If you’re building a motorcycle engine powered car, the one thing you’ll have to figure out is how to put the car in reverse. Quite a few years ago, we covered a reverse gearbox that would do the job with an input shaft on one one end and an output shaft on the opposite side. That post still gets a lot of traffic because a lot of guys building these projects are having a hard time finding a good solid gearbox to do the job. A few days ago, I heard from Jay Fleming, son of Jack Fleming who built that older gearbox, and he sent me information about a new unit just released. It looks really good.
The new box has concentric shafts, one shaft is centered within the other so both input and output are on the same side of the box. This could be a very useful feature if you need a compact installation and it gives you a lot more installation options. Like the other box, this one looks really strong and it’s rated for 120 foot pounds of torque, so it should handle all but the most outrageous power plants.
This box looks to be a strong and compact solution that a builder can easily incorporate into his car or reverse trike project. It’s Made in the USA, too.
For full details, read the press release below and visit their website, motorcyclereversegearbox.com. These units are built to order since several options are available that might be necessary for your installation. If you’re looking for a reverse gear solution, you just found one.
Press release follows:
Fleming Engineering announces production of a new universal reversing gearbox. This gearbox is tailored to fit any motorcycle or similarly powered, chain driven vehicle. We proudly manufacture in the USA.
The most unique feature of this box is the “shaft in shaft” design where the splined output shaft is supported within the flanged input shaft. This feature allows for a smaller footprint than a non-planetary reverse while also keeping the shafts on the same side of the box. This permits easier adaptation to fully-built vehicles that are currently without reverse. For certain cases, our gearbox may take the place of an intermediate jackshaft needed to offset sprockets for wider rear tires, swingarms or hubs.
The gearbox has a 6061-T6 aluminum case and high strength 4140 planetary gears and shafts. It measures approximately 12.4” long (with full length output shaft) x 6.0” wide x 7.4” high, and weighs 23 lbs without oil or options. Oil capacity is 6 FL OZ and requires full synthetic 10W30 oil. For those customers who would like to fit the gearbox into their digital design before fabrication, 2D drawings and 3D models are available.
Many options and modifications are available, including but not limited to: input and output sprockets, auxiliary outboard bearing assembly, and output shaft shortening or keying.
UPDATE: I asked Jay to send over a reference photo, showing the gearbox next to something else since seeing the gearbox alone on a benchtop provides no visual clue as to its size. So, here you go: