rollsteer/stagger

[ZERO25]

Anyone know a mathematical formula for finding the correct stagger correlating with the steer angle of the rearend?

[MasterSbilt_Racer]

Anyone know a mathematical formula for finding the correct stagger correlating with the steer angle of the rearend?

Can't be done. Angle = turn forever.

[ZERO25]

Can't be done. Angle = turn forever.

Surely in this age of technology,some engineer somewhere has attempted to calculate this!

[MasterSbilt_Racer]

Surely in this age of technology,some engineer somewhere has attempted to calculate this!

All it does is dog walk the car. Now days, the car mostly staying hiked. If it don't set down, it's always skewed the same amount, so it isn't steering.

[ZERO25]

I would find it hard to believe, back when the Cup cars were doing it, that some of the engineers hadn't researched the idea.

[CageFaraday]

...rabbit trail...

[Matt49]

The direction the axle is pointing relative to the car doesn't change the amount of stagger required to get a solid axle to roll through a corner.

[dirtrace09]

But the stagger does change the amount of input needed from the front to control where the car wants to go due to the direction in which the axle is pointing.

[hotshoe65s]

You can indeed calculate the turn radius with a given amount of rear steer. You can also calculate the turn radius with a given amount of stagger.
It is not a 1:1 relationship and there are no optimal ratios. Of course they do not act independent of each other, but there is also no magic answer. The optimal rear steer and stagger depend on track conditions, vehicle setup, and driving technique.
If you want a way to determine your turn radius or understand any characteristics on your car I have built a dirt late model/modified simulation program that has that calculation included in it. I am working with a few guys to work the bugs out of it. I would sell it to a select few people as beta testers if interested.

[fastford]

a lot of thought has changed with the amount of dynamic roll steer these cars have today , we are on 1/2 and sometimes less stagger than we were 10 years ago.....

[Matt49]

I also think it's just important to keep in mind that stagger and rear steer accomplish two completely different things. Stagger is helping the rear of the car make a turn radius around the corner without scrubbing the tires. Rear steer is helping the entire car (not rear end only) make it around the corner without laterally sliding the rear end.

[Kromulous]

Question: are you guys a set the stagger and forget it, or adjust it to get the car to do whatever better?

I always considered setting it per the track, and keep it consistent, but over the years have wondered.

Also It seems a certain amount of tire scrub is needed to make more traction via less or more stagger. It seems like the modern way is to run a lot less stagger, and more rear steer like Fastford said but why is the question? trying to create more tire scrub against the track?

Example would be to have enough rear steer and stagger to make the car go around a corner with the least amount of scrub etc, the most efficient. Then take out / add stagger out to add or subtract some tire scrub. I know there will be considerable tire scrub from the effects of cornering to begin with, side load etc.

[ZERO25]

You can indeed calculate the turn radius with a given amount of rear steer. You can also calculate the turn radius with a given amount of stagger.
It is not a 1:1 relationship and there are no optimal ratios. Of course they do not act independent of each other, but there is also no magic answer. The optimal rear steer and stagger depend on track conditions, vehicle setup, and driving technique.
If you want a way to determine your turn radius or understand any characteristics on your car I have built a dirt late model/modified simulation program that has that calculation included in it. I am working with a few guys to work the bugs out of it. I would sell it to a select few people as beta testers if interested.

CP Furney years ago published a table for determing stagger based on banking angle and rear track width. He also believed you had to add a certain % to that based on certain track conditions and reduction of tire circumference due to weight transfer.

[hucktyson]

I think any scientific calculation of what is required is thrown out the window by the track not being perfectly smooth and the track not having even consistent traction from top to bottom and the cars sliding and wheel spinning. This is not asphalt. According to all of you Kevin rumley is the smartest guy on the entire planet and snort is the best driver and the have the best funded operation .... Only the last of which do I consider true but point being there are plenty of races where he is not a factor , if the “ smartest guy on planet earth “ is unable to harness the power of these scientific calculations to produce consistently dominate results you have to conclude it’s not possible

[Jking24]

I think huck hit the nail on the head. People forget rumley was a racer long before he was a engineer. No denying the data helps but we're all still racing on a ever changing surface with mother nature fighting us every step of the way. That's what makes this sport better than all the rest the challenge!

