Hello Gentlemen,
I am trying to figure out a few things about stagger. I know what it is. But, I have also heard of guys using negative stagger in the front and positive in the rear.
I would like to know what is the affect of stagger in the FRONT of the car?
What advantage is there to negative stagger in the FRONT of the car?
How much stagger is too much - FRONT and REAR?
Do you change your chassis height to accomodate a change in stagger?

I race on rather short (116" runline) tracks. Basically two drapstrips with two hairpin turns.

it really depends on how the car is set up. I run the front end straight up, and run the rear with .025" negative stagger. with my setup, it drives off the corner better.

neg stagger is to keep it from turinig on the strait on a banked oval..

Negative stagger in the front will help it turn more aggressive......

More or less a band-aid for an Ill handling car, but there is only so much you can do right before the main...... :thumbsup:

also if your car is not turning try a little more pos stagger! i used to race champ cars!!

Oval Trucker-

A lot of racers get confused about the term "Stagger". There is no such thing as front Stagger. The term is only applied to different sizes of tires on the same axle. If you us two different size tires on the front it will affect your tweak but has nothing to do with Stagger.

Stagger is used on the rear axle to compensate for the different radii that the two wheels travel (on the same axle). That can only be accomplished with a larger tire on the right and smaller on the left since we are using left turns only on ovals. You can actually calculate a perfect Stagger based on the circumference of the turns. Negative Stagger would only be covering up a serious problem that would best be addressed with other chassis adjustments.

Basically Stagger lessens the dif action through the corner where traction is a premium, giving the car a more stable feeling, alowing an earlier return to throttle and faster lap times. It doesn't matter if the dif has to work more down the straight because you are not on the edge of adhesion like you are in the corners.

Hope that helps a little.

Gary McAllister

Gary; thats the most precise explanation I've seen. It helps. Thanks; Ernie P.

Oval Trucker-

A lot of racers get confused about the term "Stagger". There is no such thing as front Stagger. The term is only applied to different sizes of tires on the same axle. If you us two different size tires on the front it will affect your tweak but has nothing to do with Stagger.

Stagger is used on the rear axle to compensate for the different radii that the two wheels travel (on the same axle). That can only be accomplished with a larger tire on the right and smaller on the left since we are using left turns only on ovals. You can actually calculate a perfect Stagger based on the circumference of the turns. Negative Stagger would only be covering up a serious problem that would best be addressed with other chassis adjustments.

Basically Stagger lessens the dif action through the corner where traction is a premium, giving the car a more stable feeling, alowing an earlier return to throttle and faster lap times. It doesn't matter if the dif has to work more down the straight because you are not on the edge of adhesion like you are in the corners.

Hope that helps a little.

Gary McAllister

........You can actually calculate a perfect Stagger based on the circumference of the turns. .......

Gary McAllister

Great post!

What is the formula for calculating this?

Thanks

RC

i prefer 0.. front and back.. i like 0 in the rear, because as the race goes on the car seems to tighten up.. the right tire wears a bit, and it seems to help the car steer a bit more twoards the end of the race..

Thanks for the reply's guys. My DSL has been down since I started this thread and I am just now catching up on it.


Gary,
So the effect that you may feel from having two different size tires on the front is simply that you have changed the tweak to some degree. It is not helping the car turn any better because of the size of the tires?
I know of drivers that run different size fronts. I assumed it was for some sort of stagger advantage though.
Your above post is very helpful.

OVALTRUCKER, Changing tire size without changing anything else with change the chassis height in that part of the car, effecting the way the car handles. If you put a larger tire on the right front without changing any thing else the car will have less steering.

Nice work, Gary! :)

Formula for calculating? I'll give you some ideas where you can derive it from as there are many different ways to arrive at the same answer.

Your stagger would actually be different for each track, unless the tracks were identical. Although others may not agree with my theory and practical application of this, it does work.

Think of the track as an elipse (that's how I usually drive, instead of straight lines). The ends of the elipse (the sharper corners) can be approximated into a circle with a known radius. I measure this where I want my inside tires to ride...so let's say this radius is 8', making the diameter 16', making the circumference of this circle 50.26544'. I used PI as 3.14159, you can happily dwell deeper into the decimal places!

Now, this is where it gets techy...That circumference I place as an imaginary path in the MIDDLE of my inside rear tire. So, technically, the outer edge (to the left of car) of my tire travels less distance than the inner edge (towards the center of the car) of my tire. So, regardless of what your tire diameter is here, it is going to travel that line if you were to drive in a circle. For this example, say your inside tire diameter is 2".

