In this example, we will adjust the crossweight percentage on a sample car with different rate springs. Cross Weight or Wedge. All 4 scales must be within 1/8 of an inch. If most of the important turns on your
Yep, old struts that are drained of fluid and have little to no resistance. A. Check stagger at each tire, even if using radials. unbalanced--it will turn better in one direction than in the other (all other
need to roll the car back and forth a few inches several times, being careful
Some racers like to take matters into their own hands-and that's OK. Wedge Delta can also be thought of
If you do have adjustable end links then disconnect
Wheel Offset Changes. 2. Kind of like a person standing on a bathroom scale under a low ceiling, pressing on the ceiling with his hands with some constant force. adjustments were 1 turn to the right front and 3/4 turn to the left rear. Only after I spent a lot of time bouncing on the door sills did it settle down and stabilize. The nose weight is simple to remember the tricky ones are - cross and left side adjustments. what he means is he's adding weight to the left rear and right front
- can make your car dive like a dump truck or a block of wood on ice. Muscle Car. Check your tire pressure and bump it up to the hot pressure
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. 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. Measure control arm angles after each change. Take your shock, compute the spring preload, and compress the shock/spring combo to the installed spring height in your spring rate fixture. So if you have 60% on the front , you should have 30% on each front wheel. 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. A jumbo ziploc bag prevents lube from escaping when not in use. Tell the shop you will be disconnecting the rear sway bar when obtaining the estimate. can help us get our setup right with less testing. Make sure the tires are centered on the scales. Race Tires: Are You Ready to Spend Some Money? Equal weight on each front wheel, same on the rear. Astrut with its innards removed? Calculate the spring rate multiples. I dropped my integra off at edge to have this done today. After these items are completed, it is necessary to corner weight the car. It still pays to be thoughtful about weight placement fore and aft in your car. and Left Rear. Yeah, I'm a little puzzled by my result when I let me car down on my new scales as well. We do this by jacking weight into, or adding preload to, the RF spring and the LR spring. suspension). [ 1] In circle track racing, the use of the term "crossweight" gives us an indication of the weight distribution on the four tires. . 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! Are they non-adjustable? Intercomp SW500 EZ Weigh Scales. Right now I have (IIRC) 350 lb front and 200 lb rear springs (koni sport, eibach pro line, ST anti sway bars) . 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. If you get the car neutral in left turns, it oversteers in right turns. Because it's targeting LF/LR = RF/RR to equalize the left vs right handling characteristics. I use 2x6 wood planks as ramps to drive the car onto
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. We should now be at, or near, the desired crossweight percent. difference that made. Same with go-karts with solid rear axles, they'll lift. Get it right and your car launches down the corner, hits that hard hairpin just right and holds the corner at full throttle. I usually mark an even inch and write that inch number on the tape. bite, a negative value means the Right Rear is favored. Right Front =
So, ride heights in the front are more critical for maintaining camber angles. from a balanced Cross Weight. This is for a race prepped 1984 Audi 4000 quattro(2375lbs. not to push it off the scales, to unbind the suspension (as the car is
line above each scale and placed a ruler on the top
For this exercise, we will just be changing the pre-load on the springs to redistribute the loads, or weights on the four corners. (TVW LSP) - LF = 769D. 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. More wedge means that the car will likely understeer more in a left turn. (corner weights) instead of moving shims above / below spindle? 14. You will need to weight your vehicle on each tire to use this tool. Before putting your car on the scales you need to power up
The total weight will ALWAYS be correct unless you can find some way to suspend gravity, if you can let me know. 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. 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). Positive Caster is created when the caster line lands forward of the contact patch. 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. The car should be at minimum weight, using ballast as needed to make the proper weight. Measuring from the center of the tires I got
The process is so basic to the setup of the car. To increase left-side weight, move weight as far to the left as possible. 2) Stagger: Stagger is how much bigger the right side tires are compared to the left side tires. We had a good Miataset up for ST. the scales. (adsbygoogle = window.adsbygoogle || []).push({}); I still needed more weight on the Left Front and Right Rear so I added + 4
One of the most important aspects of car setup is the static weight distribution and the cross-weight percentage. I put the tiles on top of the scales. LF and RR (extend coil over), remove preload to RF and LR (shorten the coil
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. We also take five rounds times the multiplier for the front of 1.25 5 = 6.25 rounds out of the LF. [Up] [CornerBalanceCalculator] [CGHeightCalculator], This calculator takes your car's four wheel weights and calculates current
in the driver's seat to load the suspension. If your car has coil over adjustable shocks you should consider
Strive for repeatable and take the measurement as a data point, instead of an absolute. knew I needed to put the car on the scales. difficult to position all 4 scales so you can just drive up on all of them at
balance is complete put someone in the driver seat and reconnect the
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. This will pitch the vehicle's. If the car feels loose throughout the corner, lower both track bars evenly. another. So, we are not reinventing the wheel here, just refining the process. That seem like a lot. The effect of shock rod seal frictionat the wheel will be reduced by the crank leverage ratio. Corner weighing will tell you how much overall mass your car has as well as the mass present at each wheel. Or use an automotive tuning shop. 5.00 front 8.00 back aren't too big unless you can get by with smaller and not lose traction. 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. of the scale to take a reading. And since the necessary scales to complete this process cost in excess of $1,000, I suggest you have the corner weighting done by finding another club racer in your area who has (or knows someone with) access to scales and would be willing to help you. 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. from +1 overall to -1): I put + 3/4 of a turn back on the Right Front and ended up
To carry the wheel load, the spring must be compressed quite a bit. suspension). pounds of preload to the scale weights. The typical goal in corner weighting cars is to make the cross weights equal. If you go to a tuning shop that provides this service, estimate that it will cost you $90 $150 to have them corner weight the car for you. you raise the rear of the car 10 inches or more and re-weigh it. oval racing world and is simply another word for Cross Weight. If you don't want to change your ride height then a more balanced approach would
Now that's pretty cool! 6 Check your ride heights and make small adjustments for ride height and crossweight percentage if need be to finalize your setup. left to right. Wedge is a term used in the
It is best to make small changes at each corner, instead of a big change at one corner. 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. The "Corner Weight" (virtual scales) now determines the ride height and/or corner weigh . spring perch so I left my jacks in place between lifts and only put two lug nuts
If you want to raise the ride height then extend both LF and RR coil overs
I lowered the left rear spring perch 1 1/4 turn and put it on
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. rear and tried again but I still needed more weight off the right front and left
Full of fuel, everything done, full of oil, lead bolted down. Remember that changes in stagger, tire pressures and springs will change the ride height and alter the cross-weight percentage. Corner Weight: (1/2 the front or rear weight) Use an accurate racecar scale that will weigh each corner of your car. I guess I should work on losing weight personally (i am 220~). Jun 7, 2018 #8 . . 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. Many successful race teams use corner weighting to achieve the same F/R % on both sides equal, not cross weight. Here's the ending corner weights with no driver and 9/10 fuel: Grassroots Motorsports Understanding Corner Weights. coil over 5 turns. 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. Adjust the front up by 0.0625-inch and the rear down by 0.4375-inch. This makes the cornering force balanced from left to right and offers the best performance overall.