I thought they took away alot of the allowed yaw in the cars.

It sure looked like McMurry's car had a ton in it.

They should just stop showing that angle so people wouldn't question it :thumbsup:

Lol! :d

Evert car I saw was twisted.......................:cool:

Its only rear steer.

yaw is yaw, the 99 crew first started the tweaking of the rear diff housing this year, putting tons of twist or degrees of what we call "rear steer" in the rear diff housing. Carl was kickin some butt until other teams and camera crews started picking up on it looking at the cars in the straight away that constantly looked like they were in "yaw". Nascar has since put a stop to teams putting that much tweak/twisting in the rear diff housing. Nascar is only allowing a certain amount or degrees in the housing.

Omni -- that is what I thought but it just seemed they were very "twisted" tonight.

A few weeks back they said some teams found a new way to get the cars through tech again.

A few weeks back they said some teams found a new way to get the cars through tech again.

WHAT?!?!?!!?

Racers tinkering with things? Well I'll be... ;) :wave:

Didn't we have a car chassis made by trinity called the "Switchblade" that let the R/C world tinker with yaw? Take alook at the RC10R5. We get a change to tinker with it there and if the RC10L5o, yaw will hit the RC oval world

"Will hit"? Where have you been? ;)

Didn't we have a car chassis made by trinity called the "Switchblade" that let the R/C world tinker with yaw? Take alook at the RC10R5. We get a change to tinker with it there and if the RC10L5o, yaw will hit the RC oval world

You can "tinker" with any r/c car to put it in yaw...
Yaw is an aero thing, all you have to do is skew the body..
It isn't a chassis thing.

john stranahan told me rear steer is useless.

What I was referring to was the "offset" or "yaw" that the cup teams were putting in the rear ends at the beginning of the season. Not body skewing.

john stranahan told me rear steer is useless.

Sometimes maybe, not sure, could be. :D

What I was referring to was the "offset" or "yaw" that the cup teams were putting in the rear ends at the beginning of the season. Not body skewing.

And I was referring to yaw in r/c cars,
as really only needing to skew the body...
The reason why cup teams do the modified rear ends, is to skew the body
more than what is allowed by track bar, and wheelbase allowable adjustments.
Yaw is not rear steer! Yaw is not a mechanical thing.
It is an aero term...
It is about body skewing... that is what yaw is.
It is when a body is pointing in a direction,
different from the actual path of the vehicle.....
So if a vehicle is traveling parallel to the lines on a track,
but the body is pointing 2 degrees towards the pit wall,
the car is "in yaw".... :thumbsup:

Ok gotcha.

What is is called when, in respect to the center line, the front end is in one path and the rear is in another?

Looks like another Brett Bodine idea to have the cars dogwalk like old rusty Ford LTD's. NASCAR apparently liked it (but limits it for some teams) because it makes the cup cars look even more stupid, in tune with the generic touring car body with the front bumper missing, JC Whitney wing, "spec" engines and chassis with all four makes running what appears to be 351 Ford Clevelands, 1960 GMC truck rear suspensions, '65 Ford Galaxie front ends, crap-shoot Goodyear tires (similar to Firestone Wilderness AT's), restrictor plates, lucky dog, no dirt tracks, chase, yawn...
:dude:

Ok gotcha.

What is is called when, in respect to the center line, the front end is in one path and the rear is in another?

offset rear.

Ok, I thought that is what they were running at the first of the year, offset rear-ends. I am not trying to argue, just educate myself.

Ok, I thought that is what they were running at the first of the year, offset rear-ends. I am not trying to argue, just educate myself.
I understand...

You are right though!
At first.. they were running offset rear, AND they were running static rear
steer... but to get even MORE body yaw, they started toeing the rear hubs!
this allowed them to get MORE than what was 'legally' allowed
by tolerances in the track bar, and wheelbase..
So when the 'spirit' of the rule was broken, that is when they (NASCAR)
put a limit on how much you could modify the actual housing..

Some had so much built in, that some cars had a tough time
getting on the scales and inspection jigs!:drunk:

LOL!

I rememberthat now. Thanks.

It got so crazy, that some were machining special gear sets so that they
could run the pinion gears at other than 90 degrees to the ring gear!
the cost was absolutely staggering.

john stranahan told me rear steer is useless.

