Introduction: Mountain Bicycle Chopper

Picture of Mountain Bicycle Chopper

Hey, ever wanted the power to see peoples heads turn?,

get that hot girl of your dreams (the validity of this statement is unknown :P ),

or just want to look freakin cool?

Then you should invest in building your own chopper bicycle!

Its fun, not so easy, but still fun!

lets get started.

This instructable was based off of mountain lion chopper, but i will actually specify dimensions unlike the other one.

All thanks goes to Atomic Zombie!


Now that I have rode around town on this chopper eye candy, I realized what a great decision I made! The looks people give your are PRICELESS, and a couple of times people actually got out of their cars to take a picture. Trust me, this chopper beats riding on the crap 30$ murray mountain bike it was before!

Don't wait, you can pimp out your ride too! just follow the instructions!

Step 1: Get an Old Mountain Bike

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If you have a Murray mountain bike, this works best, but any old mountain bike will do.

This is exactly what the bike i used looked like.

Step 2: Remove Everything From the Frame

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Sounds easy enough, but you will have to take off all the equipment from the frame


Step 3: Make a Gameplan

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It is wise to make a sketch of your work, and since I did all the trigonometry for you, you can skip this step.

Step 4: Cut Your Forks

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Your forks should be cut where it is flat, so cut somewhere in the middle of your forks

I chose 7.5 inches down, but the height may vary on your bike.

Step 5: Forks Cut

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This is what your forks should look like cut.

Step 6: Extend Your Forks

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Now this is the part where I made the wrong decision.
It wasn't necessarily wrong, but there are better methods to use:
I bought online 2- 36in tubes that were exactly the same as my forks.
I went on to butt welding the tubes to the forks.
The forks hold just fine, but that is because I had a professional weld my forks together.
I would HIGHLY advise not to do what I did if you don't have a pro welder sitting next to you.
The wise way would to be getting tubes that fit AROUND your forks,and just slide your forks into the tubes and weld. Trust me, this will save you time and money. 




After welding your forks together, if you want to have a front brake, weld a piece of metal between the two tubes where you can mount a front brake.
I didn't think about this, and I ended up placing a piece of metal too high for a brake >:(
It doesn't make a difference, but you can get more braking power if you do this right.


Step 8: Forks Complete

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This is what your forks should look like once you are done.

If you got this far, then great, your only half way done :) .

Step 9: The Hard Part, Frame Time.

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This is where my life went to hell. I spent 2 months trying to figure out how the atomic zombie people did their mountain lion chopper bicycle, and of course there were no dimensions or anything.
So, after much research, I found a way much more structurally sound and  easier to do.

Step 10: Cut Your Frame

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The first step is to cut your frame.

Preferably cut your frame 2 inches away from the top tube and 4 or 3 inches away from your bottom tube.

Step 11: Cut Goosneck

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This is what your cuts should look like

Step 12: Cut Off the Top Tube

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Now cut the top tube completely off. Save the tube for later.

Step 13: The Bottom Tube

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Here is where I differ from the Mountain Lion Chopper bicycle. Instead of welding a tube to the already cut bottom tube; were going to get a larger diameter tube and slide it over the cut bottom tube.

I figured out that the other people who extended their frame did it exactly 2X their bottom tube. So 16in X 2=32., Buy a new tube which will just slide over you original bottom tube, and make sure the new tube is 30 inches. This method is more safe, and is easier to do.



I used a Meg Welder to weld the bike.

You must cut off the little dongles which held the gearing system from the underside of your bottom tube.

Step 14: Goose Neck Modifications.

Picture of Goose Neck Modifications.

Remember your goose-neck? now we're going to do some modifications to it.

Cut off the top tube part from your goose-neck. Be careful not to bite into the goose-neck while grinding it.

You can discard the top tube part or save it for later.


Step 15: Attach the Goose-neck to the Frame

Picture of Attach the Goose-neck to the Frame

Now that your frame and goose-neck is ready. attach both together.

