tire temp input continued here, so to not hyjack a thread

paulkish

paulkish

old fart
I copied this reply I made to Mr South 39's input here.
__________________________________________

Mr South 39 wrote: "People say that it can't be done with 57% left side weight in that class but I have proved them wrong. After that feature I had 3 tires at exactilly 205* and the LF at 209*. And that was after a 50 lap run. That is about as balanced of a setup as you will ever see."

Just some thoughts from my perspective and theories. I think for theories to gain validity they have to fit in under many situations. Since you kindly offered us your tire temp information coming off a great run and win, I've been trying to work the information into my accumulated theories about how I look at stuff. Thinking your not racing in a situation where you have a staggered, solid axle and the rear end is contributing to rolling freely around the corners, I've been looking elsewhere in my thought process for a fit. This morning during the first cup of coffee a theory of mine from the past, which usually gets beat up on here, came back to me and seemed to fit in.

I'll try to net it out. ...

Often on here racers will ask if there only interested in putting weight on the kart, "where is the best place to add the weight?". The answer will most always come back add the weight at the center of gravity, in other words put it on the seat. I on the other hand have a theory about another place for weight to be carried, because of how it will effect on track function not just a neutral storage place. All tires have specific things you need them to do for you, at different places around the track. And I'm going to state as fact to make this all work another theory I have about how grip follows weight. Grip allows for the holding of weight and like it or not weight does not cause grip, because weight could not be there without grip.

Moving on if we quickly look at tire function there is one tire in particular, which I in the past have said is a good place to store weight. That tire is the LF. Assuming you are able to get needed function out of the other three tires, the more weight you can carry or caused to be carried on the LF, the better.

Quickly to the point, here's what struck me about your numbers. If my theory is correct about the LF to be a good place to store weight, any amount of weight you can store there leaves less weight available for the other three tires. Here's the good of it. So long as the weight available for the other three tires is enough to use them as needed, the extra weight you carry easily on the LF, effectively reduced the total car weight out on the track.

Your car Andrew appears to me to be able to store weight, as indicated by the higher LF reading, essentially at the LF out on the track and effectively was lighter then the other cars.

Assuming there's grip to hold a car in and other things being equal, ain't the lightest car going to be the fastest car?

Though your car came across the scales the same as others, being able to hold or store more weight to the LF out on the track, made you able to operate the other three tires on your car as if they were carrying a lighter car. Just as an example for thought: If we look at your car out on the track your RF/RR/LR, came in at say 300#'s when everyone else in total came in at 350#'s. ... and maybe because this is all just IMHO and ain't necessarily right anyway. ... :)


edit: What I'm trying to indicate above is your setup skill got you the balanced setup at 57% left. But I think the result of your work, gave you a car which was 'effectively' lighter then every other car and that is what put you car on rails and made it fast compared to other cars.

again... maybe just thunkin and writing about the numbers you kindly shared with us.


thanks


paul
 
Paul. That is a pretty good assumption of storing weight on the LF. Although statically we do not have a lot of weight on the LF. Usuilly about 25lbs less than the RF.

We get the weight to the LF thru the sway bar, shocks and springs but we store it there thru something I designed into thei chassis. I call it "chassis bind". Buy our rules we are not allowed to coil bind or bump stop. So I "did" a few things to "help" make the chassis bind. So now I can control the amount of load on the other 3 corner with the amount of spring. So if the RF was staticlly loaded at 775lbs and dynamically loaded to let's say 1875-2150lbs.(It would be less on the RR and LR) I can now statically load the LF at like 750lbs but dynamicly right when the LF loads to say 1200lbs I have created chassis bind and the load goes from 1200lbs to infinity. Pretty much like measuring a coil bind spring. They hit a point and then go infinity off the chart.

Paul. I don't know if this would through a monkey wrench into your thoughts,,,, but. We do run a staggered, solid rear axle. GM 7.5" with a mini spool.
 
"Paul. I don't know if this would through a monkey wrench into your thoughts,,,, but. We do run a staggered, solid rear axle. GM 7.5" with a mini spool."

