What Causes Bump Steer And Roll Steer?

What is the difference between bump vs roll steer and what impact do these have on the handling of your vehicle?
------------------------------------
🙋‍♂️ Take $25 USD off ANY HPA course with coupon code: TH-cam25
Enroll now: hpcdmy.co/25offyt
------------------------------------
This [FREE LESSON] is just one piece of knowledge from a comprehensive wheel alignment course.
0:00 - Steering Isn't Always Consistent
0:18 - What Is 'Bump Steer?'
0:53 - McPherson Strut Suspension Example
1:42 - The Solution: Instantaneous Center
2:27 - Double Wish Bone Suspension
2:46 - Why It Occurs
3:08 - Rear Bump Steer Cause
3:33 - Beam Axle Example
4:03 - Roll Steer: Lowered Beam Axle Example
4:34 - Semi Trailing Arm Example | Bump and Roll Steer
5:12 - Just ONE Lesson From A Detailed Course
------------------------------------
👨‍🔧 Want to learn how to do your own motorsport wheel alignment? Check out the Motorsport Wheel Alignment Course now: hpcdmy.co/mswh
------------------------------------
#highperformanceacademy #racecraft #learndriveoptimise #bumpsteer #rollsteer #freelesson

[@richardlong6097]

I've seen many articles and videos on how to determine and adjust bump steer but this the first time someone explained why it happens. Knowing how to fix an issue is great but understanding why said issue is happening to begin with is critical if one wants a deeper understanding, and HPA excels at this.

[@hpa101]

Cheers Mike, we agree that understanding how things work is just as, or more important, than simply knowing a 'fix' or adjustment.
Every adjustment comes with a trade off and without having someone who knows the full picture of the setup when it comes to what adjustments affect what, you can very quickly end up down a rabbit hole making changes that seem to only make things worse or even buying parts to solve problems you don't really have!
You know all this though, and luckily Andre and the tutors are more succinct than me haha Appreciate the support and I'll make sure Andre sees your comment 😎 - Taz.

[@grahamerosewarne6656]

HPA always have such awesome content, teach you things that normal people won't give anyone. Merry Christmas to all the HPA company thanks for your great work during the year. You have taught me a lot of information technology. 💯🥳🎉🤟👏🤜🤛👏🙏👌👍☝️👋🤞🔥🤗

[@spikejones2776]

I love this channel thanks for the tuning tips HP Academy

[@bernardwarr4187]

Great video, definitely like to know more about the Mercedes 5 link rear setup

[@muhammadfahmi7960]

Love from Singapore ❤️❤️

[@dcmarvel29]

Clear explanation

[@hpa101]

Glad your enjoyed it Kaprikawn =) - Taz.

[@arrindaley3714]

I don't think I'd call semi trailing arms any more prone to toe out than many other designs, if the arm is level at normal ride height it should toe in under bump and droop. The problem is if ride height is changed away from the arm being horizontal and the wheels then aligned to straight ahead, some designs used bushes which could deform under braking loads to give a toe out condition.

[@miquelanesto1762]

We need some animation for the back like what was shown fir the front.

[@elbassaraghii5744]

No matter what the actual body of the car or frame has to be above the rods not below 👨🏾‍🦯
And 3 points from middle all 3 intersecting at same place is ideal but in theory only 2 have to intersect something like that ,,, but bump steer is not a joke it can kill someone

[@egeayvala1799]

i know what causes bump oversteer but i've never heard of this and i think i dont wanna ever expirience it i think a properly aligned car with good coilovers good dampers etc. would not have this problem-this sounds more like a design flow of a car like how big of a bump do i have to hit with a front engined car that my whole front end to steer because of it ? -okay maybe RE cars could have bump stter but like isnt it just the fact that your dampers are too stiff-
just like in the game dirt 4 the tutorial tells you
stiffer suspension increases grip and makes your car more aggressive in a corner but it can reduce your stability on un even terrain
since constantly bouncing on a rough terrain could cause the wheel to be in the air so in tha tmoment the inertia of the engine makes the tyres slip a little when getting into contact again with the ground like ? i dont know i just study physics in 6th grade and i expain it to myself in tis way

[@catshit2028]

I bet blown shocks probably have something to do with my bump steer 😭

[@hpa101]

Yeah that would do it!

[@NickGreiner1988]

Nyaaahh ya don't need to worry about that crap, who can afford to race at a level where those elements of fine tuning are gonna make a noticeable difference anyway? This channel seems to be aimed at people with millions of $$$, most people just want an old shitter to thrash round a short track, I don't enter anything that costs more than $40 entry fee

[@hpa101]

If you don't want to learn anything and the goal is to spend as little as possible to just keep a car running for the odd grasskahna every few months or so, we're not the channel for you.
If you do want to learn and work on your own car, note, Tim and Andre started with cheap cars and shoestring budgets which led them to careers in the industry, but it doesn't have to go down that path if you don't want it to either, and if you want a cheap or free hobby that won't cost you sacrifices elsewhere in life to fund you are barking up the wrong tree dude.
All that said and done, at a lower level of motorsport, 'that crap', aka your wheel alignment and tyres pressures etc are 100% where you should be looking as they will often get you the biggest gains for the least amount of outlay. People spend more on their engines and bullshit bling for their cars which moves the needle far less in many cases.
So if you don't want to worry about 'that crap', that's fine for you, but there are plenty of people out there who will, they'll enjoy doing it, and probably sail past you on the leaderboard in a comparative vehicle, again depending on how you compete referring to the paragraph above where maybe we just are not the channel for you and what you do with your car which is completely OK, there are many different levels of motorsport and different people enjoy different things too - Taz.

[@MRMAN-wb1tv]

@@hpa101 I actually read all of that lol. You made some valid points. I've been DIY rebuilding one of my 2nd GS300's and I started from the ground up, meaning suspension ( EVERYTHING ). Being that it has a multi link/double wishbone setup it's easy to make the car "trackable" while staying "street/daily" with adjustable parts, new wheels/tires, lowered it about 2 inches, alignment. Then got the engine, it's components and transmission together. MISSION COMPLETE! That was a mistake thinking I was done! I had all these new suspension parts and my car drove crappy, gas mileage went down, erratic bump-under-over-steer, swaying, binding during turning or steering input, and come to find out all I needed was roll center adjustments to bring the geometry of the suspension arms back to their natural travel position, also making adjustments to toe, caster, and rear traction bars.

[@P.a.r.a.d.o.x]

@@MRMAN-wb1tv Thanks for your input man, I think I'm in the exact same position as you lol I only found out about bump steer correction kits today.

[@MRMAN-wb1tv]

@@P.a.r.a.d.o.x No problem. Yeah bumpsteer is annoying and dangerous. Glad you figured it out.

[@P.a.r.a.d.o.x]

@@MRMAN-wb1tv yes, dangerous for sure, I actually drove my car as little as I could because there was no way I could control it and all of the mechanics I went to always suggested alignment / steering rack and made me waste my money. Hopefully this fixes it as mine lowered too and good luck with yours 👍