All Wheel Drive Motorcycle

Take one look at the front fork of this dirt bike and you’ll notice that it’s not really a front fork at all. A custom front end replaces the traditional design in order to give this motorcycle all wheel drive. Look closely and you’ll see the chain that drives the front wheel. The swing-arm like addition lets the front end retain all of its suspension and steering and that’s where the project gets tricky.

We actually saw this thing in person at the monthly meeting of our local hackerspace: Sector67. [Martin Lawson] got his seven minutes of fame during the presentations (they use a prototype of this scoreboard to limit each presenter), and then was mobbed with a ton of interest afterwards. We were able to get a pretty good look at how the front drive works. It starts with an additional cog fastened beside the one that drives the chain for the back end. This feeds up through some tensioners and transfers out on the left side (from the rider’s perspective) of the front end. From here the rotational force is transferred to the right right and includes a U-joint to account for steering. The last chain goes straight down to the wheel.

The idea is that when the rear wheel loses traction you’re still being pulled by the front. This is illustrated well in the video after the break. [Marty] — who has a patent on the design — is trying to get some interest from manufacturers. He says the ability ride right through poor traction terrain make this a lot easier than a traditional dirt bike for beginners to ride. But it’s obvious the professionals are having fun on the thing as well!

Here’s a PDF with more details as well as a photo album.

37 thoughts on “All Wheel Drive Motorcycle

    1. The ROKON has more advantages, being able to float it etc. Just be careful floating a new four stroke version as they didn’t account for the case oil. When floating it can end up in the exhaust and then leak onto the belt/pulleys. Try going anywhere then. I’d like to see this bike float. ;) At least they made sure to allow the front to roll at different speeds.

    2. Yes, the Rokon Trail Breaker has been around for decades. It’s a solid and reliable machine. But in many ways, it’s more similar to a garden tractor than a modern off road motorcycle. (Rokon makes a 3-point hitch for the bikes…) Until a few years ago, the Rokon didn’t have any suspension, let alone over a foot of travel on both ends. I don’t see much market overlap between the two. Really, the least you could do if your trying to troll me is do a decent google search. Ian’s old work has been on the internet for decades at and you mention the Rokon?

    3. If you want to point out an awd motorcycle, the Christini is more like what he has done here, and they make kits for Hondas and Yamahas. Still can’t beat designing and building it yourself.

    1. the weight needed to make that kind of power and speed wouldn’t make sense. Many of these bikes are sub 320 lbs. This one is likely <240 lbs in stock form (not familiar enough with KaTooM's to tell you which model other than it is a two-stroke.

      1. Well.. electric motors are actually lighter than internal combustion ones. The problem is in fact the batteries. But in this case, maybe a fuel cell (alcohol, hydrogen) works?

        1. Electric motors aren’t lighter than a 2 stroke for the same power (batteries excluded). KTM 300xc-w puts out about 55 hp range. Yes I know that electric motors are night and day difference vs IC motors for HP.

          How could you ‘clutch’ an electric motor?

        2. If electric power was a more viable way to drive a vehicle, we’d all be driving electric cars already rather than subsidising the existing very limited attempts.

          The efficiency of this guy’s chain setup would probably surprise you too.

          1. Well.. we are not all driving electric cars because they currently have a limited range and those with a fair range are expensive. However, for small racing courses like this one, electric power is a very viable solution.

        3. From a motorsports perspective especially off-road, hub motors are soooo terrible. The hub motors add to much weight to the wheel in “unsprung weight”. The more unsprung weight there is on a wheel the slower it will react to input forces from the rider and input forces from the ground. Basically if you have two cars and the curb weight is identical but Car A has lighter wheels(less unsprung weight) then Car B. Car A will accelerate faster, stop faster, and handle better then Car B. I personally think that hub motors are terrible unless limited to shopping carts (from a performance point of view), yes they are cheap, easy, and reliable but… heavy exactly where you dont want weight.

      1. The Christini motorcycles also drive the front wheel 30-60% slower than the rear wheel, and have limited torque capability. My motorcycles have no power restrictions on the front drive and gear the front wheel at the same speed as the rear. This makes assist instant while allowing the front brake to brake both wheels. The Hossack style suspension also lets me add significant anti-dive. Anti-dive is nice because the rider doesn’t have to be as smooth on the brakes. Anti-dive also preserves suspension travel so the rider can brake harder over large bumps.

  1. As others have mentioned, 2wd bikes have been around for a long, long time. However, I don’t know enough about them to know if this does something different/clever. Does it?

