Bump Steer - How does it work?

Today, I explain bump steer, what it is, what causes it, and what it does. With that explained, I talk about how we can use bump steer for benefit, and how it works in off road scenarios. And now you know how bump steer works!

[@Leo9ine]

A good camera, a good mic, a big whiteboard with tons of natural light, complex ideas in simple terms - man you've got all the parts of an excellent KZbin channel. Very professional and polished right from the start. Reminds me of Engineering Explained with better lighting and less frantic rushing. Hope to see you get famous mate!

[@PyleHD]

Yup he is great, much better than EE, but one complain I can say about both of them is the drawings. Jesus Christ they really should put a little bit more effort into making the drawings look at least a little bit better, it really isn't that hard.

[@harrypar1]

I think you should put some effort into your imagination! you can do it, it really isn't that bad! : )

[@colinellis460]

Instablaster.

[@ookiichinko]

Dude, you have to come back. You explain things so well.

[@AdelaideBikeFreeway]

Hey great articles Kyle. I was once a top level race-car engineer and you'er bang on the money. Bump steer is a critical element in car dynamics. It's also not well understood in racing circles believe it or not. The reason why i chime in here is> Importantly with bump steer on the rear. Make sure it's zero or toes in slightly on bump. Toe out is diabolical. Trust me, I've been there many times on different cars and it was always a disaster. PS: Also little known. Beam axles/live axles also have bump steer, mainly in roll.

[@hotrodray6802]

Rear steer is grossly not understood.

[@ayushraj6170]

Probably the best video on bump steer i ve found so far. Too good man!

[@Stephenc4877]

Very help fully in the process of a retro mod on my pulsar gtir track car after Rodney started knocking at the door 🥺. Finding your knowledge invaluable and I’m very great full you share it Kyle. Thank you.

[@Got09Z]

Nice explanation. Straight forward and no crap included. Thanks!!

[@andrewwithers6627]

Watched your video forever ago, and just found it again. I believe the steering system from your Hilux is what's called Pittman arm steering. It's used mainly on trucks with lots of suspension travel

[@treadhead7651]

very good, non complex explanation. thanks.

[@theshed8750]

Really good explanation

[@jin5632]

Thank you. That was really helpful. But as a consequence, does bump steer cause wheel misalignment ?

[@sampathkumar5956]

Can u please make a video on how steering setup should be made for drifting..

[@Taurus1822]

Hi, do you think that fitting a steering rack on each end of the steering axis would help eliminate bump steer (one cancelling the other one), or would it just bind and cause problems?

[@TediI47]

your wheel drawing could be better, but i respected your splitsecond Lego flex thanks for the clear explanation!

[@anthonysmith8900]

Does lowering your car cause bump steering? Do I need extended control arms. I feel like I don't have control of my car anymore and I have to turn the steering wheel too much before it turns.

[@Kalimerakis]

A topic that has been on my mind for a while: Brake fans. Like on porsche 935s for example. I can't quite figure out how they work. Do they just scoop in air, or do they use centrifugal force to push out hot air? Maybe some inspiration for a future video. Thanks for the content!

[@marchh6501]

very nice explained , also fast and to the point , at 9.30 i would like to ad something ,( and i am talking racecars now), in a corner when a chassis rolls , we speak of roll steer, in a racecar the akkerman princ. is not (so) important(a lot of racecars are made to "over akkerman") since the insidewheel does not carry a lot of load , its the outside wheel that matters ! , so when a driver gives a certain steering wheel inputthe car will roll , if the wheel would Toe In under roll the driver has to turn the steering wheel back a little , otherwise the car will turn a smaller radius than the driver intended , That feels very odd and unstable for the racedriver (and car)!!toe out under roll makes that the driver has to turn the steering wheel a little bit further into the corner , and Thats much muchnicer to drive i.ow the driver feels much more confident in the corner > faster lap times ,

[@jutny]

Could you use these bump steer principles to effectively create some sort of variable ackerman, if not a perfect application maybe something? (I'm at 3:36 and this sprung to mind) I just came from the ackerman video, after the tire video. First time watching your stuff and absolutely a new subscriber. You explain things the exact way I understand them. Oh btw you were talking about a recirculating ball steering box with pitman arm, drag link, and idler arm. edit: yup :) :) :)

[@rcbuggies57]

Don't bellcranks negate the effect, if they swing parallel to the inner hinge pins?

