Honda’s secret MotoGP transmission revealed

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Honda’s early dominance of the 2011 MotoGP season has been partially attributed to a secret new transmission that’s not a DCT, but somehow manages to shift as quickly as one. HRC has admitted the existence of the gearbox, but divulged no details. Now, a patent has been filed by Honda for a transmission which allows “continuous operation for a shift at an extremely short time interval.” In all likelihood, this is the secret MotoGP transmission. Let’s take a look at how it works.

This transmission is the source of head scratching because it’s something entirely new. MotoGP rules expressly forbid Dual Clutch Transmissions, which, as the name suggest, use two clutches to pre-select the next gear, allowing for very quick shifts. Less time spent shifting gears is more time spent accelerating, hence the performance advantage.

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The complete patent is embedded above. It’s over 27,000 words long. Published in the US with no attribution to Honda in February, it corresponds to a Japanese patent attributed to the motorcycle maker which was published way back in 2009.

Last month we connected the dots, concluding that Honda must be using a gearbox which could deliver the benefits of DCT using a single clutch. We presented two gearboxes — one made by Zeroshift, the other Xtrac — which claim similar benefits. Both of those work by using a ratchet system between each gear which allows two gears to be selected at the same time, but with only one engaged. When the transmission is shifted, the engagement of the next gear causes the disengagement of the previous one.

Well, it turns out that the mechanism isn’t between the gears, it’s underneath it. The truth about how this system works is even more awesome than I imagined.

The transmission’s 12 gears (it takes 12 to make six speeds) are lined up six per shaft, with nothing in between them. The gears on the main shaft (or input shaft) are fixed and all rotate at the same speed. The gears on the countershaft (or output shaft) freewheel. This is where things get weird. Inside the countershaft is another shaft which takes on the function of the shift forks in a conventional transmission. Operated by the shift drum, it moves 12 rods that have small eccentrics cut into them. In turn, those rods move very small pins which ride in holes drilled into the wall of the countershaft. Those tiny pins operate a set of four spring-loaded rocker arms housed inside each gear. When the pins are forced outward, they move the rocker arms up. The rockers catch the underside of the gear, thus completing a shift.

No clutch trickery is necessary, the engine power just needs to be killed for the time it takes to complete a shift.

HRC must employ watchmakers to assemble this whole contraption, it’s impossibly intricate.

It works something like this: From neutral, pull in the clutch and click the lever up to select first (GP shift, remember?). This twists a rod that’s connected to the shift drum. The shift drum pulls small inner shaft into a specific position, which forces the 1st gear set of pins up and pops out the rocker arms. The rocker arms select 1st gear and when you let the clutch out you have drive.

Out of the pit lane and front the front straight you (or a lactose-intolerant Australian, rather) you click down to select 2nd. The small inner shaft and the rest of the assemblies connected to it make a small move. The pins are withdrawn from underneath the first gear rockers and the 2nd gear pins are pushed up into position. The rockers click into place and in something like .008 seconds, you’re in second gear and have full acceleration again.

Notice how I didn’t say anything about the 1st gear rockers combing back down to their resting point? There’s basically no way for them to move until the 230bhp or so holding them in place is withdrawn. This happens when the 2nd gear rockers engage. And so on and so forth.

Other MotoGP teams say they’re already working on similar transmissions. Yamaha claims to be quite far along, identifying the problem with load transfer between shifts as the main obstacle still facing them. Honda appears to have circumvented that problem all together by equipping each gear with its own robust selectors, meaning that the power transfer during shifts should be incredibly smooth while the shifts themselves can be incredibly fast.

We bet there’s a lot of MotoGP engineers sitting up late tonight, reading this patent and scratching their heads.

via The Rider Files

  • Alex

    ::Blink::

    • Sean Smith

      It’s kind of a lot to take in. Me and that .pdf spent a whole lot of quality time together.

    • raphmay

      I think something just went over my head but I didn’t see it….

  • Ducky

    Audi’s slogan is “truth in engineering”. For Honda Racing Development? Madness. Just pure madness.

