HIGHLANDER DIY CHOPPER BICYCLE
Attitude is the one word that best fits the timeless and immortal chopper. Reaction to the chopper on the street will be mixed. Some people will give you a “thumbs up,” some will turn away, and others will stop you to find out where they can get such a cool bike. For the rider, the chopper is a bold statement of independence and personal expression that challenges conformity. It’s amazing what you can create from a chopped up bike with extended forks. Of course, the chopper is not a bike for everyone. If you want an easy-to-ride and comfortable bike, then this is definitely not the bike you want. Choppers in their very nature are awkward to drive, have a mind of their own and put the rider in a less than ideal riding position between the long seat and tall handlebars. But once mastered, the chopper and rider become merged into a single machine, and riding with grace becomes second nature. Once you are in control of your machine, it is always fun to let those you meet try to ride your chopper, and see them shake and wobble down the street as the bike defies their every attempt to gain control.
So, what defines a chopper? This is a tough question to answer, and is open for debate. Almost any radical change to the standard bike can considered “chopping”, but most people will agree that a true chopper is a bike in which the forks have been greatly extended. As soon as you make this modification, your machine will easily be identified as a chopper by the masses, and from here you may use your imagination to turn you machine into a work of art.
Extremely high and long handlebars also known as “ape hangers” are also standard accessories for a chopper. These types of handlebars make the rider stretch out and hang on as if hanging off of a monkey bar. You may ask why anyone would want to ride a bike like this, but the true bike rebels need no explanation , they just know it’s just right.
The intention of this basic chopper tutorial is to challenge your creativity, so feel free to let your imagination run wild and add your own attitude into the design.
The Highlander is a chopper that oozes with attitude and commands respect. Based on the wild “Easyrider” style low-riders of the early 1970s, this extreme bike is fun to ride and draws a lot of attention on the street from young and old alike. Although this project is custom built from the ground up, it requires only a few lengths of electrical conduit for the frame, a small piece of sheet metal for the fender, and some basic bicycle parts. This project can be built in a few evenings with only the basic tools and a little patience.
This bike is built to fit the rider and fork length is entirely up to you, so I will not be presenting a strict set of measurements for design, since the basic measurements will change according to your leg length and design style. You may want the bike to fit a range of rider sizes, or set a new world record for fork length. This is all possible, but there are some basic design principals, such as keeping the pedals high enough off the ground to avoid hitting during a turn, and making sure your legs can actually reach the pedals, that need to be followed.
As shown here, there are five basic measurements. Measurement ‘A’ will always be the same, and ‘B’, ‘C’, and ‘D’ are a product of ‘A’ and ‘E’. Confused? Sounds like we are going to build a space shuttle for NASA here, doesn’t it? Well, have no fear; this is a lot simpler than it sounds.
Basically, length ‘A’ is the same because it puts the rider a certain distance from the handlebars. If you are 6 feet tall or 4 feet tall, this length will be just fine, since the handlebars are easily adjusted forward or backwards. It has also been calculated so the frame can take a 26-inch rear wheel with a fat tire.
Measurement ‘E’ is, of course, fork length (the very essence of a chopper). This is something you will decide on, although I will make a few suggestions for practical riding purposes.
Ok, now that we know the length of ‘A’ (always the same), and the length of ‘E’, (the forks), we can than calculate ‘B’, ‘C’, and ‘D’ so that the rider can reach the pedals and the pedals do not scrape on the ground. That’s all there is to it.
As always, before you start, it’s a good idea to source out all the raw materials for the project. Since the biggest part of building this chopper is your own hard work, the list of materials and cost is very small, and most of the parts like those shown in this photo can be salvaged from scrap bikes. Here’s what you need:
About 20 feet of one-inch, thin- walled steel electrical conduit (also called EMT).
Two sets of forks from a 26-inch mountain bike (these do not have to be exactly the same, just as long as they are for a 26-inch wheel).
One head tube and fork set salvaged from another bike frame (any size fork will do as long as the head tube and forks fit together).
