In this video I show a little bit how Steering Ackerman works. And I show how it relates to the Baja. With a description of Ackerman with front steer and rear steer.
@@DougBugBuilder yeah this is great. I've been trying to figure out Ackerman on my go-kart for 3 days and couldn't find anything that explains it this simply. Unfortunately my go-kart has the tie rod ends attached in front of the wheel so looks like I can't even do it unless you can modify where the tie rods attach to the end of the steering column that would make it work. It seems like that should be possible but I haven't found anything explaining it yet. Any idea?
@@rhull3939 You can dial in Ackerman with forward steer spindles but it gets tricky. Usually you need to push the tie rod connection points outward as much as possible and move the rack back some. Not always room to do this. So like me with forward steer there is a lot more compromise to Ackerman.
@@DougBugBuilder thanks man. Yeah, I don't have room. The point is right smack I'm the middle of the tire. I read something last night that you can get it to work by not having the tie rods in a straight line to the ends from the steering rack but I can't figure it out. It says to stagger them but I have no clue.
Weight transfer during cornering increases the load on the outside wheel. More heavily loaded tyres need to run at higher slip angles so having less than "optimum" or even anti-Ackerman angles is not necessarily a problem from a performance point of view on tarmac / asphalt surfaces. Conversly, the inner tyre can not develop adequate grip levels and will scrub if the slip angle is too great. Ackerman steering is something that was developed in the days of solid tyres and low speeds, as a means of allowing independent steering systems to more closely simulate the effect of a pivoted, solid axle. It probably helped to reduce 'chatter' in corners. Tyre longevity is another matter, which is one of the reasons it is retained, to some degree on standard road cars. Running on loose surfaces is a whole new kettle of fish where steering force is dependent on more than just friction.
HI Graham can u refer a book or something other form where i can learn and understand vehicle dynamics calculation. i am watching a lot of videos and using other online sources but they mostly tell what will happen and not the calculation part.
@@nc-pf3qm A good place to start, if you can find a copy, would be Racing & Sports Car Chassis Design. It's an old book and may need some adaption of 'units' today but good stuff. It was wrttien by Mike Costin & David Phipps in the early '60s but there are copies available on-line. Mike Costin was the Cos in Cosworth alongside Keith Duckworth. I hope you've heard of them. 😃
Thank you, thank you, thank you... After hours on google and RU-vid, this one video... Within the first 5 minutes... Enlightened me! So simple, concise and yet lucid... Never thought building a weekend buggy for my daughter would bring me here... And boy, am I glad for it!
Since I'm still building my sandrail. I'm barely gonna start my spindles. This video came at the perfect time cause I had absolutely no clue this was a thing. I was the guy that was gonna use a complete fwd into my rear engine sandrail. I ended up doing a Porsche 911 transaxle with a truck 5.3 (Lm7). Your videos really help me with my suspension questions cause I really doubt myself when I'm doing this cause it's important. Chassis is built though and have everything ready to go pretty much. Just need seats and stuff too
Your Baha anti-ackerman setup is actually perfect for racing. Thanks for the clear insights. I thought I knew enough about ackerman and anti-ackerman, now I understand much more.
Thank you for a nice detailed explanation. I just needed your view and advice "for light weight vehicles like reverse trikes even parallel steering should work fine".
I was just hoping you would have a model and then bam, model comes out. The model made all the difference I had experience with the topic but you your explanation was very good. Good video.
If the steering box was back in line with the straight line between the two outer ball joints,it would help your ackerman immensely. Also,you may want to put one inner tie rod above the pitman arm and in a hole farther to the opposite side of the center line of the pitman arm,and have the other inner tie rod on the underside of the pitman arm and they will overlap and in effect 'lengthen'as they turn to push either wheel more in it's needed direction. The easiest cure for yours is bring your box back closer to the rear,then shorten the tie rods.By far the easiest 'cure'.
Great video! I emailed you some pics of my build, it was all simulated in CAD before I built it. I downloaded your files that you shared for the spindle layout, and also discovered the issue with the backwards Ackerman! The setup I have now is not perfect, but it's pretty close.
