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  • bankable trike

    I've been thinking about Evan's comment that he is going to build a trike, someday. The trouble with trikes as I see it is that they can't bank into a turn like a motorcycle. The shorter the wheelbase, the more likely they are to take a high-sided flip off the road.

    I had the same concern many years ago when I rented a snowmobile. Seemed like a death trap on turns. I sketched some ideas of a snowmobile with two tracks side-by-side, which could be edged like skis into a turn.

    My inventiveness is failing me in coming up with a trike design which can be leaned over like a bike. But unless somebody does, trikes are never going to go mainstream.
    Allan Ostling

  • #2
    we have these things driving all over the city here... and they bank a little. they dont go as far as a motorcycle, but they do bank.

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    • #3
      Well, that solves the stability problem. What is this trike, and why haven't I seen them down here in Phoenix?
      Allan Ostling

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      • #4
        Allan.. I went to college for a bit about 10 years ago.
        I was approached by the mechanical department to help out one of their students... to design a "leaning" recumbant trike.. with the single wheel at the rear.
        We used link bars like an offroad racing buggy front end. These where attached to bellcranks that led back to hand levers. You pushed the levers both in the direction you wanted to lean. This tilted the front wheels over the same way.
        Sounds simple..
        But it wasn't. We ran into all sorts of problems. At first he wanted to build it so he could just lean over and thought his hands should just rest on his belly.
        Problem was, when he pedaled it transfered the "wiggle" to the rear wheel and it went all over the place.
        Enter the hand levers and bellcranks. I figured we needed to stabilize the front end and dampen the transfered motion. That part actually ended up working very well. You could control the lean with the levers.
        Still wasn't perfect though. We needed time to adjust the amount of lean.. on a downhill banked corner this tended to sorta run away and carve the corner as IT wanted.
        Too bad.. the school year came to an end before we could finish it.
        He moved back to Vancouver and I never heard what happened to it.
        Wish I could remember more about this thing.
        Russ
        I have tools I don't even know I own...

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        • #5
          Originally posted by aostling
          I've been thinking about Evan's comment that he is going to build a trike, someday. The trouble with trikes as I see it is that they can't bank into a turn like a motorcycle. The shorter the wheelbase, the more likely they are to take a high-sided flip off the road.

          I had the same concern many years ago when I rented a snowmobile. Seemed like a death trap on turns. I sketched some ideas of a snowmobile with two tracks side-by-side, which could be edged like skis into a turn.

          My inventiveness is failing me in coming up with a trike design which can be leaned over like a bike. But unless somebody does, trikes are never going to go mainstream.
          I think one problem with banking trikes is they're generally able to bank over when stopped at a light. I have enough trouble picking up my bagger when it decides my legs are too short - can't imagine getting a bankable trike upright. And what would keep it from "banking" while going straight down the road?

          Two-wheeled bikes bank because a benevolent gawd wants you to enjoy the ride

          As for never going mainstream, meet Sam (Samantha) - she wouldn't agree! http://thevirtualbarandgrill.com/gallery/rtts2000/abh

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          • #6
            Dennis.. you just reminded me of another problem we had with the leaning trike, in the beginning.
            Taking off... it was really miserable when you first started moving. Once the speed was up a bit it was easy.
            I have tools I don't even know I own...

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            • #7
              Originally posted by dp
              what would keep it from "banking" while going straight down the road?
              Dennis,

              For trikes with one wheel in front, I think straight line stability at speed would be ensured as it is for a bike, by providing sufficient "trail" http://en.wikipedia.org/wiki/Bicycle...cycle_dynamics. But stopped, that effect would be absent -- you may have identified a fatal flaw in the concept.
              Allan Ostling

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              • #8
                Banking is part of the essential physics of having 2 wheels. You have to, and you can.....

                With three, the whole need for banking goes away, sort-of. Tied up with that is the fact that the physics are now partly working AGAINST banking.... there is not as much to stabilize the bank the way there is on 2 wheels, and it's un-natural anyhow, because a rigid frame WON'T bank.

                So you have to make a sort of "floppy trike", which acts like a trike, but somehow pivots for banking..... without losing the 'uprightness' characteristic.

