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Recumbents driven by smaller wheels tend to be hindered by the lack of large chainrings needed to achieve higher and faster gears. One solution has been mid drive clusters. It's a bit more complicated, but as our featured builder - it can be done. Instead of rambling on, let us read what Michael has done. |
I had been particularly interested in a recumbent bike that would have optimum off-road/rough-trail capabilities while at the same time exhibiting good on-road riding and on-road handling characteristics (for touring, for example). I was unable to identify any commercially-available recumbent bike that would meet all my requirements in this regard. Accordingly, I designed and recently made my own such bike. I have been riding it for the last several weeks on river trails and up and down steep hills (as well as on a number of cross country rides): I am very pleased with its overall performance.
In a nutshell, this bike is basically a recumbent "S.U. B." (i.e. Recumbent Sports Utility Bike).
Some of the noteworthy features of this bike are as follows:
1. It is a Short Wheel Base, Above the Seat Steering recumbent bike, with dual 20" diameter wheels, front and back (large travel) suspension.
2. It incorporates a Marzocchi
front fork with a nominal 65 mm/2.5 inches travel! This particular
brand of MTB fork (initially designed for a 26" diameter wheel)
features a three-inch hollow section at the bottom of each slider:
this allowed the bottom of the fork legs to be easily shortened
without affecting the functionality of the suspension. 
The existing three-inch (dropout) sections at the bottom of the forks were simply severed, allowing new SS clamp-on dropouts to be precisely attached so as to accommodate the 20" diameter front wheel. No further mods were required to this fork: I was able to use the existing fork brake posts (which were perfectly positioned for the 20" wheel rim), to result in a very robust,very smooth-riding, adjustable front fork. The separate dropouts allowed me to easily "dial in" the optimum trail after the bike was fabricated.
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3. I utilized a Cane Creek rear suspension shock, providing an effective rear wheel travel of about 100mm/4 inches. This really smoothes out the bumps and is a perfect complement to the front suspension fork. I am able to ride over substantial bumps, curbs, pot holes, stairs etc (at very slow speeds or even at relatively high speeds) comfortably and under full control. 4. I utilize a 20" long Titanium 1.125 OD tube as my ASS steering tube extension. This approach enables me to use a conventional MTB-type handle bar "clamp" or "stem" that can be easily adjusted up or down the steering tube, to suit the rider. (This titanium tube is the only "special" material on the bike). 5. I have incorporated a rigid - but very light - aluminum strut, connecting the front of the boom to a position near the top of the ASS steering tube. This allows me to put as much (forwards-backwards) force on the handle bars as I require. This is important, as covered below. 6. I have an "on-the-go" slidable seat. (The mesh back/foam seat base can be repositioned forward or backward as required via a "repositioning" indexing lever on the handle bar). (My ability to push or pull on the handle bars allows the seat to easily be slid back and forth as conditions require). This slidable seat (based on Teflon sliders and rollers) allows me to easily get on and off the bike. When going down really, really, steep hills, I simply slide the seat to the most rearward position (approximately over the rear wheel) and then I am able to use my feet "skipping over" the ground to allow the me to "skid" my way down such steep of hills under full control. (Of course, the ability to place whatever force required on the handle bars assists in my ability to remain one with the S.U.B. while in this maneuver!). |
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