[fastford]

even though we use less stagger , it is still important , we just make a lot less change than we use to , its all about tuning and staying up with the track , if you can turn the car through dynamic roll steer and use less stagger , you will pick up straightaway speed and be smoother entering the turn , which is where a lot of speed has been gained lately , the old train of thought where you enter the turn with the car flat required a lot more stagger to make the car turn when you picked up the throttle , but it made the car harder to control getting in , which usually meant having to run a lot more rear brake to get in.....

[ZERO25]

I think any scientific calculation of what is required is thrown out the window by the track not being perfectly smooth and the track not having even consistent traction from top to bottom and the cars sliding and wheel spinning. This is not asphalt. According to all of you Kevin rumley is the smartest guy on the entire planet and snort is the best driver and the have the best funded operation .... Only the last of which do I consider true but point being there are plenty of races where he is not a factor , if the “ smartest guy on planet earth “ is unable to harness the power of these scientific calculations to produce consistently dominate results you have to conclude it’s not possible

THAT MIGHT BE YOUR PROBLEM!!!

Since you don't believe dirt racing is a science, maybe that's the reason you got lapped in a 10 lap heat race!

[Jim11h]

Where was your car big boy? Can't believe how many have attacked him for trying world 100. Then have stupidity to bring that (not a nice word)(not a nice word)(not a nice word)(not a nice word) here to most respectable forum in all of 4m. Now please go back to where you belong and it isn't here

[ZERO25]

Where was your car big boy? Can't believe how many have attacked him for trying world 100. Then have stupidity to bring that (not a nice word)(not a nice word)(not a nice word)(not a nice word) here to most respectable forum in all of 4m. Now please go back to where you belong and it isn't here

keyboard warrior ^^^^^, you might wanna study your 4m history and you'll find out why everybody gives Jonny boy a bunch of crap!

Ask him about boasting to someone with half the equipment he has, and got beat like a drum at Eldora a couple of years ago!

[hucktyson]

Yes my 2016 pierce car that I cut all of the mounts off and changed everything in my garage with a jig saw , tubing bender a welder and drill press with a standard bore 430 and 3 differnt brands of shocks, never been on a pulldown rig or anything just done wig plumb bombs angle finders and string lines that I have raced a total of 6 times now including eldora..... completely on my own to decide every adjustment and completely on my own to pay every bill while running a company that takes 70-80 hours a week of my time. What’s described above is definitely double the equipment most people take to eldora ..... yes considering all of that I was clearly the odds on favorite to take home the globe ..... it’s amazing I didn’t win that race ....

[Kromulous]

I'll say this about scientific, i was talking to a fast local / regional racer and he was going on and on about .010 of bump steer. How that basically derailed his chance of winning, being fast. Then went on to tell me about how everything had to be so so, down to the rivets. Measures stagger to the 1/16th etc etc

At that point i figured one of 2 things is going on. A lot of delusion, or these guys that are really fast can tell that .010 mills can make a difference in a car, and can feel it.

Have been trying to figure out which one ever since LOL.

One thing i will say thou, guys like Rumley that are Engineers, i work with them all day, they love data. The more numbers the better they feel. So i would guess he would have calculations on various things like stagger etc.

[ZERO25]

Yes my 2016 pierce car that I cut all of the mounts off and changed everything in my garage with a jig saw , tubing bender a welder and drill press with a standard bore 430 and 3 differnt brands of shocks, never been on a pulldown rig or anything just done wig plumb bombs angle finders and string lines that I have raced a total of 6 times now including eldora..... completely on my own to decide every adjustment and completely on my own to pay every bill while running a company that takes 70-80 hours a week of my time. What’s described above is definitely double the equipment most people take to eldora ..... yes considering all of that I was clearly the odds on favorite to take home the globe ..... it’s amazing I didn’t win that race ....

And yet for weeks and weeks, you talked trash to Brian Gray! You claimed his info on here was bs, and you could outrun him with a wheelbarrow! And yet YOU didn't! You had superior equipment to him and he still beat you fair and square!

As the old timers say, don't let you alligator mouth write a check your canary rearend cant cash!

[hucktyson]

Except he didn’t beat me ....

[hucktyson]

And yes everything he says on here is BS

[fastford]

come on you two , this is the last section on this forum that we can talk and exchange ideas with out the BS , Ive been listening to you two for years on here and i like both of you , BUT , let this sh!t go........

