After 100+ parts and 45 hours of practice, I did it

I was playing with my kids and I did it what dad's do I absolutely shredded on my son's bike his tiny bike made me think it'd be cool to have a really tiny bike so I made this it's pretty small but is it the smallest bike I could not get this idea out of my head and I also had my wife taunting me yeah it seems like it could be smaller though you look like a circus freak which led to an arms race of self- one upmanship making increasingly tiny bikes I also really wanted to beat the world record and I ended up making a bike so small could fit in my pocket this ended up being really challenging with a lot of failures I had to make and remake so many parts before I got this thing working I wasn't even sure if I could physically ride this thing it took weeks of practice and crashing which my wife found thoroughly entertaining especially once I started trying to hit jumps so let's take a bad idea all the way to its logical conclusion and see if we can make the world's smallest bike and actually ride it so let's start at the beginning when I thought I would be only making one bike all right I want to make a tiny bike that's way smaller than this but I also want it to be easy so my design strategy is really focused on my water jet it cuts almost anything with a supersonic stream of water and abrasive I'm designing as many parts as possible to be 2D shapes that can be cut out of a sheet because it's fast and easy the different pieces have little tabs that fit together like a puzzle and then throw on a few welds and you've got a frame there's some parts that seem more complicated like the pedals but I was able to water jet out all the complex stuff and then do just a little bit of Machining for bearings and other stuff my whe choice for this bike gave me a bit of a headache because these are scooter wheels if I try to put a shack through here and twist it it's just going to slip so I had to machine them to accept this fancy little water jet part which will accept a key that will lock it onto a shaft now if the shaft turns the wheel turns the bike will go forward if I pedal but if I stop pedaling I want it to keep rolling bikes usually do this by having a special gear between the pedals and the rear wheel which if you pedal forward it drives the wheel but if you stop or pedal backwards it skips and it's basically a ratchet which is that ticking sound you hear there are bikes that don't do this called fixies and people who hate their knees really like them that special gear is called a freehub and this bike is just barely big enough for me to use one in a standard chain which makes my life a lot easier we just got to install them but these bikes are a lot of work why am I making one big video when I can make 500 shorts hey guys I made this quick short just to show you how to install a bottom bracket you just do this that's it thanks for watching H maybe not this bike is almost done just need the pedals and the chain if you pedal it goes forward but if you stop pedaling it coasts so cool what are the odds I can just ride this thing if you said zero you'd be right I really thought my biking experience would help me but it did not I practiced every day for 5 days I'm riding but then there was this point where it just clicked oh yeah smooth as butter baby finally yes woo this is so much harder to ride than I was expecting I really thought I'd just be able to get on it and ride it now I just want to see what my wife thinks what's with the little seat it's a bike for someone with a very small butt long legs and huge feet how you fit you really well then has science gone too far here we go looks like what a monkey would ride at the circus this not as hard it's as smooth as we're going to get what do you think I like the chunky wheels and it seems like it could be smaller your face could be smaller which is hypothetical I haven't thought that about you I hate to say it but she's really not wrong you ever see those vacuum seal bags where you put a pillow in it and it shrinks down to the size of a small wafer this is kind of like that there's a lot of air we could squeeze out by making everything smaller I was trying to figure out how small I should go and I came across the Guinness record for the world's smallest bike which they say is 8. 4 cm long and notably they don't seem to care about height I mean just look at this bike and I think the reason for this is you just can't go below a certain height without your hands intersecting your feet so what I'm going to do is take the record size subtract 1 mm from it and that's my target I don't see any good reason to overexert myself here world's smallest is world's smallest even if it's only by a millimeter just to see what I was dealing with I took a bike and scaled it down to 8. 4 cm long and it is a lot smaller than I was expecting this bike