BTW you can correct your steering radius variance dynamics (ackermans principle) with the pitman arm length, position and direction, it’s the left to right full width center-link and tie rod set up that creates the consistent relationship. If you break this up like ford does on their IFS differentials Dana 35 45 55 etc. the pitman arm is on the left forward of the axle with a rearward sweep, connects to the inner tie rod end, and the outer rod end point forward on right spindle the left tie rod attaches to a midway point on the right tie rod and the opposite side forward point on the left spindle. This creates steering input differential. On the Dana60 straight axle front ends, an independent center link in a separate but supporting position reinforces similar geometry, and bump steer not present in the ifs system is countered by a the use of a track link mounted I. A position parallel to the tie rod or drag link.
thanks for this. Im old and feeble and limited to 1/10 scale rc cars. however, next time I put additional rear drive axles on a home built rc car or build a half track truck, Ill smoke a joint or 6 so I can work out the correct ackerman easily. A great explanation.
It would be interesting to measure one of your daily driver cars to see just how close the factory gets the angles. Maybe that would get you in the ballpark of what would be acceptable. Not sure what you do for a living but you do a good job teaching this stuff in your videos.
Yeah, I'd be most curious to see how they do on the solid axle of the Wrangler. Then I could compare it to the Volvo S40. I'd think that would be pretty good.
FWIW, zero ackerman is a thing for drift cars that are intended to be doing a lot of high speed drifts, but it's a personal preference thing. I guess my point is that it appears to me that you might be able to modify that current spindle to where you can move it out to real close to zero ackerman, and that should be fine. Definitely it looks like that spindle on the old bug could be moved out to zero if you wanted. Also, I think you need to draw a virtual line between your upper and lower balljoints, and see where your outer tie rod pivot lies in relation to that line. Might be a little different than just looking at where your upper ball joint is, and in the case of that current setup, I suppose it might actually be a little less good.. I do agree that it will be fine however you leave it though. Thanks for another fantastic video!!
No entiendo nada, algún día voy a buscar a alguien que me traduzca todos tus videos, y voy a tratar de hacer un juguete para mi, es un reto personal que tengo, gracias por compartir toda tu sabiduría, saludos desde san luis rio colorado sonora, sin llorar..
Lo siento por eso. Si puedo encontrar algo en RU-vid que permita traducciones, lo haré. ¡Me encantaría que pudieras obtener el audio! Gracias por mirar de todos modos. jajaja
I don't, I just build what I think would be appropriate. I think if you were going to get that technical it would be best to draw it in software like Solidworks or something similar that can do stress analysis.
Great video, I love this series so much. Your first bug has a Anti Ackerman setup. That works well with Toe in. I’d be interested to see if you could sweep the old chassis with 1/8 toe in VS 1/8 toe out. Also when your using the cardboard templates I’m wondering how far it’s throwing you off because you don’t have inner tie rods or the rack in the template? Possibly retest that? Great videos none the less, I really enjoy them. ~WesD
More or less check it on the old chassis while you sweep it left to right. Check your ackerman while toe in VS toe out. For me I run a lot of on road Road race cars. We’re normally 1/8- 5/8 toe out to help turn in on a small short course aka Autocross. On a big Road Course we’re finding a very small amount of toe out 1/16 helps calm the twitchyness at high speeds. We also have 8-deg caster and lots of Camber gain for 3-inches or less. Thank you for sharing your thoughts on all this. I thinks it’s time for me to build something like this. Check out my Instagram Wes_D
Cool ! If only a dependable Davis mechanism could be devised and built it'd suit your baja just right, both because of its mathematically perfect differential steering (compared to an Ackerman type) as well as its standard assembly being already ahead of the spindles...
Designing a go-kart and realizing I meant to use Ackerman, but I accidentally made it forward steer... oh well :P I guess it doesn't matter that much, though. Anyway, thanks for the video! Nice looking machines, btw
so does varying the toe of the rear wheels help things? Is it another way of adjusting for an "incorrect" ackerman? Toe changes on swing axle bugs anyway as they are on trailing arms so would changing the ride height affect the way it turns within the concept of the ackerman angles? what about lengthening or shortening the wheelbase?
A lot of what you mention there will help with stability. But none of it will help with the ackerman. But the good news is if your ackerman isn't the best it really only affects you on tighter turns.
Would you provide a link to your next video that explains your outcome of your changes to the Ackerman angles. I cannot find it in your list of videos. Thanks
I never did a second video on the Ackerman. But I can tell you with the changes the steering is pretty good. Straight line running no issues obviously, tight turns you can hear it scrub some on asphalt, but it's not bad. And this vehicle is really only used at dirt tracks and trails, so really a non issue here. I hope that helps.
@@DougBugBuilder Thanks for the reply. This video was very helpful because I had a major anti-ackerman on my 1991 Dodge XPlorer motor home. With that much weight it didn't take long to eat my tire treads. I moved my steering center link closer to the axle and it worked. I guess it is the same as if you moved your steering rack closer to the front axle.
