Bearings, like sealed roller bearings,solid bushings, or spherical joints. of its weight on the Left Front and Right Rear tires, and 50% on the Right Front
I just back all of the damping off totally. Before putting your car on the scales you need to power up
Take care that the car does not accidently slide off the scale pads. Andy Hollis does this. Road racers are
lot of force to the suspension. I created a Microsoft Excel spreadsheet do the following
For our example we use: LF 200, RF 250 - 250 200 = 1.25 multiplier for the front. left to right. I don't like the lower weight ratings and plastic scale pads of proform. Those will tend to reduce friction and bind at the expense of NVH and added wear. pad capacity. Do not adjust any other wheel's spacing. If most of the important turns on your
I had to do this with my truck. LF and RR (extend coil over), remove preload to RF and LR (shorten the coil
Wedge
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. lowered onto the scales the tires will need to spread out to unbind the
for the front and rear sway bars and installed them with my girl friend sitting
Dirt adds weight, binds suspension parts and hides potential problems > The bearings come well oiled and attract a lot of dirt. Avoids a mess on scale pads and tires,prevents dirt fromcontaminating lube. If you had a car with a fully rod-ended out suspension that frictionless and frictionless tires you wouldn't need to roll the car around or bounce it or anything. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. 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. Intercomp SW500 EZ Weigh Scales. scales are connected properly--you can really screw up your suspension settings
When Wedge is balanced at
A set up plan will help you to build a race winning effort. if you have any of the scales connected improperly (i.e. 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 . I will say that if I'm starting on a fresh setup, or the car has been lowered, or I find myself making massive spring perch changes, then I will loosen all of the suspension bolts so that the bushings can relax and find their new happy place. how and why to corner balance a car. Make sure under all conditions that you will have at least minimum ride heights. Even 1/8 inch difference will make a difference, especially if you have
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. If you know the front, side, and crossweight percentages, then you can calculate the numbers. To do this, we add five rounds of pre-load to the RF. Be sure to have the weight of the driver in the seat. Equal weight on each front wheel, same on the rear. Corner Weight Calculator This is used to calculate the corner weight and Wedge. When a NASCAR crewchief says he's "adding wedge",
I
Your results might be different from mine. The roll center is an imaginary point around which the rear of the race car rolls. Disconnect the sway bar.
another. There are legal issues too at the front. Note your ride heights and
Then measure from the lower wheel rim edge up to a spot on the fender on a piece of masking tape. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. you raise the rear of the car 10 inches or more and re-weigh it. Some racers like to take matters into their own hands-and that's OK. Grassroots Motorsports Understanding Corner Weights. Or do you just mean an old, worn-out strut? I dropped my integra off at edge to have this done today. 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. One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. 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. Right handers vs left handers feel quite a bit different-I run out of suspension on right handers much more often, and on left handers the car loves having me hanging out over the inside of the contact patches working the corner. Here's a box stock 2006 Honda S2000 with 5/8 of a
This allows a slightly lower rear stance, which provides a good weight transfer entering a corner. Examine a modern push/pull rod suspension, particularly if it uses a crank link to transformthe cross weight. 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. I recommend adding an eighth or slightly more to the lowest corner just to make sure you pass tech. intentionally favor a turn direction. On oval track cars, cross-weight is usually used in conjunction with stagger (where the right rear tire is larger in circumference than the left rear tire) to balance handling. February 2017 -Suspension design process. W. William18 New member. Check your tire pressure and bump it up to the hot pressure
Thanks. LR = left rear. If most of the important turns on your
There are several ways race teams adjust corner weight. Today's oval
Granted, moment centers will stay fairly consistent with small movements of the chassis in dive and roll from the ride heights being off a little. shocks set to same length left to right (front to rear will be different). The outer rear tire drives "around" the outer front tire, allowing the chassis to efficiently turn into the corner because the rear tire to get a balanced diagonal weight on the tires. Funny. (adsbygoogle = window.adsbygoogle || []).push({}); If you prefer Microsoft Excel a Corner Weight spreadsheet is available for download here
bite, a negative value means the Right Rear is favored. Speaking of springs, it's a good idea
B. Once static weight percentages are set, work on cross-weight percentages. For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. retract the right rear tire which puts more weight on the Left Rear and
The distance from the ground to an inner suspension arm pivot point will also accomplish the above goal. turn to the RF simply to raise the ride height of the front of the car. This is my 2001 S2000 with 1/2 tank gas, 216
Left Rear tire is carrying more weight so it will get more traction and
I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? Maybe there's some sort of bind in the scales. However, for dirt oval RC cars, foam tires are the norm. springs to put more weight on the left rear (and right front) tires and
However, you can choose to use them. 8 Read the ride heights as they exist. Left Front weight:
Left Rear tire is carrying more weight so it will get more traction and
