Introduction: Make Your Own 29er Bicycle!
The pictures aren't the best because I never intended on making an Instructable but here goes.
I have wanted a 29er mountain bike for a while and stumbled across an old Trek 720 hybrid that I was going to just fix up to make into a commuter bike but was inspired. I had many parts around my shop and what you have will dictate where you can take this. For those of you unfamiliar with a 29er, it is a mountain bicycle with 700c wheels (like that of a hybrid) using a larger tire width making the overall tire size around 29" instead of the typical 26" found on most mountain bikes.
I am a welder with a number of years experience in making goofy creations and sculptures, this is the first really high end bicycle. Producing strong welds is crucial in this project so if your not experienced get someone who is. I used a MIG welder for this and am self taught I can't afford a TIG welder yet and have never taken formal classes but have become fairly proficient over the years.
Step 1: Strip the Frame
strip old frame down removing all parts and decals. This bike was particularly attractive because the early Hybrid bikes like the Trek 720 used higher quallity Cromoly steel and had the geometry similar to that of todays 29ers.
Step 2: Geometry and Head Tube
This bike being an older design used a 1" threaded head tube. This design is heavier and out dated so this was the biggest obstacle I faced. I had 2 forks to chose from and both were 11/8 threadless. I researched and found a great company called Nova Bicycle Supply and was able to order just the head tube and some other braze on parts from them that you will see I used later.
I measured the geometry and used the geometry from a bicycle made by Salsa as a template for how I would line everything up and weld it together.
Step 3: Remove Old V-Brake Bosses and Braze on Pieces
In this step a carefully cut off the brazed on pieces that guide the rear brake cable to mount to the rear brakes. This bike actually had Cantilever brakes so it also had a small tube that wrapped around the seat tube which I also removed. I used my dremel with a cutting disk for most of the work and my 41/2" angle grinder with a sanding disk to clean up the remains.
(you can see the sanding disk on the work bench under the frame in each picture)
Step 4: Remove Old Head Tube
I then cut the old head tube off the bike carefully using the 41/2" angle grinder with a cut off disk. I then used the Almost Jigless Frame Building design posted by drwelby https://www.instructables.com/id/Almost-jigless-bicycle-frame-building/
In the first picture you can see the frame chopped up in the back and the level on what will become the "Jig" for welding the new tube in place.
In the second picture I have the frame mounted to the jig and I am adjusting where the angle of the tube will end up. I had to take into consideration the length of the fork I plan to have because the fork I will be using is an inch and a half longer than the one in the photo. (hence the spacers you see under the new head tube)
I also have cut the new head tube that I purchased down to the desired length for this frame.
(FYI: I have a different fork in the photo and in the mock buildup because I was waiting on the final fork to arrive in the mail)
Step 5: Weld on Disk Brake Mount
I don't have any good pictures of this being done step by step so here is an explanation.
There are some really nice jigs that are sold normally for over $120 sometimes found on sale but I couldn't fit that into the budget and didn't expect to need it after this. (although I am reconsidering)
So I wanted to mount this brake inside the rear triangle like the Fargo is but I don't have the proper machined piece that Salsa uses to mount the brake caliper directly to the frame without the use of an adapter. With some fiddling I found using a front 6" brake adapter I could get the pads to make good contact with the rotor.
Step 1: Mount the disk to the wheel and then attach the wheel to the bike
Step 2: With the caliper mounted to the adapter in center (the caliper can slide back and forth for adjustment)
Step 3: Using a rear disk brake mount (purchased from frame builder supply) mount the caliper/adapter to the (in this case steel) brake mount.
Step 4: Place caliper over disk making sure the brake pads are in a good contact patch on the rotor and that the disk brake mount is in good contact with the chain stay.
step 5: Tack weld into place in a few spots
Step 6: Remove brake caliper/adapter and wheel
Step 7: Weld
I also welded some cable guides and an extra set of bottle cage mounts similar to what the Fargo has. I used mostly the standard style used on most mountain bikes but I did try this unique one that I thought would look cool. Unfortunately I found them to be somewhat weak and only used one on the frame. closest to the caliper.
Step 6: Paint and Logo
This is pretty straight forward, it is only a coincidence that the original color was blue I wanted that color from the begining. I chose Rustoleum's metalic blue. I first sanded everything wiped it down with acetone used a generic primer then on went the blue with some light sanding with 400 grit in between.
My hobby has been welding sculptures for some time and with some old copper lying around and running off a joke at the bike shop I began with a logo. Because I modeled the bike after the Fargo and my name is Morgan the name Morgo seemed to fit. I also wanted it to look somewhat Frankenstein after the bike so here it is below.
To mount it to the frame I removed some paint from a few points that will be covered then used a 2 part epoxy to glue it to the frame.
I then used an automotive clearcoat to clearcoat the entire bike including name badge. The name badge was polished but wiped down with acetone before gluing it onto the frame.
Step 7: Build the Bike
This bike is comprised almost completely from parts I removed from other biked I have. I invested maybe about $300 into the construction all the raw parts are very inexpensive. The only new parts I purchased were the road specific disk brakes (shorter pull for the levers used) and the Dura Ace bar end shifters (much cheaper than dual control). I also purchased new tires.
I chose the curved cyclocross handle bars because of the Fargo I was modeling it after you could easily mount flat bars more like a 29er. I also have a thinner cyclocross tire in the rear to reduce drag a little, that is another preference I went with due to where I will be riding this.
I hope this inspires more bike creativitivity!