Absolutely not Andrew. I preach my theory on a staggered solid axle as what is "ideal". I realize all things put on the track have different abilities to get to what I describe as "ideal". The only difference your explaining to me about the the car having a solid axle is I now know your car has some ability to get turning/rotating ability or what ever someone wants to call it, out of the axle axle. What ever you race on an oval it has to be turned. It IMHO is simply a case of fact, what ever turning ability your not able to get out of the back your going to have to get out of the front.

... you are making me dig deep again thought. ... I don't like to say it and it seems like an unnatural thing to say but ... maybe... just maybe... it was and is more efficient for you to get a little more turning power out of the fronts, via the LF, then my general theory about getting rotation out of the axle. I don't mind it happening, it just goes against the grain and my visions of a wing throwing weight to the LR and having a lot of hp.

I don't mind shifting my thoughts about possibilities, you seem to have shown may be true(notice I said may be, instead of 'are' ... :)

... and ... I can sort of justify it, because I see you not only storing weight at the LF, but using the stored weight to get turning effort. That's all a win win too. It allows for you to need less rotational effort from all three other tires and again an effectively lighter, faster car out on the track.

thank you, thank you thank you... I see no conflict, only a flow or shift in the process of doing what needs done.

... now to sit and digest the new numbers you force fed me. ... :)

paul
 
How you can come up with the conclusion that somebody is 50 pounds lighter, (effectively or not) even though the same weight, is beyond me.
The fact that all 4 tires are the same temp, or close, would indicate to me that all the tires are performing the same amount of work. I've always assumed that this was the goal. Maybe not all in the same place, hard to tell, but the fact that they're all the same temp means they are all doing what they're supposed to be doing, equally.
That makes me think; the kart is set up perfect!! . How could it not be?

Comments compliments criticisms and questions always welcome.
 
Good question Al. So good the first thing I thought about to reply with, I immediately questioned my thoughts because it seemed like I was rationalizing and grasping at straws for an answer.

I'm still not sure I'm not rationalizing with what I will write, but as usual I won't let it stop me. ... :)

I'm going to start out hoping you don't see the next couple of sentences as me trying to say your wrong or insult you, there only to try again to express a difference between sprint or "real race cars which turn both left and right" and LTO's.

Al though the word 'balance' is often used on here talking about LTO's, I really don't think with LTO's anything is being balanced. I'm going to throw a word in here to replace balance, when it comes to LTO's and even sprints. The word which comes to mind to replace 'balance' is function. I see being able to think in terms of balance when it comes to sprint racing, because I can see things needing balanced left and right because you turn both left and right. But I think in both sprint and LTO there is no balance front to rear, except ... nope, scratch all that and I'll try it differently.
-------------------------

A sprint kart turns both left and right and I think if the track had equal left and right turns, you and I both would expect the tires to be evenly heated left to right. I think you will agree with me that if things were good, the tires on the left and right would mirror each other. I hope I can say properly it would mean the tires on the left and right were functioning equally. Each tire on the right of a sprint kart will have specific functions turning right and the opposite two tires will have specific functions when turning left. And all tires being heated equally in the case of a sprint kart, I think you would consider generally as a good thing. Looking at things only in terms of left, right, equal function between the RF and LF, and the RR and LR is a good thing. But even on a sprint kart if tires front to rear have the same temp, it does not mean the tires front to rear are functioning equal. All it means is they have heated to the same temp. It does not mean they are functioning equally front to rear because they are doing different jobs and the tires front to rear are different. Equal temperatures front to rear, does not even mean the tires over all carried the same load or loads out on the track, because they are of different sizes. All this to make the point you can have identical temp at all tires on a sprint kart, yet because the tires are physically different the fronts did not function the same as the backs. The idea I'm trying to get across is even on a sprint kart different tires have different functions and do different thing on their trip around the track. On a sprint kart you will match function left and right across the kart, but even on a sprint kart you cannot match function front to rear, because different things are done front and rear.