One bottom bracket and crank set salvaged from another bike frame.
One gooseneck and set of ape hanger handlebars.
A sheet of 24-gauge or similar thickness steel for the fender (about 4 feet square).
Two nuts and bolts for the forks (nuts need to be about 1-inch in diameter to fit inside the electrical conduit as you will soon see).
One big seat with springs (these can be found on many exercise bikes).
One 26-inch rear wheel with coaster brake and one 20-inch front wheel.
A few chains of equal size to join together (these must fit on your crank set).
Once you understand how all the parts go together feel free to modify the design to suit your needs or style. You may want a 24-inch front wheel, or 20-inch on the front and rear, or even 36 speeds with front and rear shifters and disc brakes.
The first step will be to cut the main tube ‘A’. Since the length of this part of the bike includes a set of forks, you must put them together before you mark the tube for cutting. As shown here, the fork threads are put inside the tube, and then measured from the end of the forks to the end of the tube to be cut. The fork bearing race is no longer needed, so just tap it off with a hammer and add it to your parts collection for later use.
The total length from the fork tips to the cut on the pipe should be 44 inches. Once marked, you can cut the main tube with a pipe cutter or d hacksaw, and also cut most of the head tube from the set of forks. This will not be used since it will be inside the main tube after welding.
Once you have the tube cut, weld the tube and forks together where they meet at the base and then grind and clean the welded area. You now have the first part of the frame completed.
Now that you have the main tube welded to the forks, you must decide on how long to make your front forks, as these two parts of the bike will dictate how the rest is made. In my design, I used a total fork length of 56 inches (measured from the very top of the forks to the dropouts). You could probably make longer forks if you wanted to, but after making a few choppers, I found that this length is about the maximum length you could have on a bike and still have decent control.
This length also allows you to turn around in the width of an average city street without having to pick up the bike and turn it around manually. Of course, if show is your main reason for making this chopper, you could use the entire ten-foot length of conduit for the forks and still make a rideable bike, although it will be quite a challenge to ride!
Once you decide on a reasonable fork length, cut two identical lengths of conduit. It is important that both pieces are the same length, or your front wheel will be leaning to the side, making it difficult to control your bike.
Lay the newly welded main tube and one fork length on a flat surface, as shown in this photo. A long tube or any straight object is placed horizontally so that you can visualize your bike standing up. When the basic frame is complete, the front and rear dropouts and bottom bracket (the tube that holds the cranks and bearing hardware) should all be on the ground at the same level. This makes it easy to design the bike so the pedals will not hit the ground. Set the forks so that they are roughly 90 degrees to the main tube.
You now need to calculate your leg length (inseam) so you can set the proper distance from the seat to the bottom bracket. If you are building this bike to fit several riders, measure the inseam of the shortest rider, but don’t expect a bike made for a four-foot tall rider to fit a six-foot tall rider. If there are more than five or six inches difference, you will need separate bikes or some method to adjust the seat height.
The easiest way to measure your inseam is to stand with your back against the wall (while wearing shoes) and have someone place a ruler between your legs and measure the distance from the ruler to the ground. You can also set up a “regular” bike (remember those?) so that it is adjusted for your height and just measure the distance from the top center of the seat to the center of the lowest pedal.
Ok, now for the most critical measurement — the distance from the top of the seat to the farthest position of the pedals during a full crank rotation. To set this distance, put a tape measure in the area that the seat will be (about four inches past the joint in where the main tube meets the forks) and pull the tape 90 degrees away from this point to the length of your inseam measurement.
Place a crank arm on the guide that is being used to line up the frame so that the end of the arm is as far away from the seat area as possible. This will be your end point. You will also notice that I added some extra distance by starting the measurement about three inches away from the main tube as well.
This extra distance compensates for the extra thickness the seat will add. If you imagine yourself sitting on the seat pedaling the bike, you’ll notice that this distance (your inseam) will be the farthest distance your legs will have to travel during a full pedal rotation. If you used a regular bicycle to take this measurement, it should be the same.
