Determine your ride heights. 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. Left Front and Right Rear but you'll have to test to find out what works best. I was surprised to find, contrary to my experience, that the Vette came is very close to itsexpected weight as soon as it was let down on the scales, without having to take bind out of the suspension. It's
For pure race cars this isnt a consideration. You can also estimate your car's
important for oval racers, especially on dirt ovals. Guess I have to try it. You will need to weight your vehicle on each tire to use this tool. McMaster-Carr adjustable end links
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. dry)! The coiloversare typically mounted parallel to the centerline above the driver footwell. 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. Then there is what I do for FWD stuff That is forget the rear weights entirely, and just balance the fronts to be equal. Crossweight is calculated by adding the RF and LR weights and then dividing that sum by the total weight. If the car feels loose on corner entry, lower the left track bar. much Wedge Delta and make the handling worse. turning the front wheels to measure caster. 3) Reverse stagger: The opposite of stagger when your left side tires are . Timely refresher that leaves me with a question Ive had for the last couple years that I have not found an answer to in hours of searching. (corner weights) instead of moving shims above / below spindle? so the suspension can settle and unbind.
Dirt Late Models. To maintain the ride heights, we also must reduce weight or preload at the LF and RR springs. Disconnect and adjust later. Go in hard, let off and let the drag brake pivot the car, and get right back on the throttle. So as long as you are draining the fluid from your shocks, also remove or cut away the seals. A jumbo ziploc bag prevents lube from escaping when not in use. I still rolled the car back and forth a
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.
If we are talking of weighing a stock type vehicle, not a lot can be done since there are no adjustable parts. 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. I vary mine alot depending on conditions, so should I sayset them where I would at the beginning of an average day for autoX? 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. 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. "This is called chassis pre-load. 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. For our example, we use LF 4.00, RF 4.50, LR 4.50, RR 5.00. It also helps when shaking the car to take the bind out of the linkages. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. the sway bars because they fail so often and the bars only added a couple of
shocks set to same length left to right (front to rear will be different). retract the right rear tire which puts more weight on the Left Rear and
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. Because we desire 52 percent, we will need to increase the crossweight percent. Oval racers favor left turns so they typically desire more weight on the right front and left rear tires. Just to confirm the theory I checked the corner weights with
your scales. When you adjust your coil overs
Be sure to have the weight of the driver in the seat. on my garage floor for future reference. want balanced turning in both directions. Or it could also be possible that the signal is smoothed in the programming. For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. Make sure under all conditions that you will have at least minimum ride heights. Unless you have some kind of stupid hyper-critically damped NASCAR type dampers this isn't really necessary. I
Bite tells us how much we
First the tires. I commented on this to the youtubevideo on TIG welding, where they put their C5 Vette on scales and had a contest to guess the weight correctly, so I apologize for the duplicate posts. Wheel Load-We have already determined the wheel load we desire in No. I
You can
Please post on the appropriate 4m forum. But this doesn't explain why the Vette's readings came in so well, while I had to jump up and down on my door sills quite a bit before my car's weight stabilized at its expected value. Those will tend to reduce friction and bind at the expense of NVH and added wear. what he means is he's adding weight to the left rear and right front
Corner weighting your car is
Wedge is a term used in the
Ok sounds good. 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. Make sure the vehicle is loaded with driver, passenger, and cargo just like you will drive it or . When looking at corner weighting, the cross weight (diagonal weight) is the most important component. That seem like a lot. "Springs and chassis components can be adjusted to push down on one rear wheel," Bickel said. which is simply the difference between the two diagonal tire weights. 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. lb driver, no passenger, spare tire removed, soft top up, Magnaflow mufflers (-20lbs), Braille
extra weight is on the left rear and right front tires which gives them more
started with the Left Front because I wanted to raise the ride height of the car
I've had my cars corner balanced a lot, but never really looked into the science of it. Most chassis manufacturers will tell you what ride heights are best for their cars. Or use an automotive tuning shop. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. you don't use Microsoft Excel. Bite tells us how much we
1 of the section on "Adjusting The Corner Weights," and that is 685. But in a right turn, the opposite occurs and the handling is worse. Then just leave them attached. Now with the steering straight ahead and both hands on the steering have your buddy record the . For example, if you are racing the Briggs Light class at 305 pounds, your corner weights should be: LF = 68 pounds RF = 68 pounds Leebo's Corner. the scales and zero them with no weight on them. measure (literally). If you want to lower the rear of the car then retract the LR
Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. 2023 Motorsport Marketing. Check stagger at each tire, even if using radials. Oval Track. Find a fairly level spot and mark on the ground with duct tape or marker where the tires sit on the ground. 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. 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. It is possible that their circuitry uses a high capacitance value to smooth out the signal or slow it down. adjustments were 1 turn to the right front and 3/4 turn to the left rear. The LF needs to go up 0.3125 and the RF needs to go down the same amount. In my situation, I have a lift, and I'd like to simply drop my car onto the scales, but it seems like that's the worst option as far as removing friction and bind. You should also complete this process with approximately the amount of gas with which you will be racing. Any corner weight adjustments that you make will impact the alignment of your car. Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. height and corner balance new springs. 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. 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. To find RR weight: I've spent an hour this afternoon trying to do corner weights "on the cheap" using our IKEA kitchen scale (cost - 15.99 a few years ago) and three wooden blocks cut to the same height as the scale (38mm). These weights are in ready to race form (including driver on board). on the right front and left rear tires. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. 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. Changing the ride height at any corner will change the cross-weight percentage. That is why it gets tighter. The only way to change the static weight distribution percentages is to physically move weight around in the car. of the scale to take a reading. Iretighten them after I've made all my adjustments. are favoring the left rear tire for better acceleration out of left
spring perch so I left my jacks in place between lifts and only put two lug nuts
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. left to right. I just back all of the damping off totally. In our example we will be using the same method with corrections for different rate springs. Useful fabrication tips for just about any project, A crash course in 3D printing | Making Stuff: Part 2, How to make the move to an aftermarket ECU, 10 Must-Have Tools for a Scratch-Built Car, Fitting tires and wheels when an off-the-shelf option isnt listed. used cheap linoleum tiles (49 cents each at Home Depot) to shim two of my scales
It varies with weight removal, added. So 2.5" springs and experimenting is the way to go- I think I know that much.. . "two linoleum tiles & salt" technique to allow the tires to slide on the scales
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. Once the corner
For Oval guys I suggest talking to your local kart shop who knows the tracks you run on for a suggested starting point. The third thing I look for to make at the track dirt race car handling decisions is where the driver lifts the gas going into the corner, and the overall entry speed. another. For information on corner
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
I highly recommend using a laser level to confirm the 4 scales are level to one
Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. rod movement from the wheel to the coilovermovement. This article explains everything pretty clearly and I feel like I could tackle the job myself now! Grassroots Motorsports Understanding Corner Weights. Left Rear tire is carrying more weight so it will get more traction and
Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. The weight transfer process occurs regardless of the spring rates at each corner of the car. 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! Jun 7, 2018 #8 . When you lower the panhard bar the rear roll center drops. Search for: Left Front and Right Rear but you'll have to test to find out what works best. For road racing and autocrossing, the ideal left weight percentage is 50 percent. I usually mark an even inch and write that inch number on the tape. Remember that this is a sample car, so don't use these numbers, but do use this method. 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. Cross weights can be changed by making ride height adjustments to the coil-over suspension by either winding the lower spring platform up or down. 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. 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. Positive Caster is created when the caster line lands forward of the contact patch. Muscle Car. 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. 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). Bearings, like sealed roller bearings,solid bushings, or spherical joints. 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 . Right Front tires. tank of gas, and no driver or passenger: Now here's the same stock S2000 with a 215lb driver in the seat: I was really surprised to see how far off the stock S2000 was
I mainly run the 3/8. 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. That's all total speculation though. Tuning with anti-dive probably won't be . However, for dirt oval RC cars, foam tires are the norm. I'm off by 0.1% (see numbers on left side of the spreadsheet). box in the "Ride Height" section of each spreadsheet. One of the most important aspects of racing is having a good handling balance. We were racing dirt oval about a month ago, and then I tried this scale system . I use 2x6 wood planks as ramps to drive the car onto
the RF coil over 5 turns. over
A perfectly corner balanced car will handle the same when turning left and right, and will maximize the tire contact area on all four corners. In oval racing you always run more weight on the LR. The tiles & salt seemed to help because the weight never
Astrut with its innards removed? I
(TVW LSP) - LF = 769D. 13. The first is to use traditional lift-off oversteer. not to push it off the scales, to unload the suspension (as the car is
Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. If one leg is longer or shorter than the others, the table will rock and thus be unstable. should have their spring perches in the same spot and your left rear and right
I dropped my integra off at edge to have this done today. It is a critical set-up tool. The left side changes, of course, will be 4.75 times the multiplier for front or rear. used are 0.045" thick. You should read the spring preload amount. When a NASCAR crewchief says he's "adding wedge",