I think I did ok explaining above and making a case for there being a difference in tire use, front and rear on a sprint kart. But I'll have to wait and see what responses may come about it.

OK, assuming I just made a case for function to be identical left and right on a sprint kart, and not identical front to rear on a sprint kart lets move on to LTO's.

Here's what I think you have not yet put into your thought process Al. A LTO like a sprint kart does not get the same function from it's tires front and rear. In addition to it a LTO, unlike a sprint kart, does not get the same function from it's tires left and right. In fact a LTO's tires have a different function at all four corners and no two tires do the same job out on the track. Even though a sprint karts tires may be heated the same front and rear, it does not mean the tires front and rear did the same job. And even though a LTO's tires were heated the same or close as you interjected, it does not mean the tires did the same job or had the same function. To understand how tires become heated and what it means has to be put in the context of how they were used, to be meaningful. With a sprint kart because it turns both left and right, most of the understanding and putting into context will come from understanding the difference of how tires are used front to rear. A LTO and it's tire usage is exponentially more complex then a sprint, because understanding requires all four tires to be understood individually and in total.

... I thought I knew where I was going with this. But when I brought in the idea of needing to understand how each of the four tires is used on a LTO, it became very tough to continue. I think it's impossible for me to explain the function, how the LF is being used and why the raised temp of the LF is so significant at 57% cross, unless any thoughts about anything at all needing to be balanced between the LF and RF are thrown out. There is nothing the same between the LF and RF except the parts on each side are similar. Another thing to take into consideration and is very significant is the results were gotten(I think) with like tires on all four corners.

... another cup of coffee and another try at putting my foot in my mouth

About 50#'s lighter and 'close' in temperature.

Al, if your on a sprint kart and only turning left I think the odds your inside front or LF being higher in temp are pretty slim. I hope I'm right with that statement. The car is only turning left yet the LF is 4*'s warmer then not only the RF, but also the two rear tires and it's being done with 57% left side weight. With car weight not biased very much to the left, I think it's very significant. I think it's very significant the setup was able to mechanically and dynamically use the LF enough to get that much work out of it. Somehow he's able to mechanically push the LF into the track and ... :) I think is able to dynamically hold it there long enough to get additional work out of it. And the other significant thing is to not look at it as if the other three tires were evenly used, but to look at it in the light that none of the other three tires were 'over worked'.

and maybe because I'm just doing this because it's fun to think about, I ain't got nothing better I want to do and... for the first day in over a month I'm starting to feel better. Wow what a great day to enjoy, today and tomorrow. And all of this is just IMHO and ain't necessairly right anyway. ... :)
 
Two cups of coffee and I want to write more and more. ... :)

I have to add this in. I wrote as if 57% left was less then the norm for the racing done.

I don't know if 57% left is high, low or average, it just seemed to me it was expressed in terms of it being low and still being able to make the car work.

If 57% left was actually a high number, I'll have to re think the whole thing. ... :(
 
I just had this thought about a part of what I wrote.

I indicated it could or was a good thing to also be able to dynamically hold weight at the LF to get additional function out of it. I now wanting to do a 180 on it and say when acceleration begins you would dynamically want to transfer weight off the LF and to the rear as quickly as possible...

nawwww... changed my mind again. You'd want to hold the weight dynamically as long as possible at the LF, unless it was needed to apply hp. And I'm guessing at the start of acceleration there's not much worry about spinning the rear tires. That's just a guess and if there was a concern and the weight was needed, then you'd have to do what is needed to get weight dynamically and mechanically to the rear. ... just words not knowing actual on track needs.

... more thoughts... and weather or not the weight was needed for spin free acceleration, would also have to do with the drivers skill on the go pedal. ... :)
 
Paul. I mentioned 57% left side weight "in this class". It is a low weight. The reason I mentioned this class is because of the rules of the class. The main one being a min 6" hide height rule. That is high. And with some of the other rules in this class it make the VCG really high. With that you get a lot of chassis roll over. It really makes it hard to make the left sides work.