Now, place the second set of forks alongside the guide so the tips meet the other set of forks with the threaded end pointing towards the crank set. These two forks will be welded together to create the rear triangle of the frame. You can use curved or straight forks depending on the style of frame you want, but if one set is heavier than the other, try to use the heavier set on the bottom.
Measure the distance from the center of the crank set (bottom bracket) to the joint in the forks where the tube is welded to the top, and cut a tube to that length. You will be placing this tube between the bottom fork and the bottom bracket.
If your forks still have the bearing races attached, remove them so that the threaded part can slide all the way inside the tubes you are using for your frame.
Once you have the pipe cut for the lower part of the frame, drop it in place, and place your bottom bracket (salvaged from another frame) onto the end of the tube, as shown here. Remember that this tube is parallel to the ground, and draws a line from the rear dropouts to the front fork dropouts.
If you imagine the completed frame standing upright on level ground, the rear dropouts, bottom bracket, and front fork dropouts would all be touching the ground at the same time.
Measure the distance from the bottom bracket to somewhere in the middle of the top tube, and cut another tube to fit as shown here. The actual angle and position of this tube is not critical, so feel free to place it to suit your taste.
In my design, I found that a 90-degree angle from the top tube to this new diagonal tube looked good, but you can bring it back right under the seat if you wanted to. Don’t worry about the exact lengths of your cut tubes just yet, as we will be grinding them all to fit together before welding anyway to get a closer joint for welding.
Now, measure and cut the final frame tube that will connect the bottom bracket to the head tube. The head tube shown here has been cut from another bicycle frame and ground clean by removing the left over tubing at the welded joints. At this point, you can see the frame take its basic form, so it is a good idea to check your inseam measurements again just to make sure you will fit the bike. Remember that you will be sitting on a 2 or 3 inch thick seat just above the top rear set of forks and your legs will have to reach the farthest position of a crank rotation, so check it again! If you are satisfied that all looks good, then it's time to make some sparks.
The first weld will be at the very back of the bike where the two sets of forks meet. Cut most of the dropouts from the top set leaving only a little bit of metal to weld to the bottom set, as shown in this photo.
Weld the two forks together at roughly the same angle they were at when you first set the frame up. It’s a good idea to only tack weld all parts at first, so they can be adjusted as the frame goes together. Notice the heavy dropouts already on the lower set of forks. This is something to look for when choosing the donor forks. If the dropouts on your forks are very small or damaged you may have to find a better set from another frame, or cut them off and weld on a better set of dropouts to hold your rear wheel.
Once the two forks are joined, you can weld the other two tubes that fit over the threaded end. Since the threaded ends have no real use inside the tube, they can be cut before welding, leaving only an inch or two to help line up the tubes. Tack weld the part in place and then view the assembly from the end to ensure that the two long tubes line up with each other. The alignment of both frame tubes is determined by the alignment of the joints at the fork leg tips, so you may need to break a weld and redo it if the alignment of the two frame tubes is way off. Weld around the entire joint, and clean up the welds before moving on to the next step.
Now, you can begin welding the rest of the frame together using the same process you laid it out on the floor. Weld the bottom bracket to the tube that joins the lower rear forks, making sure that it’s positioned at a perfect 90 degrees with the EMT tubing. It is important that the bottom bracket is welded at 90 degrees to the other frame tubing so that the chain ring will be in line with the sprocket on the rear wheel. If you do not get your bottom bracket aligned properly, your chain may keep falling off. Once you have made sure that the bottom bracket is aligned correctly, finish and clean the welds.
Next, weld the tube from the bottom bracket to the head tube and weld the head tube to the top tube using only tack welds. Your frame is now in the shape of a triangle and is only missing one tube — the one that divides the frame into two parts. The angle of the head tube is determined by your chosen fork length as determined in the first few steps.
