Big Mechanical K'nex Car




Welcome all to my entry for the K'nex Instructables contest! My creation is a big vehicle with realistic mechanical features, and a bunch of extra interesting components!

I started playing with K'nex when I was around 3-4 years old and have always loved it. I would make things very often with it at younger ages, but have continued to go back every now and then to build while in my teens, and even sometimes now in my 20's. It has also came in very handy for some school projects while I was taking a mechanical technology course (and was a great inspiration for my enrollment).

I had wanted to build this since I had last used my K'nex about 18 months prior to this build, which was for a smaller and more flimsy version of a car. It still had most of the main components in it, but was still quite inferior to this new model. I had actually started building the beginning of this project before I knew about this competition, but once I realized it was taking place I told myself I definitely wanted to be part of it!

NOTE: Only the first 2 images on this first page are of the new car, the others are what I had of the old car (which is now completely dismantled). Please check out later 'steps' for more details on the new one, and open the pictures to see a bunch of extra good info and comments on both builds!

Unfortunately despite my best efforts, and probably around 150+hours of work so far, I was unable to finish everything I wanted to do for this project, however I'm still very proud of what I have so far and still consider it worthy of contesting as is. =]

Please understand though that with a project of this magnitude it is somewhat impractical to make a complete guide to building it, however I will do my best to detail the most important aspects through a mix of pictures, videos, and text!

Also please watch the video a close cousin of mine helped me to make. It will likely be much more clear to understand any moving parts. I forgot to detail a few things in it, but anything I missed I'll be sure to discuss in here.



Step 1: Build Progression/Details

What features this car has:

  • complete individual suspension
  • front wheel steering
  • rear wheel drive
  • dual universal joints per rear wheel to transmit drive through suspension
  • rear mounted V8 engine with moving pistons, connected to drive train
  • differential with very little friction
  • engine may unlatch and pivot open to put car in neutral and reveal hidden differential
  • doors with automatic slip-in latch with opening handle on exterior
  • adjustable steering wheel height
  • secondary steering lever just inside hood to be pulled/steered by chord
  • automatic locking hood with button in front to unlock
  • hood soft clicks up at top to stay open without a bar
  • seats that can be adjusted front to back on slider
  • seats have a ratchet mechanism requiring a lever to be lifted to recline
  • seats have custom upholstering
  • very well reinforced handle just under the front bumper to make it easy to pick up
  • wheels have custom made rims and tires
  • the wheels are also on steel shafts and ballbearings to support the very heavy weight of the car
  • custom wired LED headlights with 8xAA battery pack under hood and switch placed next to steering wheel, also light angle may be slightly adjusted in and out

A few main things this car has that the old one didn't, and other differences between them

  • old: rear wheel drive, front mounted V6 with straight pieces moving in and out as pistons - new: rear wheel drive, rear mounted V8 with an actual flywheel per piston
  • old: much more friction in drive train
  • old: probably around 2.5'/76cm long - new: 4'/122cm long by 2'/61cm wide
  • old: nowhere near as heavy - new: approximately 40+lbs or 18+kg
  • old: way less pieces - new: estimated at around 10,000 pieces
  • old: no seat mobility, no door latch, no lights, no secondary steering mech
  • old: had window wipers made with mini K'nex - new: window wipers yet to be installed

Plans for the future of this car:

  • will make finishing touches to small incomplete sections, and will fortify some important moving parts
  • I have a piece of plexiglass that I will cut to make front and back windsheilds
  • will make window wipers
  • rebuild the engine to be a bit bigger and look nicer
  • might add more lights
  • will add body covering with plastic sheets and then spray paint them a metallic 'dark steel' color
  • once satisfied with all that and maybe a few other things I will make and upload a new video to youtube

Step 2: Custom Wheels and Seats


  • 2 large K'nex gears were glued together, but only using the spokes from one, this gave me more surface area to attach the rim
  • Plastic sheeting was used for the wheel rim, 3 layers glued one after another to ensure wheel stability
  • holes were drilled through the layers after and a tiny amount into the gear teeth to allow more glue to set through all the layers
  • 'Diamond-plate' EVA-foam floor mats were then glued on as the tires
  • Lots of hot glue was used


  • After a frame was made with the reclining mechanism, I covered the outside corners carefully with foam pipe-insulators
  • I then put some EVA-foam shelf-liner on the bottom and back for extra cushion and stability
  • That then was entirely covered by an adhesive-backed plush felt

Step 3:

K'NEX Contest

First Prize in the
K'NEX Contest

Move It

Participated in the
Move It



    • DIY Summer Camp Contest

      DIY Summer Camp Contest
    • Beauty Tips Contest

      Beauty Tips Contest
    • Growing Beyond Earth Maker Contest

      Growing Beyond Earth Maker Contest

    67 Discussions


    Hey, Never say Never!!

    well I know you didn't actually say never, but you know what I mean haha

    Just keep your mind to it and you might surprise yourself someday! :D


    First off, I'm really diggin' your car there, man!

    I also am really amazed that it's a large scale car that shows a futuristic compact-car style that quite frankly looks better than some full-scale cars that drive and roam the roads any day. (I understand that it isn't finished). Me being a mechanically-inclined person, I'm also going crazy for the way you made the door latches, the hood-latch, and even larger functions such as the steering system and drive-axles, so realistic as compared to a full-size car.

    Me being an RC-car guy; the car shows me in both your pictures and the video, that it's calling out to run some sort of remote control electronics and run around. That car would look great driving around your neighborhood, or even parking lots if it comes to that.