Like you said. I am able to load the LF and keep the load there. I keep the load there with shocks. If I need the LF to stay loaded longer I can make that happen with shocks. If I need it to unload quicker to get more load back to the RR I can do that also with a simple shock adjustment.

This chassis bind setup I came up with about a year ago and it has been a work in progress. We are really getting it dialed in. With our regular driver(my son), we had 4 poles in the last 5 starts with 2 track records. And the last race a Speedweeks we had a fly-in driver. With hardly any laps in the truck he qualified outside front row and lead over half the race.

We got protested in the last race because it looked like we were on bump stops or coil bind. After a very extensive tech (and I think the tech guy figured out what we were doing) we were declared legal. The tech guy told the protester that he had a little homework to do.

Life is good.

And on a side note Paul. Dunn Motorsports just ordered a brand new 2014 GARC Super Late Model. It will be the next chassis on the jig. It should be on the track by June. We are very excited to say the least. Let's hope we can get it hooked up as good as the Pro Truck.
 
I'm into finger puppets Andrew. I'll be in the pits or in the stands using my hands and fingers to represent how I see cars working out on the track and mechanical actions and movements of parts of the car. I'll use them to give me a visual cue to weight shifts and other stuff. Without being specific, what you inputted with the different posts, allowed me to come up with a brand new finger puppet. I think it's allowing me to partially see your concept of chassis bind and how springs can set ride heights and chassis operation, to direct forces to cause a chassis to do specific things. Your welcome to use my finger puppets, since they are very difficult to patent. ... :)

My new finger puppet, which give me a handy visual representation of both spring usage and selection and ride height adjustments. The only lacking with the puppets is at this time I only have two hands and they will only be able to represent the front end as viewed from the drivers seat. Toe puppets would be to cumbersome to include at this time, so I'll stick with just two hands to create the puppets.

Here's what I want you to do. Make two fists and hold them up about a foot away from your face at eye level, with your thumb and first finger facing you. Now extend the thumb and first finger of each hand, towards each other and have the tips of the fingers on each hand, about six inches apart. If done correctly you will have the thumb and first finger of each hand pointing at each other and they will be able to be opened and closed in an up and down motion. Your new finger puppets will not only be able to open and close, but you can also slightly raise or lower each changing the height relationship of one hand to the other.

Now that you have your finger puppets working, I need to let you know what they represent if you have not already guessed. The represent the working parameters of the springs on each side of the front end, your right hand being the right side and your left hand being the left side. Raising and lowering your hands in relation to each other, represents how the working parameters of the left side compares to the right side.

Now this next part is key. I stated parameters instead of the operation intentionally, so you would not think about the finger puppets in terms of actual operation, but in terms of relationships. Next I have to throw in some stuff on springs or how I see springs, so we can be on the same page. I see springs 'mainly' as setting the total mechanical movement up and down at each corner. Stiffer springs will allow for less over all chassis movement then softer springs. An example would be that if you put a softer spring on the RF corner and wanted to maintain the same ride height setting, you would mechanically have to raise the RF corner to accommodate the softer spring. Your ride height would remain the same with the softer spring, but chassis travel because of the softer spring would have the potential to go up higher. Stiffen a spring and you lessen the over all travel up and down that can be made. I'll stop on that I think you will see it.

Now back to the finger puppets. You have your two puppets again in front of your face, with the thumb and first finger pointing towards each other and able to open and close. TA DA ... Altering how far open or closed the two fingers on each hand are, represents how stiff or soft a spring you have on each side in terms of the limit of chassis travel. You are not to operate your fingers to represent the chassis moving, but just use how far they are open or closed to represent the possible distance of chassis travel. You will be able to see a representation of how total chassis movement on the left, compares to total movement on the right. Now here's the cool thing. By raising and lowering each side you will have a visual cue to how spring selection on each side, will relate to each other. I can and I hope you can then put forces into the picture. Can you now see how both spring selection and spring settings, can effect each other when an imaginary force transfers from one side to the other. well, I can anyway. ... :)

What the puppets allow me to see is how vertical height and the operating limits, can effect how force can transfer across left to right and right to left. I can see how the positioning of the two relationships will change by how the car is operating out on the track and how changing the tie down or ease of up in the shock, can hold or release forces traveling across the front.

