We’ve covered a lot of motorcycle powered cars on The Kneeslider and one of the questions we often get is “what do you do for reverse?” Some builders go with a ready made unit, most of which are a bit pricey, while other guys engineer their own method, lots of variations, there. Jack Fleming, over at Roadstercycle, was having the same issue as everyone else and finally decided to get a major race transmission builder to produce a solution that was small, lightweight (just over 15 pounds) and able to handle up to 500 horsepower. Jack gave them the specs and here’s the unit he got back.
Specifications:
6.750 long x 5.1 in diameter, length is 12″ without couplers and 13.25 with couplers.
Just over 15 lbs. without couplers.
1.375 x 10 tooth spline shafts.
4 mounting holes on the bottom
Comes complete with a shift lever.
You can have one for $1050 plus shipping.
It looks pretty beefy as well as compact so if you’re thinking of dropping that Hayabusa engine into a car body of some sort, you might want to check this out.
An updated version of this gearbox is available as a kit on eBay: Reverse Gearbox Kit.
Here’s a complete gearbox: Motorcycle Reverse Gearbox
todd says
Awesome. Beats cutting a hole through the floor a’ la Flintston’s. I had always figured you could use some sort of off-the-shelf industrial solution but then I heard they are noisy (straight cut gears). This one is 50% less expensive than a Quaife.
-todd
Brian Zooom says
I think that this gives the perfect excuse for someone to put that Hyabusa motor in a Smart car or a Mini or MK1 chassis VW like a Rabbit.
Nate Atkins says
So if i had a lets say 1984(or low ’80’s) VW rabbit, i could dump a yamaha or other sportbike engine in it? Would i need new gears because the r1 does over 60mph and the rabbit does 60mph top speed? and the car does tp of 5-6k rpm and the r1 does 12k+?
MikeC says
This now completes a very important part of my delusion of building a Ariel Atom ish AWD, fully independent suspended car based around a twin turbo GL1800 motor. I can see it now – 200 ish HP, 220 lb-ft of torque, reverse, and 1600-1800 lbs. Yee Haa. Gotta start modeling as soon as my bike build is done…
frozen prairie says
Will they be building a beefier version for those of us who use more than 500 hp when backing up ?
Jordan says
The power has to go through the gearbox whether your in reverse, or drive. What’s really odd about this setup, is that you would have six gears of reverse.
Chris says
frozen prairie makes a good point. Isn’t this thing severely over-engineered by a factor of about 10? Who backs up at more than 5 MPH, using more than about 10-15 HP max? Could it have been made less beefy (“flimsier” just sounds bad) and weighed and cost half as much?
cl
WOL says
cos the power will go through the gearbox when you are going forward aswell. no?
Paulinator says
They should develop a complete electric option for less weight, complexity(?), and money.
captcha was “scrota under”…isn’t this a family-rated site?
WillyP says
I can’t imagine an electric option weighing less or being less complex.
and from the site: “It’s 500 HP in forward not reverse!”
If you need more than 500hp in forward you probably need a car transmission, not a motorcycle anyway.
James says
If they can afford to get 500hp out of a bike engine, my guess is they can afford a full on sequential 6spd from quaife, and the custom bell housing and with clutch assembly to go with it. The upshot is that most other units crap out at 150hp… too close for comfort with my 140 and less than most desirable cycle engines.
frozen prairie says
You guys, I was kidding. Sheesh !
JC says
I would think that six speeds in reverse would be lots of fun, and actually useful for some stunt shows like you see at Universal Studios (They may use something similar already)
Riku says
It’s pretty amateurish to rate a gearbox by the hp number, anyway (rather than torque)…
BoxerFanatic says
I wonder how it would fit between the transmission output, and the paralever driveshaft on a BMW motorcycle driveline…
I have ideas, but they didn’t have an easy reverse gear… this could be good.
anton abdila says
I would like some more information about the reverse gear component advertised. I wish to install a motor bike engine on my Fiat 126 and I think I will be facing this problem for sure. Is this reverse gear installed at the drive end of the motor cycle final drve end.
Stephano says
I’m building a reverse trike and need a reverse gear for it, will the gear box shown work? If so how do you hook one up to spin only one rear wheel? Any visual aids for the mentally challenged greatly appreciated.
Thanx for your valued time!!
rafe03 says
Back in the lean days just after WW2 nothing except auto based power trains were available for powerboaters in the UK. By shifting gears around in a (British) Ford transmission, 4th gear would be used for forward & what had been ‘third gear” was changed to reverse operation by “rearrangement” of the existing spur gears & running roller chain over the (now undersized) gear wheels. All available from the breakers yard!
Perhaps now in modern times, 1st gear forward could be sacrificed & changed from gear action to roller chain operation. OK, maybe it wouldn’t take 500 Hp but careful driving might help it last for the 0.0726% of the time when backwards was required.
I’m not a gearbox guy but there are some clever chaps out there in KneeSliderLand. Lets rub some little grey cells & see if it’s possible. Could be cheaper & lighter than $1K & 15 lbs. Anybody got a Hayabusa apart in their shop that could check it out for us?
Graham Riley says
Hi from South Africa.
Stephano there is quite an easy way to couple this box to your 3 wheeler.
Have a look at an ATV rear wheel set up – lose one side – add a belt cog and viola, you can run a belt drive (ala Harley) to your rear wheel. The best part is you don’t lose too much power driving the rear wheel.
Am also building a reverse trike prototype and will share once we have all the design registration / patent features all signed and sealed. We will be going into production some time in 2011. Two seat one behind the other with a very different but workable front suspension setup. Look for it about April 2011.
cole says
Hello if you spin one side one way does the other side sping in the opposite direction?
Jay says
Only in reverse. Otherwise, the input and output shafts are “locked” together to form one “solid” shaft.
mikal laane says
I like Graham Riley’s idea.
I am putting a GSXR K7 1000 engine in a Reliant Kitten with FR configuration. Gearbox linked to a flange with propshaft driving and independant rear axle.
I can not understand why just one gear (reverse) cost soooo much money to install and use with a motor-bike engine!!
A replacement gearbox for the GSXR-1000 would be less. I am confused.
Isn’t there a cheaper simpler option?
Thanks Mikal
Jay says
You hit the nail on the head on why they are costly when you said reverse. Making a shaft to spin in two directions in such a small space requires a lot of engineering and manufacturing time. Believe me, I have spent a lot of time just figuring out how to make one work, then to just add manufacturing to it.
There may be cheaper options, but none that are more simple. Move a lever from forward to reverse, sounds pretty simple.
James says
You guys are awesome!!! I’ve been looking for this unit forever. All my research had led me to units costing at least 1500 and were no where near as heavy duty. My project is a 32 Ford Tudor inspired sedan at slightly larger than Legends car scale with a one seat cockpit and a Honda Valkyrie F6. Front grill is an enlarged modern honda emblem (strangely enough it has the same relative outline). Magnuson supercharger and 3-1 headers and true duals, good for 140hp. Expected curb weight is 15-1600lbs.. I’ll keep you guys posted. I’m hoping someone on here can help me find a prefab (trike?) IRS subframe complete with arms hubs and axles. I plan to use a Winters 7in for center setion with inboard rear disks. Also need a source for custom spindles as I want to incorporate a motorcycle 360 front brake system. Thnx for the info!!