Next you want to know how far your OUTSIDE tire must travel. This is simple, measure the distance from the inside edge of your left rear to the outside edge of your right rear (given you run the same width tires left/right). If not, measure the distance from the middle of each tire. Let's say that distance is 6", which then makes the imaginary circle have a diameter of 17' instead of 16' (8.5' x 2). The distance this tire travels is 53.40703', which is a much greater distance than the inside tire...by more than 3'.

So, now you ask how much bigger do you make your outside tire? Hmmm...Ideally, you want each tire to rotate the same number of times as you complete one full circle. So, the diameter of your inside tire is 2", making the circumference 6.28318". However, in FEET, that is 0.52361'. So, your inside tire rotates approximately 95.99786 times to make one full circle. If both tires were the same size, you would be scrubbing off speed as you corner, as your diff will have to make up for the difference. To find out how big your outside tire needs to be, you would take the bigger circumference (outside wheel travel or the bigger imaginary circle's circumference) and divide it by the number of times your inside wheel rotates. Here, the answer would be 0.55634' (circumference in FEET), or 6.67608" (circumference in INCHES), making the diameter 2.12506". <-- That is what you want your outside tire's diameter to be if your inside tire diameter was 2", for THIS example.

Now, please all of you really picky guys don't get upset...I know there are SEVERAL other factors that determine this, such as weight distribution, centrifugal force, etc...but you'll never get a perfect answer unless you drove a perfect circle! I hope this answer makes sense...I'm sure I could make it easier to understand, but I am trying to trigger your thought process a little! If I made a mistake in my calculations, I sincerely apologize.

NOTE: I have not tested changing the width values...In other words, because of deformation of tires in a corner, you could try measuring from the inner edge of the inside tire to the middle of the outside tire, it will yield a diff. number, but I haven't tested how it affects the handling on the track. If you REALLY wanted to be technical about this, you could taper your tires to match the circumferences identically, and if you did this right you would end up with the same contact patch, but the tire would completely follow the circle, with no scrubbing of speed....but again, we don't drive in perfect circles!

Im sorta new to this. Why would rear stagger be nessesay when these cars have differencials to speed up the right rear.Im talking about a pan car.

thanks

Well, a differential doesn't speed anything up, it merely compensates for tires turning at different rates. Just like a real car, the tire with the least amount of grip will slip first (unless you are using LSD or posi, etc...) Any time a car is 'diffing', it is losing energy needlessly, which equates to speed in most cases. A big reason for a differential are the corners...if you've ever driven a TRUE 4WD truck, like a rock crawler, they turn like crap on flat roads. Reason being because the inside tire is traveling the same distance as the outside, even though their requested (steering wheel turned) paths are not the same. In that case it is usually the inside tire that slips, causing a rocking motion in the car. If the tire is slipping, it is losing traction. In oval, you want as much traction as possible (at least I do). The explanation of a contact patch would be a whole other thread! :) But simply put, tires only have so much traction, regardless of what direction it is in or combination of directions, they all add up to the same number.

ALRIGHTY THEN!!!

I'm gonna have to read SuperXray's post a couple dozen more times in order for it to sink in. But, it is very interesting.

I suppose a guy could compile a spreadsheet that would give you the stagger required for a given radius. And as long as you could measure the radius at a given track you could go back to the pits and reference that number with your spreadsheet. That could be kinda neat.

You can actually derive a formula when you know the width differential (distance between your tires as I explained) and the diameter of the circle. Then you just have to plug in the diameter (unless you change tires), and walla...We use this methodology quite a bit in engineering. GOOD propellers on boats and airplanes use some of the same relations, to maximize air/water flow. Approximating the circle on the elipse requires measuring the track's running line and then deciding where you actually STOP turning the wheel on the track, which can be quite difficult, so I'd suggest just guessing, by splitting the track into 1/3 segments. Segment 1 being the left end, Segment 2 being the straight away, and Segment 3 being the right end. Make sense?

Thanks Superxray for the equations...saved me looking it up!

He's also right about many variables due to different lines being run through a corner instead of an exact radius every time. None of us are machines, we drive by feel, so in the end that's what is most important. An oval race car feels good and stable in the corners with Stagger, how much is up to the feel that's best for you. I run .050 t0 .100 everywhere (open modified). Some racers are surprised, but I rarely have a push in the car. (Newman loose)

I do know that reverse Stagger is part of a problem, not a solution to a problem.

