I acquired my Bacchetta Bella/ATT LWB recumbent recently. Before deciding on the Bella, I took a look at and test rode several RANS dual 26" models. (I wanted to test drive a RANS X-stream 26, but was unable to find any of the lower priced versions within 500 miles.) Bacchetta bikes have always impressed me, and being somewhat new to recumbents, I thought the lower BB height of the Bella would be a better choice.
I am very happy with the Bella, but the small tire up front doesn't feel right on the back roads and forest service trails I ride on, and I wanted some additional BB height. The geometry of the Bacchetta Agio, (now out of production) looked particularly interesting.
Inspired, I felt the need to try out a larger fork and 26" tire. I ordered an inexpensive chrome-moly fork with the requisite 300+ mm steering tube and put the Bella/ATT-(26)2 together in an afternoon. The result is shown above, with a 1.75" Schwable Marathon on the rear, and a borrowed mountain bike front wheel. The final configuration will likely be a second Marathon up front.
Technical Details
OK, so much for the fluff. Did I just pick a random size without consideration of the effects? Of course not. Using the specs from the fork, I took the Bacchetta stock image of the Bella, and applied the expected rotation from the increased front-end height, to get an idea of the resulting profile.
The net result is a slackening of the head-tube angle by about 6.5 degrees, and a increase in trail from 60mm to about 200mm. The changes make slow speed navigation easier (for hill climbing). To be precise, the larger tire seems to allow the quick small corrections required to maintain slow-speeds. At the high-end, the configuration is rock-solid (no more white-knuckes on the downhills). Stated another way, it feels like the 'turning ratio' was increased at low speeds, and a gyroscopic effect kicks in a higher speeds. On the downside, there is a tendency for the wheel to flop sideways when parked, and the turn radius is increased due to the longer wheelbase (72") and overall length (96.25").
The increased frame height makes the original kickstand useless. I chose to add on an extention to the kickstand show below. An alternate would be to use a custom snap together 'click stick' (http://click-stand.com/).
As always, your mileage may vary.