Hey kat1sh. Mr. Stranahan is mistaken, it most assurdly is used and it works very well thank you. Just ask any QSAC 1/4 scale R/C racer. I use between 1/16 to 3/16 toe in my rear end track dependant.
If the NASCAR guys had a fully independant suspension (Corvette Type Rear) in the rear of their COT cars you might see it used a lot more.
Besides the poor crew chiefs need something to help get those bricks to turn left.

katfish-not exactly what I said. I use 1.6 degrees of left rear steer all the time. Right rear steer is not helpful on our track from what I see. I made a note in my thread that you guys use it on asphalt with offset pod and high traction sometimes. My oval car is yawed all the time. It is very helpful.


http://www.rctech.net/forum/electric-road/222869-crc-battle-axe-genxpro-10-1-10th-pan-brushless-lipo-4c-road-oval-tipsandtricks-13.html

Mike-so what direction is your toe on that 1/4 scale? Would that be toe in on the right rear?

Pic you can clearly see my left rear steer in this shot. Rear axle is at an angle to the frame. I have 1.6 degrees left rear steer dialed in. It eliminates corner exit hooking and the right rear wheel toe in improves rear grip allowing hard rear tires on both sides. This ain't your daddy's oval car.
john

john stranahan told me rear steer is useless.

Hey John,
katf1sh stands corrected. I kind of figured that most hot shoe oval guys used it to a certain degree. Back in the old days we over drilled our 10L, Delta & TRC rear pods where we could at least tweek our pods for some steering help.
Our BRP 1/18 scale cars even use it. But yes my right rear of my 1/4 scale is toed in 1/8 of an inch.

I see that you run foams is this a carpet car? Do you run any rear stagger in you tires?

katfish-not exactly what I said. I use 1.6 degrees of left rear steer all the time. Right rear steer is not helpful on our track from what I see. I made a note in my thread that you guys use it on asphalt with offset pod and high traction sometimes. My oval car is yawed all the time. It is very helpful.


http://www.rctech.net/forum/electric-road/222869-crc-battle-axe-genxpro-10-1-10th-pan-brushless-lipo-4c-road-oval-tipsandtricks-13.html

Mike-so what direction is your toe on that 1/4 scale? Would that be toe in on the right rear?

Pic you can clearly see my left rear steer in this shot. Rear axle is at an angle to the frame. I have 1.6 degrees left rear steer dialed in. It eliminates corner exit hooking and the right rear wheel toe in improves rear grip allowing hard rear tires on both sides. This ain't your daddy's oval car.
john

Nope it isn't, What brand car is it?

Mike-This is a homemade car for asphalt. Thanks for the rear steer report, left steer like my car. This is topical because we call our top class sprint cup. There are mechanical traction advantages to twisting that rear axle (like right rear toe in) as well as possible aero advantages.

The rear of my car is a 3 link with Panhard bar type like on current full size Mustangs. The front is dual dynamic a-arms with damping like on most full size race cars these days. It did very well in our last oval series, usually 3 to 5 laps ahead on flat asphalt. We are a fairly new oval club but some of our guys had 15 years previous experience. I have a similar wide pan road car with a newly designed dual-A arm front end using CRC pieces. It should work the same as the one on this car, but has nicer looking pieces.

I offset my left rear tire positive by about 10 mm to counter corner exit hooking. This along with left rear steer allows me to use more throttle here than the other guys because my car is tuned to exit straight. I don't stagger the tire sizes to any significant degree. I do leave the inside tires a little larger for the main.

Now the car we had trouble with that might be the source of confusion had right rear steer, but it also had a centered pod with an offset pod right hand hub. This offset the right rear 10 mm positive. It was difficult to drive on our track like this. With the pod offset left to match the hub, it was better. Without the right rear steer it was better still. Just a property of our asphalt probably. Noone need take offense if their used car needs to be tuned differently at a different track. I did soften my words in my thread with an edit. This may help the problem.
john

John if I looked at that picture right you have twisted the rear so that the rr is forward. that is totally ass backwards and regardless of what you think it is hurting you way more than it is helping you.

Dave- I know it is backwards. I prefer to call it left rear steer or right rear toe in as on Mikes 1/4 scale. Maybe the same as the Nascar example above (nose to the wall) if it was from the real racing. I have tried right rear steer. When I get on a battle axe soon I won't be able to do this left steer to any big extent, so I will do without. Maybe when the rest of the guys pick up those 5 laps on me I'll fix it on this car. I don't have a left offset pod. I don't even like moving the motor left 1/8 inch on this car. I get by without that pink left rear. This reduces my rear scrub. xxpink/purple on the left rear.