[hucktyson]

Fastford he’s just another faceless nameless clown. Anyone who doesn’t say who they are shouldn’t be allowed to post.

[ZERO25]

Stick to deck building jonny boy.....that might be the one and only thing you're an expert on!

I bet Brian Gray would love a chance at driving your top of the line Pierce/Cornett around the Big E.....at least the car would know what its like to go fast one time!

[MasterSbilt_Racer]

I'll say this about scientific, i was talking to a fast local / regional racer and he was going on and on about .010 of bump steer. How that basically derailed his chance of winning, being fast. Then went on to tell me about how everything had to be so so, down to the rivets. Measures stagger to the 1/16th etc etc

At that point i figured one of 2 things is going on. A lot of delusion, or these guys that are really fast can tell that .010 mills can make a difference in a car, and can feel it.

Have been trying to figure out which one ever since LOL.

One thing i will say thou, guys like Rumley that are Engineers, i work with them all day, they love data. The more numbers the better they feel. So i would guess he would have calculations on various things like stagger etc.

That guy is full of crap...

[Jking24]

That guy is full of crap...I myself can't feel anything under. .012 bump .................

[hucktyson]

The idea of feeling 0.010 of bump steer when the RF stays compressed and the tires start toed out .375 and feeling 1/16” of stagger when stagger changes almost every time you measure the tire is laughable.

[hucktyson]

This reminds me of the time gray did a video of holding a fence post against the tire while
Someone jumps up and down on the front end as a way of measuring bump steer

[billetbirdcage]

20K to win 100 lap race...

2 drivers lead most of the laps and ran next to each other for most of the race, until late when another got both of them and won (passed them about lap 87 or so).

Those 2 cars where the same brand and very close on set up and car A has X stagger while car B has Y stagger. X - Y equaled 2" difference. I don't know what stagger the winning car ran so can't comment.

So how do you make a calculation on which car had the right and which had the wrong stagger out of car A and B?

Hmmm.

[ZERO25]

20K to win 100 lap race...

2 drivers lead most of the laps and ran next to each other for most of the race, until late when another got both of them and won (passed them about lap 87 or so).

Those 2 cars where the same brand and very close on set up and car A has X stagger while car B has Y stagger. X - Y equaled 2" difference. I don't know what stagger the winning car ran so can't comment.

So how do you make a calculation on which car had the right and which had the wrong stagger out of car A and B?

Hmmm.

Maybe they were both wrong......and that's why Z won! :)

[billetbirdcage]

Here is a puzzle for someone to try:

Say I have 4" stagger measuring off the car and 6PSI on LR tire and 10 in RR:

What is the true stagger the car see's?

How much does the stagger change from the RR and/or LR tires being loaded differently at certain points of the corner?

How much does my LR tire diameter change on the straight (higher wheel RPM), if I was using a "Wide" tire on LR vs a STD LR tire?

My RR tire is 92" in circumference, what is the actual rolling circumference with the static weight on the tire and what is it at max load at some point on the track?

something to think about....

[billetbirdcage]

At that point i figured one of 2 things is going on. A lot of delusion, or these guys that are really fast can tell that .010 mills can make a difference in a car, and can feel it.

Have been trying to figure out which one ever since LOL.



If you believe the myth (true or not, I have no idea - IMO it's myth) that been told to me so many times over the years by numerous people:

Bloomer is testing with a shock company, makes some laps comes in and tells the shock guy it needs 1 more click of rebound and tells him to add it on this corner. Well shock guys say even the best of drivers can't feel one click so he does 2 clicks. Scott makes some more laps comes in and rages on shock guy:

"I told you one click not two"


LOL......Shrugs

Note# this was supposedly on the almost full open range on the shock like the LR rebound where 1 click makes very very little change

[ZERO25]

Here is a puzzle for someone to try:

Say I have 4" stagger measuring off the car and 6PSI on LR tire and 10 in RR:

What is the true stagger the car see's?

How much does the stagger change from the RR and/or LR tires being loaded differently at certain points of the corner?

How much does my LR tire diameter change on the straight (higher wheel RPM), if I was using a "Wide" tire on LR vs a STD LR tire?