Right Front =
extra weight is on the left rear and right front tires which gives them
hard work but it makes all that high dollar suspension work together the way its
camber angle of the wheels (-3.5 front, -3 rear). Or maybe I read the post wrong. I still rolled the car back and forth a
I borrowed some scales to weigh my Terceltomorrow. It has to, it's just the laws of physics. 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. 12. Doing the multiplication to square that number, we get 1.1056. Strive for repeatable and take the measurement as a data point, instead of an absolute. Similarly, dirt oval cars often represent crossweight as "bite", or weight on the left-rear tire relative to the right-rear tire. If you do have adjustable end
racers add "wedge" by adjusting the right rear spring perch--they
Delta is equal to (Right
you don't use Microsoft Excel. lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille
For that level of caring, I wouldn't think too much about it. With an oval track car turning to the left, weight will transfer from the inside to the outside. Brake pads badly taper worn - replace. More stagger usually loosens the handling in left turns, so more cross-weight is used to tighten it up. But in a right turn, the opposite occurs and the handling is worse. measure (literally). much Wedge Delta and make the handling worse. Less tread on hard slick is good. need to roll the car back and forth a few inches several times, being careful
scales are connected properly--you can really screw up your suspension settings
shifted by more than 1 pound after rolling the car on the scales. Astrut with its innards removed? as Left Rear Bite + Right Front Bite. decided to try 5 turns total of spring perch movement to balance the car. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. should have their spring perches in the same spot and your left rear and right
Jacking weight will not alter the left side or the rear percentages. Now, look into details about the matter. I put the car on the scales and input the four corner
Cross-weight percentage compares the diagonal weight totals to the car's total weight. 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. Caster creates stability as the geometry . For our example we have LF 3.625, RF 4.75, LR 4.625, RR 5.75. Here is what you do. LR 175, RR 350 - 350 175 = 2.00 multiplier for the rear. surface. 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? Typically, this adjustment will make the car tighter on corner entry or in the center, and a little looser on exit. , Left Rear =
Wheel offsets can make a huge difference in fine tuning the chassis which will allow the driver to find a good racing line on the track. height and the shocks set to the exact same spring perch height
The CG height
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. Since oval
The spreadsheet's second page has a good article that goes into more detail of
Always
I
want balanced turning in both directions. 2 coils cut off springs 4 corners. If you moved only one point, then the problems begin. Using dead struts and lots of bearings will help. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. line above each scale and placed a ruler on the top
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. Wedge Delta can also be thought of
Corner balancing, sometimes referred to as "corner weighting,"
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. Just to confirm the theory I checked the corner weights with
The driver is optional based on No. Because karts have so much caster having the steering turned even slightly will cause a big change in the corner weights. Corner_Balance.zip Excel spreadsheet. Toe inn a 1/4 inch. to balance your car in one big step. 14. Record each spring rate. 1) Tweak: Tweak is the amount of weight on the LR as opposed to the RR. the scales. 50% then Wedge Delta will be 0. 13. While several different setup parameters could have caused this situation, a likely cause is excessivecross-weight. 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. We delve deeper into race suspension tuning basics here. Ah, OK, thanks for the clarification. Left front weight + right rear weight = right front weight + left rear weight. Some engines are used in two different classes with the only change being exhaust system. Even 1/8 inch difference will make a difference, especially if you have
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). Lowering the cross weight does the opposite of raising the cross weight. In our example, the front average is 4.25 and the rear is 4.75. This will pitch the vehicle's. Any corner weight adjustments that you make will impact the alignment of your car. We now take five rounds out of the RR and add five rounds times the rear multiplier, or 2.0 5 = 10 rounds to the LR. balancing see my corner balance how-to and
I saved a copy of the spreadsheet for each
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. Do these percentages apply for front wheel drive cars? Ok sounds good. You will have to repeat this every time you lower the car onto
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. I just run higher pressure for the street, I feel mine is pretty close as is. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? Corner-Weight Distribution Bickel points out that corner-weight distribution refers to the amount of weight carried by diagonally opposed pairs of wheels. When I weigh my cars I try not too overthink all this binding stuff. 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? 12. At the front, we will move the LF and RF adjusters up by 0.0625-inch. I can see binding throwing off each corners weight but the sum should be the same. May 2017 -Dirt late model pinning RF & heavy axle tube. My left rear is something like 150lbs heavier than the right rear, with both fronts even at ~740lbs each on a 2425lb FWD car. It's better to make many small changes than to try
Check stagger at each tire, even if using radials. close to where I wanted it. Corner Weighting Get the rear percentage as close to the manufacturer's specs as possible. In April 2013 I corner balanced the S for the first time in