Check that everything is in alignment by looking at the frame from all angles, especially from the front and rear. The head tube needs to be aligned correctly or your forks will leaning to one side. This error will be quite noticeable because the forks are so long.
If something looks out of alignment after tack welding the parts together, then tap the piece straight if you can, or break the weld and try again. Once you have everything looking straight, weld in the last tube, the one that connects the bottom bracket to somewhere in the top tube, dividing the frame into two triangles. This tube is left for last because it can be placed just about anywhere and the actual frame geometry dictates its length.
Remember that professional frame builders have jigs that hold all the parts together, but what you are doing is true art. Have patience!
After hours of welding, grinding, breaking and re-welding, you now have the perfect chopper frame, right? Yes! This next part (a frame gusset) not only adds strength to the front of the frame, it enhances the Highlander’s looks as well.
The gusset is made from a piece of sheet steel of approximately 12 gauge and can be practically any shape you like, even in the shape of flames if you have the patience to cut the piece that way. This simple gusset was made by first test fitting a cardboard mockup and then using it as a guide to trace out the part to be cut from the scrap sheet metal.
Once you have cut and test fit your gusset, weld it in place. I decided not to make a gusset that would go right up to the head tube because it would be hard to get in there with a grinder after to clean up the welds. It's time to take a break so you can sit back and admire the work of art you have created. Your frame should now look something like this one if all went well. Clean up all the welds with a grinder, filling in any holes and gaps before you move on to the next stage.
It’s time to give life to your chopper and create those radically extended forks. Place your frame on the ground so it is sitting on the rear fork legs and bottom bracket shell. You can now determine the length to make your fork tubing by placing on end on the ground ahead of the bike while the other end rests on the front face of the head tube shell. Mark a cut line on the tubing at the top of the head tube. Look back at the first photo (note length E), to see how the fork leg tubing runs at the same angle as the head tube until it hits the ground ahead of the frame. Once you have determined the optimal fork leg length, cut two tubes to be used as your fork legs.
The chopper fork legs will be held in place by a set of two plates and top bolts. You will need to weld a nut into the top of both fork legs. Try to find a nut that will fit snugly into the tube so it will align to the center easily as shown here. When you have found a nut that will fit snugly into the tubing, carefully weld it around the edges, being careful not to wander into the threaded area in the center of the nut. You may want to thread in a spare bolt just to protect the threads inside the nut when making this weld.
When you have both nuts welded into the top of the fork tubes, weld a set of dropouts (salvaged from another set of forks) on to the ends of each fork leg. You will notice that on the forks shown here, I welded an entire section of the donor forks on to the ends of the new fork leg tubes. I did this because I liked the tapered look of the dropouts on the donor forks. This system will work fine, but you will have to find forks that are roughly the same thickness as the tubing, or there will be an ugly seam. Also, remember that if you are adding length to the forks, you will need to compensate by removing the same amount from the EMT fork legs or your chopper will lean backwards more than expected.
The forks used on this chopper are called “triple tree forks”, and are commonly seen on motorcycles and some extremely hefty mountain bikes. There is an upper and lower plate connecting the fork legs to the head tube and this assembly is extremely strong as well as stylish. To make the plates for the triple tree fork, you will need a plate of 1/8-thick steel with enough room to draw two six by three inch squares, as shown here.
If you read ahead a bit further in this tutorial, you will get a better idea how this fork set is going to fit together. Basically, the lower plate is welded to both fork legs and the fork stem, and then the top plate bolts on to the top of the forks using a set of bolts that fit into the nuts welded at the ends of the tubes.
The dimensions of the triple tree plates are as follows: length A is 6 inches, length B is 3 inches, length C is 2 inches, and length D is 1 inch. Mark these shapes out on your sheet and then cut them out using a zip disc or a jigsaw with a steel cutting blade. All sharp corners are rounded using a file of sanding disc in your grinder.
