These days there are fat tire bikes and then there are FAT TIRE BIKES. One of our newer forum members, Joel Wilmoth from Phoenix, Arizona recently posted photos of the ultimate fat tire bike called “GIRTH” and I knew we needed to do a story on it. I remember the first moment I saw this beast and how it took some effort to pick my jaw up off the floor. Words started flying through my head like…insane, ridiculous, impractical, incredible, ingenious, AMAZING! How on earth could someone ride this thing? Surely it must be hard to pedal and steer? Well, for all of the skeptics out there, let’s dig a little deeper into the story of this fantastically fat foot powered flyer.


Joel is a native of Phoenix and has spent his whole life in that part of the country. From an early age he was always wrenching on something…bicycles, cars, trucks…almost anything that had moving parts. As a kid, he and his friends were always modifying their bikes into whatever was cool at that time. From motocross to ramp jumping, cruisers and wheelie bikes, they had fun with their two wheeled creations.

As Joel got older, the need for project money drove him to a job at a local Chevron station. At the age of 15, Joel was repairing tires, pumping full service gasoline (remember that) and cleaning the vehicles after they were repaired. Eventually that led to him doing repairs on the cars like brake jobs, tune ups and suspension work. After working there for 20 years, Joel had the opportunity to buy the service station and he jumped at the opportunity. For the next 12 years Joel owned and operated the business until he finally got burned out. After 32 years Joel finally sold the business and was able to spend more time focusing on the hobbies that he loved.


One of the things Joel and his buddies enjoy are NASCAR races. They like to take their custom bikes and hang out in the infield with all of the other fans. At the time they were riding some fat tire bikes with 4″ wide tires and were getting some attention…specifically from another guy who decided he wanted to outdo their bikes. He made a comment that he was planning to build a bike with 6″ wide tires that would put them all to shame. Well, seeing how Joel has a competitive spirit, he took it as a challenge and decided that he’d build a bike that couldn’t be topped….we’d say he pulled it off.


A few weeks after the race, Joel began doing research and coming up with plans for the ultimate fat tire bike. His buddy Craig of Craig’s Custom Upholstery came over one day and saw the drawings he had come up with. Joel told him the motivation behind the bike and what he had envisioned. They both had a good laugh about it and then discussed more ideas about the project.


First on the list of to do’s was to find a ridiculously large set of tires. Joel has a friend in the dirt track racing world that hooked him up with a set of 105 x16/15 Hoosier dirt track tires. That equates to 22 inches of tread width! Next on the list was a set of 15×17 bead lock rims. Joel said,

“I had to figure out what to do with the hubs in order to adapt the rims to the axles. I took the rim centers to Mark at Premier Waterjet and had him cut some hubs for a 1 1/4′ axle. I did the junkyard thing and found a Honda ATC front end, brake master cylinder and caliper. Next I had to figure out the bends for the forks. Since I don’t have a tubing bender I went to a fab shop and showed them what I needed and had them do the four bends. I then made the axle and caliper mounts and welded it together. From there I could then figure out how to lay out the rest of the frame.”


Joel ordered all of the needed parts off of Ebay (axle bearings, jackshaft, chains, crank set, Sturmey Archer 5 speed hub and sprockets) and then it was time to have all of the frame tubing bent. Joel approached Dan at Sinister Fabrication for the tube bending and while Dan was a bit apprehensive at first, he eventually got into the crazy project and created all of the tubing that was needed. Joel got it all home and it was time to figure out how to put it all together. “I had to figure out how to mount all the gearing, jackshaft and the shifter knob. Next I had to make all the brackets and mounts and weld them to the frame.” He found a headlight from a Harley Fat Boy that he converted into a 9 volt LED set up. Several other cool features were then added to the bike like the leather covered tractor seat with air bag suspension and a Chevy small block piston rod for the front end.


From idea to completion the project took a total of 6 months. As you can imagine, building a bike like this doesn’t come without its challenges. Figuring out the correct gearing and the overall engineering of everything is enough to make most folks throw in the towel. Fortunately for Joel, his vision kept him going and the final results rewarded him well.

When most folks see the bike, especially bicycle enthusiasts, the first thing they usually say is…”looks impossible to steer and ride.” Joel says… “I got it all put together and took it for a test drive. I knew turning wouldn’t be the easiest, but was happy to find it manageable. More surprising than that was how easy it pedaled. The gearing was perfect…tons of low end.” Granted, this isn’t a bike that you take on long road rides or race anybody with…that’s not what it was designed for. Sometimes building a bike like this is about taking on a fun challenge and making people smile. Joel says that he took it to the NASCAR races in Phoenix in November 2015 and the response was overwhelming. Thousands of photos and videos were taken by people at the race and it definitely got a positive response. Joel said…“It was funny to see people walking past cars and trucks worth tens of thousands of dollars just to look at this bike.”


While Joel did the majority of the work on the bike himself, he does give credit to a few of his friends for their help. James O’Malley, a machinist and engineer friend had a huge influence on Joel and encouraged him to dream big and build cool stuff. His friend Craig also played a part in giving input and doing the seat. Another friend named Monica Chavez who is a professional welder did the tig welding on the piston assembly. All in all, they managed to turn out the ultimate fat tire bike.

Joel’s not sure what his next project will be, but if it’s anything like GIRTH, it will certainly be a jaw dropper.

And for the skeptics who don’t think it can be ridden…


This Post Has 3 Comments

  1. LukeTheJoker

    Great stuff!

  2. William Pratt

    Ok, when can I put my order in? Joel, That is so totally cool, I have to have one.

  3. The Renaissance Man

    Great job, but every time I look at that spike behind the seat it makes a certain sphincter muscle draw up! ouch.

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