By lengthening or shortening a leg, it increases or decreases weight on the other legs. 1 Establish the corner weights you think you need for your car. In circle track racing, we often, and almost always, have different rate springs on each corner of the car. suspension changes to track your progress. important for oval racers, especially on dirt ovals. . The first is to use traditional lift-off oversteer. It's stuff closer to 60/40 or 40/60 where you need to stray from crossweighting. Now that's pretty cool! The following weights are with the front Comptech adjustable
You can see that the leverage ratio in the crank link reduces coilover(and thus shock) travel, and It is best to make small changes at each corner, instead of a big change at one corner. 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. it would help the car turn left and accelerate better. about 1/8" of wheel movement) to reduce the weight on the right front and left
You've tried springs, shocks, different bars, neutralizing the anti-roll bar, and nothing seems to work. section). Currently, dirt car racing involves a left-hand weight measurement of 53.5-55, along with a wedge between 75-125 pounds. turns. Or it could also be possible that the signal is smoothed in the programming. Calculate the average existing ride heights front and rear. 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. The height of the rear roll center (and the front also) is critical to handling. tires. This keeps the ride heights as close to ideal as possible. I lowered the right front spring perch 1 full turn (equates to
A jumbo ziploc bag prevents lube from escaping when not in use. The more rear weight bias, the tighter the chassis will be coming out of a turn. I added the
if you have any of the scales connected improperly (i.e. The shock length as it is installed in the car at ride height. Less fuel equals faster speeds. Changing the ride height at any corner will change the cross-weight percentage. If the diff spins at 200rpm and the car is going straight, both wheels spin at 200rpm. . If we subtract the existing ride heights from the desired, we have front low by 0.0625-inch and the rear high by 0.4375-inch. Don't just blindly cross weight it thinking it's the "right" way. That is why it gets tighter. Positive Caster is created when the caster line lands forward of the contact patch. Firstly, you need to balance out your RC. This gets very tedious, given the number of iterations it typically takes to get the corner weights right. 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. Rolling the car onto the scales from a small ramp that's the same thickness as the scales seems like a better option, but does it truly remove all the bind? Then the car will move more easily from one setting to another. Calculate the spring rate multiples. supposed to. "There's a lot of freedom when it comes to setups using various styles of springs" in dirt late model racing, said a source. height and corner balance new springs. anti-roll bar with the end-link adjusted so it's easy to insert the
I was booked for 100 laps split across four or five sessions. The rear is 2.125" wider. They kept saying that it would go anywhere on the track and anywhere they pointed it. Our current setup is as follows - 270 lbs Car & Driver Cross Weight = 48% Rear Weight = 61% Left Side Weight = 51% LF = 56 lbs RF = 48 lbs LR = 82 lbs RR = 83 lbs Here is a screenshot with some random-ass corner weights. So, they don't care if the scales are level, they will get what they want from unlevel scales. Moving weight to the front of the kart will provide more front-end grip. However, many cars cannot make the 50 percent left-side weight percentage due to driver offset. them for the corner balance. to get the desired corner weights your ride height will change. 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. With my KWV3 shocks I had to remove the wheel to adjust the
If your car's diagonal corner weights are not equal then its handling will be
If one leg is longer or shorter than the others, the table will rock and thus be unstable. over
Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. To add weight to a given corner, raise the ride height at that corner or lower the ride height at an adjacent corner. If you want to lower the rear of the car then retract the LR
Keeping track of Bite and
TVW - (RF + LF + LR) = 603. A place where you can add in your Photo Galleries. These are your current calculated weights: Total Weight = Front Weight = % Left Weight = % Right Weight = % Rear Weight = % Cross Weight = 50% is optimal Bite = Bite should be positive for oval racing Wedge = % Wedge Delta should be positive for oval racing can help us get our setup right with less testing. Once you have returned the wheel corresponding to the spring change back to its measurement, the other wheel measurements will be OK. 3. Crossweight is of no concern to the track officials. To test this, put the car on scales, and just tip the setup board and see how much the numbers change. All 4 scales must be within 1/8 of an inch. Bounce the car at each corner to free the suspension from any bind, then roll the car onto the scales. I weigh 220. and measured between the outside bottom rim edge is 67.75" front and 69.875"
Wedge Delta should be positive for oval racing. To keep things clear I call this added weight Wedge Delta
% Wedge Delta will be 0 at 50% Wedge.
The only way to change the static weight distribution percentages is to physically move weight around in the car. Would be interesting to see how close to ideal I got it though, given how well it handles already. corner weight calculations: Corner_Balance.zip
2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. Same with go-karts with solid rear axles, they'll lift. You will have to repeat this every time you lower the car onto
No, not as in the law, but in being legal in tech. Took it to be corner weighted and it transformed the car in to a front runner that the drivers raved about. Or am I missing something? tires. All rights reserved. upgrading our street stock suspension part 2 the rear end. document your current ride heights and your coil over changes each time
Measuring from the center of the tires I got
Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag.