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Bored waiting on the Chili Bowl to start and some bs from me


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#1 dirtstudent2

dirtstudent2

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Posted 14 January 2023 - 12:00 PM

I'll leave out who I wrote this too because it's a long time ago now maybe even 15 years ago.  I'm now into pushing my thoughts out there about a way to slow the instantaneous unloading of the LR at the moment of turn in. I've spread my thoughts out there enough now I hope maybe to maybe see my thoughts on the track this coming year.

Anyway here's some stuff from many years ago now.

 

enjoy:  

 

HOW A STAGGERED SOLID AXLE WORKS
by me cause I'm old a bit ill, tired and bored 

edit up front: This started out as an essay and ended up as this letter to you(who I will not name).

I've written this and preached this so many times now, the story just flows out of my fingers.

When ever I hear someone explain stagger in terms of how a Styrofoam cup rolls I cringe.

Yes more stagger in general will create more turning effort from the axle and yes if there's a general trade off for balancing stagger; it's about do you use less stagger supporting forward acceleration or more stagger enhancing turning ability. I'm not about or into any specific stagger, for any specific situation. I'm about and my theory’s are about, choosing the the correct stagger for the situation, your racing needs and the ability of the vehicle your racing to use stagger. But when I'm asked the question, “How does stagger work and what happens when you adjust stagger?”, this is my reply.

Assuming you already have a staggered solid axle, there are 'only' three things which can be altered when stagger is changed:

First a change in stagger will adjust ride height at one or both rear corners of the car.

Second when the axle is rotating, stagger creates a difference in tire surface speeds between the right and left rear tires. When a change in stagger is made, the difference in tire surface speed between the left and right tires is changed.

And third speaking only in terms of the LR(left rear) tire, changing stagger changes the 'potential' for the LR tire to either slip or grip, depending on your ability to apply weight to the LR tire.

The key word in the previous sentence is 'potential'. To understand what I mean by 'potential', requires being able to see there is relationship between the slower surface speed of the LR, the faster surface speed of the RR and the track surface. Explaining 'potential' further what follows assumes your already slowing down and turning into a corner. Under those conditions you have x surface speed at the LR tire and your pushing the LR tire into the track with 100 pounds of force, creating y amount of friction or braking action with the LR. The braking action at the LR will allow the RR with it's faster surface speed to rotate around the LR. If you put more force to the LR more friction will be created and you will receive more braking action from the LR.

But since the LR is rotating while moving across the surface of the track, a change in LR tire surface speed by putting on a smaller LR tire, will increase the difference between the surface speed of the LR tire and how fast the LR tire is moving across the track. If the same weight of 100 pounds remains constant, by increasing stagger you have just increased the 'potential' for the LR tire to slip on the track, because you increased the difference in surface speed between the tire and the track. In fact it will slip more and not provide as much braking action at the left rear. That means to maintain equal braking action from the LR tire if you increase stagger by putting a smaller tire on the LR, you must also do something to increase weight applied to the LR. If you do not you will not get equal results and you will loose rotation.

The above paragraph explains what I mean by increasing 'potential'. It is explained using a potential for increased slip, but the reverse is true when decreasing stagger by putting on a larger LR tire. Expanding on the thought process and my theory, the same applies to the RR but to gain initial understanding it's much easier to see it using the LR for an example. In addition there are similar relationships that have 'potentials' for change. They are how the right and left rear tires work together and how the axle assembly in total works with the track.

Expanding a little more words like slip, braking action and grip, fit in easily when trying to pass on a general idea. In actuality what alters in each rear tire are slip angles, slip ratios and lateral slip ratio. But there is no need to go into slip angles and slip ratios when trying to pass on my unique theory on how stagger works.

Before going on it must be understood that I do understand different view points when thinking about how tires interact with the track. From discussing this with many people over the years I have come to the conclusion there are two general ways racers look at setup. Dirt oriented racers who come from a winged background will in general think about setup from the back first. And asphalt oriented racers and even dirt racers who normally do not get very deep into stagger think about setup from the front first. There is no right or wrong way but the end results of their considerations will always end up the same. If there is one thing that transcends all high hp LTO(left turn only) race vehicles, it is you can dump all the weight an hp you want onto the right side tires and go faster until you exceed the capability of a right side tire or run out of hp. Once the capability of a right side tire is exceeded your only option to go faster is to better use the left side tires. I only noted the above because I know you are involved with racing higher hp race cars.

Continuing on with that thought, once it's realized the only way to go faster is to better use the inside tires, the only debate becomes how your going to use the left side tires. I'm probably boring you already and I'm not going to now start explaining theories on why and how the inside tires need to be used. Those ideas get into the need to split slip angles, why you might want to load one rear tire over the other. I already partially explained and started to get into a why you would want to load a particular rear tire when I met you two and you both were kind enough to listen to me.

In closing if you read books on how race cars work and study the math on how race cars work, though it's meaningful to how “real” race cars work and cars in general work, we do not race “real” race cars we race LTO race vehicles. And all that is written does not necessarily apply. I'm into theory and have tried to explain a few of my thoughts. When ever I write something I always try to end with a question. My question to you ending this letter is the toughest question of all. Does grip follow dynamic weight transfer or does dynamic weight transfer follow grip.

Sorry to be so long winded and thanks for reading


ps... I watched interviewed at the track from the stands and he said Attica and the Grove were the two tracks that had left the most challenge for him.

For what it's worth probably nothing as I like to say, my opinion of how to beat the Grove is to solve the initial moment of turn in issue entering turn three. The problem to over come there is created because high speeds at entry cause centripetal forces to over come efforts of the wing to hold the LR down on the track. It's a classic example of a tied down LR being lifted up off the track. The problem I described leads to turn three being taken in two ways. Either you accept the fact the LR is going to loose traction immediately at the moment of turn in or you drive farther into the corner and force winging over to push the LR(with it's slower surface speed) into the track. It's a tough corner, either loose some ability to maintain momentum rolling into the corner or drive in hard hoping you do not loose too much speed winging over and also end up getting on the RR too soon.

I do not have any experience trying things to solve such a problem. But logically I think some of the initial lateral forces at turn entry might be directed more laterally via a Jacobs ladder adjustment or mounting alteration. And doing so may help assist in efforts to better pin the LF. Other then those ideas I think the other necessary thing to be fast at the Grove would be the drivers ability to roll through turn two, neither forcing the issue high or low.

Again I've only been to the Grove maybe five times, but from what I see turn three is key. which also sets up for getting through turn four well and on to the straight. That to me is key along with being able to roll through, not diamonding off turn two high or low, using the additional rounded distance for acceleration.

 

 

Hope it was a fun read.

I'm having fun just thinking about the crap some may spew at me because of my how it works theories.  

 

 

 
 

 





 




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