You should grind off the new bottom tube of your frame into a U shape so that it will accept the goose-neck.

The two pieces should fit perpendicularly. 

*Optional * grind a "U" shape to the new bottom tube so that the goose-neck will fit properly.


If the goose-neck is not fitting at a 90* angle to the bottom tube, cut the bottom tube off the goose-neck,

and quickly weld it back on @ a 90* angle.

Step 16: Check Up

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Your frame should now look like this.

Step 17: Now Weld a New Top Tube

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Now that the bottom tube and goose-neck is complete, weld the top tube.

The top tube i bought was 30 inches, grinded down it was around 28 inches.


Step 18: Spray Painting.

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To spray paint.

Get some high powered PAINT SRIPPER from any hardware store.

Apply the stripper to your bike, wait some time, and rub the paint off with some steel wool.

Wipe off all of the paint, then apply some MINERAL SPIRITS or PAINT THINNER. This will remove all the grime.

Buy some AUTOMOBILE PRIMER and apply to your bike. Apply about 2 coats.

Buy whatever color you want, and apply 3 to 4 coats. FOLLOW YOUR SPRAY PAINT BOTTLE INSTRUCTIONS!

After the spray paint has dried, apply ENAMEL FINISH CLEAR COAT . Apply 2 coats.

Step 19: You're DONE!

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Your chopper bike is complete. All you have to do now is to go to a bike shop and have them re size your chain onto whatever sprocket

place you want, and to re do your brakes.

For the chain I chose The largest sprocket on the front part (where the pedals are) and the third counting from the smallest sprocket on your back wheel. 

The back brake and the front brake can be zip tied back on.


SidduN1 (author)2016-12-17

nice i am going to dooo this bike ? zoombeeee

ianpallen (author)2016-08-21

This brings back memories. I had a bike in the 70's and I had 6 sets of front forks all joined together. A 16" wheel on the front and had to fit a 24" wheel on the back. Original wheels were 26". No brakes as they would not fit. lol. But that was the 70's when we were crazy kids on bikes. lol

YaënD (author)2015-03-24

hello thanks for this, i'll try to do the same with a kid bike for may son. the funny is that you go the the shop for your chain after doing crazy things on your own ! :D

RA productions (author)2014-12-04

Great project!! The bikes look great

joshuagabriel.cortes (author)2014-11-25

hahaha just upgraded the forks of the mountain bike and with small wheels. :3

joshuagabriel.cortes made it! (author)2014-11-25

hahaha just upgraded the forks of the mountain bike and with small tires. :3

otherunicorn (author)2014-11-03

Or you could use inserts of a smaller diameter to join tubes of the same diameter, which is what I did on mine.

ottawafm (author)2014-08-06

You should alter the lower tube between the pedals and handle bars by putting a 20 hp motor! Then heads will turn!

athakur17 (author)2014-07-15

hey i made.

husamwadi (author)athakur172014-07-15


I see your main frame looks more beefed up than mine, did you mod that?

That looks sick man.

athakur17 (author)husamwadi2014-07-20

yess i made from strong pipe and weld it. Can u tell me what Colour should i put on my bicycle. I am Confused about Colour. Pls

kavo (author)2011-06-07

why do you have to modify the frame?

husamwadi (author)kavo2011-06-08

If you dont change the angle of the goosneck, and extend the frame, you will make an akward/unstable bike which is impossible to drive.

HammE (author)husamwadi2013-12-23

That's what I did with my bike, lol! I can stablize it though

Mitchvdk (author)2012-06-07

this is what i made

husamwadi (author)Mitchvdk2012-10-04

Awesome, that looks better than mine lol!

hey I see you didn't take me advice about the front brake...wait there are no brakes!

good job bro, I like it!

Mitchvdk (author)husamwadi2012-10-05

Wow thanks man but it does have a brake lol. I shall post a new photo because it looks a lot better right now but thanks for the inspiration!

