I've just built a recumbent bicycle from scrap metal yard bike parts. Still gotta put brakes on, chain guides and gear cables but took it for a test anyway. Fell over when getting on once, glasses fell out of pocket while doing so- found 40 mins later, phone fell out of pocket twice- not broken, crashed into a bollard at a bike path- arse up- slight swollen ankle. But the chain never came off so tomorrow will see it finished and ready for an inter town test of 20km. Think my knee is a bit sore too......
I knew all these principles in theory, but it was nice to see them in practice. I want to design a two-seater quad, and so I'm working through issues for both the front-end and dual-drivetrain/back end. By the way, I really like the kingpin-based steering handle.
In explaining the principle of Ackerman I feel you left out some important points. You failed to mention that a line drawn from the kingpin centre of rotation through the tie rod Hiem joint ends up in the centre of the rear axle or very close to it, then however depends a lot on wheelbase too as wheel base determines the centre of the minimum turn circle and therfore the angles needed by each front wheel. Because of the difference in the angles left and right when you turn and then project a line from each front axle out to a line through the rear axle on either side the line these three lines will intersect. As you pointed out the turn radii for the inside and outside wheel are different and thus the steering angle for each is decreed by four factors. King pin caster and camber wheelbase and length of steering arm. I would not ave welded the crank arms either as you have just weakened the forged steel that they are. Pinning them to the kingpin and retaining them with the Axle would be more preferable.
A key comment should be mentioned with regard to true Ackerman steering. You welded a short tab that the tie rod end bolts to, on each of the recycled crank arms (now serving as steering levers). How did you determine how long that tab should be? Well, for True Ackerman (not near Ackerman, where tires scrub), it's length should be so that if you draw a line from where the crank arm is welded to the hub, thru the tie rod end bolt hole in the tab, it must intersect the center of the rear axle.
Great update! Ultimately, your low back will thank you if you change the seat before doing any long rides. Those sorts of bowl type chairs conflict with the curvature of your spine. Outstanding, anyway.
Are there some easy ways to make the tube welded the right way for the wheels to get Ackerman law setup?. Maybe make some in paper and sand the square tube that way get a easy way to get both ends precise right.
You can download an Excel spreadsheet that calculates all the part lengths and angles to be compatible with Aakerman (Ackerman?) geometry. Besides positive or negative caster (cars have negative caster...two wheeled bicycles have positive caster) there's also camber. Positive caster means the top of the tires are further apart than the bottom of the tires and negative camber would be the opposite. This is accomplished by tilting the steering knuckles toward or away from each other. I don't know why camber might be something other than zero when the wheels are pointed straight ahead, but the steering knuckles should be tilted a bit so that the axis of the knuckle points to the center of the patch where the tire meets the road. The result of this is that when one front tire hits a bump, the jolt doesn't throw your steering to the right or left.
tinny- you are correct that caster directly affects the tendency for a steered wheel to return to center, but you may also find that changes in the toe in/out will also have a direct effect on the steerings stability (with the affect noticed more as speed increases). just a little something else for you to consider.
Hi Mary! Hi Tinny! I had a 'bent trike at one time. The one thing I ran into with it was "torque steer". Very unnerving at high speeds! As you put pressure on one pedal or the other, the rear wheel would camber over causing the trike to suddenly turn resulting in the machine wobbling back and forth, opposite the pedal pressure. With the single seat boom and no panhard bar, you're probably going to experience this issue with your trike if you intend to go very fast.
Hi, in order to lower the back a bit more, you could also swap the rear wheel with one which has a smaller diameter I guess, sure the will change your top speed
if both wheels are perfectly vertical and they both are free wheeling....i thought it doesnt matter...the wheel on the outside of the turn will turn more, but since it is free wheeling..it doesnt matter.....the only time i see free wheel front ends angled in on itself is with riding lawn mowers...but i have been told that is to get traction..where the outside wheel on the turn actually has a bit more bite into the turf
Im loking for 6061-T6 aluminun square tube 1 1/2" x 1 1/2" x 1/16" online but Ionly find 1/8" wall. I was checking different information online and everybody talking about 1/16" wall not 1/8" wall. Can I build a recimbent with 1/8" wall?
Tinny ..if you need to change the caster more without lowering it you can heat the beam that goes from tire to tire and twist it i used to bend I beams on trucks to aline them and the only way was to bend them..Dave
I have a question how do i get the front two wheel with bigger 3/4" or 5/8" axle bore coz i was going to use go kart spindle and I found online is 5/8 or 3/4 and i need your idea to make suspension thanks
Pawitra,try using a 20 mm front hub. Formula makes a good unit at a fair price. I build a tadpole for a 400 pound rider and the hubs have held up fine.
I’m pretty sure it’s Ackermans “principal” not Ackermans “law”. A law implies its physics and there’s no “wiggle” room. You’ll find on automobile and racing design, they don’t follow it exactly. If it were a “law” Sheriff Ackerman would throw everyone in jail that broke the law....just kidding, good journey of discovery. Thx.