Or, you don't see it and nobody by me see's it. lol ... If I throw a sway bar across my mental picture it allows for even more possibilities.

And if I include the same picture of the back and not only work things the same way across the back but diagonally, the possibility of creating a 'chassis bind', becomes super clear. Wow... so easy I feel like I'm giving something away I should keep to myself. The last sentence was just to provoke replies like, yeah why didn't you just keep it to yourself.


paul
 
Hello again Andrew. Your information about the high center of gravity made something else click for me, which you may or may not be able to relate to. Many years back now I saw a problem a big block modified was having on the track. Big block modifies, though the general idea of them is there rolling over on to the right sides all the time, there not really. They have the same need to be better able to use the front end to make the whole car preform better. Anyway I noticed the car had a problem with tire presentation at the RF in the turns. Specifically what I identified was front weight was being projected too far out on the RF tire. I was able to pull some pictures up of the car in operation on the net in addition to watching it work live on the track. What I keyed in on which lead to fixing the problem was the angle of the drivers head in the turns. I reasoned(and reasoned correctly in this case) if I looked at how the drivers head was leaning, I could get an indication of how weight was being projected. From the picture I surmised the car was rolling over too much and because of how the front end was set, weight was projecting to far out on the RF tire. What I suggested was a slightly stiffer bar be put in the LR corner of the car to limit how far up the chassis could go on the LR. And also suggested where the weight rolled around up front could be lowered a bit. To my surprise when I discussed it with the driver, the driver told me they were about to put a slightly stiffer bar in the LR corner. I don't know if they changed anything up front but I do know the bar went in the car as I had suggested and they won the next time out at that track. I also during the same conversation with the driver suggested because of track conditions he may want to consider moving a little more towards point and shoot or dimonding off a little entry. To my supprise, next time out and for most of the rest of the year he was running it hard up into the corner with a quick turn to run straight across the end of the track before running down onto the straight. Lots of bull to say I think I can see how the spring in the LR can effect how the RF tire is able to be used, under certain circumstances.

sorry, just starting to feel a little better and if I don't write bull on here, I may have to go do some work around the house.


paul
 
Just had another dumb thought.

I think historically on here with karts, low cross has been considered faster. But I also remember the general jest of it being, except for very high grip situations, yes low cross can be faster but it's a lot more difficult to make it fast with lower grip situations.
 
Paul. When I think about rear springs I pay more attention to how the spring unloads more than I think about how much load it will hold. The thing with a rear spring is, a 300# spring will unload quicker than a 200# spring. So if the rear end of the car was loose under entry it could be too stiff of a rear spring causing the rear to unload to quickly. Kind of like flinging the weight forward. A softer rear spring could solve that problem. Now if you put the softer rear spring and the car got better on entry but got tight on exit then it then it should have been a shock change. Not the spring.

Paul. With your finger puppets. When you added the sway bar you were on to something. With the bigger bar the more you load the RF the more pull down you get with the LF. So let's say it takes a combind spring rate of 1500# to hold the front of the car up. 700# LF and 800# RF. 100# split. Now think about the suspension travel in the corner and the amount of roll over on the RF. Think about the sway bar pulling up the LF suspention trying to stop all that roll over. Now take that same 1500# but think about it with 600# LF and 900# RF with a sway bar. See how the LF suspension travels up quicker and farther. You see how there is less roll over in the frontend. There is also an added benefit with this setup. When you get back into the throttle it actuilly pulls the LR down harder and faster to create less roll over in the rear of the car.

Remember a few years ago me explaining to you how I can get a 0 total roll center or even less on my super late model. How my car has .120 roll over in the front end and I can get -.125rear roll over which gives me a total -.005 roll center. That is with my super. 59% left side, 4" ride height with a LTO tubed chassis. I have figured out how to make this work with Street Stock GM metric chassis class car.(Pro Truck)

This is what it take to get all 4 tires loaded equally and get the temps equal. When somebody ask on here what are the perfect tires temps. It is no different than what is a perfect setup. The answer is balanced.
 