It looks like Forward steer would cause oversteer. In the case of a go kart you would then want a wider front track (wheel base) because wider front tires lead to understeer due to the rear axle being solid.
You got me thinking Doug I need to check my baja king link pin. Longer wider . woods chrome Allie stuff . thanks for the kick in the brain bucket . mine is rear steer tie rod to the same rack and pinion box as yours . what front breaks are you running? Mine are to small and the rear locks up first . $ ? .
Mine are Jamar combo spindles. But I'm in the same situation. Although they brake pretty hard, the rear lock up and the front does not. Glad I got ya thinking. lol
Not really, although I do try to set them up so they are at least 1/2" away from the inside of the wheels. This allows dirt and rocks to pass between the calipers and wheels if possible.
If I can leave a suggestion, I would try to move the steering rack to the back. Your shock looks like it is in the exact middle of the lower arm so it will not interfere, you may just have to get a different rack (that has the shaft coming from above) to help with steering shaft routing/angles. If not an option, while you move the steering arms on the spindles may as well make some new ones that sit as close as possible to the rotor so that the ackerman will be "less worse" 😂 rotors don't flex and your spindles look beefy so I'd say a few mm clearance between them would be enough
Great ideas! I originally was trying to mount the rack back like where you are describing. But the steering shaft was impossible. At least with this rack. So I went with the front steer. I really like your idea on hugging the rotor though. I'll consider that. Thanks for the idea.
Moving the steering rack rearward should resolve the ackerman issue. 1st and 2nd gen miatas are front wheel steer and the steering rack sits behind the attachement points for the tie rods. Its all about the triangles. Take the triangle that you make with the centerline of the rear axle and the pivot point of the spindle and youll get an angle. Its probably going to be around 20 to 30 degrees depending on track width and wheel base. Thats the angle youre shooting to make between your steering arm and your tie rod connection arm. So lets say you need your tie rod connection arm to be offset at 25° angle for your Ackerman to be right but you have to make it at 20° to keep bumpsteer in check. you can move the steering rack rearwards (in your case) to increase the angle between the steering arm and the tie rod arm by and additional 5° to get your magic number of 25°. Hopefully that makes sense. Unfortunately i cannot upload pictures for you.
Great video mate very informative 👍keep it up! I have never tackled a steering or suspension build it looks pretty intimidating if im honest. Just wondering if your first bug is actually 5.2 ish degrees out of this acra...thingy 2.6 to get it equal then another 2.6 to get it to zero scrub? Im not being critical or trying to be smart , just seeing if im undstanding the concept correctly. Anyway cheers mate, love your vids and thanks the work you put into sharing with us. 🤙
Keep in mind I'm going a little OCD with this. Building a front end doesn't have to be this neurotic. If I could remove the 2.6 degrees then I'd be at neutral steering. I don't know how much it would need to be true Ackerman. I'd need to lay it out like I did on the board. But it would probably be a couple degrees. But pretty much what you described.
@@DougBugBuilder thanks mate, I think it's all above my pay grade but I might give it a go one day. I agree physical models are the way to go with things like this. Rock on brother 🤙
It might good idea to move, the main pivot of tire , inboard, to improve the pivot-set alignment. Instead of move the secondary one. thanks for attention, enjoy.
Hi, i'm from Brazil and love yours videos! I would like understand how do you define the king pin and caster angles? Can you explain the proportions which then?
In this video I explain the King Pin or Angle of Inclination towards the end of the video. ru-vid.com/video/%D0%B2%D0%B8%D0%B4%D0%B5%D0%BE-lkB96TFPZsM.html And I set my Caster to 7 degrees in the chassis, just from past experience. But it is adjustable from the upper control arm.
I know I am late to the party, but when you are measuring the angle of the buggy you showed 29 degrees for the inside wheel and 31.6 degrees for the outside wheel. By that method doesn't that mean the inside wheel is following a tighter arc? So it has slight amounts of ackerman? And is not actually anti ackerman?
what if you flip a arms and spindles from left to right side and move suspension forward accordingly. then you should have room for rear steering. would be cool to see the diffence and for you to give a hands on verdict on the effect. steering rack would need to be upside down too or be 2 axles with a gear on each to change direction of rotation.
If you measure the center point at rear axle and put it in front of your vehicle you will have correct Ackerman angle and location in front.for front tie rod locTion
My rotor ends up being in the way too. The rack position will affect it, but honestly it has to be pretty far forward or back to actually have any negative effects.
