LTO kart racing stagger question
- Thread starter paulkish
- Start date
my theory is probably the simplest and quickest way to determine if your calculations, deductions, spreadsheets, mathmatical formula's and all that is working or not....
sit down, put a helmet on and race.....if you have the stagger, air pressures, tire compounds and chassis setup right, then your going to the front....if not, then your going backwards.
i'm not arguing with any of the aforementioned items....only that on one level, your talking about spending a lot of time looking at a computer screen and figuring...on another level, your talking about racers who look at the tracks (thanks jack!) and see what's going to work and what isn't.
when i was a cop, the first thing that i did when i interviewed any new cop to my shift was to determine whether thier judgement, training and experience would be beneficial to get the job done. same in racing, you have to be able to read the track conditions, determine what is needed and what isn't needed based on your experiences with similar tracks and know what the limits of your equipment is. couple all this together and you will move forward. all the math formula's, equations, spreadsheets and data is good....but the only true test is what happens when you pull the rope and leave the grid to start the race....
sit down, put a helmet on and race.....if you have the stagger, air pressures, tire compounds and chassis setup right, then your going to the front....if not, then your going backwards.
i'm not arguing with any of the aforementioned items....only that on one level, your talking about spending a lot of time looking at a computer screen and figuring...on another level, your talking about racers who look at the tracks (thanks jack!) and see what's going to work and what isn't.
when i was a cop, the first thing that i did when i interviewed any new cop to my shift was to determine whether thier judgement, training and experience would be beneficial to get the job done. same in racing, you have to be able to read the track conditions, determine what is needed and what isn't needed based on your experiences with similar tracks and know what the limits of your equipment is. couple all this together and you will move forward. all the math formula's, equations, spreadsheets and data is good....but the only true test is what happens when you pull the rope and leave the grid to start the race....
Sickle Hill Kartway
New member
Hey Al, lets put your spreadsheet to the test. My track is 680' in the groove. The turns are 85' radius, with about 15* of banking. How much stagger should I be on?
alvin l nunley
Site Supporter
The
How did I do?
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)
I'll assume a RR tire circumference of 34 inches. I will assume a tread width of 33.50 C-C. The software says 1 1/16 stagger with up to minus .25 for the banking. 170 between the straights means pretty big turns with very short straights.
How did I do?
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)
Barry Hastings
Member
Seems there is a LOT of single minded focus on stagger. Now I havent been in the oval game for quite some time, but I have different ideas on stagger. Now again, my ideas are not based on super high cross setups, so my results may not be the same with the high cross.
I try to look at the kart as a whole. All forces act on the center of gravity. When there is enough lateral force to move weight from left to right in the turn the static weights change. When the steering angle is added to make the turn, static weights change. Now, if the CG is high enough and Lateral G is enough the inside wheels are unloaded. (if the cross is low enough the inside rear will be less than the RR down to it doesnt touch the track anymore.) Now, All of this depends on if the RR has enough grip to carry the entire rear weight on it, you could have the LR fall off and wouldnt effect the turn untill the Lateral g went away.
With the old setups (think Banshee old) i would use my rear stagger to only help with the transition from the straight until the Lateral G unloaded the inside rear enough that it wouldnt drag in the center of the turn. Then of coarse as the Lateral G came back down would get back on the stagger once again for the transition back to the straight. More straight the less stagger i would run.. Say 1/2 inch when everybody else was on 1 1/8 or so. I also looked at the cross weight as a timing device as to when the kart would unload the LR and "pivot" in the turn.
Now for the disclaimer. That was for when the track had a LOT of grip. Less grip its tough to get the weight to transfer. Could lessen the Left side weight to get the same thing. But that is a lot of chasing the baseline. Get it right could be stupid fast. Get it wrong could go way past out to lunch.
The biggest thing to take away from this, IF everything else is wrong, the right stagger wont help. Get everything else right, the "right" stagger is easier to find.
Just something to think about...
(again, havent run ovals in 10 years, please take with a grain of salt)
I try to look at the kart as a whole. All forces act on the center of gravity. When there is enough lateral force to move weight from left to right in the turn the static weights change. When the steering angle is added to make the turn, static weights change. Now, if the CG is high enough and Lateral G is enough the inside wheels are unloaded. (if the cross is low enough the inside rear will be less than the RR down to it doesnt touch the track anymore.) Now, All of this depends on if the RR has enough grip to carry the entire rear weight on it, you could have the LR fall off and wouldnt effect the turn untill the Lateral g went away.
With the old setups (think Banshee old) i would use my rear stagger to only help with the transition from the straight until the Lateral G unloaded the inside rear enough that it wouldnt drag in the center of the turn. Then of coarse as the Lateral G came back down would get back on the stagger once again for the transition back to the straight. More straight the less stagger i would run.. Say 1/2 inch when everybody else was on 1 1/8 or so. I also looked at the cross weight as a timing device as to when the kart would unload the LR and "pivot" in the turn.
Now for the disclaimer. That was for when the track had a LOT of grip. Less grip its tough to get the weight to transfer. Could lessen the Left side weight to get the same thing. But that is a lot of chasing the baseline. Get it right could be stupid fast. Get it wrong could go way past out to lunch.
