automotive engineering professor Chris Birdsong; excellent seminar. one of the best explanations on front end geometry i"ve heard in a long time. you"ve explained what, why and proved your statements. please keep the videos comming
Chris,This is what racing is all about fixing bad designs on old cars and make them work. I guess you got tired of sheet metal work(you made it look too easy,that’s how good you are)Nice video
Appreciate you De-BSing aftermarket parts for our mopars. In the Mopar Performance Oval track books I have it says to put shims inbetween the steering box in the K member to raise or lower the pitman arm to match the height of the idler arm
Chris, thanks for bringing your wealth of racing geometry knowledge to the masses. Thats why this channel kicks ass. I also dont know how you guys live with that heat. Stay frosty dude.
A great explanation of an often overlooked science. I was exposed to "BUMP STEER" when we started to mess with the solid axels back in the flathead days. About the time we stated splitting the axel in half to make an "independent suspension". Really started to be sort of around when we began using 55 Chevy front clips. Your explanation was spot on. Many thanks.
thanks for the education makes me wonder what my stuff has for bumpsteer I know one of my cars was pretty bad so the idler pitman being changed was probably why that suddenly got bad
Here in Australia we are RHD and the mopar steering is good as the idler arm and steering box are mounted directly off the chassis rails. This keeps the pivot points almost over the top of the torsion bars or lower inner bushings We have A B and C bodies in RHD
If you hooked that rig up to my '83 Dodge D150, that gauge would read "Yes". Factory manual steering slant 6 / 4 speed A-833 short bed, I swapped in a 318. Gutless as the day is long but she's a fun old rig to drive.
Love the content! Trying to get my 68 dart w/ smallblock to handle tighter on street and future autox events. Drop balljoint brackets and tweaking the TRE angles like you have plus adjustable UCA should get me decent area? 🤔
I found in road racing that a little toe in on full bump keeps the car tracking straight when braking hard for a corner. Once you get back hard on the throttle and the inner wheel goes into droop it will toe out and give you ackerman and help the car turn. The stiffness of your sway bar will determine how much.
Thanks for putting out these videos and helping the average joe get the most out of their Mopar. What alignment specs do you shoot for when setting up for street/autocross?
With a Longacre gauge, I measured 0.082" toe out with 3" in bump/compression from static ride height in my particular 68 A-body w/'73 spool K-frame. Then, 0.114" toe-in with 3" jounce/extension from static ride height. I needed to take out shims to improve, but it already had no shims. So I'm sorta stuck, unless I start bending and welding stuff. Just my car, most every setup is different.
@@junkerup Is 3" up and 3" down from static overkill on range? Some other range more practical? My measurements are with a Heim tie rod setup. *Also check out my post on your other LBJ extension video for fitment applications.
There is a popular idea of using a 1973 and newer disc brake spindle for an easy disc brake conversion on 1972 and older B-bodies. The only thing is the 1973 and newer spindle is about 3/8 inch to 1 inch taller than the 1972 and older spindle, would this mean in increase in bump steer for a street driver? It would be convenient to use disc brakes off of FMJR bodies on older B-bodies but not if driveability becomes noticeably worst.
Not trying to argue, just clarify I guess. How do you figure toe out under compression causes oversteer and toe in causes understeer? I can see the toe in I guess, by adding steering input while at the limit it's over using available grip, but I don't see any way the car towing out would cause oversteer. It reduces steering angle for sure but it's not affecting the rear. I have fully custom built control arms, roll center correction and steering angle/ratio increase I built on my Mercedes drift car so I'm pretty well versed in suspension geometry but always open and eager to learn more. I just made my first finals and lost(tires went away in the last round😔)against some catalog built drift cars in my one of one Mercedes, so I'm pretty proud of that. The car has been evolving for quite a few years as I learn and become more experienced fabricator and machinist as well as my drift experience growing.
@@junkerup ok. That's not oversteer though. Really if the car is loose in the rear the toe in under compression will cause oversteer. Bump steer sucks all around! Nice to see someone who has a grasp on suspension geometry messing with junk that shouldn't do what it does. There's actually a couple guys that drift b-bodys near me. I'm not sure what they have done in the front though to be honest.