Hi how you doing today I love your project and convince me to do one myself and I was wondering what was your angle on the arms where the two front tires meet is it a 30 degree angle or a 40 degree angle or a 45 degree angle I would love to know that no help me out a lot I appreciate your time and thank you if you do help me
Tinny, you have that steering geometry down pat. I'm impressed with the fact you applied Ackerman's law. More caster will give you more stability. Hi Mary!
Get your tie rod end located on that line. Camber? Unnecessary without a working suspension. Caster? No caster means quick steering less friction. A l'l caster will help you track straight but will slow you down when turning. You realize caster causes the whole thig to lean when turnin, right? Why not just put a steering stabilizer on it?
tie rod? lol it's a centerlink. Bounce on a centerlink? Why not just use guard if you are so....clumsy? Overall, you're pretty good, using toe in and ackerman math. A simple triangle. Draw a line from the pivot point of your front wheel to the center of the rear axle.
I've just built a recumbent bicycle from scrap metal yard bike parts. Still gotta put brakes on, chain guides and gear cables but took it for a test anyway. Fell over when getting on once, glasses fell out of pocket while doing so- found 40 mins later, phone fell out of pocket twice- not broken, crashed into a bollard at a bike path- arse up- slight swollen ankle. But the chain never came off so tomorrow will see it finished and ready for an inter town test of 20km. Think my knee is a bit sore too......
Great Video! It's going to help me alot when I weld my steering components together for the trike I'm building. Thanks Tinny your videos are great!
Some excellent points that I never, otherwise, would have known. Thanks for sharing your wisdom sensei..
Good job, explain very well, needed to see and analyze the steering system, and your video has been very useful to me, thank you very much, greetings
thanks man!!! you gave me some really important practical knowledge by ur car. and nice vehicle man!!
Awesome tinny i appreciate all the info i can't wait to see it rolling, thanks.
Another great video. I always enjoy coming home, waiting to see what you are up to. I 've learned a lot. Keep up the videos and ..... Hi Mary!!!!!!!
I like this! Principals of suspension geometry at work. Very smart solution to the caster problem too.
This was very interesting. Thanks for explain this out.
I love going the the junk yard looking for parts. lots of fun your doing a great job there.
Caster angle..you nailed it. Great video I'm in the same boat. Lol. Ran outta bike parts.thx
High Mary,
nice homebuilt bike,
excellent class on design principles of steering mechanisms
buzz
I knew all these principles in theory, but it was nice to see them in practice. I want to design a two-seater quad, and so I'm working through issues for both the front-end and dual-drivetrain/back end. By the way, I really like the kingpin-based steering handle.
i really enjoyed watching this. very informative, thanks!
In explaining the principle of Ackerman I feel you left out some important points. You failed to mention that a line drawn from the kingpin centre of rotation through the tie rod Hiem joint ends up in the centre of the rear axle or very close to it, then however depends a lot on wheelbase too as wheel base determines the centre of the minimum turn circle and therfore the angles needed by each front wheel.
Because of the difference in the angles left and right when you turn and then project a line from each front axle out to a line through the rear axle on either side the line these three lines will intersect. As you pointed out the turn radii for the inside and outside wheel are different and thus the steering angle for each is decreed by four factors. King pin caster and camber wheelbase and length of steering arm. I would not ave welded the crank arms either as you have just weakened the forged steel that they are. Pinning them to the kingpin and retaining them with the Axle would be more preferable.
A key comment should be mentioned with regard to true Ackerman steering. You welded a short tab that the tie rod end bolts to, on each of the recycled crank arms (now serving as steering levers). How did you determine how long that tab should be? Well, for True Ackerman (not near Ackerman, where tires scrub), it's length should be so that if you draw a line from where the crank arm is welded to the hub, thru the tie rod end bolt hole in the tab, it must intersect the center of the rear axle.
great video...specially how you explained caster ...
Great update! Ultimately, your low back will thank you if you change the seat before doing any long rides. Those sorts of bowl type chairs conflict with the curvature of your spine. Outstanding, anyway.
Are there some easy ways to make the tube welded the right way for the wheels to get Ackerman law setup?. Maybe make some in paper and sand the square tube that way get a easy way to get both ends precise right.
You can download an Excel spreadsheet that calculates all the part lengths and angles to be compatible with Aakerman (Ackerman?) geometry.
Besides positive or negative caster (cars have negative caster...two wheeled bicycles have positive caster) there's also camber. Positive caster means the top of the tires are further apart than the bottom of the tires and negative camber would be the opposite. This is accomplished by tilting the steering knuckles toward or away from each other. I don't know why camber might be something other than zero when the wheels are pointed straight ahead, but the steering knuckles should be tilted a bit so that the axis of the knuckle points to the center of the patch where the tire meets the road. The result of this is that when one front tire hits a bump, the jolt doesn't throw your steering to the right or left.
Hi David, we have a trike project and we need cad design of steering system with tilt ability. Do you make CAD design?
gr8 work bro. u r a true engineer
tinny-
you are correct that caster directly affects the tendency for a steered wheel to return to center, but you may also find that changes in the toe in/out will also have a direct effect on the steerings stability (with the affect noticed more as speed increases). just a little something else for you to consider.
