18 replies to this topic

[DavyLee2]

What is the advantage or desired result of a shortened wheelbase
I can only guess that it would help the car turn left ?

[dirtstudent2]

What is the advantage or desired result of a shortened wheelbase
I can only guess that it would help the car turn left ?

 

ditto again great question

 

we read on here stuff about it and a DQ, now maybe someone could explain what it is and the advantages which would warrant a DQ.

 

 

otherwise like a lot of things written on here it's all "sound and furry signifying nothing".  

[honeybadger1]

i already answered this you goons.  Bring LR forward gives you rear steer.  Also, more weight transfer to the front on decel and more weight transfer to the rear on accel.

[dirtstudent2]

Both us goons were asking about what a shortened wheelbase does not rear steer.

 

It's obvious rear steer shortens the left side wheel base.  The results you state are not obviously the result of the left side wheel base being shortened.   

Edited by dirtstudent2, 17 September 2019 - 01:51 PM.

[dirtstudent2]

"more weight transfer to the front on decel and more weight transfer to the rear on accel."

 

That's a very interesting generality about rear steer.  thanks

 

 

edit:  I think I also see rear steer occur when a car is neither accelerating nor decelerating, the driver is just sort of on it through the turn while maintaining a set speed.  With that in mind wouldn't understanding of rear steer force you to separate mechanical chassis operation because of engine output from acceleration or deceleration? 

 

Thanks for the reply you got me thinking more on it trying to bring dive and anti dive into what rear steer and jacking the chassis is doing.  Maybe we should look at the results of rear steer as altering front chassis to dive while accelerating?  Might it be a sort of diving the front towards the track under acceleration similar to dive while braking?  Sorry it's sort of hard to think about dive occuring at the front while accelerating, but maybe easier or even able to fit it in while maintaining a set speed?  Maybe making the rear steer/dive about planting the right front? 

 

... don't know but fun to think about and thinking of it more maybe what makes a great Late driver is their ability to maintain their chassis action with the right foot, while neither accelerating nor decelerating? 

Edited by dirtstudent2, 17 September 2019 - 02:29 PM.

[honeybadger1]

 

"more weight transfer to the front on decel and more weight transfer to the rear on accel."

 

That's a very interesting generality about rear steer.  thanks

 

 

edit:  I think I also see rear steer occur when a car is neither accelerating nor decelerating, the driver is just sort of on it through the turn while maintaining a set speed.  With that in mind wouldn't understanding of rear steer force you to separate mechanical chassis operation because of engine output from acceleration or deceleration? 

 

Thanks for the reply you got me thinking more on it trying to bring dive and anti dive into what rear steer and jacking the chassis is doing.  Maybe we should look at the results of rear steer as altering front chassis to dive while accelerating?  Might it be a sort of diving the front towards the track under acceleration similar to dive while braking?  Sorry it's sort of hard to think about dive occuring at the front while accelerating, but maybe easier or even able to fit it in while maintaining a set speed?  Maybe making the rear steer/dive about planting the right front? 

 

... don't know but fun to think about and thinking of it more maybe what makes a great Late driver is their ability to maintain their chassis action with the right foot, while neither accelerating nor decelerating? 

 

 

 

the weight transfer and the rear steer are independent effects of the wheel base being shortened

[dirtstudent2]

 

 

the weight transfer and the rear steer are independent effects of the wheel base being shortened

 

Thank you,

 

Though it's probably not obvious I think that's where my thinking about it and writing it down took me.

[dirtstudent2]

Is the rear steer thing strictly a driver 'feel' thing?

 

I try hard to put physical properties to it actually making the car steer and everything I look at for me doesn't fall into anything logical really steering the car.  The only 'close' I seem to be able to get to a real rear steer is how it may effect how weight is projected at and around the right front tire and in general to the right of a front roll center. 

 

I guess if it makes the driver feel like the cars turning left because of it or driving forward more to the left and adjusting you can either enhance the drivers feeling or take away from it, it has to be real.

 

A lot of driver feel things I've studied over the years turn out in my opinions to be timing changes which alter how weight is directed through a chassis.  I can't seem to even do that with rear steer and it's hurting my brain.     

 

thanks for the response, I know I'll get at least a morning or two of coffee thought out of it 

Edited by dirtstudent2, 17 September 2019 - 03:33 PM.

[modracer30]

I remember this being done in early 90s with stock cars and now it's big news.

[dirtstudent2]

Here's my explanation of what rear steer does.  You won't read or here it anywhere except from me or someone who's heard it from me.

 

Rear steer hangs the nose of the car out over the banking of the track.  From that you can look at all the other things which happen because the car is able to drive forward and around a turn with front nose weight hanging to the left over and down onto the track.