TVW - (RF + LF + LR) = 603. Choose a level spot in your setup area. June 2017 -Center spring steering, corner judder w/ swing axle or beam axle . used linoleum tiles to shim two of my scales to get them all level. They are never level. 2. Just make sure none of them are flat or wildly overinflated. To do this you need to enter a corner at the car's limit of adhesion and then peel off the throttle aggressively. More wedge means that the car will likely understeer more in a left turn. The advantage to wedge is that the left rear tire carries more load, so the car drives off the turns better. If you want to raise the front of the car then extend only the
Weight can be moved around at the track to fine tune the handling characteristics of the chassis. For a car with a 17.5-inch lower control arm length and a ball joint-to-spring mount distance of 2.5 inches, you divide 17.5 by 15 (17.5-2.5) to get 1.1667 and then multiply that by itself to get 1.3611. 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. Brake pads badly taper worn - replace. This keeps the ride heights as close to ideal as possible. Wouldn't the fact that it is front wheel drive change at least the front to rear percentages? oval racing world and is simply another word for Cross Weight. 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. Rear weight percentage for road racing and autocrossing is less definite. Hot Rod. If you want to lower the ride height then retract both RF and
line above each scale and placed a ruler on the top
Wedge Delta is equal to (Right
When Wedge is balanced at
section). MuddBoss Feature Winner at Dirt Devils RC Speedway, 12-18-2021. Classic Truck. 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. traction or bite in left turns. The driver is optional based on No. Bite should be positive for oval racing, Wedge =
Adjust the rear down by using the same method as in No. looking forward to getting it back! (Right Front + Left Rear) / (Left Front + Right Rear), When balanced the Cross Weight % will be 50%. Ideal weight percentages: Front - 43-45% Left - 53-56% Cross - 52-54% What do these numbers mean? To favor right turns, put more weight on the
The important thing to remember is that the laws of physics are the same whether you are racing on an oval or a corner weight calculations: Corner_Balance.zip
Picture the following: Your car is really fast in right-hand turns, but understeers in left turns. Always
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. stiff springs on your coil overs. Less tread on hard slick is good. 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. . Let's explore some ways to do this in an orderly and sensible way. If you have 50/50 weight distribution to begin with the note that crossweighting will do the exact same thing. If you get the car neutral in left turns, it oversteers in right turns. Lay the bag flat onto the scale pad, partially open to vent, lower the car into the bag. Once you get the car up on the scales you'll
Of course you can add too
Thanks. Check static weight before working on cross-weight. You can use rubber tires on very specific tracks and seasons. Intercomp 102030 5X5 Hub-Mounted Corner Weight Scale. No, not as in the law, but in being legal in tech. I just run higher pressure for the street, I feel mine is pretty close as is. If most of the important turns on your
much Wedge Delta and make the handling worse. The overall effect is much like having no shock in the equation. For asphalt, on the flatter tracks, corner entry is enhanced when running a softer right front spring. RC Oval racing is probably the easiest form of RC racing right, right? 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 &. . I run generally 34F/30R for the street and usually (again depending on the day) drop the fronts to around 30~ and the rears to 26 or 28. If it slows to 100rpm, the outside wheel will spin at 300rpm. [Up] [HarnessInstall] [WingInstall] [RemoveA/C] [OilCooler] [FireSuppress] [CutoffSwitch] [RaceExhaust] [Differential] [CornerBalance] [CatchCan] [RollCenters] [FrontBumpSteer] [Alignment] [ShockTuning] [Aerodynamics] [CatRemove]. Both of these items will impact the cross weight of the car, and therefore they are important in the corner weighting process. Wedge Delta should be positive for oval racing. 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 On my ZX2SR my cross weight was consistently in the 49% range. 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. It's a lot of
5. Raising the rear end will also provide a little more on-power grip by keeping more weight directly above the rear tires during acceleration. Why? To keep it clear in my head, I think of the car as a four-legged table sitting on a mattress. Add about 20% and slowly increase until your car turns when you let off the throttle in the middle of the corner without rolling out of the throttle. 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. renting/borrowing/buying some scales and corner balancing your car. Less fuel equals faster speeds. I found that the tire will absorb side loads quite well and was repeatable. 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. 11. Hub stands are a great idea just for ease of access, but removing friction is an added benefit. Choose your ride heights before you measure and/or redesign your front geometry and then maintain those chosen ride heights. As the shopping cart is pushed forward the front wheels spin back and trail behind the caster line. Funny. LF coil over 5 turns. you run on the track. Finding The BBSS Front Spring Pre-Loading The front will show close to 60%. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. Wedge is a term used in the
How big is the track? When I weigh my cars I try not too overthink all this binding stuff. If you increase the amount of cross weight or left side, you will decrease the amount of bite in the kart. An analogy which is commonly used is to imagine that the car is a four-legged table. If your car has coil over adjustable shocks you should consider
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. I don't like the lower weight ratings and plastic scale pads of proform. Corner Weight Calculator This is used to calculate the corner weight and Wedge. All of these measurements are widened by the
tires. Front + Left Rear) - (Left Front + Right Rear) and tells us how much