To create the proper placement of the holes for the fork legs, place a piece of tube with the same diameter as your fork legs into each of the corners of the plates as far to the edges as it will go without hanging over and trace a line around it. For the lower plate, this traced area is ground or cut out so the fork legs will fit into the hole for welding.For the top plate, you need to find the center of each circle you traced and drill a hole large enough for your bolt (the one that fits the nut welded into each fork leg) to fit through.
The top plate also has a hole for the fork stem to fit through. This hole will be slightly larger than one inch, so it fits snugly around the threaded tube without being forced on.
Once you have the holes cut into the plates, you can round off the edges with a grinder as shown here on this completed top plate. Make sure that you leave enough area around the top plate to cover the fork legs once they are bolted in place. When grinding the edges, place both plates together in a vice, so that they will be of equal size when you are done.
The next step is to weld the threaded fork stem (salvaged from another set of forks) to the bottom triple tree plate. The fork stem should be a match to the head tube you are using so that all of the bearing hardware will fit together properly. Cut the fork legs form the stem at the crown area and then grind the tube clean. When welding or grinding near the crown area of the fork stem, remove the bearing race so it will not be damaged by tapping it off with a hammer. The fork stem needs to be welded in the correct position on the triple tree plat and so that it is 90 degrees to the plate
The fork legs are also welded to the bottom triple tree plate, but they must be positioned correctly so that the top place will sit flat on the tops of the fork legs as well as the top fork bearing race. You can see how the top plate is installed in the next photo. I recommend that you install all of the fork hardware (including bearings) and then fasten the fork legs to the top plate using the two nuts. This way, you will know for sure that the fork legs are in the correct place on the lower triple tree plate for welding.
This photo shows the triple tree fork assembly put together correctly. When you are welding the lower triple tree plate to the fork legs, you should do so with everything put together as shown here so that you will know for certain that the fork legs are in the correct position on the lower plate. It's a good idea to use tack welds when you are aligning all of the fork parts so that you can make any necessary adjustments before completing all of the welds.
To ensure that everything is straight before the final welds are done on the bottom plate, take the forks apart again, install your front wheel and then have a look down the ends of the forks as shown here. If your front wheel is way out of alignment, you may have to break a weld and fix it. Some slight side-to-side wheel misalignment can be corrected by setting the wheel in the dropouts at a slightly different angle.
Once everything looks good from all angles, complete all of the welds to the bottom triple tree plate, and clean up the welds using your sanding disc.
Now, let's make a cool custom phat fender for that low-rider look. Sure, you could just slap on a simple chrome fender from an old granny bike, but why skimp out now after all of this work? This part of the project involves a lot of welding and grinding, but it’s not complicated.
You will need a sheet of 12-gauge or similar thickness sheet steel that has enough room to draw two 28-inch diameter half circles on it as shown here.
The basic idea is to create two sides and a top, then weld it all together. Sounds easy enough, right? First, get whatever rear wheel you plan to use on the bike, an install a tire. If you plan to use a nice fat rear tire, put it on now because we need to know what diameter to make the inside of the fender. Take a measurement from the axel of your rear wheel to the farthest edge of the tire and add 1.5 inches to this distance. This will allow for clearance.
Tie a string to a marker, place it on the sheet, and draw a half circle so that the edges of the arc are at the edge of the sheet. This minimizes waste. Now, decide how deep you want your fender to be, and draw the inside arc from the same point. I made my fender four inches deep, but you could go less or more, or even tapered if you like.
You will need two sides and a top for the complete fender as shown in the next photo. The top strip is as wide as the distance between the top set of fork legs that make up the rear of the bike because you will be welding it there. My fender is 2.5 inches wide. This is a fairly standard width for a pair of forks. The top strip also needs to be as long as the distance from the front to the back of the fender, so you will need to make this measurement with a flexible tape. You will also notice that I added some styling to the front and rear of the fender sides, flaring them out at the rear.
Once you have drawn the fender template, cut it out using whatever method works best for you. I used a jigsaw with a metal cutting blade and although it was a long process, the final product needed almost no grinding or re-shaping before welding.