[@daverosgarrett8040]

You could be thinking of the 'parallelogram'/'trapezium' steering design for the Hilux example.

[@karansharma3162]

sir can u plz explain how castor angle leads to change in camber while turning

[@babarjaggo]

Hi Kyle, I have 2007 camry. The car slightly pulls to the left when my hand not holding the steering wheel. The steering plays (pulls randomly right or left) on rough road and pulls more on when the road is banking. I had the vehicle checked several times at the dealer and wheel alignment shop they said nothing wrong with the alignment and suspension condition is good except the left strut. The left strut can't return after compressed. Is it possible that this be the cause of left pull and steering bump?

[@noncog1]

Watt's link on steering arms? feasible? First problem would be applying force with arms that give, but maybe a modified version on an altered axis?

[@KYLEENGINEERS]

Now uploaded in 50fps, can you tell the difference? Plot twist: still filmed in 25fps =P

[@Bullshit_Media]

Nope xD

[@frankfitzpatrick5300]

Can you explain bunp steer on a 4 wheel independent UNEQUAL A-ARM suspension system ?

[@tapanmehta7924]

won't this bump setting harm the steering rack & pinion?

[@adamniven]

If I may make a suggestion, although your whiteboard sketches are good, I would have an easier time understanding the information if you used dynamic (but simple) computer generated graphics to better demonstrate the various scenarios you cover for each topic. I often need to watch your videos multiple times to fully grasp the concept. Not a criticism on your videos so much as a statement of my limited intelect... Your videos are very informative, keep them coming! 👍

[@ironhead65]

+KYLE.DRIVES does this have the same drastic effect on something like an original VW Bug? Their front suspension was more a drag link style vs. A-Arm or McPherson strut. Looking at making a large-ish off-road Go-Kart and was thinking double A-Arms would be too difficult and a McPherson might be too costly. The VW front end looked like an interesting thing to work out a design for.

[@antoniskaloterakis7996]

Great explanation As i think of it isnt kingpin inclination produces bump steer ?

[@hotrodray6802]

Scrub radius balance between hitting a bump jerking and tire rolling vs tread squirm when steering. There is a mouthful.😨

[@stevenolson95]

Cool! you should model some things in cad just like to were talking about in the video. I think it would be really interesting!

[@KYLEENGINEERS]

+Steven Olson Oh, I have plenty of geometries modeled from various racecars I have designed or worked on over the years, the question is if I should show you guys or let you try it out for yourselves... ;)

[@stevenolson95]

+KYLE.DRIVES I think it would be pretty hard to get people to try on their own unless they were SERIOUSLY interested. I've played around with a little bit of AutoCAD and gotten more into depth with Autodesk Inventor. thing is I wouldn't really know where to start, or more importantly what program to use. I think I could make something work though in Inventor (booting it up right now!)

[@KYLEENGINEERS]

You sound like you are pretty seriously interested then! Tell you what, I'll make you a deal, this video hits 5k views, I'll make a vid on how to do it in CAD, I'll even throw in calculating driveshaft plunge in CAD for free!

[@cptinsano43]

+KYLE.DRIVES that sounds like pretty sweet deal.

[@artemtsvetkov3655]

+KYLE.DRIVES that would be awesome!

[@richardwallinger1683]

hi as a 1980 Donnington championship gt winner and Cadwell park outright lap record holder I am up to speed on bump steer . but now at 75 years old I am resetting the rear toe in and the front tracking on my 2007 Citroen C6 saloon car .which was all over the place . Amazingly my son drove it 1500 mil;es from the UK to Portugal and he claimed it drove very well. MMMM impossible to say because my first drive in this lovely looking car. the hydraulic suspension refused to raise up to normal . and it was a disaster, Now 5 months later and I have rebuilt the poorly unloved C6 and setting up the tracking . Unfortunately the tracking wanders quite wildly with the car at differing ride heights . My next attempt is to set the tracking at normal height and chec what the bump steer is doing at various suspension travel settings .

[@Flowermouth]

Hope you are well mate

[@karthikgovil7219]

What is the name of that steering system mentioned at @5:45

[@michaelratcliff4440]

I want to say he’s talking about swing steering in that small example.

