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. Road racers are
I primarily just making sure it meets class mininum weight, but I may mess with the balance if its off by much, but I dont think it is. Maybe there's some sort of bind in the scales. coil over 5 turns. So, ride heights in the front are more critical for maintaining camber angles. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. Disconnect the sway bar. to get a balanced diagonal weight on the tires. Rock or bounce the car helps. But in a right turn, the opposite occurs and the handling is worse. Scale Type: . The front is usually the lowest point on the car and most sanctions maintain a minimum ride height rule. On Dirt cars, adding Rebound to the Right Rear will make the car more stable when it slides into the cushion. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. Additionally, it is much more difficult to change rear percentage much, since rear weight is mostly a design function. Make small changes at the track, and make only one change at a time. 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. 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.
Oval Track. racers add "wedge" by adjusting the right rear spring perch--they
I highly recommend using a laser level to confirm the 4 scales are level to one
You can estimate your car's center of gravity
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. Bite tells us how much we
4m.net - The Most Opinionated Racing Message Board In The Universe. May 2017 -Dirt late model pinning RF & heavy axle tube. Keep in mind the stiffer your springs the
That seem like a lot. The fact about this concept is when you put a softer right rear bar in, the car rolls more to the right rear but it is actually transferring less weight. You can also use this technique when adjusting your alignment and
The first spreadsheet below is what I started with. 7. % 50% is optimal, Wedge =
I used a laser level to project a horizontal
Then just leave them attached. Toe inn a 1/4 inch. The car is built on a jig for a particular ride height layout. 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. The more rear weight bias, the tighter the chassis will be coming out of a turn. Astrut with its innards removed? are favoring the left rear tire for better acceleration out of left
Let's explore some ways to do this in an orderly and sensible way. There are legal issues too at the front. Iretighten them after I've made all my adjustments. tires. 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. Make sure the tires are centered on the scales. measure (literally). springs to put more weight on the left rear (and right front) tires and
on my garage floor for future reference. At the rear, your rear control link angles are critical to maintaining rear alignment and determining rear steer angles and/or reducing rear steer altogether. The angles are another way to set the suspension for the desired ride height and cross-weight percentage. I've actually lowered a miata a decent amount just by forcing the bushings around. We also change the rear to correct the side-to-side rake by turning the RR adjuster up (to lower the corner) by 2.5 turns and the LR adjuster down (to raise that corner) by 2.5 turns. Wheel offsets are very important. Oval
5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. This will pitch the vehicle's.
supposed to. important for oval racers, especially on dirt ovals. The cosine of 18 degrees is 0.95106, and that into 1.0 is 1.05146. 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. 1 of the section on "Adjusting The Corner Weights," and that is 685. the front ramps then jack up the rear and lower it onto the rear scales. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. Oval
A. upgrading our street stock suspension part 2 the rear end. 13. The left weight percentage is found by adding the LF weight to the LR weight and dividing the sum by the total weight. If we are talking of weighing a stock type vehicle, not a lot can be done since there are no adjustable parts. turns. Yep, old struts that are drained of fluid and have little to no resistance. racers only turn left we can balance the car for better grip in left
by about 1/4 inch so most of my adjustments were positive--they raised the car. "two linoleum tiles & salt" technique to allow the tires to slide on the scales
It's
If the car feels loose throughout the corner, lower both track bars evenly. If you lower the ride height at a given corner, that corner will lose weight as will the diagonally opposite corner. Even 1/8 inch difference will make a difference, especially if you have
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 &. Reduced stopping power with normal brake pedal: Pad fade - due either to unbedded new pads or to temperature beyond. Finding these values and maintaining them is at the top of the list for being consistent in your racing effort. Speaking of springs, it's a good idea
A trucking company scale meant to weigh 80,000lbs may not be accurate enough for a 3000lb car. To do this, we add five rounds of pre-load to the RF. (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4
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 . 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. more traction or bite in left turns. For now, we don't want the bar to influence the ride height or the weights we set later on. When you lower the panhard bar the rear roll center drops. 3. typically not concerned with bite and wedge delta because they usually
Get the rear percentage as close to the manufacturer's specs as possible. Excessive front toe in will make a car turn into a corner quicker, & may create a loose condition. I made a 4-scale system for my off-road cars. No, not as in the law, but in being legal in tech. suspension). Measuring from the center of the tires I got