is smaller than the wheel of the last bike that I did it is going to be very difficult to fit everything into this size I guess that's why it's the world record so it took a bit of finessing but here's what I came up with like the other bike I was able to make a lot of parts on the water jet but when you go really small you have to pack more functionality into fewer parts so there's more CNC stuff this is the frame basically the main body of the bike and this is the fork which holds the front wheel there was no room to fit normal bike components so I had to make my own stuff making the gears is pretty easy but how to make it Coast was not obvious remember a normal bike uses a free Hub like this which is just way too big I eventually found a one-way bearing they let a shaft rotate freely in One Direction but if you turn it the other way it locks up putting this all together we have the pedals going into the oneway bearing if you pedal forward it locks up and Spins a gear and you go forward if you stop pedling the wheel spins the chain the other way and the one way bearing spins freely and the bike coasts and then the last thing we need is some tires so we're going to cast some Wheels I made a 3D printed mold that fits around my wheels we're using a two-part polyurethane to get a nice hard rubber this is a pretty cool process that works surprisingly well nice it kind of looks like a giraffe and even though it looks huge it has the same footprint as my prototype oh I love it it's so tiny I should be able to just drive it away I had a lot of practice on the other bike this should be easy here we go ow all my practice on the other bike did not translate to this bike I don't know why but this thing is just totally different to ride I think it's going to take a lot of practice and that got me seriously wondering if I want to spend a bunch of time learning to ride a bike that's 1 mm smaller than the r record and then my wife said Oh I thought it was going to be smaller which just sealed the deal I'm done so all my talk about bitting a record by a millimeter being cool was just coping it is way cooler to crush a record we're going to go as absolutely tiny as we possibly can I was initially thinking two times smaller then I thought why not just go for three and that sounded great until I printed out a scale model it is smaller than I was expecting the wheelbase on this is about the size of one of the wheels on the last bike and remember we only care about the length between the wheels it's going to have to be taller to be able to have cranks and handlebars that I can actually hold my gut reaction was that this would be impossible but I think there might be a way so here's what I'm thinking a normal bike has the pedals Between the Wheels but if we push them up we can shrink the wheels down and squeeze them right up against each other and then delete the vestigal seat squeezing all this in means some pretty complicated CNC Parts normally I'm doing three axis CNC mill which means a machine that can cut laterally and vertically which works great if you want a hole on the top but if I side I have to take the part out and rotate it and if you want features on all the sides you're going to be moving the part a lot and if you want to machine something in this direction it's possible but you're in for a bad time so I think it's time to pull out the big guns this is a five AIS Mill a 5axis machine is just like a three axis except it can rotate the part in any direction that's why it's five instead of three which means it can machine on this side and this side on this random angle or even all of the angles at the same time so cool this is super useful for the tiny bike because I have to fit so many things into just a couple tiny pieces and with this I can pretty much just design it however is best for the bike and it should be able to make it and all I can think about is all the things that I'll be able to do with this for future projects it's going to unlock some pretty interesting stuff so if that's interesting to you don't forget subscribe it is so satisfying to press a button and then have finished Parts like this there's a tiny little frame it's a little chunky but it's the only way I can make it strong enough to hold me this is the belt drive system and the rear wheel has a oneway bearing in it so that it can Coast it's kind of weird looking this is the front and rear wheels and you steer like this the rear wheel is driven by this belt via the pedals and this long stick is what holds the handlebars it's the Teeny tiniest little itty bitty bike the height of the handlebars I need to clear my feet really drive home how absolutely tiny this bike is so there's two questions will it collapse under my weight and if it doesn't can I actually ride it there's only one way to find out all right here we go definitely hard to balance on

that's a very unfortunate failure mode let's try again did you hear that here it is again that's the sound of a tire giving up its Soul finding something that wouldn't immediately break was a real challenge because I only have about a millimeter of space I eventually discovered that gaffer's tape works really well but then I discovered whoever designed these pedals was a real you can't use them without your foot hitting the crank and jamming everything up and I tried every shoe and even no shoes but the pedals are just too small so I went back and made some humaniz pedals for it I was feeling pretty good until my worst fear happened this is going to be problematic the belt is skipping if you put too much force through these belts the teeth can skip I think what's happening is I'm hitting a little tiny bump and the bike has to lift my whole body weight which makes way higher force and it skips I think we pretty much have to fit a chain in here so what we're going to do is engorge the rear wheel which will make more room for a chain ring to fit this will make the bike about half the size of the record instead of a third but what else am I going to do and of course this means we get to