    Thanks Sean for the layman’s explanation, but I have to wonder how a Japanese engineer could be sitting at his desk one day and think “Brilliant! That’ll work perfectly!”

    Just to emphasize, here’s a rear differential from a Honda ATV that our Formula SAE team took apart when I was still in school: http://www.youtube.com/watch?v=ZAtFTR-dMwY

    • Steve

      Formula SAE!! Takes me way back. I was with the UT Austin Formula SAE and Mini Baja teams from 87-90. Do they still do that or is it all about solar and fuel efficiency now?

      • Ducky

        You’re an old guy! Formula and Baja are still the biggest (most talked about) competitions. There’s hybrids, electrics, alternatives, supermileage, etc. but they are still small in comparison to the 130 or so teams that participate in every Formula competition.

        • Steve

          Going fast will always be popular. Getting the best gas mileage just is not as compelling a goal. After all, here we are at a web site named “hell for leather,” not “minimizing fuel consumption.”

  • Coreyvwc

    Honda should win the manufacturers cup just for having designed that. It makes me feel stupid.

  • Charles

    This might be a good time to mention that most of these transmissions can be traced back to the John Deere Powershift, which itself is very similar to the Husqvarna automatic motorcycle transmission.

    • Sean Smith

      There’s really nothing similar to this out there right now. If this was just a new take on old stuff, I wouldn’t have taken the time to make a big deal out of it.

    • Jens

      The Husky shiftbox came also direct in my mind, we have a couple around here in the swedish Military bikes. Require a lot of oilchanges but run quite stabil, no question that somebody will come up with a system like that.

      On one way Honda impress me, but thats the next level of money spending. Now we have adittionel to the electronic battle a fine mechanic battle coming up, what will strike down from MotoGP to the other competition. I just have seen with what power BMW continue the work on race ABS and tractioncontrol for Hobbyracers… stay alert racingworld. To save the sports a electronic bann from the sanctioning bodies might be a must, but the manufacturers want to see their technologies on the track in competitions like WSBK, what ist understandable. Bikes like the S 1000RR or the RSV4 are filled up with gadgets the companies tell the customers they must have to run quick and safe. In 2 years in Europe the ABS is necessary for all new bikes.

      The Rotax powered Buell/EBR concept without wheelie and Tractioncontrol is, as I see one of the last what for now can hold against that trend, at least on the highest clubsportlevels.

      If we dont like to see in the future paddocks fivetimes more laptop´s than bikes on the raceweekends, the true pure racebikes need a protection, most practical with a lower weightlimit. The argument that technical progress is today in electronic only, failes because there are still innovations on the mechanical field to make, as the Honda gearbox shows very well.

      Light and intelligent engineered motorcycles are not for the museum or the historic racedays. They are the essence of motorcycling and we must give purness a future.

  • http://twitter.com/hagus Luke

    Urgh, here we go again. Ignoring the maths and the physics, you could listen to Alex Briggs who tweeted about it, or to Burgess *and* Stoner who went on record:

    http://moto-racing.speedtv.com/article/motogp-burgess-honda-gearbox-not-rocket-science

    If you want evidence of why Honda is fast this year, look no further than who has the bike between his legs.

    Rossi: “Stoner is the favourite for the championship, but I also say that to bring a jinx on him,” he jokes. “I give him 10 out of 10 for speed and talent, but a bit less for tactics and cunning. He is a mad man who often repeats the same mistake.”

    … says Rossi from his vantage point on the fourth row of the grid. You’ll crash too trying to keep up.

    Now Stoner’s on the machinery his rivals have been enjoying for the past three years and suddenly his talent doesn’t have to work quite as hard. But no, let’s chalk it up to a magic gearbox!

    As I write this Stoner just schooled the entire field in a wet warm up for Jerez. They must have forgotten to turn Pedrosa’s magic gearbox on because he was in seventh.

    And Rossi came in second. He’s “only” half a second behind Stoner! Quick, let’s invent some other magic parts to account for the deficit! Or perhaps it’s the milk served by Ducati hospitality?!

