Intro to Racecar Engineering: 10 Caster

Smitty describes the set-up of the front wheels and its importance to the driver's control. This is the tenth in the video series developed for UCI's racecar engineering program. (Smitty and the Professor series)
mechanicaldesign101.com/smitty...

[@road2racect]

I wish to just say thank you for this video on caster angle... l thought it was brilliant... l am from Australia & run my own small auto business that specialises in high end wheel alignment / chassis set ups for race cars... ln the last few days l have been using what ever means possible to brush up on the effects of caster for race cars with emphasis on finding the optimum caster setting for a particular race car... Of course there must be multiple variables including the vehicle, tyre choices, track type & much more.... Though the part l remain most interested in is how do we know when we have reached the optimum level of positive caster & the effects on vehicle performance, grip & feel when go beyond this point... l guess what l am saying is "What point is to much positive caster a bad thing"...? To conclude l thought your vehicle model and the demonstration on scales delivers a powerful understanding on this aspect of caster geometry... Thank you again for taking the time to share your knowledge & experience for all of us who remain hungry to further learn our craft & understanding in suspension geometry... Peter

[@datadrivenmqb]

Great demonstration! My only objection is if you are loading the inside front more, it means it will be rolling more as well. You're going to get the same amount of weight transfer dynamically regardless of caster setting... But with the outside wheel naturally moving upwards, and inside moving downwards, it's giving more roll motion into the chassis. You're basically changing the individual ride heights a small amount like shortening and lengthening the legs of a table. This also equates to more body roll in the entire chassis (assuming >50% front weight distribution like most cars). Front wheel drive stuff in particular is very sensitive to caster changes, and in my experience when making a big change, it also affects the rear camber angle since the body is now tilting over further. Generally to maintain balance (if desired) a small adjustment out back is needed. More caster allows the wheel turning forces to peak sooner than actual grip peaks, but also stronger through the steering wheel. It makes the car easier to drive at the limit, and as you said especially under hard braking.

[@ChrisWilsonEngr]

Hi Smitty. Previous student. Sincerely wish all UCI undergrad had to take this their first year. Appreciate the video. Keep up the excellent work!

[@joshriker4173]

I never understood these concepts until now. Great explanation and visual demonstration.

[@lindltailor]

Best explanation on KZbin on caster. Thank you!

[@gerardscheffer8848]

That was exactly what I wanted to know. There is more to caster and Ackerman than I expected. Now I know about the tire load I understand the effect better. Thanks so much!

[@shreymishra6402]

Sir you are amazing .......spent my 4 years in the racing team but never understood the concepts so good.......you made me understand these in minutes.

[@1justgo]

Excellent explanation. Thank you.

[@ElChasco_official]

I really LOVE that channel

[@davem1633]

Great video thank you very much 👍

[@TanmayPanchal46]

You are just amazing sir. Most amazing explanation of caster and weight transfer I could find on the internet. Would have been absolutely perfect if it were high quality video, nevertheless the content is mind-blowing. Thanks.

[@erenmertkorkmaz7142]

I feel like i found a treasure. Great video

[@MagVair]

I would be happy to build & race cars for this guy for the rest of my life! 😁👍

[@maheshperera171]

thanks and very good explanation

[@jrheavyduty]

I’ve been watching n learning. I’m installing a rack n pinion on a gm A body ‘80 Malibu. My inner tie rod is at the lower a arm pivot. Should the rack be installed forward or aft of the tie rod centerline

[@mattadams6641]

Would it help rear load under turning to increase rear camber

[@kyledecell554]

So on a normal McPherson strut design I’m guessing the strut would be the king pin?

[@qwertykeyboardwarrior]

Good job man thanks.

[@BenCarpenterWrites]

Such a great video! Wish the camera angle was better 😬

[@johnellison3030]

Yeah. Kinda ruins the whole video doesn't it.

[@cahyahurip342]

so if it always goes behind the pivot point, then why the caster in car somehow always positive? does it make a wheel always forced to turn behind the pivot point? i still confuse.

[@shawneliason790]

Good Info.. I Learned a lot.. Sorry for poking fun.

[@domenicozagari2443]

THE ZAGARI SYSTEM OF STEERING USES 2 STEEL CABLES TO STEER, WHEN YOU PULL ON ONE CABLE THE OTHER WHEEL IS A BIT MORE FREE TO DO A WIDER CIRCLE.

[@isaacprins7298]

Hey there, I was wondering if there would be any issues if my caster was positive (on a dbl wishbone) but my coil over was mounted on the lower arm, in a negative angle. I.e. The caster and the line of the suspension forms a "V".

[@jmont8659]

What did you find? Did you see bending in the suspension arm/connectors as it was loaded with a moment force?

[@zukobringas5096]

On a ‘double wishbone’ the ‘coil over’ has nothing to do with any geometry mentioned. It just functions as a spring (for ride height) and dampener (for shock absorbing).

[@tensevo]

v good

[@Zickcermacity]

2:00 10° caster angle? I wish my Honda had 10° instead of 2.5!

[@chriss4154]

videos 10 and 11 are swapped

[@Zickcermacity]

How about having all Kingpin and no caster angle. Say, 15° of kingpin, and maybe no more than 0.5° caster angle?

[@RaceTeq17]

You will have so much dynamic camber loss [when steering] that all other effects are minimized because of lateral grip loss. As a general rule you want to have "a bit" more caster than KPA.

[@Zickcermacity]

@@RaceTeq17 I believe my old 1996 Ford Contour(started out life as Mondeo in Europe) had 2-3deg caster and over 12deg Kingpin/SAI

[@tensevo]

you may find you have no steering feel.

[@Zickcermacity]

@@tensevo Both forces lend 'weight' to the steering, just in different ways. SAI via gravity and lift, Caster via pneumatic trail, similar in nature to the front wheels on a grocery cart.

[@tensevo]

@@Zickcermacity only if you have a scrub radius. If your steering angle goes through the contact patch there will be very little lift.

[@shawneliason790]

FisFad? 0:25 Im so lost

[@m3oonh]

Fist fight

[@GavinRemme]

I feel like I’m watching a smarter every day video minus destin haha.

[@jjqerfcvddv]

Alright!! alright! alright!.......Your lingo is more like "Mathew macconaughey" 😎😎

[@shawneliason790]

BoogAboo? 0:13 wtf?

[@corvairkid17]

Quandary, dillemma

[@maheshperera171]

trolley wheels run negative caster, it automatically turn due to the force as you show but cars are running positive caster as your demonstration,... wheels will turn other way if you remove the tie rods and drive forward, .... your two comparisons are wrong ....

[@supremeleader8796]

In his example he was driving the wheel from the wood, the wood is leading the wheel. in cars wheels drive the chassis, the wheels are leading the chassis. Good point tho, i nvr gave it much thought until i saw your comment. He didnt explain clearly

[@cahyahurip342]

thats logic.. i feel so confused about the compared demonstration between trailed trolley wheel and car caster then about when car's going reverse. .

[@guloguloguy]

.....[terrible camera view!!...]

[@theeastman9136]

Terrible camera position; the speaker is between the lens and the demonstration. Reshoot this, we're interested. Thank you.