things being equal). Right Rear =
Minimizing the hysteresis is good, but it also minimizes the shock/spring contribution to effective 'at the wheel' unprung weight (mass). Do this by making equal changes to the adjusters on each side. [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. I dropped my integra off at edge to have this done today. "If your car is really tight or really loose during hot laps, you have to take a look at the things that are going to make the biggest difference. front left and
weights into the spreadsheet (the blue numbers in the left "Corner Weights"
The spreadsheet's second page has a good article that goes into more detail of
the front ramps then jack up the rear and lower it onto the rear scales. end-link into the anti-roll bar's hole. Finding The BBSS Front Spring Pre-Loading And what do you mean by "lots of bearings"? It is best to get 50 percent left-side weight when possible. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? "Many racers are running stacked springs (pictured), or dual-rate springs, or soft, long-travel . 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. on the right front and left rear tires. 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. Adjust the rear down by using the same method as in No. 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). per wheel. racers discovered they could insert an actual wedge into the left rear
I use 2x6 wood planks as ramps to drive the car onto
This is my 2001 S2000 with 1/2 tank gas, 216
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. 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. if you have any of the scales connected improperly (i.e. You can estimate your car's center of gravity
Just to confirm the theory I checked the corner weights with
. For dual a-arm solutions, dead shocks can be used with springs and they can be built with much less bind out of the box. The other two corners will gain weight. I still rolled the car back and forth a
To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and You can drop the front end slightly or raise the rear end for more aggressive turn-in. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales
If you want more turn in one direction put extra weight into the inside rear or outside front. The roll center is an imaginary point around which the rear of the race car rolls. Jun 7, 2018 #5 . rear should be the same. 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 % Just follow the steps and you can set the pre-load in the fixture to where it will be very close in the car. To find RR weight: You will need to weight your vehicle on each tire to use this tool. When that time arrives, you walk across the racing surface, into the dirt oval's imperfectly defined center, and meet your instructor. Before putting your car on the scales you need to power up
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. 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
You could also raise the left front or right rear ride heights to do the same thing. 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. Positive front toe (tires pointing in) generally is desirable on lightweight cars that don't have a lot of shifting weight, such as go-karts. CG Height Calculator, Cross Weight % =
few inches several times on the scales before each reading though just for good
Since oval
Struts and trailing arms generally arent great in this case as they have a lot of inherent bind. Same with go-karts with solid rear axles, they'll lift. Let's explore some ways to do this in an orderly and sensible way. Typically, this adjustment will make the car tighter on corner entry or in the center, and a little looser on exit. A place where you can add in your Photo Galleries. and Left Rear. line above the scales and then stood on each scale and placed a ruler on the top
I saved a copy of the spreadsheet for each
The distance from the ground to an inner suspension arm pivot point will also accomplish the above goal. In April 2013 I corner balanced the S for the first time in
lowered onto the scales the tires will need to spread out to unbind the
I
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.
If you get the car neutral in left turns, it oversteers in right turns. 11. Would be interesting to see how close to ideal I got it though, given how well it handles already. decided to try 5 turns total of spring perch movement to balance the car. Muscle Car. You will have to repeat this every time you lower the car onto
Even if you pay someone a small amount of money for their help, it will be far better than buying the scales yourself. Equal weight on each front wheel, same on the rear. Its important to measure and note your
This makes the cornering force balanced from left to right and offers the best performance overall. Besides the eventual move to an adjustable ride height set up, I feel like I need 100 lbs or so more spring in the left 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. I found that the tire will absorb side loads quite well and was repeatable. At least for road racing. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. 3. 3) Reverse stagger: The opposite of stagger when your left side tires are . Front + Left Rear) - (Left Front + Right Rear) and tells us how much
A good starting point would be tank of gas. Left Front weight:
tiles) on the left front and 1 on the left rear to level the scales. Or use an automotive tuning shop. to balance your car in one big step. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. 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. For that level of caring, I wouldn't think too much about it. renting/borrowing/buying some scales and corner balancing your car. A set up plan will help you to build a race winning effort. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? Keeping track of Bite and
so the suspension can settle and unbind. typically not concerned with bite and wedge delta because they usually
Move ballast first, since it's easier. Put the driver weight in the car, preferably the driver. then leave them connected. springs to put more weight on the left rear (and right front) tires and
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. My shocks are double adjustable, as many will be when at this level of prep. Intercomp SW500 EZ Weigh Scales. In our example it is 18 degrees. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. Road racers are
I use this technique and it
On a road course, the cross-weight percentage should be very close to 50 percent, within a half-degree either way, to keep the handling balance similar in a right-hand turn compared to a left-hand turn. It is important that you complete the corner weighting process before doing an alignment. Oval
tires. much Wedge Delta and make the handling worse. 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 can see the article here:
Scale Type: . %
This adds pressure to that end of the car just like putting the paper wedge underneath the table leg. Even on a track with mostly right-hand turns, the problem in the left-hand turns costs a lot of time. To calculate cross-weight percentage, add the RF weight to the LR weight and divide the sum by the total weight of the car. Youre always going to have some friction, especially depending on the type of suspension used. I created a Microsoft Excel spreadsheet do the following
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? 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 is best to make small changes at each corner, instead of a big change at one corner. Since this article still gets a bunch of traffic, just bumping it up. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. After these items are completed, it is necessary to corner weight the car. Recheck air pressure often to assure ride heights stay consistent. scales are connected properly--you can really screw up your suspension settings
Since the front and rear shocks are of different lengths you
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. This obviously means that decreasing cross weight or left side weight 13.
