Instructables

Build A Massive Snowmobile Tank Bike

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Picture of Build A Massive Snowmobile Tank Bike
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After getting inspired by the final episode of American Choppers and then seeing my neighbors driving around on their snowmobiles, I set out to make a crazy combination of the two as a pedal-powered monstrosity.  I designed and constructed this bike in just under three weeks using three broken bikes, some steel tubing and angle iron, and an old 1990 Polaris snowmobile track. 

It’s a fun challenge recycling old bike parts and converting them into a new bike, and this massive, 7 foot long bike provided some unique challenges.  Integrating the tread with the bike frames and turning through a big track on a heavy bike that doesn’t allow for traditional high-speed steering is definitely an adventure.   

A MIG welder and a regular hacksaw served as the primary tools for construction, in addition to a common set of wrenches and screwdrivers.  This is definitely a great project for diy bike or snowmobile enthusiasts with some junk bikes, scrap material, and free time.
 
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Step 1: Planning the Internal Frame

After getting all the necessary tools, parts and as many bikes as possible, start by planning out how to integrate the snowmobile track with the bike frames.  Children’s mountain bikes with 20” tires fit nicely inside of the track, and the knobby mountain bike tires fit snugly in the gap where the sprockets are supposed to fit.  I found that the limited space inside of the tread accommodated a three wheel configuration more easily than all four wheels.  

Start by disassembling the two bikes for the interior assembly down to just the frame with the pedals.  Cut down the frames so that they fit inside the track with enough clearance for it to rotate.  The frames will be kept parallel with the addition of the third wheel between them in the back. Center the third wheel down the middle of the track by welding the seat and chain stays from an additional bike frame to the inside of the other bike frames, giving another set of dropouts where the wheel could conveniently be attached.  When welding to the bike frames, make sure to sand or grind all of the paint off of the surface of the metal.  The dropouts on the third wheel also make it easier to remove the tread by just taking off that third wheel first.  *Be sure to dimension the assembly so that the track is snug with deflated tires so that once you inflate the wheels, the track will be tight without having any other mechanism to tension it.
thrawn111 months ago
On the epic scale, this is pretty damn high! How much did it end up weighing? Having made 3 bikes myself I can appreciate some of the issues that arise from having donor bikes that don't quite match, well done.
jsmith259 (author)  thrawn110 months ago
Thanks so much! Not quite sure how to weigh it effectively, but you don't want to be carrying it too far! Yeah, it's definitely a fun challenge converting old bikes into new ones.
Mikey2.011 months ago
I'm sure you could put snowmobile ski on the front and actually ride it in deep snow. Hows the turning radius?
jsmith259 (author)  Mikey2.010 months ago
I'll have to try it next winter! The wheel's nice for right now because it still runs on the sidewalk or in mud, but I like the idea of making it more of a true snowmobile.
curtman2911 months ago
Very cool! I would wanna have half the track for weight reasons. Then you could turn alot easier also. But still a very cool design!
jsmith259 (author)  curtman2910 months ago
Thanks! It's definitely very heavy and very difficult to turn, a half-track would be an interesting improvement!
skidoooutlet11 months ago
I want to make a snowmobile type bike like that! You guys should make a video tutorial on how to make this.
jsmith259 (author)  skidoooutlet10 months ago
I would recommend it, it was a lot of fun to build. I'll try to put together a tutorial as well.
OMGosh that is so cool! Gave you a vote! Ure soo gonna win!
jsmith259 (author)  Enjoying Electronics10 months ago
Thanks so much, I really appreciate it!
Instructables are always editable after the fact, you can add video later right?

I would think that some kind of shin guard for a short section of the upper track might be nice to help keep your legs off of the track edges.

I also think you should try changing out the steering to a twin-stick sort with linkages running forward to the forks. That way, you keep the ability to steer sharply and still be able to do so from further back.

I bet you don't need a kickstand.