Chris, do you have any experience with the B-body geometry when Mopar quick-ratio pitman and idler arms are installed? As I recall, the longer arms raise the drag link higher than the standard idlers, but I assume the extra length means the larger radius sweep as the arms spin may contribute to more aggressive droop from center to lock, and thus might benefit the geometry of the tie rod assembly only over a limited degree of steering input. I'm curious if you've had any experience with these that you may be able to share. For reference, I'm running FMJ spindles/knuckles, so while I am gaining a bit of height on the UCA (which are +1.5 FFI tubulars), I'm limited at what I can do with the steering arm height (obviously, I can't benefit from your kit as I'm not running drum spindles).
@@junkerup Good to know. Thanks for being the absolute guru on this; trying to learn front end geometry _starting_ with a B-body is NOT a good idea without the right tutor, but your videos have been absolutely phenomenal. Thanks a million!
if they only put the steering in front of the lower control arm at the same points. then this problem would not exist and the oil problem would be gone on top
A man full of knowledge is a man worth watching. You're a legend Chris. I'd love to turn spanners with you.
automotive engineering professor Chris Birdsong; excellent seminar. one of the best explanations on front end geometry i"ve heard in a long time. you"ve explained what, why and proved your statements. please keep the videos comming
I always remember a scene from original Vanishing Point where Kowalski drives over several bumps and Challenger front wheel flops around...
Chris,This is what racing is all about fixing bad designs on old cars and make them work. I guess you got tired of sheet metal work(you made it look too easy,that’s how good you are)Nice video
Appreciate you De-BSing aftermarket parts for our mopars. In the Mopar Performance Oval track books I have it says to put shims inbetween the steering box in the K member to raise or lower the pitman arm to match the height of the idler arm
Thats interesting one 🤔
Chris, thanks for bringing your wealth of racing geometry knowledge to the masses. Thats why this channel kicks ass. I also dont know how you guys live with that heat. Stay frosty dude.
A great explanation of an often overlooked science. I was exposed to "BUMP STEER" when we started to mess with the solid axels back in the flathead days. About the time we stated splitting the axel in half to make an "independent suspension". Really started to be sort of around when we began using 55 Chevy front clips. Your explanation was spot on. Many thanks.
thanks for the education makes me wonder what my stuff has for bumpsteer I know one of my cars was pretty bad so the idler pitman being changed was probably why that suddenly got bad
Here in Australia we are RHD and the mopar steering is good as the idler arm and steering box are mounted directly off the chassis rails.
This keeps the pivot points almost over the top of the torsion bars or lower inner bushings
We have A B and C bodies in RHD
If you hooked that rig up to my '83 Dodge D150, that gauge would read "Yes". Factory manual steering slant 6 / 4 speed A-833 short bed, I swapped in a 318. Gutless as the day is long but she's a fun old rig to drive.
Thank you for the teaching moment Chris!
Chris your the only u tuber that's giving out great information!
Really nice and simple explanations. Cheers
We need a course on Ackerman!
Yeee Yeee ! ,,,,,love this channel thank you Chris for all the great content, Yeee Yeee!!!👍
Super interesting!
I got a lil duster, im always after the handling!!
Im gunna have to watch more of your videos
Love the content! Trying to get my 68 dart w/ smallblock to handle tighter on street and future autox events. Drop balljoint brackets and tweaking the TRE angles like you have plus adjustable UCA should get me decent area? 🤔
I found in road racing that a little toe in on full bump keeps the car tracking straight when braking hard for a corner. Once you get back hard on the throttle and the inner wheel goes into droop it will toe out and give you ackerman and help the car turn. The stiffness of your sway bar will determine how much.
Great video Chris,I see lots of fab going on in the back ground . Can you get us up to speed on what you are up to 👍. All the best Danny UK 🇬🇧
Thanks for putting out these videos and helping the average joe get the most out of their Mopar. What alignment specs do you shoot for when setting up for street/autocross?
Ackerman!!! Angelo did a pretty good explainer during his drift Cuda build. But of course, he used a Mustang II rack and a custom Flaming River rack.
Chris, this was very entertaining lesson I must say.
Will you show the tweaking of the pitman in an upcoming video?
With a Longacre gauge, I measured 0.082" toe out with 3" in bump/compression from static ride height in my particular 68 A-body w/'73 spool K-frame. Then, 0.114" toe-in with 3" jounce/extension from static ride height. I needed to take out shims to improve, but it already had no shims. So I'm sorta stuck, unless I start bending and welding stuff. Just my car, most every setup is different.
That’s not bad, but yeah every car is different due to aftermarket world these days
@@junkerup Is 3" up and 3" down from static overkill on range?
Some other range more practical?
My measurements are with a Heim tie rod setup.
*Also check out my post on your other LBJ extension video for fitment applications.
Preach it...
Great explanation! Which bump steer kit fits the mopar steering arm?
Will you do a rear setup to 👍
There is a popular idea of using a 1973 and newer disc brake spindle for an easy disc brake conversion on 1972 and older B-bodies. The only thing is the 1973 and newer spindle is about 3/8 inch to 1 inch taller than the 1972 and older spindle, would this mean in increase in bump steer for a street driver? It would be convenient to use disc brakes off of FMJR bodies on older B-bodies but not if driveability becomes noticeably worst.
It's not 3/8" to 1" taller. It's about 3/8". It doesn't change. It's not that drastic.
I wonder what led them to design such a wonky geometry. The 70s was more than 50 years ago but there were cars that handled decent
Need to fire your dry waller Darin garle darn it😊
👍🏻👍🏻
👍💪 Excellent!!!
Not trying to argue, just clarify I guess. How do you figure toe out under compression causes oversteer and toe in causes understeer? I can see the toe in I guess, by adding steering input while at the limit it's over using available grip, but I don't see any way the car towing out would cause oversteer. It reduces steering angle for sure but it's not affecting the rear. I have fully custom built control arms, roll center correction and steering angle/ratio increase I built on my Mercedes drift car so I'm pretty well versed in suspension geometry but always open and eager to learn more. I just made my first finals and lost(tires went away in the last round😔)against some catalog built drift cars in my one of one Mercedes, so I'm pretty proud of that. The car has been evolving for quite a few years as I learn and become more experienced fabricator and machinist as well as my drift experience growing.
It makes the car darty, which ever tire has the more load is going to dart that direction
@@junkerup ok. That's not oversteer though. Really if the car is loose in the rear the toe in under compression will cause oversteer. Bump steer sucks all around! Nice to see someone who has a grasp on suspension geometry messing with junk that shouldn't do what it does. There's actually a couple guys that drift b-bodys near me. I'm not sure what they have done in the front though to be honest.
Good times 🎉 not too sure about a butt welded tie rod but you said it was just for mock up. If you welded a sleeve over it might be legit?
👍
What's up Chris! It's Anthony in Fort Lauderdale. Do you still have the 68 Charger?
Chris, do you have any experience with the B-body geometry when Mopar quick-ratio pitman and idler arms are installed? As I recall, the longer arms raise the drag link higher than the standard idlers, but I assume the extra length means the larger radius sweep as the arms spin may contribute to more aggressive droop from center to lock, and thus might benefit the geometry of the tie rod assembly only over a limited degree of steering input.
I'm curious if you've had any experience with these that you may be able to share. For reference, I'm running FMJ spindles/knuckles, so while I am gaining a bit of height on the UCA (which are +1.5 FFI tubulars), I'm limited at what I can do with the steering arm height (obviously, I can't benefit from your kit as I'm not running drum spindles).
I do know the longer pitman and idler have better bumpsteer but I haven’t checked the Ackerman on that
@@junkerup Good to know. Thanks for being the absolute guru on this; trying to learn front end geometry _starting_ with a B-body is NOT a good idea without the right tutor, but your videos have been absolutely phenomenal. Thanks a million!
Got a bump steer gauge that you would recommend?
Where did you buy those bumpsteer tire rods? I cant find them anywhere for a Mopar.
Gregpolhnas
🦅🇺🇸💪😎👍
would like to see the chevelle run again
It did…not good
if they only put the steering in front of the lower control arm at the same points. then this problem would not exist and the oil problem would be gone on top
Will your lowering brackets work on a 73 b_body
I don’t believe so
Thanks but boreing lve heard the word bump or bumpsteer enough for a while
UHHH ????
Uhhh what
@@junkerup my head hurts
The 1965 and 66 chevy impalas were just as bad.