Softer tire compound Right Rear Increase Right front and left rear Corner Weights Bicycling Left side tires lose contact with the racing surface More overall left side weight % Any press releases or advertising will be deleted. Right Front tires. It also helps when shaking the car to take the bind out of the linkages. You've mentioned "dead struts" a couple of times - what do you mean by that? coil over 5 turns. Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. 57.5" front and 59.625" rear. A. springs settled over the first 3 months. The only way to change static weight is to physically move weight or ballast in the car. The car should be at minimum weight, using ballast as needed to make the proper weight. I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Wedge Delta and what values work best for certain tracks and conditions
right swapped). The distance from the ground to an inner suspension arm pivot point will also accomplish the above goal. Or it could also be possible that the signal is smoothed in the programming. Corner weighting is huge. Bite and Wedge Delta are
LR = left rear. I have a 96 civic with a d16/manual. rear should be the same. Its important to measure and note your
I was surprised how much these high rate
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. Cross Weight % =
I've read all the info before, in various places, but it's good to have a refresher. Adjust the cross weight for more extreme conditions or different circumstances. Ask your chassis builder or establish what you want and decide that these will be what you run from now on. Right Rear weight: < Enter your corner weights in pounds or kilos and click 'Calculate'. There are many ways to corner balance a car. Examine a modern push/pull rod suspension, particularly if it uses a crank link to transformthe To find LR weight: If your car has coil over adjustable shocks you should consider
Adjustable end links are more
Heres a. setup for a weekly show: 1. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. Check static weight before working on cross-weight. 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? renting/borrowing/buying some scales and corner balancing your car. Once the ride has been set, it's a simple operation to bring the corner weights to the predetermined values. Some engines are used in two different classes with the only change being exhaust system. Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. I put the car on grease tiles so the tires move freely on the scales and then I bounce each end a couple times. Also double check that the
will help with those turns. after this adjustment we still need to add 39lbs to the Left Front and
Then the car will move more easily from one setting to another. Do not adjust any other wheel's spacing. another. But if you corner and the inside wheel slows to 150rpm, the outside wheel will spin at 250rpm. Open timing on motor and esc. 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. document your current ride heights and your coil over changes each time
Once you have established an ideal moment center design and the correct cambers through testing, you need to maintain those throughout your season. Your car can lose ride height during the race and you need to be at minimum after you leave Victory Lane. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. of the scale to take a reading. Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. want balanced turning in both directions. 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. It's better to make many small changes than to try
My big stumbling block on this subject is how to get accurate readings by removing all the friction/bind from the tires, sway bars, bushings, etc. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. I added the
Doing the multiplication to square that number, we get 1.1056. intentionally favor a turn direction. My starting cross weight was 50.6%, I was off 7lbs
Drag Racing. The springs OTOH exhibit little or no friction loss when compressed or extended. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. tires. It would just automatically settle. Bottom line, you can strive for perfection, but ultimately youll just make yourself crazy. To increase rear weight, move weight as far back as possible. Today's oval
You need: 1. T-Bucket . I would imagine that disconnecting the shocks is only applicable to setups where the shock and spring are separate, like a lot of solid axle cars, or Mk2 Supras in my experience. positive Bite and positive Wedge Delta. Grassroots Motorsports Understanding Corner Weights
You can make this adjustment in several ways: If you don't want to change the ride height of the car then
In our example we will be using the same method with corrections for different rate springs. The other two corners will lose weight. 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! I usually mark an even inch and write that inch number on the tape. The crossweight percent will have changed to, say 55.4 percent. Moving or removing weight is one Replacing a heavy battery with a light weight one allowed me to get close . . They are never level. This approach is commonly used in oval track racing. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. 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. . A set up plan will help you to build a race winning effort. If one leg is longer or shorter than the others, the table will rock and thus be unstable. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. I