    • Sean Smith

      This transmission business just happens to be a topic that’s interesting. I don’t remember ever saying that the transmission is absolutely the ‘thing’ behind Stoners speed. He’s obviously an amazing rider, and a transmission does not a bike make. Relax and enjoy your MotoGP coverage everywhere else. I’ll keep on writing about the new and interesting stuff over here.

      • http://twitter.com/hagus Luke

        In the last HFL article there was some highly optimistic math proposing that the gearbox was wholly responsible for the testing time gaps between Honda and the rest, which gave me the impression it was considered ‘the thing’ behind the speed.

        Sure my mind is clouded because Stoner is a favorite and people love to rag on him. I should lighten up, I know.

        But the best thing you can say about this gearbox at the moment is that it exists and it’s interesting to analyze. Is it providing riders with an advantage? Even a partial advantage? For the press it’s a foregone conclusion, whereas I see no empirical link.

        It’s interesting to read about, but nobody seems to be saying ‘lord, this is a very complicated gearbox for an almost negligible advantage. Stoner even says it’s harder to upshift. Will it last all season? Is it worth it?’

        I promise to lighten up ;) If at all possible …

        • http://hellforleathermagazine.com Wes Siler

          Actually, in the last article, both sides of the “argument” were presented. We do that in most articles here. Performance claims from the makers of similar gearboxes and quotes from both HRC and Yamaha engineers downplaying the advantages. You simply chose to seize on the performance claims made by the gearbox makers and get all riled up.

          As far as I can tell, you don’t actually have a problem with this article. It analyzes a patent and explains how the device in that patent works. You’re just talking shit.

          • http://twitter.com/hagus Luke

            There’s no problem inherent with this article at all, aside from it owing its existence to the general hype around Honda’s gearbox.

            I may be talking shit, but it’s also the heart of the matter. Does this gearbox explain anything? It was the wrong comment thread to harp on about it, so for that I apologize.

            • http://hellforleathermagazine.com Wes Siler

              There’s hype because it’s way more interesting than yet another “110% thanks redbull” rider quote. Honestly, for a bunch of superhumans tearing around a track on machines that surpass the space shuttle’s technology, everything about MotoGP except watching it live is supremely boring.

        • Ducky

          Why are you so upset over a gearbox?

        • Sean Smith

          Maybe this will help:

          Pedrosa had this to say about the effect of the transmission on the rest of the motorcycle.
          “It’s smoother…Basically when you are in the corner, the shifting it’s a little smoother so the bike doesn’t do so much like this (pumping with hands). So if you are changing with bikes or maybe this corner going up, the bike is not shaking so much on the shifting. So this is something positive, because the shock is not doing any reaction aggressively and the traction is more stable.”

          That’s basically what I was trying to get across in the first article. This thing isn’t a giant deal, it’s more like that last click on the compression damping that makes everything work like magic.

          It’s a hair faster down the straits, and it’s silky smooth every time you shift. If you watched today’s race closely, you will have noticed the Ducatis bucking and shaking as they stand up under power leaving the corner. This is the kind of thing that this transmission helps out with. Not some giant revolutionary change, just a small subtle one that helps the bike go just a hair faster.

    • http://www.facebook.com/beastincarnate BeastIncarnate

      Sensitive much?

  • Turf

    I approve as it’s not electronic

    • Ben

      AHMEN!

      more power, less weight, more wizardry and werks unobtanium secretes like it should be.

      Not software updates.

      • Myles

        Why does everyone hate electronics so much? Should we go back to carb’d two-strokes?

        When everyone boo-hoo’s about anything digital it makes me feel like the rest of the posters are 100 years old. The digital world has impacted us positively in a powerful, real way in nearly all aspects of life. Why is it bad for bikes?