It is true that the dif is designed to compensate for the different radii traveled, and a perfect, new dif may not need Stagger technically, but that's rare and Stagger just helps the dif to make a smooth feel through the corner which makes it easier to go faster. Don't know if it really makes the car steer more, but you can get on the gas sooner and harder if the car is smooth through the corner.

Different size tires on the front will only change the tweak on the front as Mr. Valentine described. There's a lot of racers all around the country that are very sharp on setup...maybe they should be issued badges.

I do have a basic philosophy in racing though...no matter how strange it sounds, if it works that's all that matters.

Gary McAllister

I do have a basic philosophy in racing though...no matter how strange it sounds, if it works that's all that matters. - Gary McAllister

Boy ain't that the truth!

Gary
When you say .050 to .100 are you talking diametre or circumfrance.

I can't speak for Gary, but I'm pretty sure he's talking about tire diameter differences. In other words, if one tire is 2.00", then the other tire would be either 2.050" (adding 0.050") or 2.100" (adding 0.100"), giving it stagger.

Yes, diameter....right tire larger. Any calipers will work for a quick measurement.

Gary McAllister

I do know that reverse Stagger is part of a problem, not a solution to a problem

Gary McAllister

ok, then. What is the solution? I've been running my KSG's this way for as long as I can remember, and the cars have more often than not been the fastest start to finish compared to anyone else in the class (4 cell pro-stock) where I race. Now, apparently I am leaving something on the table. Is it as simple as putting .100" of stagger in it, and adding an oz to the LR?

pancartom, changing one thing on a car that is running fast, normally doesn't equal a faster car. Nor does just slugging in more left rear due to the more steering gained by running more rear stagger. Your entire setup may have to be changed to equate to a faster setup. Best bet is to get a second car and strat playing around with some off the wall, compared to your current setup.

I once calculated the difference in radii for the track that I run on (K&N) and the amount of stagger required to equalize the rear tire rpm's was a huge diameter delta (like .075"). Then the issue of what will happen to the car on the straights comes into play. Will the car stay down too much because it is always trying to go left. I'm not sure, but on our track (steeply banked) I don't know for sure that many if any guys are running rear stagger beyond just .010- .020 difference between the two tires which is virtually no stagger at all. The thing that some guys don't seem to get is that the diff should be darn near perfect before worrying about stagger. A lot of guys run diffs that are not nearly as free as they should be. Fix that first then if you need more, talk to somoene that's fast and actually has used stagger at the track or a similar to the one you run at.

Well, also, one thing I left out is that my post relates ONLY to flat tracks. A banked oval is much different.

PANCARTOM-

Helping each other on the internet can be like feeling around in the dark. If your car works great with reverse Stagger, then you probably have evolved the rest of your set up to work with it. Since we are not actually at your races it's hard to say if normal Stagger will help. Most likely you would have to make other changes to acommodate it. The suggestion of a second car to try new set ups is a good one if cost is not a problem. I always have a second car to play with new set up ideas. The best car in the heats goes to the main.

My Stagger numbers are for large, flat tracks with wide sweeping corners. Usually banked tracks use less Stagger. You can only answer most of the questions with your own experimentation.

Gary McAllister

Mike and Gary, thanks for the feedback. I am running a gen 2 car now, but still have the gen 1 car i had been running. I guess it would be a good test mule. I'll have to try some different things with the old car Saturday.

Thanks again.

Oval Trucker-

A lot of racers get confused about the term "Stagger". There is no such thing as front Stagger. The term is only applied to different sizes of tires on the same axle. If you us two different size tires on the front it will affect your tweak but has nothing to do with Stagger.

Gary McAllister
That's absolutely correct for an RC car. I think the only reason full scale cars deal with front stagger is when you are on the brakes, the smaller tire has more braking force, and will pull the car down in the corner.

Can You Explain The Correct Banked Stagger Setup

ICEMAN96, Normally you run the tires closer to the same size on baked tracks. Maybe .010 -.020 stagger. You will get some guys telling you to run a larger right front, but all that does is give that side of the chassis more ride height, whichs tends to help you get off the turn better. But you don't need to cut the tire larger just adjust your ride height. Instead of having to mess with expensive tires, I'd rather play with 10 cent washers.

Thanks That Makes Sense.

can you write out this formula so i can try it when i get to the track?

=(((C11+0.5)*PI())/((C11*PI())/((C12*PI())/12))*12)/PI()

I think that is it....I have it in an excel spreadsheet. If you put it in one or just use it replace the C11 with track turn diameter and then C12 with LR tire diameter. I also made a chart with different track diameters and tire sizes. Although once you get what tire size difference you need the size of tire doesn't matter.