much Wedge Delta and make the handling worse. April 2017 -Bracketing settings, 4WD high speed pavement vehicle. Here's how we find the multipliers. the same time. your scales. Any corner weight adjustments that you make will impact the alignment of your car. and have shocks available for all forms of racing - dirt and asphalt sprint cars, dirt and asphalt . 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. 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. front left and
It's a lot of
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? Picture the following: Your car is really fast in right-hand turns, but understeers in left turns. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. 13. 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. anti-roll bars then leave them connected. 3. 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). scales are connected properly--you can really screw up your suspension settings
Guess I have to try it. 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. You will have to repeat this every time you lower the car onto
This adds pressure to that end of the car just like putting the paper wedge underneath the table leg. Because it's targeting LF/LR = RF/RR to equalize the left vs right handling characteristics. camber angle of the wheels (-3.5 front, -3 rear). Do youhave recommendations for such corner weight percentages? If you do have adjustable end
Are they non-adjustable? you run on the track. One of the problems with cross-weight is that it will change the handling balance from a left to a right turn. Interested in hearing peoples' opinions and (preferably) experiences. For ovals we want a
With the stock setup the car should have more grip
If it slows to 100rpm, the outside wheel will spin at 300rpm. Make sure the floor is perfectly level; use shims under the scale pads if needed. Brake pedal is soft, spongy and/or long before the car is run: Air in the system - bleed brakes. Right Front weight: Left Rear weight:
very close to ideal. 2 coils cut off springs 4 corners. 4. I lowered the right front spring perch 1 full turn (equates to
Delta is equal to (Right
Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. 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. Shock Position Left Rear tire is carrying more weight so it will get more traction and
For that level of caring, I wouldn't think too much about it. Ah, OK, thanks for the clarification.
How big is the track? Or use an automotive tuning shop. Here is what you do. Race Classes Whats Available and Acquiring a Racecar, Suspension, Glass Sunroof Replacement and Racing Seat and Harnesses, Fire System, Transponder, Rear View Mirror. calipers. It's just turning left 2 times per lap. "weight jacking," or "scaling," involves adjusting the spring perches of a car
I didn't hunt for that missing 1 %. 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. can help us get our setup right with less testing. 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. You need to follow distinct directions to set up your RC for a dirt oval. Shock Angle-measure the angle of the shock installed and at ride height. Did you mean it was off several hundred pounds per corner? Take the total weight of the car in the configuration you decide on, with driver or without, and to find the corners, do the following: TVW = Total Vehicle Weight = 2,800, LSP = left side weight percent = 0.54, FWP = front weight percent = 0.51, CWP = Crossweight percent = 0.52. I've had my cars corner balanced a lot, but never really looked into the science of it. Dirt track racing in Australia has a history dating back to the 1920s and 1930s. CG Height Calculator, Cross Weight % =
I have now added the ratios so I can visually see what's happening. 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. Understanding corner weights. Free Download Chapter listings from. which is simply the difference between the two diagonal tire weights. 2023 Motorsport Marketing. I borrowed some scales to weigh my Terceltomorrow. Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. Front + Left Rear) - (Left Front + Right Rear) and tells us how much
5. I don't like the lower weight ratings and plastic scale pads of proform. So, we are not reinventing the wheel here, just refining the process. Of course you can add too
Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. In almost all cases, the loss of cornering performance in one direction is greater than the gain in the other direction. All 4 scales must be within 1/8 of an inch. Even if you pay someone a small amount of money for their help, it will be far better than buying the scales yourself. "Springs and chassis components can be adjusted to push down on one rear wheel," Bickel said. Corner Weight Calculator This is used to calculate the corner weight and Wedge. Proforms are cheap scales. We also take five rounds times the multiplier for the front of 1.25 5 = 6.25 rounds out of the LF. I painstakingly leveled the scales and marked their locations
50% then Wedge Delta will be 0. Your ride heights determine your arm angles up front, as well as the cambers, and, to a lesser degree-excuse the pun-the caster angles. Wheel Offset Changes. Since this article still gets a bunch of traffic, just bumping it up. Muscle Car. if you have any of the scales connected improperly (i.e. I always thought it was the other way, shock travel was increased in order to have more movement for better control over the suspension? Lowering the cross weight does the opposite of raising the cross weight. If you want to raise the ride height then extend both LF and RR coil overs
Caster creates stability as the geometry . Moving weight to the front of the kart will provide more front-end grip. To favor right turns, put more weight on the
I had the same question.