        (Just FYI – my bike doesn’t have anything electronic besides the headlight and radiator fan. No ABS, No EFI, and damn sure no traction control. Having said that, I don’t see how any of those would negatively impact my riding experience)

        HFL – can we have a feature discussion as to “why” these things are bad? Is the motorcycling community more afraid of technology? Is the average viewership super old? Are people afraid that they won’t feel the same about their passion if it’s less dangerous/more accessible (how ironic)? I just really don’t get how the same person who appreciates a half-assed garage project “cafe-racer” spilling oil all over hell hates something that makes a motorcycle fast. Not speaking directly to Turf or Ben – just a running theme I’ve seen in the comments.

        • http://worldof2.com/ jpenney

          I’m pretty sure that you answered your own question. For a supposed sect of rebels, most motorcyclists don’t want any change, ever. .

        • slowestGSXRever

          I like electronics…

        • stephen

          Some people prefer cheap, easy to work on cycles we can fix ourselves and not have to be a computer genius to fix.

          • Myles

            I think you’re misunderstanding traction control.

            Let’s take, for example, last model’s zx10r versus this model zx10r. The new one has a sick traction control system. The old one doesn’t. Neither even require a computer to work on, never mind a genius level understanding. There’s a little black box that tells the engine what to do . . . if (for some crazy reason) the box is not functioning you buy a new box. Just like any other part. It’s a fixed system that doesn’t require (or allow) end user input. Just because a bike has traction control doesn’t mean you have to plug a laptop into the gauge cluster.

          • http://www.thisblueheaven.com Mark D

            Yeah, that transmission looks SUPER easy to work on. You certainly don’t have to be a genius to understand it ;)

        • http://hellforleathermagazine.com Wes Siler

          There’s a lot of inherent conservatism in motorcycling. We try to break that boring old mold with our content. Don’t worry, the dinosaurs will eventually evolve or go extinct :)

          • Turf

            RAWR

          • http://rohorn.blogspot.com rohorn

            A noble motive indeed.

            I’ll bet there is far more digital firepower used in designing and manufacturing this transmission than all the electronics on the bike.

            I also have no patience for those who bitch and whine about technology from a computer and over the internet. I’ll make exceptions to those who send the HFL staff replies via telegraph.

            I also think Honda is doing this to illustrate that rules intended to simplify matters and reduce costs always have negative unintended consequences.

            • Turf

              I’m 24 a moto courier currently in the process of starting a shop. I’m all for electronic rider aids on street bikes. Top level racing is a different matter. Back when F1 started using a ton of electronics it became entirely unwatchable. Top level riders shouldn’t have a bank of computer power telling them what they can’t do. Should we bring back carb’d strokers? Hell yes, do you remember how fun those things were? Unfortunately they’re no where near relevant to todays market and your average weekend warrior sportbiker wouldn’t get it.

              No one said they hated all technology all the time, using the internet doesn’t even figure into the discussion until my bikes swingarm has wifi. I get to play with a new RSV4 soon, cant wait to fuck around with it’s electronics. Of course there is a ton of design power behind it, they use computers to design birdhouses, doesn’t mean the birds can’t use them because they don’t have ipads.

              The original point was I much prefer a mechanical solution over an electronic one.

              • Jens

                Here is the theory: Electronic riderassistancesystems killing (mechanical)engineers inventions. Why looking for mechanical grip when the tractioncontrol do the trick, why hold the frontend down by weightbalance, seatposition and chassisgeometry when the wheeliecontrol do the job? With the RC8 as an exampel, real low laptimes are without TC and WC impossible. Ok when everbody have it, the engineers must come back to the base, as Honda shows.

                Nobody like to go back to carbs. Rider assistance systems may help roadriders to stay alive. My question is if we need these in Clubsportracing, already a S1000RR TC map for the tire of your choice is app. 500$. Before you bought the software Trackupdates for 3.000$ In times everybody is talking cuttin down the costs, this way looks wrong.

                • http://hellforleathermagazine.com Wes Siler

                  Very well put Jens. You should write an article for us on the difficulties of campaigning (and winning) a non-electronics bike in a series dominated by bikes with TC, WC etc.

                • http://rohorn.blogspot.com rohorn

                  Dead serious now – how much would this gearbox cost? Do you have the hardware and software to make one? If you did, could you make it?

