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Thread: Transmissions. The Final Chapter. (Summer, 2018)

              
   
   
  1. #1
    Senior Member Ted Dillard's Avatar
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    Transmissions. The Final Chapter. (Summer, 2018)

    I was gonna put this in Fight Club, but was like, hey, what's to fight about? We have all the answers now, right?

    Back in '08 and thereabouts, we didn't have any actual cases of transmissions being used, so it was all pretty much theoretical, and believe me, the theory went on for quite some time. Now, we have some actual examples of transmissions in use, and, more importantly in my opinion, examples of them not in use.

    So what are the conclusions?

    First, and most pointedly, bikes like the Mugen, produced by a company with pretty near unlimited resources (I'll see if I can find that link. Here you go: https://www.bennetts.co.uk/bikesocia...he-future-hold), dominates IOM without ever using a transmission. Mugen could, without so much as a blip in their budget, build any transmission they want, if the engineering suggested it would give them an edge, yet they haven't. No record holding race bike of any sort has run a transmission - except for Brammo's track wins.

    No production car, period, runs a transmission. I can't think of a single reason (or even excuse) why Musk wouldn't run one in even an experimental Tesla if he though it would be better, but he doesn't and it ain't.

    Brammo was the most notable example of a production bike with a transmission. The performance figures were pretty far from decisive. See this story: https://evmc2.wordpress.com/2013/04/...mo-comparison/ That's a performance comparison in 2013 between the Empulse and the Zero SR. Here are the conclusions:

    "The Brammo off-the-line acceleration is quicker. Even though the bike is 80 some-odd pounds heavier it is clearly out-accelerating the Zero. 80lbs is a lot, and probably more than just the additional weight of the transmission (which I guess is around 40-50lbs) so that is a clear, conclusive fact. By distributing the torque curve of the electric drivetrain – admittedly much wider than a gas engine – you are getting more torque off the line, and more torque at the top end. You’re keeping your top speed of around 100mph, but able to pull off the line. The Zero, like any bike without a transmission, has to compromise between gearing that gives you good acceleration off the line, and the top speed. You can gear it high to get faster top end, but it’s going to overload the motor and bog off the line.

    "That said, 6 gears is probably too many. After a few years of hashing the subject out on the forums, the conclusion I came to was that you maybe need 2 speeds, OK, three. Motorcycle.com agrees: “After now having twice tested the Brammo Empulse R we are convinced that six gears is, at least, three gears too many. It’s our opinion either a Low/High or Low/Mid/High transmission will more than suffice.”

    "The interesting surprise is the Zero’s better “roll-on” performance. This is likely due to the lighter weight, since the motor, at high speed, is now spinning fast enough to overcome any low-speed loading issues. This is interesting because, apparently, you can hammer out of a curve better on the Zero than the Brammo, even with the ability to downshift the Brammo. I’m not sure what to conclude from this, except that, once you’re rolling the benefits of a transmish may be lessened."


    ...which are pretty much my conclusions after beating this horse for ten years now. My conclusions from that are that the Brammo transmission decision was more about the rider experience than performance, as they claimed. The fact that people were talking about it being an option to keep the motor cooler because overheating issues rather than running a bigger motor is something I can't really say is more than chatter, but the chatter who chatted it to me was 1) reliable and 2) on the inside of the Brammo moat. After a few years, you started seeing clutch and transmission leakage issues on the Brammo forum, too. As Richard is fond of mentioning, there are a whole lot of crappy transmissions out there, and very few good ones, even in the ICE motorcycle world. Also interesting was the user experience. More than a few, and almost everybody I read reports from, simply stuffed the Empulse in one gear and left it there. Highway ride? Tall gear. Around town? Short gear, fast starts/stops.

    Chris Bell, AKA Brutus, was an early transmission devotee, and started with a Harley transmission on his first bike and abandoned it soon after. He said it just wasn't worth it, if you want to hear exactly what he said, I can try to find the message, but he builds his own reduction gearboxes for the Brutus, and it's not a problem doing a two or three- speed tranny. He won't, though.

    I, personally, still suspect it'd be fun to run a high-low range gearbox like the old dual-purpose bikes back in the '70s, but I'm pretty sure there's a good reason why they went away, and I certainly don't think it's worth it for me, a small builder, or a major company to invest money in what the engineering and practical experience shows is unnecessary.

