Questions about corner balancing;
a) is it worth getting hub stands or is it doing it with tires on same ?
b) if using tires on method - how do we avoid binding from tires ?
c) how often should corner balancing procedure be done on a race car ?
d) I have noticed corner weight moving this past year at each race event. What causes such major movements ?
e) has anyone performed this process on a 4 post lift ? My lift is fully level - wondering if this is suitable or doing it on the floor better
Your help would be greatly appreciated.
Hub stands make it easier, but are not required.
Roll the car and/or have some sort of platform that allows for free movement of the contact patch. Cheap version: garbage bags with a bit of oil inside.
I would say whenever there's reason to believe it may have changed - big hit or movement of masses in the car. But if you want to cross every i and dot every t, you do it as often as you can to make sure.
I think we need more information on the massiveness of the movement and how it's being measured.
If your post platform is fully level, why not?
In reply to Keith Tanner :
We do sprint racing and just noticed that without changing ride height weight was moving around between events. Does shock dampening (making shock harder / softer) affect the weight distribution ? We play with those settings quite a bit.
Right now car shows following;
LF 850. RF 608
LR 422. RR 545
cross 42.5%
In reply to Dbracing :
Are you setting the tire pressure to the same number every time you weigh the car? Are you weighing it with the same tires each time? Slight pressure or circumference changes will change the corner weights.
In reply to DeadSkunk (Warren) :at the track we are constantly changing new rubber Same rims, just fresh rubber
My first thought is that the car isn't settled on the suspension. Damping settings won't theoretically change the corner balance but a heavily damped shock might make it more difficult to settle the car.
If you're doing this frequently, hub stands do make it a lot easier. They're really handy for setting heights and generally checking suspension as well.
In reply to Keith Tanner : which hub stands do you recommend ?
Fuel level the same? Oil level?
In reply to L5wolvesf : fuel level would be slightly different Maybe 40lbs variance
Dbracing said:
In reply to L5wolvesf : fuel level would be slightly different Maybe 40lbs variance
Sprint cars have their fuel cell out back IIRC. 40 lbs off the light end will make a difference.
You might also consider a set of wheels/tires (old used ones) as a set just for chassis weighing. Then you have eliminated a variable.
I use my hunter alignment rack with the plates unlocked to keep the bind/preload out of the equation. I know that's ot available to most but it works nicely.
L5wolvesf said:
Dbracing said:
In reply to L5wolvesf : fuel level would be slightly different Maybe 40lbs variance
Sprint cars have their fuel cell out back IIRC. 40 lbs off the light end will make a difference.
You might also consider a set of wheels/tires (old used ones) as a set just for chassis weighing. Then you have eliminated a variable.
On a car with asymmetric cross weights, I'd think so. On a more symmetrical car if the fuel cell is on the center axis, fuel load won't change the percentages. How are you evaluating corner weights, actual weight on a given tire or the diagonals?
Dbracing I use the Paco Motorsport hub stands because we sell them at work. I don't have experience with others.
You are racing sprint cars on dirt ovals? And you are worried about corner balancing? Are you trying to go slower?
Corner balancing on almost any track I can think of will yield slower lap times, on an oval it is exactly what you DO NOT want to do.
In reply to AnthonyGS (Forum Supporter) :
Road racing - not dirt track.
Dbracing said:
In reply to AnthonyGS (Forum Supporter) :
Road racing - not dirt track.
Then balance it on a set of tires that are representative of the tires you'll race on, set at your hot tire pressures. Make some wood platforms the same height as the scales and you can roll the car onto the platforms to adjust and rolling the car back and forth will get rid of any bind in the suspension. I always did my corner weighting on a known flat concrete floor for consistency. My corner weights didn't change much from one race weekend to the next, 25# would be a big change for me. The collars on my coil overs would slip slightly and it took me a while to figure that out by marking them carefully to spot the rotation.Over the course of a season bushings and springs will change some from the abuse, shocks ,too. Do you set the ride height with the suspension arm bolts loose or tight? You could have a situation where the suspension bushings are preloaded and slowly wearing , thereby changing the corner weights. As Keith indicated, a set of hub stands would be helpful for tightening suspension with it loaded. What type of car are we talking about?
I have always wondered at what level HPDE driver would corner balancing make any difference whatsoever? Very prevalent in the Pcar world but I cant imagine many have the abilities to take advantage of this small amount of benefit right?
In reply to Olemiss540 :
I certainly couldn't quantify a difference on my race cars, an ITB VW and a SpecMiata. I just did it to have a good starting point and to remove a possible variable. I know some of my more experienced competitors were deliberately setting the car up with a built in bias for right turns as the course was more rights than lefts and there was a right turn onto the long straight, so a right turn biased car could take that corner at higher speed and carry it the length of the straight. I wasn't that sophisticated.
Would love to have the magazine do a test and article on this! Start with a perfectly corner balanced vehicle at that kart track they use, and gradually take it out of balance and see how the times change running both directions.
For road racing I have always understood that cross weights should be as close to 50% as possible and with the driver or equivalent weight in the seat,
What do you guys use for Slip Plates ? Tile with grease method seems messy.
In reply to Dbracing :
For slip plates I once used cheap plastic grocery store bags, slippery to begin with then added oil.
I used tiles with grease, and it WAS messy.
Tiles with some table salt was way less messy.
Half a newspaper under each tire always worked for me.
AnthonyGS (Forum Supporter) said:
You are racing sprint cars on dirt ovals? And you are worried about corner balancing? Are you trying to go slower?
Corner balancing on almost any track I can think of will yield slower lap times, on an oval it is exactly what you DO NOT want to do.
The oval guys I know definitely use corner weighting scales - they just aren't aiming for equal left-to-right. :)
Dbracing said:
In reply to AnthonyGS (Forum Supporter) :
Road racing - not dirt track.
Does your track cross over itself at any point? Is it a figure 8? If it's not, you should set it up to turn the direction you turn most.... if you want to go faster.
Right now I don't think it would turn well left or right.
Most all racetracks you turn one direction a lot more, and one a lot less. Setup your car to do that.