                  What is involved changing gear ratios on this?

                  Do you have a laptop and the ability to use it? Is it OK to spend time at the track twittering results to non-participants but not OK to spend time tweaking the wheelie control so that it is optimised for the rider’s skill?

                • Jens

                  I will Wes, season starts in 10 days and I will keep you updated from race to race how we are doing in the BEARS fighting the BMW and Aprilias. Rohorn, you got me wrong we are not at all against using newest technologies. We use Catia 5 for our constructions and just setted up a 2D Datatrecording to understand what happen, so we love hightech, try to map a bike without state of the art technologies.

                  But I also see the risks for the sport by exzessive use of rider assistance systems.

                • http://rohorn.blogspot.com rohorn

                  Jens,

                  Thanks for the reply – my apologies for my exagerations. What your team (and Erik’s) does is very inspiring – I hope you have a kick ass year at the track!

    • Sean Smith

      It might not be, but literally everything else is. ;)

  • Dan

    Having trouble viewing the embeded file on an iOS device (surprise, surprise). Mind including a direct link to download/access the PDF?

    • Dan

      Nevermind – found a link on the Rider Files page.

      Update: which links to the PTO site, which displays documents as Flash (or so I gather from the question mark that sits where the text and drawings should be).

      Looks like I’ll need that PDF link afterall.

      • Myles

        Both sites (jp and us) are throwing errors even in a full browser – limits reached and all that. I think a lot of people all over the world are into this.

      • Myles
        • http://hellforleathermagazine.com Wes Siler

          Thanks for responding, sorry Dan, we were offline. Have fun reading 27,000 words on your iPhone ;)

  • Glenngineer

    Not entirely different than a Rohloff hub, really.

    • Sean Smith

      After watching the Rohlhoff assembly video, the shift mechanisms seem to be pretty much the same.

      • Glenngineer

        Honda’s system is more complicated, doesn’t allow any dead space, and is definitely (obviously) designed to cope with more power, and there is the whole planetary vs. paired gear thing…but the similarity is striking.

        Isn’t Rohloff’s website fantastic? It navigates a little weird sometimes, but so much detailed and well presented information.

        • Sean Smith

          I’m pretty sure it’s because everything about them is Made in Germany. Super cool company.

  • http://rohorn.blogspot.com rohorn

    I can’t imagine this having that same hypnotic clickity skip click sound that old Sturmey Archer hubs have in certain gears.

    At least this will make a Rohloff look dirt cheap.

  • Archer

    THIS is why ventures like MotoGP have merit. Without the competitive environment of MotoGP and the like fostering efforts to improve mechanical systems, we might find ourselves buying 1930′s tech for the next 50 years.

    Oh, wait a minute. Was that a Harley that just went by my window?

  • Steve

    Computers make the hardware more useful. Lots of industrial automation over the last 30-40 years has taken the same basic processes and make them much more useful and productive. Computers are useless without the hardware but good computers help you get several time the productivity, or do things that were previously undoable without the electronics.

    When my fuel injected 2001 VFR starts up first push of the starter and is ready to ride in seconds I am thankful. When my carburated 2009 Ninja 250 takes 3 minutes of careful choke and throttle work to get rideable I am annoyed and wish it had more of that computer stuff.

  • T Diver

    I don’t really understand your technical fancy talk. Basically what you’re saying is Honda just said, “Booyaa! Patent Mutherfuckers!”
    I’ll go download the PDF and try to replicate it on my Ninja. Thanks for the tip HFL!

    • lucky j

      Haha… that should’ve been the headline for this article.

  • http://pinkyracer.com pinkyracer

    I still say it’s cheating. walks like a DCT, talks like a DCT, then it’s a DCT. At the level they’re all at, “one click on compression” is clearly a massive advantage. I’m so sick of Honda, Honda, Honda, Yamaha, Honda, Yamaha…

    Although I do concede that when Stoner wins the championship this year, he won it fair and square. Against the rest of the Hondas.

    And how on earth did you find out Stoner’s lactose intolerant? Did you try to buy him an ice cream?