What most people want on my track is to be able to drive around the oval without spinning out.
john

flewwwwwwwwww nevermind

John if I looked at that picture right you have twisted the rear so that the rr is forward. that is totally ass backwards and regardless of what you think it is hurting you way more than it is helping you.

Depends on the track used to do it all the time with my modified when the track would dry out. came off the corners harder and straighter.

Depends on the track used to do it all the time with my modified when the track would dry out. came off the corners harder and straighter.

exactly.

Mr. Stranahan has the right idea for a loose track. We use a similar setup on our racecar so the driver can get on the gas harder and sooner coming off the turn. I see the opposite alot on carpet to get the cars to turn better. Which also works on tighter tracks with our racecar especially if we are tight in the center. We aso use the trailing arm angles to do a lot of the turning so when the car is staight again the rear end is square again in the car.


I like your work John. I use trailing arms on a few of my r/c cars and have worked out a full suspension pan car on paper that we'll be trying out soon.

Kool!

Chis-Thanks. Be glad to consult.
John

John, that is a cool car!

Have you ever run it on a banked track with caps against traditional Pan Cars?

Scott-I have not. It should do well on the banked track. That dampened front suspension helps a lot. I have run it against standard pans on the flat oval. I think it may be 1 lap faster on the oval (same driver and power). The more powerful the motor the more the gap. In 13.5 LiPo it is showing really great corner exit speed compared to the standard pans. Cornering speed is now also very good with the harder tires. Plenty of left rear steer on the 3-link. Not possible on the standard pan.

I have run a similar wide pan (middle pic above). Against a standard pan. Same power. same driver. The 3-link was 1.3 seconds faster. Mikes-HobbyShop.com track. It just had more steering traction and more forward traction from the better suspension. No rear steer here.

It would be interesting to see it run against them on caps.

I assume you are running on parking lot flat tracks then.

What does it weigh?

flat asphalt (really on sealer these days) part of the big 1/8 track at Mikes-
41 ounces on 4 cell, 2 ounces of lead added to 13.5 Cell/LiPo to make 43 ounces.
We use this ice on practice days, but have a couple of wagon wheel type boards on race day. Small club. We may or may not Make it. I am hoping for the best.
Latest body. No chassis under it yet.
John

That is great you are at weight like that.

So I understand what you are saying in reguards to rear steer:

Left Rear Steer = Right side of car shorter due to angle of rear axle.

Right Rear Steer = Left side of car shorter due to angle of rear axle.

yes. Now this is also how Nascar is yawing (or is banned from yawing) the car. I disagree that it is only an aero advantage. Mechanical traction is changed considerably in the corner and on corner exit by either right or left steer.

You are running, what you call "LEFT REAR STEER", basically turning the rear wheels the "same way" or the "same plane" as the front wheels.

Where as the norm in pan cars is to do the opposite. In a way to make the rear of the car much like the trailer connected to a truck. When the combo turns, if looking from the middle, the front is going left and the rear is going right.

Yes. An apt anology. What I did is determine what caused the main problem drivers have on our track. The problem is corner exit hooking. This is not an oversteer condition as instead, the front end lets go and moves to the inside of the track. There are two things happening that are important. One, the front unloads due to a torque reaction from the motor on power; the front end lifts. Second the right rear is heavily loaded; this causes a torque steer to the left when you apply power out of the corner. This creates the hook. You can combat this in several ways to prevent a spin. Jake uses a soft left rear and hard right rear. That soft left rear provides a torque steer to the right. Whether intentional or not it combats the natural tendency to hook left. I tried it. I use a left rear steer; the rear steers left the car goes right. We also both probably use generous left downtweak. The left rear is loaded more than the right rear with the right rear shock collar. The extra starting load we can put on the left rear combats the torque steer to the left. A third powerful tool which I can also use on the standard pan car is left rear wheel positive offset. This steers the car by torque steer to the right on corner exit.

The end result is a car that exits the corner straight and fast. It does not wiggle inward. It does not have a tendency to hook on corner exit and spin "in".

One of our guys broke his T-plate once and ended up with left rear steer by accident. Magically his corner exit spins were stopped. This is worth about 5-6 laps for two extra spins in a race.

There are many ways to solve this problem. I like some left rear steer at my track.
john

yes. Now this is also how Nascar is yawing (or is banned from yawing) the car. I disagree that it is only an aero advantage. Mechanical traction is changed considerably in the corner and on corner exit by either right or left steer.

