4 bar rearend trail

[stock car driver]

Duhhhhh....In school, did you fail reading comprehension? See post 10 above!

post 10 says nothing except that positive caster increases the wheelbase which is incorrect...

Ill block your dum as new user name your not even a racer you should stick to the tailgate where you can be around like minded dumbies instead of actual racers who know something.

[JustAddDirt]

Whomever that engineer was I am sure he is not employed in racing now, or someone finally told him he is doing it all backwards.
Not trying to start a pissing contest here, but I have been setting and trying stuff on dirt cars for 25 years, and have a pretty good track record at it.
Plus asphalt stuff, I would bet would not want much of any castor in the RF on backstreer, because how much do they backsteer, and need the jacking effect it provides?

[25jrjr]

Whomever that engineer was I am sure he is not employed in racing now, or someone finally told him he is doing it all backwards.
Not trying to start a pissing contest here, but I have been setting and trying stuff on dirt cars for 25 years, and have a pretty good track record at it.
Plus asphalt stuff, I would bet would not want much of any castor in the RF on backstreer, because how much do they backsteer, and need the jacking effect it provides?

His name was Ray Stonkus. In his latter years, he crew chiefed for Rick Crawford. Before that, he won a ton of races in asphalt late models. Pretty sure, he knows his stuff.

http://racing-reference.info/crewchiefs/Ray_Stonkus

[25jrjr]

post 10 says nothing except that positive caster increases the wheelbase which is incorrect...

Ill block your dum as new user name your not even a racer you should stick to the tailgate where you can be around like minded dumbies instead of actual racers who know something.

Please do.....as the only positive thing you add to a discussion is......NOTHING!

Why haven't you ever been banned? 4m minds want to know!

[junebug]

Hey racer22 if u can just call the chassis builder or anyone else u know with same type of chassis as u...they should have refence points for checking trail...when the cars on the jig is the easiest time to have everything square and they usually have a place to measure it from set up when ever they build it....i kniw u said ur new to modifieds and some of these other ways described are pretty complicated for a new racer

[25jrjr]

Refer to the caster section at the bottom of the page. I would like to hear an explanation how positive caster doesn't lengthen wheelbase.

http://www.car-engineer.com/suspension-design-definitions-and-effects-on-vehicle-behavior/

[rsawyers9]

On a dirt modified, you cannot adjust the lower control arm. So to increase positive caster, you have to adjust the upper balljoint toward the rear of the car, effectively shortening the wheelbase by a small amount.

[25jrjr]

On a dirt modified, you cannot adjust the lower control arm. So to increase positive caster, you have to adjust the upper balljoint toward the rear of the car, effectively shortening the wheelbase by a small amount.

Since the upper and lower balljoints are connected by the spindle, if you tip the top back how can the bottom not move forward a slight amount.

What about Ford style lowers?

[JustAddDirt]

25jrjr
that link you posted, in the diagram, you need to look at which way forward is ( it is listed in black to the left of the illustration). I think you are confused.

also read what you posted above., and think about it. the spindle is 2-3" above the centerline of ball joint, so if you move the upper ball joint rearward the spindle snout goes back as well (shortening wheelbase). If the lower a arm never moves, how can anything tip forward?



I work with SAI (Steering Axis Inclination) angles daily, and build the computer software that calculates it if you vehicle has been in a collision.
I know what I am talking about here.

[RDBracer]

positive caster moves spindle back this is true but the contact patch of the tire moves forward since the piviting point is the lower ball joint.

[25jrjr]

positive caster moves spindle back this is true but the contact patch of the tire moves forward since the piviting point is the lower ball joint.

yep, always been my thinking too!

[dave41]

what is truth

haha, positive caster makes the wheel base shorter.

your way of checking each side is a complete waste of time, all your measuring is the wheel base you can do that wheel to wheel with a tape measure, that side to side measurement has nothing to do with a rearend and lead or trail.

if you are on here I don't see your post

[JustAddDirt]

no, still wrong

no, the tire contact patch is directly under spindle pin, but the steering axis moves forward of tire contact patch, as positive castor is increased.

[25jrjr]

no, the tire contact patch is directly under spindle pin, but the steering axis moves forward of tire contact patch, as positive castor is increased.

Can you post a diagram? Im from Missouri!

[billetbirdcage]

Can you post a diagram? Im from Missouri!