"Now think about the suspension travel in the corner and the amount of roll over on the RF".

Actually I think about entry roll over onto the RF a lot. It's more then just setting the height when weight gives additional ability to the RF. With RF height settings what ever spring you use, IMHO comes manipulating and timing the engagement of the RF. Correction on the timing part of it.

>Timing RF engagement on entry is a matter of you can't get engagement or additional function from the RF, too soon after turn in.<

The goal is for instantaneous engagement, but it's impossible because mechanics cannot keep up with dynamic weight movement. What's generally needed at the RF is to maintain spring rates and ride heights both prior and after RF engagement, but with with a process requiring less mechanical travel. I may be out in left field again, alone on that thought. ... :( butt I don't think so. ?

"There is also an added benefit with this setup. When you get back into the throttle it actuilly pulls the LR down harder and faster to create less roll over in the rear of the car."

I'm going to throw a wild thought in here. When there's high grip and lot of grip potential in the tires, I think it's remedied often by changing the direction of weight projection to a more outward direction in the turn. I only reference that to indicate the direction of dynamic weight forces can be altered.

Now back to forces when acceleration starts, which will be moving from the loaded RF back to the LR. This is referencing intentionally using or adjusting the path of returning weight, to alter how the LR is loaded. I'll leave it at the following thought. Hypothetically if we could direct dynamic weight to the LR via the LF, would the following happen? The returning dynamic weight would still travel instantaneously to the LR, but if redirected to the LF on it's path to the LR, wouldn't it arrive from a more advantageous direction? Aiming returning weight from the RF more straight back rather then at an angle, would both reduce roll and present weight to the LR from a direction it could better use for acceleration. My logic is if we can control how dynamic weight is aimed out to the right in the turn, there's no reason we can't aim or control the path of returning weight. Nothing at all says the return path for transferred weight, has to be the same path. And that takes this back to being able to engage the RF as soon as possible after turn in is started.

You mentioned becoming loose on entry. This is humor and also may fit into the above, maybe? Yep I'm aware of how the back can become loose. That is related to very often on here. But when you think of higher hp stuff and what I generally relate to with higher hp stuff is a bit different. Unless a car was totally out to lunch, I have never ever seen one of the higher hp stuff I relate to spin out going into a corner. In fact it's pretty darn near impossible for one to spin out going into the corner. Push into the wall or not turn, yep. But spin out, never. ... :)

Thanks and I really am truthful when I say this is all just IMHO and ain't necessairly right anyway. ... :) i'm just winging it on here and thunkin and writing as I think, weather I'm thinking correctly or not


edit: I was reading through what I wrote and it hit me that if your getting more weight to the LF, it's all goodness too because weight at the LF is already positioned to head directly at the LR. As opposed to heading towards the LR, from more of a RF direction.

edit again: I think the thoughts on the possibility of controlling and directing weight returning to the LR, also apply to karts. And I think I can fall back to previous thoughts on how controlling returning weight can be if nothing else, a fine tuning aid with karts. And can also be used to help reduce rpm loss in turns. maybe ?

edit again and again: My hope and dream is there's at least one kart racer out there reading this who will say, yeah I think I see it and I think if I try ....(this or that), it will help. ... and will be saying to themselves they can't wait to try what there thinking about at the track. butt, proly not
 
This is for Andrew only.

Andrew, we had a discussion on the old forum that was quite heated about tire temps. I have read this post and the one that prompted it. I went back through years of data and some recent data. You had mentioned that when the data that I had showed rear vs front of +10 and a right vs left of +10 and a cross vs jacking axis of 0, my driver complained of the kart being too free, not loose where the azz was hanging out but just too free.