Welding the fender together is an easy process. Lay one of the sides on the bench and begin to tack weld the center strip at one of the ends. Bend the flexible strip along the side as you place another tack weld about two inches from the first, and then repeat this process until the entire strip is tack welded to the side.
Next, place the other side on to the strip and tack it in the same manner. The completed tack welded fender will look like the one in the next photo. Now, check the fender for straightness and adjust it so that both sides are 90 degrees to the top strip.
Once you have tack welded the fender into a solid shape, completely weld the entire joint and then fcarefully grind it glean using a sanding disc, Filling any holes and then repeat the sanding process until the edges look perfect. This as a long process, but will result in a very nice looking final product, as shown in the next few photos.
Although this is not a hard weld to make, getting the fender to line up so that the rear wheel is not rubbing inside is quite a chore. The first thing you need to do is place your rear wheel onto the bike with a fully inflated tire.
Now, you will need to tape some 1.5-inch foam or wood blocks to the top half of the tire to hold the fender in the correct position with the same 1.5 inch clearance between the tire and fender along its entire inside length. Once the blocks are in place, put the fender over the wheel and into the correct place on the frame. You also need to put wedges along the sides of the wheel so that the fender has equal spacing on each side of the tire.
Once you have everything blocked in place, make a few solid tack welds to join the fender to each side of the frame until it is secured in place. Once the welded area has cooled, remove the blocking and see if the tire rubs by giving it a spin. You may get lucky right away, or you may spend the next hour bending the fender until you get it right, but with patience it will all work out.
When the tire seems to be aligned properly inside the fender, remove it and complete the welds along the forks, taking care to not burn through or overheat the thin steel. When you put the wheel back in, you may need to repeat your adjustment routine because the heat may have warped or pulled the fender out of alignment again. Don’t worry; it will fit if you just have patience. I had to take the wheel on and off the bike about 10 times before I found the correct spot!
If you managed to get past the fender alignment puzzle, then you can take a breath because the rest is smooth sailing. You need a place to sit on the bike, so find yourself a seat. I chose a big wide seat from an exercise bicycle that looked like it would fit nicely with the chopper.
These types of seats are easy to find on both exercise equipment and “granny” bikes (you know, the old blue and white style seats). If you can’t find a seat like this, anything will work, but remember your inseam measurement and try to keep the seat as low as possible to the frame. The seat will be placed on the frame so that it is as close to the fender as possible, so you get a nice low rider style chopper.
Now the fun part - the pre-painting test ride! Put on a crank set, handlebars, chain, and the rest of the parts and then head out on your new chop to see if it holds together. Does the fender rub? Are the forks straight? Do the pedals have adequate ground clearance? Does the chain stay on? Hopefully, everything turned out well, but if not, it’s not too late to get out the hammer and make things straight.
Chances are that your bike will ride just fine and after a block or two of wobbling, it will just start to feel right. You will notice that these long choppers like to get moving a bit before they are totally stable, but once moving, ride just as smooth as any cruiser. Do you like all the “thumbs up” and horn blasts from your impressed observers?
Ok, back away from that chopper and get a few cans of primer and spray paint. You can really do a great paint job with a department store spray bomb if you take your time and follow the instructions on the can. Let your primer cure for a day before adding the paint, and always use short strokes with the nozzle held at least 6 inches away from the frame as you paint. I ended up with a cherry red frame and used silver for the forks, but feel free to mix and match the colors, adding stripes, splatters or decals to your completed ride.
One of the hardest parts of building a bike like this is waiting for the paint to dry before putting it back on the road! Have patience, it will be worth it.
It sure feels good to roll down the street on a completely custom DIY chopper, doesn’t it? How far do you get before crowds of people stop you to look over the bike and beg to have a test ride? Be prepared to stop often and answer questions about your sweet ride, and hey - we are totally cool with you sending over some new bike hackers to our site to join in the fun! Well, we hope that you enjoy your new chopper and when you are out riding, remember the rules of the road...you own it!
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