    So yeah. That's where the discussion sits after actual, real-world testing and implementation, like it or not. Does that close the door on transmissions? In the engineering and motorsports world, no door is ever closed. There was a day I thought 2-strokes were dead, and hell this past couple of years, they're racing them again.

    Any questions?

    ...and yeah, I had to take it there.
    Last edited by Ted Dillard; 5 Days Ago at 0835.
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    Senior Member Stevo's Avatar
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    Quote Originally Posted by Ted Dillard View Post
    There was a day I thought 2-strokes were dead, and hell this past couple of years, they're racing them again.

    Any questions?

    ...and yeah, I had to take it there.
    My theory on that is the fact that the manufacturers know that electrics are going to outperform 4T bikes. 2T engines are lighter and have less moving parts. They are getting more refined with efi, turbos and small superchargers. I suspect that we will see 2T more in the near future as gas vs electric becomes the new battle. IMHO
    Last edited by Stevo; 5 Days Ago at 0919.
    Current rides: '96 Honda Ohlins VFR, '03 Cannondale C440R, '03 Cannondale Cannibal, '06 Yamaha 450 Wolverine 4x4
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    Empulse R #24 frodus's Avatar
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    The Tesla Roadster originally had 2 gears, IIRC.

    Most DIY electric car conversions have a transmission, although no other EV's from manufacturers seem to have one that I can find, except Brammo.

    Some prototypes have, but I think ultimately they've trashed them for a larger motor that can handle the entire range of driving.

    I'd have liked Brammo to have just gone larger motor, but they didn't.

  4. #4
    Senior Member Ted Dillard's Avatar
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    Right, on the car conversions - I think that's mostly because it's so easy to just bolt a plate on the tranny housing and couple to the input shaft, but what I don't know about converting cars you could fill a book with. (HEY. That gives me a thought. )

    Quote Originally Posted by Stevo View Post
    My theory on that is the fact that the manufacturers know that electrics are going to outperform 4T bikes. 2T engines are lighter and have less moving parts. They are getting more refined with efi, turbos and small superchargers. I suspect that we will see 2T more in the near future as gas vs electric becomes the new battle. IMHO
    Interesting theory, though I think it gives them too much credit for being too aware of electrics. I kind of thought it was just more about them having all this swell stuff that we never had before - like you say, turbos, pumps, watercooling, efi... I just know the 2-strokes I've seen in the past year call to mind the term "raped ape".
    Last edited by Ted Dillard; 4 Days Ago at 1039.
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    Empulse R #24 frodus's Avatar
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    Ted,
    Absolutely it's because it's easier to bolt in a plate than it is to interface into the differential or create something to couple to the CV joints. Lots of people just keep it in one gear.

  6. #6
    Senior Member Ted Dillard's Avatar
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    That's it? I start a new transmission thread and all I get is differentials and CV joints? I was positive you'd wail on me hard...
    Power in Flux: The History of Electric Motorcycles
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    Senior Member T Rush's Avatar
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    tesla dual motor all-wheel drive cars just use different gear ratios per motor instead of a transmission....rear motor geared for acceleration, front motor geared for sustained higher speeds efficiency
    https://www.reddit.com/r/teslamotors..._on_dualmotor/
    ....this is what I was trying to explain before; so it could be applied to a elmoto with dual motors vs a transmission, to expand on the dual motor concept that other thread was started on

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  10. #8
    Empulse R #24 frodus's Avatar
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    Quote Originally Posted by Ted Dillard View Post
    That's it? I start a new transmission thread and all I get is differentials and CV joints? I was positive you'd wail on me hard...
    HAHA!

    I think we both the pro's and con's of both by now since we've discussed already. No need to do it over again

  11. #9
    Senior Member Ted Dillard's Avatar
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    Quote Originally Posted by T Rush View Post
    tesla dual motor all-wheel drive cars just use different gear ratios per motor instead of a transmission....

    Right. NOT a transmission.

    Yup, Travis, and NOW WE HAVE A THREAD WE CAN POINT THEM TO lol
    Power in Flux: The History of Electric Motorcycles
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  13. #10
    Senior Member T Rush's Avatar
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    yeah, that was my point

    but wait, so now you made two more new threads about transmissions, when you can't even handle people reading and posting in one of your many old ones
    ....I think you are being overly obsessive

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