Too much weight on left rear ?
- Thread starter david17n
- Start date
Ted Hamilton
Helmet Painter / Racer
If you raise the seat a hair, you'll get more Vcg transfer and dynamically unweight LR some... Don't know enough from your description to tell. We'd need to know track size, corner radius, engine type, tire type and composition, prep regime, and corner weights... It's possible you could be bound up from your description, but to really know we need more info.
racing promotor
Moderator
Dought it over loaded left rear if it drove Ok, it just added little to much left causing your tires to not be in the track enough to generate good Forward bite causing RPM's to drop, or track just changed and Tires were off some.
alvin l nunley
Site Supporter
I'm assuming you're talking about a loss of 300 RPM at the top. A kart with stagger is going to be dragging the smaller tire down the straight. I can see, that with more weight on the LR, it's a little harder to drag that tire.
Seems to me that the stagger is a compromise between getting around the corners fast and getting down the straightaway fast. Putting extra weight on the LR just makes that compromise a little more difficult to figure out.
Of course we have to assume nothing else is changing. If the engine compression is down a little, if the air density is down a little, (or even up a little causing you to go lean) if a leak down test shows your down a little, all these things can contribute to a drop in rpm.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Seems to me that the stagger is a compromise between getting around the corners fast and getting down the straightaway fast. Putting extra weight on the LR just makes that compromise a little more difficult to figure out.
Of course we have to assume nothing else is changing. If the engine compression is down a little, if the air density is down a little, (or even up a little causing you to go lean) if a leak down test shows your down a little, all these things can contribute to a drop in rpm.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
Was the kart sliding before the adjustment?
Was this change made then right back out on the track?
Did the lap times increase?
Al, you have stated many times how heavy the left rear is. Do you really think this is the tire that's dragging? Unless something is done wrong, set up wise or harder left rear than right sides, it isn't.
Was this change made then right back out on the track?
Did the lap times increase?
Al, you have stated many times how heavy the left rear is. Do you really think this is the tire that's dragging? Unless something is done wrong, set up wise or harder left rear than right sides, it isn't.
alvin l nunley
Site Supporter
I've never been much for taking someone else's word for anything. It's just the way I am, Sorry. If you can give me some definitive reason for your theory, I would love to hear it.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
racing promotor
Moderator
He ask a simple question and gets all this mumble jumble, what and the He** would moving a seat have to do with stagger dragging a tire down the straight.
Kart is a QRC cage kart with 1.25" Rr stagger. L. R. tire is a Burris SS33 with Black Sand prep at 8 psi & R.R. is a SS33 with no prep at 9 psi. Every race I make an experimental adjustment to find out what effects the amount of RPM drop in the corners . I wasn't trying to fix any handling issues. The lap times increased slightly. I'm thinking my next adjustment should be to increase rear sprocket teeth & or move the seat incrementally to the right but open to suggestions. The loss of 300 RPM at the top was probably closer to 250 RPM. I'm no expert at chassis adjustment but I cannot remember ever making an adjustment that effected the RPM so much.
alvin l nunley
Site Supporter
apparently you don't know! It was such a simple question, and such a simple answer.
From the desk of Al Nunley
Comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory. (Al Nunley)
jack burroughs
member
Al , do you really think the L/R is dragging if the straight is run in an arc? On dirt , or any oval, you need to not have the L/R drive too much because it will make you drift up off the corner and usually develop a push.
rebsfan4
Member
Lack of grip or lack of load/weight at the RF is what causes a push from center off. Not enough turning force.
It baffels me why people say the LR is thr problem. Everyone says
"add rear stagger". Well stagger is a tool used to free up the RR by a reduction of weight transfer. That weight remains on the LR or goes to the RF. Ideally most of it is redirected to the RF. Realistically, not all of it makes it there.
Sorry Jack, Not picking on ya. MUCH RESPECT!!! Just a different thought process. LOL