[@ayushshrivastav2993]

sir can uh please tell me how i can calculate tie rod length form Ackerman geometry

[@extendedanthamma5687]

Ayush Shrivastav if you design to avoid bump steer in lotus shark, u'll get the coordinates of inner and outer ball joints of tie rod,

[@Sebastianrogersmusic]

Can you help me.. I just installed a rear camber kit on my 2012 honda accord hfp. The rear tires were out -3 degrees the camber kit corrected this issue on the alignment. Its now 0 degrees but now when i go over a bump im getting bump steer and i never had this problem before. The kit also had a front ball joint kit which wasnt installed. Will that kit correct this issue? Also i was reading that if you just angle the rear tires -1 degree it will fix bump steer. Your thoughts or suggestions?

[@BrodeyDoverosx]

Sebastian Rogers camber doesn't effect bump steer. The ball joint in your kit will help a lot.

[@Sebastianrogersmusic]

well how come when I put the rear camber kit in... all of a sudden I have bump steer?

[@juanjoqwer]

Cortate un poco los bigotes de las axilas hermano!!! jajaja.... muy buenos los videos. Excelentes.

[@beri232]

My truck tends to wander when hooked up to my travel trailer and is difficult to keep in a straight line... especially at highway speeds. This all started after I installed a Bilstein levelling kit. I’ve had it into 2 Ford dealerships and they have not been able to fix it. They just keep throwing parts at it

[@charlesnash4809]

Maybe borrow a similar trailer and see if the problem remains or improves as a starting point. It may be better to look at the trailer's tracking.

[@jasonboggs5454]

Recirculating ball steering is not sloppy it is only sloppy when its worn out I have both types of steering and if you can tell which steering is in the car I would be very surprised also the steering box car steers quicker...!

[@Bullshit_Media]

I got a solution: Just remove springs and dampers and hardmount them or what its called, no bumpsteer ;) xD

[@dethkon2284]

what if the control arms where the thing turning? what then?

[@phmaximus]

live axles are the worst..... I like what the monster truck guys do with the axle mounted racks, but,,, there will always be that little bit bump steer in the suspension

[@MIGuy]

FUTURE ... hydraulic computer controlled steering servo on each wheel mapped for each track.

[@anime5h_m1shr4]

5:44 Pitman Arm?

[@faisal3398]

Recirculating ball, comes on rangers, hilux, navara etc...

[@chengong388]

Why can’t we just have four vertical tubes fixed to the chassis, and then have wheels mounted to pistons that go in the tube? All wheels stay perfectly aligned all the time.

[@travisharrington9857]

You are forgetting the height of the rack. No one ever talks about that

[@flamingronin]

Converting 25fps to 50fps makes it smooth like diarrhoea. Just film it with your GoPro mounted to your head so you can get 60fps.

[@AR-hj8xi]

liar

[@flamingronin]

+Adnan Rahman I don't know what you're taking about. I've never lied about anything in my life.

[@AR-hj8xi]

+Daniel Luong this is the second vid of kyles that ive seen u comment on.

[@flamingronin]

+Adnan Rahman What are you talking about? I haven't commented on this video. You must be delusional.

[@gadgetdeez7069]

Ackerman (Rack mounted forward or backward) has 0 to do with bumpsteer. Ackerman is a longitudinal dynamic, not a vertical/bump dynamic. FAKE NEWS!

[@hotrodray6802]

Seriously reconsider your observation during suspension travel with steering input.

[@pranavnaiknaware7814]

dude.... why you dont shave ur underarms?? .....overall is a well performance bro...

[@cliffhillquist2377]

Pranav Naiknaware What? Are you gay? What guy shaves his underarms?

[@rkgsd]

Cliff Hillquist Shaving with a razor is one thing Trimming is another. There are plenty of guys that shave underarms. Plus deodorant can't make full contact with the skin with too much hair. Commonly done by athletes and those who don't want to be a cave man like you. You sound insecure in your manhood.

[@michaelwyant3331]

I thought this comment was about lower control arms. nope. sadly disappointed by humans once again

[@cliffhillquist2377]

rkgsd. Well, I have finally concluded that since you are from that third world country (India) your ideas on personal hygiene are a moot point anyway.

[@hillarylevenworth8824]

Pranav, only women shave their underarms in Australia. What do women do with their pubic area where you live?