                Just as there isn't as much that forces/allows/stabilizes a bank on a "floppy but strangely stiff 3" vs 2 wheels, there is less that would keep it upright on the straight.... With 2 wheels, you HAVE TO be upright to go straight, just as you HAVE TO bank to turn.

                With the trike, what forces a floppy frame upright? You can't really counter-bank or do the natural actions that keep you upright normally on 2.

                If you can make the frame free enough to bank, how is it different from a 2 wheel with a trailer? Seems like you lose the whole trike stability thing by trying to imitate a 2 wheeler, while the "trike-ness" of it keeps you from USING the slightly unstable nature of the proposed floppy frame......

                I'm getting cornfustikalated just trying to identify the issues......
                1601

                Keep eye on ball.
                Hashim Khan

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                • #9
                  Originally posted by J Tiers

                  With the trike, what forces a floppy frame upright? You can't really counter-bank or do the natural actions that keep you upright normally on 2.

                  If you can make the frame free enough to bank, how is it different from a 2 wheel with a trailer? Seems like you lose the whole trike stability thing by trying to imitate a 2 wheeler, while the "trike-ness" of it keeps you from USING the slightly unstable nature of the proposed floppy frame......

                  I'm getting cornfustikalated just trying to identify the issues......
                  You just need a big gyro to add a bit of precession. I'm thinking a 460 Lincoln V8 might work. But if it does go over...

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                  • #10
                    Originally posted by dp
                    You just need a big gyro to add a bit of precession. I'm thinking a 460 Lincoln V8 might work. But if it does go over...
                    So long as you mount it sideways it would do something, but precession I don't think would be any help....... long-ways it won't do anything but try to pitch you over if you gun it.......

                    I did see a V-6 bike a while back..... Huge rear wheel, BIG bike,..... don't want to have to pick THAT up..... But it was very cool.
                    1601

                    Keep eye on ball.
                    Hashim Khan

                    Comment


                    • #11
                      the Dodge Tomahawk is a V-10 Motorcycle using a Dodge Viper engine.

                      im not sure how these trikes lean, i know they had one at the boat show i went to a few months back, and if you sat on it, it would stay upright, but if i leaned to one side, it would tip a little. i saw a guy riding one a couple weeks ago, and it really leans when you're going faster and turning, but im not sure how.

                      trikes don't need to lean to keep traction, but if it didn't lean, and you took a corner at 100mph, it would throw you off fairly easily..

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                      • #12
                        heres the website for the ones ive been seeing... http://spyder.brp.com/ it kind of sounds like its an electronic stabilizer of some sort.

                        it has a dynamic stabilizations system, but watching their videos, it doesn't lean. the rider just shifts their weight to one side or the other. im sure the one i was on tipped from side to side though..
                        Last edited by Dragons_fire; 05-13-2008, 12:42 AM.

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                        • #13
                          Guy just down the road from me, Arthur Allen invented a sand yatch that would do this.
                          He then went on to take a patent out for the same design to work on a three wheeler.

                          BMW copied this and brought a trike out using the same design of bellcranks but as he's retired and on pension he had no way of fighting BMW.
                          They never even replied to any of his letters or even letters from a solicitor.

                          Do a search in the UK patents office for details.

                          .
                          .

                          Sir John , Earl of Bligeport & Sudspumpwater. MBE [ Motor Bike Engineer ] Nottingham England.



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                          • #14
                            Large collection of designs, human power and motorised, some more successful than others:

                            http://www.maxmatic.com/ttw_index.htm

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                            • #15
                              Top Gear featured a banking three wheeler a while back, it was made in Holland - they reckoned only a country where drugs were legal could have come up with it. The two wheels and engine were at the rear. The front part with the passenger and single wheel did the tilting. The tilting was quite radical, up to 45 degrees I think. The tilting was not explained, except to say that the harder/faster you turned, the greater the tilt. It seemed like a lot of fun. Anyone recall the name?

                              edit: Just looked at the website that Bikepete posted - it was the Carver.

                              http://www.carver-worldwide.com/Home/Index.asp?nc=1
                              Last edited by Peter S; 05-13-2008, 07:30 AM.

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