Hi Mary! Hi Tinny! I had a 'bent trike at one time. The one thing I ran into with it was "torque steer". Very unnerving at high speeds! As you put pressure on one pedal or the other, the rear wheel would camber over causing the trike to suddenly turn resulting in the machine wobbling back and forth, opposite the pedal pressure. With the single seat boom and no panhard bar, you're probably going to experience this issue with your trike if you intend to go very fast.
Hi, in order to lower the back a bit more, you could also swap the rear wheel with one which has a smaller diameter I guess, sure the will change your top speed
wow thats great. very nnice design
Dang it, Tinny. Now I want a trike to carry around my alcolhol stoves!
@minibulldesign How did that little inverter welder work for you? Your welds look good.
G'day Mary from Australia.....
Hi Mary :) I just ordered one of your stoves and grate ovens and was wondering how many days shipping it took?
Fun! Thanks!
if both wheels are perfectly vertical and they both are free wheeling....i thought it doesnt matter...the wheel on the outside of the turn will turn more, but since it is free wheeling..it doesnt matter.....the only time i see free wheel front ends angled in on itself is with riding lawn mowers...but i have been told that is to get traction..where the outside wheel on the turn actually has a bit more bite into the turf
Im loking for 6061-T6 aluminun square tube 1 1/2" x 1 1/2" x 1/16" online but Ionly find 1/8" wall. I was checking different information online and everybody talking about 1/16" wall not 1/8" wall. Can I build a recimbent with 1/8" wall?
buena iniciativa, en Perú también queremos construir prototipos así.
Tinny ..if you need to change the caster more without lowering it you can heat the beam that goes from tire to tire and twist it i used to bend I beams on trucks to aline them and the only way was to bend them..Dave
@IVOIPSG Where can we get plans or more info??
does the tie rod clear when your sitting on it with the shock compressed?
Is that a version of the Atomic Zombie - StreetFox plan? I am working on a full suspension version of it
Not sure how getting low gets you out of the "slipstream". The slipstream is not at a certain height I suspect.
i have the same question about ackerman-camber-caster...
did u anything discover about it?
Ackerman was a very smart man and patented this principle and then sold it to Henry Ford for $5000 i think.
minibulldesign
minibulldesign
good job
Hi!What kind of hub you are using in front?
I have a question how do i get the front two wheel with bigger 3/4" or 5/8" axle bore coz i was going to use go kart spindle and I found online is 5/8 or 3/4 and i need your idea to make suspension thanks
Pawitra,try using a 20 mm front hub. Formula makes a good unit at a fair price. I build a tadpole for a 400 pound rider and the hubs have held up fine.
Does Ackerman's Law still apply to Leaning Tadpole trikes.
When Both Front Wheels Lean,
that Adjustment for Turning should Not Apply.
Man thats looking cool. is the seat ok?,
it looks like you will be laying back a bit too far.
I’m pretty sure it’s Ackermans “principal” not Ackermans “law”. A law implies its physics and there’s no “wiggle” room. You’ll find on automobile and racing design, they don’t follow it exactly.
If it were a “law” Sheriff Ackerman would throw everyone in jail that broke the law....just kidding, good journey of discovery. Thx.
@IVOIPSG I asked him for a signed stove a while back and didn't get it. :( Still love the stove though.
Hi how you doing today I love your project and convince me to do one myself and I was wondering what was your angle on the arms where the two front tires meet is it a 30 degree angle or a 40 degree angle or a 45 degree angle I would love to know that no help me out a lot I appreciate your time and thank you if you do help me
Are you asking about the degrees of caster?
The arms
Thank for helping me
Actually it is called a tie rod---look up tie rod. It ties the two wheels together.
I liked my. very simple.
Tinny, you have that steering geometry down pat. I'm impressed with the fact you applied Ackerman's law. More caster will give you more stability. Hi Mary!
sorry for broken posts. Limited by youtube.
Get your tie rod end located on that line. Camber? Unnecessary without a working suspension. Caster? No caster means quick steering less friction. A l'l caster will help you track straight but will slow you down when turning. You realize caster causes the whole thig to lean when turnin, right? Why not just put a steering stabilizer on it?
Olá! Sou fan dos seu projetos! Mas quando assisto seus vídeos sinto a falta do tradutor, para português Brazil! Obrigado!!
What is the size tyres ??????? Plzzzzzzz.,,,,,,,,,,,,,,, tell me. I am thank ful to you if you tell me size of tyres.
Not sure on this one but I finally settled on 20x3.10
The rear tire is a standard 26x2.50
Thanks
oooooo
hi mary!!
tie rod? lol it's a centerlink. Bounce on a centerlink? Why not just use guard if you are so....clumsy? Overall, you're pretty good, using toe in and ackerman math. A simple triangle. Draw a line from the pivot point of your front wheel to the center of the rear axle.
gostei (Y)
too much BS , I want simple DYI plans !