Anyone have a theory on why adding left side weight tends to loosen the car?
Printable View
Anyone have a theory on why adding left side weight tends to loosen the car?
Just left side weight percentage. Not at a particular end of the car.Quote:
Originally Posted by DirtRacer9x
Off throttle drags the car left. On throttle takes a moment longer and speed for the wt to transfer to the Right for side bite. Roll centers,roll couple and CGH plays into it .
Increased load on dirt tires equals more traction....to a point. As track dries out, more weight needs to transfer to right side tires to increase grip. Most racers used to change left side weight for the feature but are now crutching the car with rear end adjs. Mark Bush has been stressing this in DLM mag for several months now.
"Left side weight loosens car on entry" is part of the sentence. the other part is "off the throttle"
So, what about extra left side weight makes the car loose when off the throttle?
Post #4 touches on it. With more weight on the left side when the tire slows down it will drag the car to the left.Quote:
Originally Posted by rob burgoon
Must be a pretty small effect then? Does it do anything midcorner?Quote:
Originally Posted by blncfn57
Well, of course. Every change in the car effects it differently at different points on the track. It's always a give and take deal. Picking up the throttle too soon or too much mid corner can either slide the nose across the track or cause you to spin out, depending on how hot you approach the corner. The biggest mistake I see (usually by the guys running in the back) is guys not getting the car pointed in the right direction before getting in the gas. Using left side to help the car turn and rolling through the center patiently should result in being able to drive off the corner better. Use less left side (or at least mount weight higher) when track is tacky and faster. JMO, I'm sure some will argue, but to each their own.Quote:
Originally Posted by rob burgoon
Interesting, most of the stuff I've been reading says move the weight up for the slick when you're not getting as much weight transfer as in the tack.Quote:
Originally Posted by blncfn57
It's a mess trying to figure this stuff out. The GRT and Smith book says rear steer is used for the heavy/tacky to make the car turn, and the Circle track articles say to use rear steer for the slick to keep the tires under you. Amazing that the books agree so little.
Books can be good and books can be really bad unfortunately. I have a pickup load of them and they contradict each other on most subjects. But that goes for talking to some top notch drivers also . Some of the fastest Cats I know have theories on stuff that actually does not work the way they think . Its frustrating . The only thing you can do is collect all the knowledge you can and take it to the Dirt . Then hope you get it figured out before you go broke . I think I got it know , but know I'm broke ! lol
If the CG is 24 inches high and the width is 70 inches, it looks like way, way more than 3% weight moves from the left side to the right side. So that theory is out.
I should prop up the LR with something to full droop and remeasure corner weights....
24" ht is just part of the equation . You must factor in the leverage arm created from CGH to the Roll center length as to how much wt is actually transferred in roll from centrifugal force or just thrown as a mass laterally that transfers very little to the outside tire . That's why the short or J bar is adjustable .
guess I'm lost as to what you're trying to prove wrong.Quote:
Originally Posted by rob burgoon
Proving wrong my own theories about weight distribution and the role of static left side weight. Just trying to look at the suspension from different directions to understand it better.Quote:
Originally Posted by blncfn57
Think of it this way. When slick the car gets less traction and instead of rotating it slides fairly flat. It's harder to get lr back on the bars when it's flat. Add some weight up high and it'll roll over a bit more. That will allow lr to get on the bars to make more cross and tighten the car. U can't get any cross when the lr isn't on the bars to some degree,That loads rr more and makes it even looser. Hold 25 lbs of lead at your waste and run down the driveway and turn left. Then hold it above your head. You'll get it real quick.Quote:
Originally Posted by rob burgoon
Is it really that hard to get the LR up on the bars though? All I have to do is give the pedal on the right a stern look and up it goes.Quote:
Originally Posted by Dirtmod13
Where the weight is in relation to the CG. Pick up a bag of concrete from the floor and then pick it up from the back of your truck? It takes 3 ft more work to make it happen from the floor.
That's why low and left is a bad move without the adhesion to get the CG to move about the roll center.
So why do guys put weight up high then? This isn't asphalt. Instead of criticizing why don't you tell us how it works?To disprove his last statement try this. Take your lawnmower and bolt 100 lbs under neath. Pop the clutch and see if you transfer any weight to rear. Now bolt the same weight to the safety roll bar over head and pop the clutch. You'll (not a nice word)(not a nice word)(not a nice word)(not a nice word) near tip over backwards. that is transferring weight. That helps drive. But like all things it can be overdoneQuote:
Originally Posted by DirtRacer9x