The biggest thing to take away from this, IF everything else is wrong, the right stagger wont help. Get everything else right, the "right" stagger is easier to find.
Just something to think about...
(again, havent run ovals in 10 years, please take with a grain of salt)
Sickle Hill Kartway
New member
Al, I apologize. I seem to have given you some wrong info. It is 85' from straightaway to straightaway. that would be the diameter of the turn, not the radius. My bad.
alvin l nunley
Site Supporter
new calculation, with the new turn radius at 42 1/2 feet; calculated stagger; 2.0 inches.
that's a lot of stagger to drag down the straightaway so some Compromises would have to be made.
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)
Sickle Hill Kartway
New member
LOL. Thats what a lot of guys are running.
Sickle Hill Kartway
New member
It is a lot, but thats what the front runners are running. You can definitely see the chassis at work. Sickle Hill Clone Heavy: http://youtu.be/F41anqHvKTY
jsstump#70
Member
I will have to say that I have Als spreadsheets. Have had them for well over a year now. They provide me with WAY more information than I can put to use or can comprehend many times. His spreadsheets are only as good as the information you plug into them. I would recommend them to anyone seeking more information or someone wanting a better understanding of things. I don't always agree with Al but I have yet to be able to prove his spreadsheets wrong. They only calculate what I tell them to. For them to do their job, I have to do mine.
The Closer
Member
It looks like Al understands Sir Isaac Newton's laws.
alvin l nunley
Site Supporter
thank you for the kind words. If you have any questions, my phone number is on almost every page. I'm retired, and I'm handicapped, so I'm home most of the time.
Several things have been added in the last year or so, if you want the updates send a request to anunley@austin.rr.com
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)
rebsfan4
Member
Why would anyone think it needs to?
Be that as it may, his Stagger Spreadsheet performs a geometric calculation that neglects Dynamics and Newton's Laws of Motion.
The argument for more stagger with higher banking is based on the assumption that the effects of Dynamics are not negligible.
alvin l nunley
Site Supporter
my spreadsheet simply calculates the number of rotations that the RR makes and matches the circumference of the LR so that it makes the same number of revolutions.
Here are Newton's 3 laws of motion;
First law: When viewed in an inertial reference frame, an object either remains at rest or continues to move at a constant velocity, unless acted upon by an external force.[2][3]
2.Second law: \begin{smallmatrix} \mathbf{F}=m\mathbf{a} \end{smallmatrix} . The vector sum of the forces F on an object is equal to the mass m of that object multiplied by the acceleration vector a of the object.
3.Third law: When one body exerts a force on a second body, the second body simultaneously exerts a force equal in magnitude and opposite in direction on the first body.
Sorry for the cut and paste not coming through.
My theory is; banking would call for less stagger, not more.
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)
paulkish
old fart
When I watch the helmet of the lead driver at 1:57 in the video, by following helmet motion I see the driver leaned over on the LR exiting the turn and then straightening up on exit. I see two way to look at why it's being done. The first and most obvious is he's leaning over fighting the g's apex out and probably through the apex. Then as the turn eases, he eases and sits back up.
I see more too it than that. I see indoor racing with tighter turns where drivers sit straight up through the turn and hold their body position, as best they can. There fast too and I assume the driver up front is fast. With both being fast I want to justify what the driver in the the picture is doing in terms of how things work and this is about stagger.
Here's the way I describe what's happening, especially now knowing the driver may be on 2 inches of stagger. I see him leaning because he has found doing so makes the kart fast and he's not just trying to be comfortable. I see the leaning as dumping weight on the smaller LR tire going in and through the apex. That allows the axle to roll around the LR slowing down going in and he also is rolling the apex. (see insert arc in my signature). Now to be fast he also will need to accelerate. Because he's leaning on the LR his acceleration will initiate off of the (low gear) left rear. His straightening up is not just because it's now comfortable to straighten up, but it's also faster because he's then shifting into high gear for the straight.
end of that for now and on to another thought
__________________________
Now we all ask and wonder about does stagger hurt you down the straight, because one tire or the other must be slipped. In the case of the video the kart with the driver moving to a sit up position is slipping the LR.
Next thoughts must come about why is the LR slipped instead of the RR. IMHO, if the kart was setup different and he slipped the RR instead it would be faster. But in the case of the video and 2 inches of stagger ok to be a front runner, 2 inches of stagger are used and the LR is slipped because it's good enough to win and that's what most do.
IMHO, a stranger to the track, who came there with no preconceived idea about how folks setup for the track, would use less stagger get off the LR later, get onto the RR later on down the straight and be faster.
... let the arrows fly. ...
and this is just IMHO and ain't necessarily right anyway.________________________
I want to throw something else in here to help persuade thoughts. A lot of times when someone just can't get the top end they want at the end of the straight, it's because their shifting into high gear too soon and running out of engine.
That same driver that is leaning to the side in the turns would do it at a flat track or a high banked track. Some drivers lean and some don't. Has nothing to do with the 2" of rear stagger. It's a comfort thing for drivers. I used to do it and not even realize it. Once I got on scales and saw how much leaning to 1 side or the other affected my cross and left side weight, that is when I finally forced myself to try and stay as straight as possible in the seat