 

Do you actually get any steering of the rear to the left because of it?, I think NO.

 

Might you get steering because the rear is driving the car forward at and/or towards the left of the right front tire? I think maybe and possibly likely.

 

Can a driver feel the car being steered to the left?  From reading on here and having much discussion over it by a notable Daytona/Sebring racer and modified owner, probably yes.

 

Am I correct on any of the above, heck I don't know but I'd like to be and like to know what may or may not be correct. 

[dirtstudent2]

More on rear steer.

 

The only turning you get out of your right front tire is per the amount you can push the right front tire into the track and then and only then have the track push back at the right front tire, turning the front of the car.

 

Rear steer obviously moves the right front tire over to the left putting it more in the path of forces accelerating the car from it's rear axle.  It's obvious to me adding force to push the right front tire into the track makes it push harder into the track.  Only two results will come of it.  The first is it may cause the right front tire to slip.  If the right front tire does not it will cause the track to push back harder at it and impel more turning of the nose of the car to the left.  From that all I can muster is the end result of all the camber gain now used at the right front is not about just gaining right front grip but about gaining additional push back from the track to help turn the car and also hold the front end in.  It's obvious to me the more turn you can get out of the front end especially from the right front the better you can hold in the front end.  Get more turning up front and you can then control the direction of your acceleration without or with minimal stagger.

 

edit:  Winged sprint cars are gradually shifting more towards the same use of the right front but I doubt many see it happening and even fewer understand why..

Edited by dirtstudent2, 17 September 2019 - 05:32 PM.

[DavyLee2]

I thought rear steer was when the left rear wheel moves ahead of the right rear wheel and steers the rear end to the right or steers the rear straight while the Driver is turning left
Now if you were setting up the car for a minimum wheelbase
Why not start on the left at the minimum and then move the right side back a little
Instead of try to cheat the minimum

Edited by DavyLee2, 17 September 2019 - 08:22 PM.

[dirtstudent2]

"I thought rear steer was when the left rear wheel moves ahead of the right rear wheel and steers the rear end to the right or steers the rear straight while the Driver is turning left"

 

I enjoy thinking about how things work and writing it down.  It's fun and entertainment for me along with hoping to learn along the way.  My mind mixes a lot of things together when I do it and I enjoy trying to pick a clean path through the jumble of thoughts while writing.

 

DavyLee2 I think what you wrote is as good and accurate as anything I tried to put down into words on here. 

 

Thanks and I'll ask you and others if what you wrote is the long time accepted thing which rear steer does? 

 

What you wrote and the easy way to think about how it alters weight transfer per what honeybadger1 explained seems to fit together and make it clear.  

 

Thank you both for the fun and information.  I'm still thinking though how acceleration can/could help push the right front into the track can still be a factor. 

[dirtstudent2]

"Now if you were setting up the car for a minimum wheelbase
Why not start on the left at the minimum and then move the right side back a little
Instead of try to cheat the minimum"

 

I think the shorter wheel base on the inside thing is about it being easier to roll the inside tires through the turn when there closer together.

 

If the car wheel base is measured with the chassis resting and it meets needed length on both sides, that's good enough to pass tech.  What ever someone can figure out to make it change within the rest of the chassis rules is part of the racing game and they should be applauded for their off the track racing skills.  Making the end of the axle move and being able to control the amount of movement is no different the being able to alter how much the left front moves back when you turn left.

[dirtstudent2]

"Why not start on the left at the minimum and then move the right side back a little"

 

I missed the jist of your question in my reply above so I'll give it a guess here.

 

My guess is with the tightness of turns in general if you had a choice you'd probably shorten both sides.

[Retort]

"Why not start on the left at the minimum and then move the right side back a little"

 

I missed the jist of your question in my reply above so I'll give it a guess here.

 

My guess is with the tightness of turns in general if you had a choice you'd probably shorten both sides.

However you must keep in mind that the Tiffin valve needs readjustment or it will bump the Fostoria function. Nullifying the wheelbase quotient

[DirtxxxRacing]

However you must keep in mind that the Tiffin valve needs readjustment or it will bump the Fostoria function. Nullifying the wheelbase quotient

 

I hate it when that happens.

[dirtstudent2]

However you must keep in mind that the Tiffin valve needs readjustment or it will bump the Fostoria function. Nullifying the wheelbase quotient

 

so accurate and easy

[DavyLee2]

However you must keep in mind that the Tiffin valve needs readjustment or it will bump the Fostoria function. Nullifying the wheelbase quotient

We tried that but the tires would go flat before the end of the race
Then we heard that was cheating so we quit before we got caught !