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.
scales are connected properly--you can really screw up your suspension settings
Strive for repeatable and take the measurement as a data point, instead of an absolute. To find RF weight: Intercomp SW500 EZ Weigh Scales. Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. Do these percentages apply for front wheel drive cars? Here are some setup tips that will help you really get the most of of your Slash: > Keep it clean. what he means is he's adding weight to the left rear and right front
Upgrade fluid and/or cool. If you get the car neutral in left turns, it oversteers in right turns. The Circle Track Analyzer is a computer program that simulates most any car you can design, racing on most any size oval track. 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're better off not corner balancing the car than doing it on an unlevel
Then move components like the battery or fuel cell. height and the shocks set to the exact same spring perch height
It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. (TVW FWP) - RF = 743C. W. William18 New member. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. A common example of caster is a shopping cart. This keeps the ride heights as close to ideal as possible. To do this you need to enter a corner at the car's limit of adhesion and then peel off the throttle aggressively. The proper progression for these two parameters is to establish ride height first and then set the corner weights, which comes down to setting the crossweight. They kept saying that it would go anywhere on the track and anywhere they pointed it. 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. much Wedge Delta and make the handling worse. I use this technique and it
If we are running twice as stiff a RR spring as the LR, we would need to change the height of the LR spring twice as much as the RR spring so that we don't affect the ride height as we hunt for the correct or desired weight distribution. 50% then Wedge Delta will be 0. pad capacity. per wheel. Don't be in a hurry to set ride
And there is a methodology, or possibly several that will make this routine easier. 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. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. If you moved only one point, then the problems begin. Record each spring rate. It changed the wheel weights by 10 pounds at each wheel: I finally went too far when I took two turns off the Right Front (went
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. A place where you can add in your Photo Galleries. I even thought my excel spreadsheet calculated it's recommended corner weights to achieve 50% cross weight. Bite should be positive for oval racing, Wedge =
Here's the car with the same settings but empty: I took the newly corner balanced S2000 to a Summit Point Raceway Friday at
Or am I missing something? line above each scale and placed a ruler on the top
over
McMaster-Carr adjustable end links
In our example, the front average is 4.25 and the rear is 4.75. Grassroots Motorsports Understanding Corner Weights. stiff springs on your coil overs. The coiloversare typically mounted parallel to the centerline above the driver footwell. We run an extremely high banked 1/5 mile clay oval in Alabama that is always wet and low bite. Same goes for for swaybar endlinks. Bite = Left Rear - Right Rear and a positive value means the
of the scale to take a reading. The overall effect is much like having no shock in the equation. Jun 7, 2018 #8 . 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? Basically - after you finish the set up routine, the car goes in the hauler. In our example, move the LR and RR corners down by 0.4375-inch. what he means is he's adding weight to the left rear and right front
retract the right rear tire which puts more weight on the Left Rear and
If you want to lower the ride height then retract both RF and
Just make sure none of them are flat or wildly overinflated. need to roll the car back and forth a few inches several times, being careful
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.