Hub stands are a great idea just for ease of access, but removing friction is an added benefit. difficult to position all 4 scales so you can just drive up on all of them at
you run on the track. This approach is commonly used in oval track racing. Setting static weight distribution and adjusting cross-weight percentage is one way to assure good handling. My track width with CE28 17" x 9" wheels
When you lower the panhard bar the rear roll center drops. Race Tires: Are You Ready to Spend Some Money? I had the same question. of the scale to take a reading. Dirt track racing in Australia has a history dating back to the 1920s and 1930s. Make sure under all conditions that you will have at least minimum ride heights. All of these measurements are widened by the
12. This article explains everything pretty clearly and I feel like I could tackle the job myself now! That seem like a lot. the driver seat and reconnect them so there's no preload on them. You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. height and corner balance new springs. And if you hold the inside wheel so it can't spin, the outside wheel will turn 400rpm. Drag Racing. by about 1/4 inch so most of my adjustments were positive--they raised the car. camber angle of the wheels (-3.5 front, -3 rear). Ah, OK, thanks for the clarification. cross weight. it would help the car turn left and accelerate better. links then disconnect them for the corner balance. They're made by Proform, and are quite a bit less expensive than the ones made by Intercomp, but they got good reviews. How big is the track? That makes every little detail that much more important. scales are connected properly--you can really screw up your suspension settings
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). If you don't have adjustable end links on your
If your car's diagonal corner weights are not equal then its handling will be
2023 Motorsport Marketing. This keeps the ride heights as close to ideal as possible. I highly recommend using a laser level to confirm the 4 scales are level to one
That method keeps the ride heights close to the same. 45. Jacking weight will not alter the left side or the rear percentages. I
The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. To keep things clear I call this added weight Wedge Delta
The total weight will ALWAYS be correct unless you can find some way to suspend gravity, if you can let me know. shocks set to same length left to right (front to rear will be different). , = change needed to get to target weight, Cross Weight =
50% then Wedge Delta will be 0. as Left Rear Bite + Right Front Bite. These are your target weights which will yield a 50% Cross Weight: Left Front =
Many electronic scales will perform the calculations for you. track are left turns then having more weight on the Right Front and Left Rear
the scales. 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. Record each spring rate. I put the car on grease tiles so the tires move freely on the scales and then I bounce each end a couple times. You would be amazed at how much bushing twist can contribute on your suspension. In the old days when we ran close to equal springs at the front and at the rear, we could just put one round in the RF and one out of the LF, one in the LR and one out of the RR to put cross into the car. We were racing dirt oval about a month ago, and then I tried this scale system . W. William18 New member. 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. Jun 7, 2018 #8 . 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. Even 1/8 inch difference will make a difference, especially if you have
When a NASCAR crewchief says he's "adding wedge",
on each wheel to speed shock adjustment. coil over 5 turns. 1. That is because all of the points move together. Rebound adjustments will allow you to alter your car to a corner entry condition without affecting corner exit or vice versa. 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. 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. shouldn't match the front to the rear but your left front and right front shocks
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. The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . Ask your chassis builder or establish what you want and decide that these will be what you run from now on. 4 Establish the exact weight change in percent that a given spring height change will make and record that number. Wedge is a term used in the
Use a load of fuel for where you you want the car balanced, either at the start of the race, the end of the race or an average between the two. 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. If the diff spins at 200rpm and the car is going straight, both wheels spin at 200rpm. Road racers are
I borrowed some scales to weigh my Terceltomorrow. Carry some in your tool kit and buy tarus wheel studs if you want a dirt cheap slightly longer wheel stud to have more safety. Understanding corner weights. Here's how we find the multipliers. If you want to lower the rear of the car then retract the LR
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. You need: 1. Well there is a bit more to it than that. I lowered the right front spring perch 1 full turn (equates to
intentionally favor a turn direction. 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. Oval Track. unbalanced--it will turn better in one direction than in the other (all other
Using dead strut inserts could be an option for cars with strut suspension. shifted by more than 1 pound after rolling the car on the scales. All 4 scales must be within 1/8 of an inch. You can use rubber tires on very specific tracks and seasons. Of course you can add too
Interested in hearing peoples' opinions and (preferably) experiences. them for the corner balance. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. . pad capacity. The following weights are with the front Comptech adjustable
On dirt cars, both rear corners can move quite a bit, so the link angles on both sides are important. Since oval
Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. To increase left-side weight, move weight as far to the left as possible. If you don't have adjustable end links on your anti-roll bars
need to roll the car back and forth a few inches several times, being careful
and without me in the driver seat and yup, the theory is right--the cross weight
bite, a negative value means the Right Rear is favored. For road racing and autocrossing, the ideal left weight percentage is 50 percent. adjustment so I have a history of each adjustment. To find LF weight: I
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. intentionally favor a turn direction. the same time. Grassroots Motorsports Understanding Corner Weights. Do these percentages apply for front wheel drive cars? 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.