I looked at some notes and when the rear vs front and the right vs left got closer to 0 and the cross vs jacking reached 0 the more stable the kart became and the less the driver complained. I never achieved the perfect balance but got pretty freaking close on dirt. What stood out the most was the tire prep used and when the tires came in. The driver would complain that the kart was too free, but the stop watch indicated he was the fastest the more the ratio became. To me this indicated the comfort level of the driver with a free kart. Some like a very snug kart and some like a super free kart, where some like in the middle.

That debate as bitter as it was opened my eyes and made me discover this trait with several different drivers over the years.

I have received several emails from people who use KartCalc and the chapter on tire temps in my chassis manual. The data received is now much clearer. Driving style plays an important factor in overall setup.

I knew it all along but never really them together. Kinda the same with front stagger. Front-end geometry plays a factor. A heavier driver needs less front stagger and more caster and a lighter needs more front stagger and less caster to achieve the same result. The heavier driver has more chassis flex to absorbe than a lighter driver.

I will say publically I am sorry for the heated debate but it made me learn something, and that is what a true forum should be.

We all have ideas and theories and facts and so on, in the end we take what has been discussed, etc and apply it. Sometimes it works and sometime it does not. In the end we all need to step back and say, WOW, tis was opposite of what I expected. Then commonsense says do the opposite.

Nobody can be 100% correct, there are way too many variances to factor in.

Which is the purpose of my chassis manual, it just gets you to thinking...

Even though I have retired I absolutly love karting.

Mike McCarty
Chassis Manual (Only $17.95)
www.kartcalc.com
 
Oh by the way... FLA was devine on my visit there. I came home from a near record snow fall and back to very cold.

BTW, Allgiant Air... transportation costs eat up all your savings.!
 
very Interesting,Good stuff, Here's a few things that came to mind after reading all this, Food for tought.
Take the spring from a ball point pen, compress it then let fly, Take the 200lb spring compress it the same amount let it fly, witch one went the furthest.
Is it because the lighter spring had more energy at the same hight, Or is it the 200lb'er needs to be compressed more to equal the same energy.
I invision it like a drag car leaveing the line. soft high energy front springs,
Flip side of the coin I think the weight will transfer away from and unload faster from the heavy spring to the lighter,say its the LR spring thats heavy, some weight gos to the RR & LF most to the RF, now add cross, then add weight to the LF,
You can not tansfer anything to something thats not there , the LR unloads, Balanceing act off the Lf/RR , Is the RF (spring/ cross/weight) the key to this balanceing act.
Are the tires on a kart the springs or the timers/shocks, Or is the frame the spring or the shocks?
Cross, weight on Rf / LR but then you turn, Caster = weight transfer to LF/RR.
Question on the LF tire temp, Would't that be a cooler temp if it is griping better and not sliping.
Tim richmond drove a three wheel supermodified - no LF- mind you, in testing said that it was the fastest & best car he ever drove, it was band before makeing one race.
Also in my neck of the woods a suspension less super proved its domance. Were's it start were's end what may seam wright is usualy wrong !

Donn
 
30 k said:
Tim richmond drove a three wheel supermodified - no LF- mind you, in testing said that it was the fastest & best car he ever drove, it was band before makeing one race.
Donn
Click to expand...
now that’s really interesting.
I’m trying to imagine a kart without a LF. Almost like having no caster. And no kingpin inclination. What would that do? One thing; it wouldn’t take the weight off the RF. The RF caster would just lower the front end. There would be no mechanical lowering of the weight on the RF and LR. Centrifugal forces would still lift some weight off the LR.
I wonder, if you had the stagger set right on the rear, for the turn radius, wouldn’t it be good not to lift weight off the LR?

comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.
 
msquared said:
This is for Andrew only.

Andrew, we had a discussion on the old forum that was quite heated about tire temps. I have read this post and the one that prompted it. I went back through years of data and some recent data. You had mentioned that when the data that I had showed rear vs front of +10 and a right vs left of +10 and a cross vs jacking axis of 0, my driver complained of the kart being too free, not loose where the azz was hanging out but just too free.