Those calipers and rotors came in the Combo kit from Jamar. www.kartek.com/parts/jamar-performance-combo-link-front-disc-brake-kit-with-2-piston-calipers-and-10-rotors.html
Why can’t you just have rear steer? Are there any advantages or disadvantages to having rear or forward steer? Maybe I missed it in the video if you talked about it. Also, what engine is going the new chassis? Do you have any plans to step up to an LS engine?
I would rather have rear steer. But with this setup I need the rack really far forward so I can have a safe steering link from the rack to the steering wheel. If I pull it back I have to add U Joints and the angles are pretty tight. This chassis will have an Ecotec. My goal (dream) is to get a LS in one of these chassis. But I won't do that until I have a transaxle that can really stand up to the abuse of it.
In my opinion, the biggest reason your baja doesn’t steer well in the dirt has more to do with the non-Ackerman steering than being light on the front. Though a light front makes the effect worse
Ackerman was good enough for horses and carts but the future does not have much more room for this old bollocks.Ackerman is the past there is much simpler and safer way to sort this out. It is called evolutionary design and will be presented soon. Remember,Ackerman is for carts 250 years old crap. There must be other way but maybe it is just easy to copy for many of you guys 250 years old in F1? Can't be right.
@@rickrack78 And the knives are working more less without need for change or the spoon so I don't have no suggestion also on improvements of those. I'm not here to argue or proving you anything what I'm saying is that Ackerman is out dated and not suitable anymore for safe modern design. Ackerman is the reason why car design haven't changed since Ford T. Square box, engine on the front,4-5 seats,boot even the electric Marvell the Tesla washing machine on wheels is the old Ford T you guys polishing the turd here Ackerman is the handbrake of progress and not the solution. Horses and carts pal not 200MPH flying riders.
My understanding is that Ackerman is for perfect conditions, but with slippage and loss of friction as off-roaders will often encounter, having a toe-in on the wheels helps with stability in most conditions so I wonder if the pro-ackerman linkage was chosen to enhance stability on variable terrain.
Personally I think the design was more "this is what fits". But you're right, Ackerman isn't that important for offroad. But I'll still do what I can to get it as close as possible.
Hey Mike, little update I ordered a Mig welder for the panel I plan on butt welding I am not sure if I will Tig or Mig, but I think in the future for building up an edge or a seam the Mig will probably be the best bet, what do you think, thanks
Good call, I think once you get used to the Mig you'll use it a lot. I use Mig when I can, but I still use the Tig if I need to be clean, or I really need to control the heat, or if it's aluminum.
Your cardboard demo is for a single point of attachment. The buggy has two points of attachment. Cross the attachments and you will be fine. Passenger side steering rod to drivers side bolt hole (rear). Drivers side rod to passenger side bolt hole (front). This is still Ackerman's theory. If two attachment points they need to cross.
I can't argue with you. But the point of the cardboard was really just to visualize for people how the Ackerman works. Pretend this buggy is solid axle. 😂
Making it rear steer would solve the Ackerman issue for sure. But the reason this is front steer is because there isn't room with the A Arm suspension to have the rack and pinion mounted that far back. So for clearance the rack has to go forward and makes it need to be front steer.
I’m a little confused about how you are measuring your angles for measuring your Ackermann. I believe you are measuring the acute angle between the rotor and the front axel. Please correct me if I’m wrong. I think that the inside tire should have the smaller (sharper) angle and the outside tire should have the larger angle. It’s really hard for me to see in this video, but I’m thinking that your steering ball joints are actually outside of the tire pivot points (which makes it Ackermann steering, and not the reverse). It might be a compromise to the actual approximation of Ackermann but I believe if you drew a line from your steering ball joint through the axis of steering rotation, then it would be pointed towards the middle of the car. If you have reverse Ackermann steering, that line would point outside the car. Please correct me if I’m wrong but from what I see in the video I think your car is approximating Ackermann steering better than you think. (Not talking about the new one you are building)
You are correct about the angles, but my steering ball joints are inside the tire pivot points. Really hard to tell when the wheels are turned. But when they are straight if you imagine a line to the rear axle center you can see they are inside that line. The Ackerman wasn't horrible. But the outside tire was turning sharper than the inside tire. At least what I could tell with how I was measuring. It wasn't to technical.
On dirt you should be OK. You also have the scrub angle of the tires that differs from side to side. As your speed increases on the dirt a little anti ackerman is a good thing