redesign and remake most of the bike all right the chain fits and doesn't hit the ground and I guess the bike is doing a reverse Carolina squat I can't balance at all but it almost kind of works but doesn't something look a little off oh this is bad so remember how I made bigger petals because they out further they generate a lot more twisting force on the shaft and yeah I think my only option is to redesign and remake a bunch of these parts so that I can fit a thick crankshaft in here this is the last thing I feel like doing I really don't want to do this but I want it to work properly so what am I going do let's make some parts we get to remake the frame the fork the axle the cranks the gears the spacers yeah this was a major over oversight old shaft new shaft I don't think that's going to bend now that is one beefy little man but I still can't ride for a reason that I really wish I would have noticed before I remade everything when you pedal the bike it tilts side to side when I put the big pedals on it can't tilt as far and there's just not enough clearance now I even tried making really short cranks that would give me more clearance but I don't think there's any way to hack around this we just have to get them higher which means we get to redesign and remake everything I'm just going to give you a taste this is the new frame it raises the cranks about 20 mm up and it has plenty of clearance I call it the tall boy we've modified this so much it's basically unrecognizable from where we started so we need to see where we stand in relation to the record 5. 3 CM 1. 6 times smaller than the record which I'm okay with and here's a size comparison to the current world record the thing to remember is that even though this has big handlebars and big pedals that's just because I have big hands and feet the actual bike is very tiny and that's what makes it so hard to ride so the bike seems to work but oh it's still not clear if I can ride it is so much worse than the first bike what makes it so hard is just geometry when you push the cranks down they extend past the front wheel and it tips the bike forward and then because the wheels are so close together on this bike it really can't resist twisting like this so I can't pull my feet through the bottom of the stroke because it'll just twist the bike out from under me I spent over a week practicing multiple times per day I have two terabytes of footage of me failing to ride this thing but at some point it kind of clicked I'm still not very good and my feet hit the ground a lot I have a really hard time I'm going more than a few feet it's also really hard to stop but this thing is totally ridable it's not perfect but I think it's as good as I'm going to physically be able to do right now all I want to know is what my wife thinks I thought you were making a bike not a scooter this doesn't look like a scooter all right here we go H still getting the hang of it a through F what would you give this baby C+ it's the world's smallest bike you could really ride it I'm working on it are you getting paid off by some competitor Big Bite what is an a take it off a jump it has metal wheels so the that'd be the last thing the bike ever

did well there's your C+ what if I take the first bike the big one off a jump that give me an a can give you an overall a all right well I just got to find a jump of some kind some of the stuff that I make might seem like magic like how does the moving hoop know where to go but it's not magic it's science I've spent a lot of time learning stuff which is what enables me to make stuff so if you're learning technical stuff so you can make stuff too check out this video sponsor brilliant I like to describe brilliant as a tool that's really good at taking technical information and getting it into your brain it works by taking a technical topic and breaking it down into a series of bite-sized lessons so let's say you wanted to learn Vector math this is something that I use all the time it's actually how the moving hoop knows where to go there's a whole set of lessons on this they work by teaching you the theory and then having you work examples the lessons are also interactive and have you solve solving actual problems so you're learning by doing which is just the best way to learn and then the lessons are the right size to do one or two a day which makes it very easy to learn consistently which is huge I used to try to cram textbooks doesn't work now I spend 30 minutes a day learning new stuff and it is shocking how much you can learn if you do this consistently and I have so much stuff to learn I mean just look at all this it's like every kind of math computer science machine learning data science a ton of stuff you used to have to go to college for not anymore so if you're looking to level up your problem solving abilities check out brilliant I used it a ton it works great and you can try it for free for 30 days just go to brilliant. org stuffme here you can also click the link in the description and you'll also get 20% off an annual premium subscription and that's it thank you brilliant for sponsoring this video and I hope you check it out and get to experience the joy of learning all right it's jumping time it's the ramp I craft cred on the driveway so I should be able to crash again all right which foot do I lead with I'm nervous all right here we go that was close oh okay hold on oh pretty good that was a land are you satisfied yes nice I get an A