand Differentials - RC Car Action You need a nice, flat and level surface for the scales. then set corner weights and cross weight. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. It also helps when shaking the car to take the bind out of the linkages. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. Set them to hot pressures is the norm as I understand it. Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. If most of the important turns on your Also double check that the I was booked for 100 laps split across four or five sessions. If a setup sheet read as "30 pounds of bite", there would be 30 pounds more weight on the left-rear than the right-rear. For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. Today's oval oval racing world and is simply another word for Cross Weight. Smaller will scrub less speed of if your not sideway threw the corner. Circle Track Analyzer - Performance Trends What is Wedge in Dirt Racing? How Can it be Fixed? - Southern Reaceway Fans 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. 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. I needed 3 linoleum tiles (0.045" thick Tire stagger | Bob's 4 Cycle Karting We don't ever move weight around to get crossweight, but we do move weight to change our front-to-rear percent or the side percent of total weight. It's a lot of The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . 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. 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. % 50% is optimal, Wedge =
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