I looked at some notes and when the rear vs front and the right vs left got closer to 0 and the cross vs jacking reached 0 the more stable the kart became and the less the driver complained. I never achieved the perfect balance but got pretty freaking close on dirt. What stood out the most was the tire prep used and when the tires came in. The driver would complain that the kart was too free, but the stop watch indicated he was the fastest the more the ratio became. To me this indicated the comfort level of the driver with a free kart. Some like a very snug kart and some like a super free kart, where some like in the middle.

That debate as bitter as it was opened my eyes and made me discover this trait with several different drivers over the years.

I have received several emails from people who use KartCalc and the chapter on tire temps in my chassis manual. The data received is now much clearer. Driving style plays an important factor in overall setup.

I knew it all along but never really them together. Kinda the same with front stagger. Front-end geometry plays a factor. A heavier driver needs less front stagger and more caster and a lighter needs more front stagger and less caster to achieve the same result. The heavier driver has more chassis flex to absorbe than a lighter driver.

I will say publically I am sorry for the heated debate but it made me learn something, and that is what a true forum should be.

We all have ideas and theories and facts and so on, in the end we take what has been discussed, etc and apply it. Sometimes it works and sometime it does not. In the end we all need to step back and say, WOW, tis was opposite of what I expected. Then commonsense says do the opposite.

Nobody can be 100% correct, there are way too many variances to factor in.

Which is the purpose of my chassis manual, it just gets you to thinking...

Even though I have retired I absolutly love karting.

Mike McCarty
Chassis Manual (Only $17.95)
www.kartcalc.com
Click to expand...

Mike. I'm glad you got something out of that. That's is the main reason I post, to get people to thinking. It seems to work.

And you are so right. What is a perfect setup for one driver is totally out to lunch for another driver.

Heck. We have two different drivers in our Pro Truck. When one drives one weekend and the other the next. We have to change all the springs and shocks, the brake bias, and the steering wheel to produce the same lap times. Driving style is the biggest factor in determining a setup.

When you mentioned tire temps on the karts you also mentioned tire prep. That is the main reason I do not probe tires on the karts. Prep plays to big of a factor in the temp of the tire it will over rule what the pyrometer is telling you. You front to rears could be a +10 but that just might be the prep talking to you. If you have some goat and kreo in the fronts and and HL2 in the rears than the fronts would be hotter than the rears due to the prep but the pyrometer is telling you that you have a balance issue. If you are prepping tires with different preps or just different amounts of preps you should just leave the pyrometer at home. It will hurt you more than help you. To many variables.

Glad you had a good time in sunny FLA!!!
 
alvin l nunley said:
now that’s really interesting.
I’m trying to imagine a kart without a LF. Almost like having no caster. And no kingpin inclination. What would that do? One thing; it wouldn’t take the weight off the RF. The RF caster would just lower the front end. There would be no mechanical lowering of the weight on the RF and LR. Centrifugal forces would still lift some weight off the LR.
I wonder, if you had the stagger set right on the rear, for the turn radius, wouldn’t it be good not to lift weight off the LR?

comments compliments criticisms and questions always welcome.


If the data does not support the theory, get a new theory.
Click to expand...
Forgot to mention it had two RR's, front and back of each other, He also said not haveing the LF was like the crutch was missing werd feeling, Apparently it layed down some serious G's , Consider two it had a alum big block hanging off the left. Is the RF the key to unloading the LR, Or combination of Cross weight and rear stager compromising the perfect size for turn radius. Donn
 
alvin l nunley said:
now that’s really interesting.
I’m trying to imagine a kart without a LF. Almost like having no caster. And no kingpin inclination. What would that do? One thing; it wouldn’t take the weight off the RF. The RF caster would just lower the front end. There would be no mechanical lowering of the weight on the RF and LR. Centrifugal forces would still lift some weight off the LR.
I wonder, if you had the stagger set right on the rear, for the turn radius, wouldn’t it be good not to lift weight off the LR?

comments compliments criticisms and questions always welcome.
If the data does not support the theory, get a new theory.
Click to expand...

And why would you want to lift weight off the LR?
 
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