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.
They now sell the gearbox as a kit on eBay: Reverse Gearbox Kit
Here’s a complete gearbox: Motorcycle Reverse Gearbox
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:
Meehawl says
Looking at that uber industrial, heavy set end result, I would guess that the design department is full of dead eyed individuals that don’t respond well to subtle and nuanced humour. Undoubtedly bulletproof, but lacking in “less-ness”
Paul Crowe says
It does look sturdy, but without a reference in the photos, it might seem larger than it is. The prints over on the website show the dimensions and it’s smaller than you might think. The square end plates are 6 inches per side, so it’s not a huge piece. Among the options offered are a shorter output shaft, too. Considering the power some motorcycle engines can produce, you don’t want flimsy. Think turbo Hayabusa or some such. I’d rather have a bit more than I need as compared to pieces all over the street..
Meehawl says
I’m a fan of sturdy. I used to build very high pressure (up to 46k psi) pumping equipment for the oil industry, driven by 600hp+ diesels and the safety margins had to be huge due to the potential of fatalisationism occurring through material failure. Even so, that product still looks like something I’d optimistically drop on to a pocket battleship from altitude if my last bomb had missed. I still like it, I just think that making friends with a local foundry owner or inviting a product designer over to the smoko hut for tea and bikkies wouldn’t have made things worse.
Jim says
“fatalisationism” now that is an impressive expression. Even more impressive than “collateral damage”.
The gearbox is an impressive bit of kit. Reading about things like this is why I keep an eye on the site.
Meehawl says
I wasn’t sure whether I should employ the expression “fatalisationism” so I chucked it in to my “awesomenessonometer”, and it registered a bold 7.5 on the “Schmickter scale” so in it went. Like you, I am also a keen Kneeslider fan and now there’s some regular posting I’m like the first person to be run over by a steam train, chuffed to bits.
Jay Fleming - Fleming Engineering says
Meehawl,
I appreciate the comments. I hadn’t seen them until this morning. The current housing design is a first run, per se. New housings are in the works, one of which is a cast aluminum version. The end plates are 6″ square and the housing length is 5.75″, so it’s pretty compact for the application. The output shaft can be shortened to minimize overhang if the customer’s application allows.