Front Suspension Geometry| Ep.5 KPI & Scrub Radius. Explained
HTML-код
- Опубликовано: 18 фев 2021
- Episode 5 we talk about KPI (KingPin Inclination) and Scrub Radius. These two features of your front suspension go hand in hand. We show that when certain changes are made, how it effects your kpi and scrub radius and how they should relatively be set. Let us know in the comments any specific topics you would like us to touch on in future episodes.
Socials:
IG: fdf_fab
Facebook: FDF- Fallaise Design & Fabrication
Website: fdfraceshop.com 
Авто/Мото
It'd be so cool to see a CAD assembly of the front suspension. Then you could graph the camber curve isolating variables one at a time, also simulating ride height and how it affects the dynamics when its going through its full suspension travel (then you could also get into spring rates and dampening). Love the videos man!
This was a perfect visual demonstration for us people that understand things better by seeing.👍
Such a great video!!!
Great videos, very informative and the jig makes it a lot easier to understand. Thanks for doing this
Thanks for sharing knowledge with us. Great as always 👌👍👏🙌
3 years ago...900 subs - I remember those times 😅 Mindblowing how you growth in yt too..I backed to these video due to the newest vid about E36 knuckle. Could you refresh my/our point of view on the setting in case of this vid? here you are talking about lowest possible changes thru motion range, but I have a feeling watching wagon drifting, that you are generating a lot of jacking nowadays. How it is achived in newest kit? KPI is still low or, scrub low but more caster? Japanese drifters still have (from old school) the tendence to throw 50mm spacer on the fronts, which doesn't 'match" with the negatives from this vid :D Will be thankfull for the answer!
Going to do an experiment on the rear of my fiero sense it uses a front suspension flipped 180 as the rear maybe extending the upper mount outward may reduce some of the rear tire movement that causes the bump steer idk just a guess if you see any red flags in this thought please do tell
Is a positive 6mm offset or a -4 mm offset ok? Those are the two options that I'm seeing with my new potential setup.
Hey Josiah, I have a question regarding scrub radius. All other settings being equal is running a +35 offset wheel with 20mm spacers the same as running a +15 offset wheel without spacer when it comes to scrub radius? I assume regardless of how you make the wheel poke out, with spacers or with low offset, it has the same scrub radius?
Masters in motor mechanics 💯💥💥💥💥💥💥💥👏👏👏👏👏👏👏👏👏😘😘😘
SALUTE YOUR HARD WORK SIR HIGHLY INTELLIGENT INTERESTING INTELLECTUALS PERSON 💯💥💥💥💥💥💥💥💥👏👏👏👏👏👏👏😘VERY WELL EXPLAINED 😘
Would i be right i saying that kpi turns in to caster at lock and this is why some people describe cars with high camber and low caster as flopping to angle?
Great vids man I’m adhd a fuk did you say if zero scrub or inside or outside was better?
So in my understanding the lead tire must be flat for full grip is that how it works ?
Do rear suspension next! Explain everything about the 350z rear grip kit!
They have a video on it already.
@@LycheeMonstaMedia thanks. I've seen the 1 minute one they put up, but looking for a more detailed explanation like what he is doing on the front suspension. For example- Why would we want dynamic toe in instead of just static toe in (I would think static toe in with less squat would be more consistent but a lot of people do the opposite). How does the 25mm roll center correction change car handling if we keep the same ride height as before we install the kit? How does toe in affect forward bite vs side bite in drift(does it equally add both or only forward bite?). Plus I'm sure there's a bunch if other info he could pass on for us of those that are interested in the advanced side rather than just the basics of what it does. Trying to decide between just bushings vs a grip kit.
Are you guys going to talk about recommend front suspension setups for various cars?
They are talking about car suspension geometry and how it affects handling, not recomended setups
@@chomin3025 I'm aware I've watched all of the other videos lol. I'm curious if they are going to go through recommend setups for various chassis.
@@e30gangsta I would like to do so
@@chomin3025 sounds awesome thank you!
This video is amazing. Can you explain bump steer on a mcpherson suspension? and how to correct it?
When you're lowering your car the steering arm will be on an angle. Preferably you want the steering arm horizontal so when the wheel travels the angle won't be that big. When there is a angle, the distance will be smaller like Pythagoras many years discovered. I've lowered my cars too, but lowering give more body roll that needs to be compensated by stiffer springs and sometimes bump steer.
It's easier to follow when I make a drawing.
So a deep dish wheel up front would increase scrub radius and give undesirable pull while in drift?
Wellllll... assuming that dished wheel's tire would sit "further out" than whatever you run now: Yes, as far as more scrub radius is concerned. Whether that's undesirable or not, depends on a lot of factors, including your personal preferences :)
I’m not sure this will get answered because of the age of the video but I hope it does. You said that keeping KPI, Castor, Ackerman and Scrub low is beneficial to keep change at 70 degrees minimal but you also said low KPI means a higher scrub radius. How do we counteract this would it be by running a more positive offset wheel etc. to reduce that scrub radius and get it closer to intersecting with the KPI angle at the ground??
The example he showed as low kpi was almost 0°, he is showing the extremes that are realistically not achievable because it shows a visual effect on his display if it only changed something a few fractions of an inch you wouldn’t even be able to tell as a viewer watching this (not everyone’s an engineer) it’s more to explain the basics so you can be more educated on what parts you get to set up your car for example not putting -40 offset hot boy wheels on with -8 camber and wondering why the car isn’t a dream to drive. You are correct with low kpi a positive offset wheel will help minimize the scrub but you’ll still have limitations what wheels are available and how much room you have before you’re wheel contacts the frame or control arm etc so keep that in mind. There also isn’t a end all be all perfect set up some drivers like other things which is also why he explains the characteristics of each setting. I’m sure if you email them directly they can provide a more accurate information for the exact car you have or want to set up on what values are stock and achievable with their kit
@@zackdoubleZ I appreciate the reply man, I do understand the exaggerated way this is set out I more just wanted to know if my thinking was correct. Unfortunately there’s never a perfect setting is there haha. I am currently designing an angle kit for an Aussie car to sell to people and want to make it as good out of the box as possible and make sure I understand and know what I’m talking about when potential customers come asking me why theirs doesn’t handle like my car and things they may be doing wrong. Thankyou for confirming what I originally thought in my head man.
@@dalesaward1227 no problem I have built a few kits myself and as the years go on there’s more information to learn it seems, I build some lcas and working on some other parts for f body Camaros just cut and welded knuckles but tubular arms with heims/uniballs and on car caster adjustable working on some brackets to bolt on instead of cutting and welding the knuckles to be more adjustable and save needing cores and shipping. I’m the same way been testing for over a year to be able to provide the best information I can about setting up the car with the kit shocks springs wheel offsets alignment everything I can do to help
1:09 High offset and low offset should be flipped, right?
It's one of those things, depends on how you look at it. A lower offset wheel has the mounting face further inward. And a higher offset has the mounting face further outward, (assuming the tire is on the same position on both) so visually that's what I was thinking but I can see how you thought it was backwards, I apologize for that haha.
@@FDFraceshop perfect response thank you!
With hunter equipment how to get kpi or sai only
On the measure caster page, select SAI /IA only, follow on screen prompts