    My main question about the car is this: "How much does the car weigh?"

    You've also received my vote for the contest. :)

    1 reply

    Thanks so much for the encouraging words buddy! it's very rewarding to have someone really appreciate my work! :] And of course thanks for the vote as well!!

    I was thinking the exact same thing since I started the project! There's actually space in the butt of the car on either side of the gears that pass the drive from the engine to the differential! But what I'd Really like to do if possible is; (if I end up winning that ferris wheel :P) I'll use the pieces to make another car, but superior, based off this one and make that one RC! Please check out the messages I sent to 'knex akbar' on his comments in here! :D (also the comments with 'lucas_the_boss' have some quick info you could check out also, concerning this cars build)

    And the car is approximately 35-40 pounds now I would say (I don't have a scale at my place, but I had weighed it at my parents place once when it was maybe a bit more than half of what it is now..)

    sonic broom

    4 years ago on Introduction

    Very cool! I like all the little features and the car is very complex which I like. but it has a little bit too much non KNEX for me. I'm also going to add this to my best KNEX cars collection. Good luck! in the contest.

    5 replies

    Well I'm glad you still like it :] There's still around 9-12thousand pieces of k'nex to be liked anyways lol.

    I personally like being crafty in other ways also though, and don't mind mixing what may seem as two or more art forms to create superior results. In so many manufactured items these days things are made with different materials, and companies will mix their expertise to create better products.

    My dreams are to make this really look like a finished product with as many realistic features as possible, thus I will continue to add non-K'nex things until I'm satisfied with it.

    Also lets not forget how big a roll the K'nex played into these realistic features, and that I wouldn't even have this project without it! :P

    No disrespect there, I just like to be more open minded and add more possibilities to what I make! I encourage you to step outside the box too sometimes and see what you can do!

    The non-k'nex is not all that abundant bytheway (yet), currently its only the wheels (plus springs and shafts), seat upholstering, and lights.

    And its not like K'nex hasn't made their own wheels, I just wanted bigger ones (and I still decided to use their gears for them). Also that grand prize ferris wheel they have I heard uses a metal shaft of its own to support all the weight of the wheel like I did for mine. Plus Cyber K'nex sets have their own lights too, so I wasn't all that far out from them if you ask me.

    In terms of weight I guarantee the non-K'nex is less than 3%, and believe me it was still a big challenge hehe.

    Good convo' though man, always nice to talk with other K'nex activists :]

    Yes we all have are style of building. There is a new KNEX robotics set coming out soon that might have some use full parts for your complex projects.

    Ya I heard something about that.. I may end up being inclined to purchase one of these at some point.... hehehe

    Btw, I just randomly found this recent video of some young kid on youtube that I would say is going to grow up into a pretty inventive guy. He improvises other things he owns to work with his K'nex to make his little contraption move, and I think he's pretty bright for that :)

    If you're interested, check him out here!


    4 years ago

    It is EXCEPTIONAL! It is incredible, the emtire engine, the seat, adjustable steering wheel, the hood, everything... If you don't win, I will have to unsubscribe !

    1 reply
    knex akbar

    4 years ago on Introduction

    This is by far the best knex car i've ever seen... WOW

    Are you going to publish full instructions at some point?

    I would totally build this! :D

    3 replies

    Thanks so much! ^~^

    Well something I'd really like to do with those ferris wheel pieces if I win them would be to use them (plus probably have to still order a good amount more) to make a mid-rear mounted engine model aside from this one (instead of the actual rear mounting of this one) based off this one and make plans of that!

    For this one I could definitely give some more detail, or rebuild certain key portions to show, but a full build would surely require me to dismantle many things on it and I would really prefer not to do that unfortunately. :/

    (I estimate this build I have now to be in the field of 9-12thouasnd pieces, and is heavier on some pieces rather than others. I'm almost completely devoid of many of the most important pieces..)

    I would also make certain other changes however like; making it stronger with some more support(s) in certain areas or use a few new ideas I have on the matter, make large weight reductions in other areas of the car where possible, change the exterior figure in a few ways like making it sleeker and 'cooler', and otherwise just make some other simple optimizations and small changes.

    A new one would be way easier to document and post bit by bit for everyone!

    And one last thing... For the new one I'm seriously considering making it Remote Controlled!! :P :D

    Remote controlled... can't wait!

    Also an easy way to make instructions of big things like this is to work your way backwards, start by taking a small bit off the car and take pictures, then take another piece of the car and make pictures of that and so on untill the car is fully disassembled.

    Ya me neither!! But we might have to wait a bit unfortunately until I'm done school again to make a bit more money to spend on the RC stuff though and more K'nex, lol. And I'd like to mention that I don't think the moving K'nex inside will be able to handle anything too ridiculous in terms of power so it might not go all that fast compared to its size.

    Also as previously stated, I regrettably would like it to stay assembled to keep it. Also in my opinion it would be much easier to use it as a base blueprint when I can see it in person all together, pictures and videos would be harder to read for me than the real thing. Then documenting a new one will also likely be in better order that way! (Sorry to be a butthead on this one bud).

    Otherwise I'm sure I could also quite clearly define the main components for anyone to make a base model by just remaking and documenting certain parts of it, add that to some other guidelines and descriptions, and you'd probably be able to make all your own finishings and extra cool gadgets on top of it! :]

    Amazing! It's nice to see all those gears in a small place, very compact. The outside looks beautiful as well!