My RR tire is 92" in circumference, what is the actual rolling circumference with the static weight on the tire and what is it at max load at some point on the track?

something to think about....

That was Mr Furneys contention some 10-15 years ago. He always contended that you added an x amount of % to the static stagger based on different track conditions.

[Kromulous]

Cant use quotes, but Billet i have heard some strange things about Bloomquist. My brother watches him like a Hawk and he says he has brake bias / shut offs on all 4 corners. I dont know thou, obvously he is a special breed so who knows.

Im not much of an arguing type of guy, most of the guys i talk to tell me these type of things and i just nod and agree but in my mind i always wonder where reality fits in.

[powerslide]

Cant use quotes, but Billet i have heard some strange things about Bloomquist. My brother watches him like a Hawk and he says he has brake bias / shut offs on all 4 corners. I dont know thou, obvously he is a special breed so who knows.

Im not much of an arguing type of guy, most of the guys i talk to tell me these type of things and i just nod and agree but in my mind i always wonder where reality fits in.

I've noticed it looks like his RR rarely sparks where his LR is like a flame thrower, wasn't sure if it was different pads on each side or just my eyes playing tricks or??? I think it helps keep heat out of the RR as well. I just didn't think that would be enough brake for most of these cars especially the brake dragging guys

[hucktyson]

That would only matter if his rear end is unlocked which is may be.

[Krooser]

Perhaps he has an air locker?

[Krooser]

So Mastersbilt Racer gets banned for saying some guy who Krom talked to is full of cr*p? Come on ModJr1... that's pretty lame!

[powerslide]

So Mastersbilt Racer gets banned for saying some guy who Krom talked to is full of cr*p? Come on ModJr1... that's pretty lame!

i was curious what got him banned... Surely they deleted what he got banned for if it was that bad

[fastford]

I agree powerslide , swapped a lot of info with masters over the years , i have never saw him out of line , especially compared to some of the other BS that gets a pass on here.....how about an explanation please?

[Kromulous]

Yeah thats really lame 4m.net

MBR is a great contributor in the Tech section.

[billetbirdcage]

i was curious what got him banned...

He knows what post it was, but he's not sure why that drew a ban. Anyways he got 30 days for it. (I think it was about a promoter, not that it was bad just something about one probably like saying something about rocket or another sponsor of the website.)

[fastford]

wow , i guess i better go back and read the rules , im bad about skipping over stuff......

[CageFaraday]

Yes my 2016 pierce car that I cut all of the mounts off and changed everything in my garage with a jig saw , tubing bender a welder and drill press with a standard bore 430 and 3 differnt brands of shocks, never been on a pulldown rig or anything just done wig plumb bombs angle finders and string lines that I have raced a total of 6 times now including eldora..... completely on my own to decide every adjustment and completely on my own to pay every bill while running a company that takes 70-80 hours a week of my time. What’s described above is definitely double the equipment most people take to eldora ..... yes considering all of that I was clearly the odds on favorite to take home the globe ..... it’s amazing I didn’t win that race ....

Huck, if you did all that on your own, you have my complete respect. Wow.

[CageFaraday]

Cant use quotes, but Billet i have heard some strange things about Bloomquist. My brother watches him like a Hawk and he says he has brake bias / shut offs on all 4 corners. I dont know thou, obvously he is a special breed so who knows.

Im not much of an arguing type of guy, most of the guys i talk to tell me these type of things and i just nod and agree but in my mind i always wonder where reality fits in.
Bloomy been using 4 wheel brake cutoffs since before “On the hook” was a thing. He has lots of little details that set his cars apart.

[ZERO25]

A good friend of mine, several years ago, put 4 wheel brake cutoffs on an asphalt car and wore them out.Im not saying that was what made him so dominant, but it definitelty helped. He also had different sized calipers on all 4 corners. I posted that on here as a possibility for dirt cars, and of course was scoffed at.

[Kromulous]

You have to understand people's depth, as i call it. Some Drivers can drive a race car and cant ever tell you anything, some can pin point a shock being maladjusted (Bloomquist). You could have 4 corner bias valves on some Drivers cars and they could never tell you anything different, or ever adjust them. Some guys can go out there and dial it right in. Doesnt make the idea right or wrong, or the end all be all either. Although in some hands it can make all the difference.