Now, when will you add a gokart motor?
jsmith259 (author)  Shadetree Engineer10 months ago
Thanks for the tips! Shin guards are definitely on the to-do list- riding right now leaves some marks where the track occasionally rubs on your legs. I might try the twin stick steering as well...steering this heavy bike always needs improvement!
mysss11 months ago
This looks like an awesome achievement. It seems like it would work a lot better as a recumbent...which might be more chopper-y, I'm not sure about that part. It looks like it sort of would work with the ultra-low-seat style of pedaling most people seem to use; but I'm pretty sure it'd be a lot more comfortable and efficient if you used a "proper" pedaling style with your legs extending roughly all the way...with a giant snowmobile tread to turn, I'd want all the help I could get!
jsmith259 (author)  mysss10 months ago
Thanks, definitely worth looking into. We just arbitrarily mounted the seat in a location that was convenient to put it where we could still reach the pedals, but I'm considering moving it. I like the idea of a recumbent.
Gaark11 months ago
Totally hard case!! Love it!!
jsmith259 (author)  Gaark10 months ago
Thanks!
MCUman11 months ago
From the pictures, the little angle piece joing the pedal cranks is absorbing all of the lateral stresses. You might consider adding a couple of cross-frame members to stiffen the carraige. Interesting concept. Well Done.
jsmith259 (author)  MCUman10 months ago
Good call. The addition of the third wheel between the two frames took away some of the stress, but we did need to weld another bar between the frames afterward, it's tough to tell in the photo though
jcarlyle111 months ago
That is the coolest thing I have ever seen!!! but I bet those handle bars don't do too much, do you have to get off to turn a corner? Would be worth it anyways i bet.

+1 for video!
jsmith259 (author)  jcarlyle110 months ago
Thanks! Definitely very difficult to get used to turning, eventually can get some wide turns, still a work in progress though!
http://www.youtube.com/watch?v=hlgdL-Z0rHc

(snowmobile bike appears towards the end)
voyageur1011 months ago
This is awesome! A full video of the bike in action would be EPIC! Thanks.
jsmith259 (author)  voyageur1010 months ago
Thanks so much! Working on it!
Machshop11 months ago
Awesome and original design/build! Kudos for the out-of-the-box thinking that created a so NOT so out-of-the-box result! Add me to the video request list!
jsmith259 (author)  Machshop10 months ago
Thanks so much! Working on it!
husamwadi11 months ago
ride thru the drive through like "waddup I got a snowmobile tank bike"... LOL AWESOME.

It's different, have you tried no hands? can you pop a wheelie, if you could pop a wheelie that'd make you an insta boss!
jsmith259 (author)  husamwadi10 months ago
I like the sound of that! If I can pull that one off, I'll be sure to get a video for you
veryrealperson11 months ago
I wonder how this actually performs in mixed weather/ice without snow. Chicago may be forced to witness this beautiful franken bike
jsmith259 (author)  veryrealperson10 months ago
Couldn't quite get it all together while there was still snow on the ground! Working on getting it all ready for next winter!
Eunix10 months ago
Congratulations on winning the bike contest, this IS a great instructable.
jsmith259 (author)  Eunix10 months ago
Thanks!
husamwadi10 months ago
congrats on the GRAND PRIZE!!!!

now you can fix dat monster bike with your new toolset!
jsmith259 (author)  husamwadi10 months ago
Thanks! For sure, still got a lot of fine-tuning to do haha, the tools will definitely help!
bajablue10 months ago
Woo HOO, jsmith!!!
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jsmith259 (author)  bajablue10 months ago
Thanks so much!
jsmith259 (author) 10 months ago
Hey guys, big thanks to everyone who voted for the bike and helped me out in the contest!!! Thanks for all of the comments too, I appreciate the feedback! I'm working on some adjustments now, I'll definitely work on putting up a detailed video of the bike soon as well.
srilyk11 months ago
I want to see a video!
agm8811 months ago
thumbs up man!!!!!!!!!
neil170111 months ago
Mega and more stable than sliding down a slope on the snow with a ski attached to the bottom of a front fork,wobbling about all over the place,much more stable this is it be,may the force of awesome creativeness be with you,always.
Kiteman11 months ago
O M G ...

Please tell us there's video?
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