Thundermoon99 (author)Mitchvdk2012-10-30

hell yeah white walls

IndianDrives (author)2012-05-04

I think this is the place where we will get best ideas for building own chopper bike. Cheap Cars for sale

awesomevampire (author)2011-08-03

yo husamwadi,
am a pre teen and i want one of these, but what do i do
if i get ant taller i'll out grow it really quick (i'm really tall)
or should i mak it and make mods when i get taller

pretty pretty please with extra ice cream, hot fudge, and rainbow sprinkles on top !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!

husamwadi (author)awesomevampire2011-08-05

listen....there's no such thing as "too tall" for anything.....

If you mod a 26in bike using my methods and measurements, there is NO WAY you could out grow the bike, unless your dad happens to be big foot.

so go ahead and do whatever whenever- with your sprinkles and rainbow pony pickles.

p.s: don't hack your sister's account, unless you like a hand print across your face; take it from a guy with experience.

tallest (author)husamwadi2011-08-15

Funny thing... I'm 6'8" and basically all standard frames are far to short. I'm planning on adding a small frame section to the bottom that pushes the pedals further towards the front tire and creates more leg room.

husamwadi (author)tallest2011-08-17

you do that wooly mammoth. :)

LETMESEE (author)2011-07-29

A guy up the street from me did this a couple months ago ....He let me ride it but it was so hard to control!!!!!!!!!!!!!! :P

husamwadi (author)2011-06-18

hey guys, check out my new instructable:


vishalapr (author)2011-06-15

This is really cool, well done , rated 5*

Andy244 (author)2011-06-09

cool chopper dude, enjoy it!!

Cheap cars (author)2011-06-07

nice chopper bicycle! Thanks for sharing a lots of information.

Used cars

struckbyanarrow (author)2011-05-29

i see a snapped headtube in your future, good job anyways!

yep, i hear some creaking...... :P

mikeasaurus (author)2011-05-23

Nice rake!
I've seen signs of bike with rake's similar to this fracturing near the head due to stress of the front wheel being so far out, is there a threshold calculation based on frame thickness/rake degree or is just a prototype? Other bikes I've seen have adopted a tension cable from front hub to frame which you may consider.
Either way, the bike looks great!

husamwadi (author)mikeasaurus2011-05-23

You should show me this "tension thing", actually this is the first time I have ever made anything from my own, let alone complete it :)

I don't know how long the forks will hold, they are really sturdy though. My rule of thumb is "The First pothole's gunna be the Last pothole :P"

mikeasaurus (author)husamwadi2011-05-24

Here's an example of a tension string placement. From what I've seen the tension is held by steel wire with a thickness of about 10mm, from the from wheel hub to somewhere on the frame. I think this would only be necessary with bike with a wide rake, but there's probably a calculated 'sweet spot' where you can maximize the rake without a tension string.

Whatever, this is a homebrew project and there is no need to over-think it. Have fun, break your bike, rebuild it better than before. Be safe and have fun. Keep building those 'choppers!
(typical bike silhouette with tension string example in red)

husamwadi (author)mikeasaurus2011-05-25

Thanks, I will consider it.

my current problem right now is that the front wheel is so old that the spokes lost their tension; aka the wheel is warped and about to taco.

I need to find a new wheel :P

banks412 (author)2011-05-25

Atomic Zombie may have some advice on this 'threshhold calculation' issue. I just bought his book "Atomic Zombie's Bicycle Builder's Bonanza ", and there's a huge section in there about building choppers.

Sweet bike, bro. Once I'm able to afford a welding rig and learn the basics, this looks like something fun to try!

husamwadi (author)2011-05-23

Please rate 5 stars!

If you have any questions, feel free to ask :)

About This Instructable




Bio: a dude with a million dreams, hundreds of ideas, and a drive to achieve! If I make an Instructable, It is usually phenomenally AWESOME, and ... More »
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