Same way with new inventions, Rumley device, i am sure a lot of people said it will never work...

[CageFaraday]

You have to understand people's depth, as i call it. Some Drivers can drive a race car and cant ever tell you anything, some can pin point a shock being maladjusted (Bloomquist). You could have 4 corner bias valves on some Drivers cars and they could never tell you anything different, or ever adjust them. Some guys can go out there and dial it right in. Doesnt make the idea right or wrong, or the end all be all either. Although in some hands it can make all the difference.

Same way with new inventions, Rumley device, i am sure a lot of people said it will never work...

I worked with Buck Simmons during his drive for a 1000+ wins on the John Deere car. He had always been my hero growing up as he is from the same general area in Georgia I'm from. Another friend of mines dad was tapped to be the crew chief that I worked with at Carrera Racing shocks and he knew how much I idolized Buck and asked if I wanted to be their shock guy. I of course jumped at the chance and for the next 2 seasons we raced together, 2002-2003. I expected Buck to be sharp on chassis or tires or all of the above with all the races he'd won, something like 995 wins, when I cam along, but he wasnt. Buck had many many tools in his drivers tool box, but setup and working on the car wasn't included in that. Now he could take the car out for exactly (1) lap and tell you where it was good or bad and exactly how it was performing, but he left what to do to it up to somebody else. He taught me a lot about driving and the psychological end of things, the head games, but nada about the cars. I've met very few drivers that could actually tune the cars effectively, which is why when people ask who's gonna fill Bloomquist or Moyer's shoes, I draw a blank. The number of guys who drive as well as they set the cars is up is miniscule to be certain. It was the same way when I kart raced, most were clueless on proper setup or tuning.

Today we have Davenport/Rumley together is formidable, but apart, less so. Bobby Pierce and his dad are pretty strong together, but apart not so much. Bloomquist has had many top notch crewchiefs, once he had (2) of the best at once, but regardless of who's turning his wrenches he rises to the occasion 9 times outta 10.

I got off topic, but it was something I wanted to share. I don't believe there is or can be a magic perfect formula for setting stagger on a DLM, even if you had NASA or GM or Delphi in your pit. The reason why is that you can't include all those sensors needed to measure the cars attitude under actual racing conditions, its illegal and testing would only get you so far because the surface won't be the same the next time you race on it. In cup the surfaces stay static for long periods of time unless they repave it so you can't use data acquisition and a multi-post rig to mimic the cars attitude in a lab environment and be precise. Dirt is different week to week depending weather, the water truck driver and the motor grader. You in many ways see a different track every time you go out, so data acquisition would be of limited help. This is also what makes dirt racing the best, you never can completely master it, like a woman always changing. Just enjoy the ride.

[hucktyson]

That’s what makes this game sooo interesting and soo hard. When you start from scratch on a suspension you have a million variables , literally everything is up in the air. Then racing at different facilities on completely different surfaces. Trying to figure literally everything out in 300 laps total at 4 different tracks on everything from dead slick to wide open. Oh yeah and only run special events where everyone has an xr1 , longhorn , club29 , Bloomquist etc etc . Oh and I almost forgot race against guys who run twice as many laps in February as I do all year and I don’t start until August when they already had all year to get dialed in. That challenge is what I love about racing. Obviously it would be much easier to buy an XR1 and hire a consultant but honestly I wouldn’t take pride in that. I’ve been putting cars together from the ground up since I was 10 , I have never bought one that was together , building it and trying to figure it out is the part that makes it fun. The results have not shown yet but it is getting better the problem is everyone else is getting better too and to actually show improvement you have to improve to where they were and beyond where they got at the same time. I love this $hit I just wish I had more time for it

[fastford]

cage , ole buck was a character , i thought a lot of him as well , i think the last time i saw him was in the years you mentioned at talladega , dont he have a grandson thats racing now?

[CageFaraday]

cage , ole buck was a character , i thought a lot of him as well , i think the last time i saw him was in the years you mentioned at talladega , dont he have a grandson thats racing now?

He has a son that he had late in life, LOL. I can't remember his name, he was maybe 4 when I saw him last. He use to wear a matching fire suit to Buck's when he came to the track. Buck was a player right to the end, I learned many life lessons in my time with Buck and he still owes me a half a dozen cheeseburgers, but that's another story.