Before we get too far off the beaten path here,
there is a difference between yaw, and rear steer...
A car can be perfectly square, and be in yaw.
Yaw is an aero term, you can call it anything you like however,
that is your perogative..
I never said increasing the yaw angle did not AID in cornering.
Traction is changed, because the car in yaw, has more downforce from
the rear wing.. there is more of it in the clean air.
But yaw in itself, is NOT mechanical!
You may SET the car in yaw, from mechanical means.

So Yaw is this, the body is put on the chassis at an angle of attack, if you will, into the turn.

Is that right?

So Yaw is this, the body is put on the chassis at an angle of attack, if you will, into the turn.

Is that right?

It could be.
But more accurately.... let's say you were in a helicopter looking down
at a car traveling down the highway.
The car is going perfectly straight, but it looks crooked...
The center of the rear of the car, is 3 inches, or 3 degrees to the right
of the center of the front of the car...
Then the car is in 3 degrees of yaw.
REGARDLESS of any chassis adjustments.
The chassis could be perfectly symetrical in every way.
OR it could have 5 degrees of axle offset.
OR it could have 5 degrees of rear steer.
OR both!

It is the difference between the path traveled, and the path pointed,
so to speak...

Or to put it in the opposite direction.
Lets say you have 3 degrees of rear steer,
and the body is mounted 3 degrees 'crooked'.
The car will be traveling 'straight'... it will not be in yaw.

Make any sense?

Well kinda.

Let's take the body off/out of the equasion.

1) The front is evenly mounted, left to right, from center. The rear is offset by "X" inches, to the right/outside, but straight. Is this yaw?

2) Same front end as #1. The rear is centered but turned. This is rear-steer, but is it yaw?

3) Both front and rear are centered, the body is mounted "crooked". Is this yaw?

Well kinda.

Let's take the body off/out of the equasion.

It's really hard to do that, because in the discussion of yaw,
and the COT, it is all about the body and getting it as skewed as possible
to the direction of travel..

It's really hard to do that, because in the discussion of yaw,
and the COT, it is all about the body and getting it as skewed as possible
to the direction of travel..

Gotcha.

john here is what you said.

"So here is what we noticed at the bench. There was right rear steer dialed in. Let me discuss this just a bit. When a car reaches a steady state in a corner and is drifting there is a certain slip angle that is developed by the right rear tire. The tire aims slightly inward of the actual path. Increasing this slip angle with rear toe in (like almost every other race car in the universe) or left rear steer (like my oval car) increases rear grip and does wonders to correct corner exit ovesteer. Most of the cornering effort is at the right rear since it is loaded up. The reason for corner exit improvement with left rear steer is as the rear steers left the car goes right on corner exit. Just where you want it to go toward the outside board.

Adding right rear steer does just the opposite, it decreases the slip angle, the rear is loser; in addition, though, on corner exit, the rear steers right the car goes left right into the center board with a big hook. A couple of our guys went to the carpet nats. They could not find a soul using right rear steer. So maybe it's just a phase oval went through. We took out the right rear steer"


i gotta tell you on alot of tracks right rear steer is a noce option to have...and on carpet tracks even more so.

the information you are providing is for a track with 0 bite in it..now it's all good to pass along info about your track and what it takes to get the car around your track..

but alot of your info is misleading the rest of the country...

you also said

" have not seen an oval chassis that allows a left rear steer adjustment, but I have seen plenty where the front wheels can move in or out on the chassis. Try moving the right side out left side in to experiment with some left rear steer. The body will have to be reset eventually. Give us a report. Use this to cure some residual corner exit hooking you may have. The less of this problem you have the more throttle you can use on corner exit"
John

you won't see any oval cars worth a damn with left rear steer options because most tracks we use our oval cars on have bite in them...

we spend time freeing up our cars...you spend every waking hour trying to find bite..

but you act as if every track in the usa is low bite like yours?

honestly if i had to take my oval car that someone spent hours upon hours figuring out how to make a good kit and than butcher it up like your i would fly helicopters instead! some surfaces best used for parking cars on than racing them.

think about it...you made frankenstein to run on that surface..the other poor guys have normal oval chassis and you put 5 laps up on them? this sounds like alot of fun to me?


buy some carpet and put it down on that bannana peel track you got and have fun racing the other guys..not having fun putting F1 technology on you car..