    1. To first order, there is now torque steer because the driving torque crosses the steering axis at right angles to the steering axis. Still, if you go looking for it, you can find situations where the U-joint knuckling will jerk on the handlebars a bit. (i.e. spinning burn outs with your foot down)

  2. I find it interesting that half of the pictures have the front wheel off the ground…

    Plus… a universal joint? So you basically can’t turn and get decent performance out of the front wheel… this is basically the entire reason why CV (constant velocity) joints were developed. With this motorcycle if you turn the front wheel will be at a non-constant speed because the resistance fluctuates, basically “pulsing” fast-slow-fast-slow… That sounds like a nightmare to use if you actually are climbing something with the front wheel. Sounds like breakage to me.

    I think I agree with the others, while I’m sure it’s a cool/fun project, and I like reading about it, there are tons of improvements to be made just from a quick glance. Plus, trying to get manufacturers on board seems fruitless when there are already systems out there that fulfill the very, very limited market.

    1. The first prototype use a U-joint because it’s easy to get one with load ratings. They’re also STRONG and well sealed. The later machines kept using a U-joint because high power and large steering angles rarely coexist on a motorcycle for long so the knuckling is rarely an issue.

  3. I’ve always thought Yamaha’s 2-trac was a pretty brilliant piece of engineering. Even if it never took of (because, well, an experienced rider can get anywhere without it).

    “The patented 2-Trac system uses a hydraulic pump situated on top of the gearbox, and a chain running in an oil bath drives the mechanism. The system pumps hydraulic fluid via high-pressure hoses to the front wheel hub which is fitted with a hydraulic motor equipped with a single gear. When the fluid has passed through the motor it passes through a filter and returns to the pump.”

  4. I remember someone reviewing an all wheel drive bike on the old format Top Gear 25+ years ago. Their main complaint was when riding down a track the front wheel would tend to climb out of the ruts rather than follow them. That one had conventional telescopic forks and the chain going through an elbow linkage to allow for suspension movement.

    I wonder if anyone’s done a hydraulic drive. Some trucks use these for AWD as it’s much lighter and easier to route the power than propshaft and diffs. You only need the two wheel drive forwards and at relatively slow speed, it could free-wheel at higher speeds.

  5. There are really not many tracks a well ridden moto cant get up and in the video it looked like he was having just as much trouble as the other bloke, cool idea an execution but I think it would be better to spend more time riding and less time mucking around with it. Also what happens when you get to a corner? Most moto’s turn at speed by going sideways, this looks like it would be much slower in corners

    1. The bike does take corners differently. The closest comparison would be 2WD vs 4WD rally cars. At the end of this video Pete ( ) pulls a zero-lock power slide just like the 4WD rally cars. It also hooks up like nuts riding a berm. At the beginning of the video you can also see Pete slide back on the seat because the bike hooks up so well.

      Personally the bike is so docile and easy to control under power, I’m in the habit of entering corners slow and powering the whole way through. Not the fastest way to take corners, but you won’t wash-out the front tire entering the turns.

  6. I’m sorry but the ROKON is as wide as an old 3 wheel ATV and clearly looks as heavy as a dump truck!

    This thing is a modified trails bike and looks orders of magnitude more lighter, more agile and looks easier to modify and existing trails bike than having to trawl ebay for something that’s as rare as hens teeth and would go for a lot of well earned beer tokens!

    Sick of the bleeding nay-sayers sometimes!

  7. The main problem with hydraulic drives is that it is very difficult to get high speed and high torque ( at low speeds ) with a fixed displacement hydraulic motor. Along with Marty, I am interested in high speed applications for 2WD motorcycles, not the “utility” applications that the Rokon was designed for.

    There is no question that the “Aliens” ( top racing riders ) will still be able to get an off-road motorcycle to any place a 2WD motorcycle will go, but 99% of us do not have the skills that these guys possess, nor are we willing to take the risks that they do. For “our” 99% of the riding community – I am convinced that a 2WD motorcycle can eventually be made to be faster, safer and easier to ride than any standard off-road motorcycle.


  8. KTM did test a version of the Ohilns hydraulic 2WD, but never put it into production, neither KTM nor any other major manufacturer has ever mass produced a 2WD. The
    Yamaha 2 TRAC was a limited production run ( using the Ohlins hydro 2WD system )..

    The 2WD KTM’s and Honda’s you see around are US made “Christini” conversions – and Marty’s conversion too of course. ( And a handful of other less elegant mechanical and hydro conversions )


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