#11
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On Mon, 21 Jun, Just zis Guy, you know? wrote:
David Martin wrote: I was just thinking about this and considering what pushing a rear steer trolley is like. There is only one word I can think of to desribe the thought of rear wheel steering on a fast downhill and that is SCARY (followed by lots of road rash and a stay in hospital). ISTR that Thrust SSC was rear-steer. It was, and when teh engineers proposed it as teh solution to various problems it was mightily poo-pooed. It'll never work, inherently unstable, blaah blaah. In fact, read on in the thread for the sort of comments heaped on teh rear-steer proposal. They built a steering prototype by taking a mini, locking teh front wheels straight, detaching teh back axle and substituting a long pylon with steering wheels on teh back, such that the geometry was a scaled-down version of the Thrust proposal. Apparently it steered beautifully, no problem at all, as long all teh linkages were fully 100% ok and there was no slop in anything. regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
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#12
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On Mon, 21 Jun 2004 15:44:19 +0100, Doki wrote:
Does anyone make a FWD / rear steer recumbent? Seems to me you'd save a lot of chain length. Perhaps they'd struggle for grip up hills? There are FWD,FWS tadpole trikes - russian titanium ones turn up occasionally. There's also one that is FWD via a differential, and steered by braking teh front wheels individually, like a tank. The back wheel is just a castor. I quite like that as a scheme, but I don't think I'd dice with rush-hour traffic on downhills with it - seems to me it has teh potential to pirouette and dump you on teh road if you forget yourself and tug on a brake inappropriately. regards, Ian SMith -- |\ /| no .sig |o o| |/ \| |
#13
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in message , Peter Clinch
') wrote: Doki wrote: Does anyone make a FWD / rear steer recumbent? FWD, certainly. Zox and Flevo are the obvious examples, plus the Very Serious Speed machinery used at the likes of Battle Mountain is sometimes FWD (well, it's not like they have to go round hairpin bends...). Rear steer is a different matter. I think it was in C+ that someone asked this and Mike Burrows answered it. IIRC he basically said that what's fine in theory doesn't work quite so well in practice and rear steer bikes tend to be patronised by people called Koko with large red noses... The Flevo is an interesting exception to the usual rules: it doesn't steer at either wheel but has a hinge in the middle of the bike, and can be ridden completely no hands as far as steering goes (though bars are provided to mount brake and gear levers) Can you post a URL: All I find on the Flevobike site URL:http://www.flevobike.nl/indexmodellen.html is a very nicely finished and interesting looking velomobile (come to think of it, it's reviewed in the latest VeloVision). I can't find any reference to your hinged in the middle bicycle (but being unable to read Dutch is a drawback here). -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ ;; I'd rather live in sybar-space |
#14
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in message , Doki
') wrote: Mark South wrote: The problem is that to turn away from an obstacle you have to steer towards it. This means that situations can arise where it is not possible to avoid the obstacle with rear steering but it could have been avoided with front steering. I'm afraid I don't really *get* countersteering. I must do it, but I've never noticed myself do it. Probably all bunged away in the brain stem and never consciously thought about. Countersteering is one of those things about cycling which people have religious beliefs about. In practice you can steer a bike by starting the turn by turning the handlebars the opposite way, in order to get the wheels out from under the CoG, but it isn't necessary or even common. If you had a radio controlled bike with a rigidly mounted crash test dummy this would be the only way to steer it. But 90% of bike steering at any normal speed is balance and body weight, and countersteering is very rare in practice (I very rarely do it and watching other people I very rarely see it. Mind you, cycling theorists will tell you this is impossible. And that wheels stand on spokes and that steering is a matter of gyroscopic precession, and all sorts of other things which are indeed partly true or true under some circumstances, but which True Believers recite as mantras of universal truth. -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ ...but have you *seen* the size of the world wide spider? |
#15
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Ian Smith wrote: On Mon, 21 Jun 2004 15:44:19 +0100, Doki wrote: Does anyone make a FWD / rear steer recumbent? Seems to me you'd save a lot of chain length. Perhaps they'd struggle for grip up hills? There are FWD,FWS tadpole trikes - russian titanium ones turn up occasionally. There's also one that is FWD via a differential, and steered by braking teh front wheels individually, like a tank. The back wheel is just a castor. I quite like that as a scheme, but I don't think I'd dice with rush-hour traffic on downhills with it - seems to me it has teh potential to pirouette and dump you on teh road if you forget yourself and tug on a brake inappropriately. Get a little lug you flip over to lock both brakes together like you do in a tractor then . Or two sets of brakes on each wheel - one for steering and one for braking. |
#16
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In ,
Simon Brooke typed: in message , Peter Clinch ') wrote: Doki wrote: Does anyone make a FWD / rear steer recumbent? FWD, certainly. Zox and Flevo are the obvious examples, plus the Very Serious Speed machinery used at the likes of Battle Mountain is sometimes FWD (well, it's not like they have to go round hairpin bends...). The Flevo is an interesting exception to the usual rules: it doesn't steer at either wheel but has a hinge in the middle of the bike, and can be ridden completely no hands as far as steering goes (though bars are provided to mount brake and gear levers) Can you post a URL: All I find on the Flevobike site URL:http://www.flevobike.nl/indexmodellen.html is a very nicely finished and interesting looking velomobile (come to think of it, it's reviewed in the latest VeloVision). http://home.hccnet.nl/Mark.Maier/rec...evoracer99.jpg There's one, it's a Flevoracer. A |
#17
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Simon Brooke wrote:
Countersteering is one of those things about cycling which people have religious beliefs about. In practice you can steer a bike by starting the turn by turning the handlebars the opposite way, in order to get the wheels out from under the CoG, but it isn't necessary or even common. If you had a radio controlled bike with a rigidly mounted crash test dummy this would be the only way to steer it. I've got one of them [1], and that is indeed how it steers. But 90% of bike steering at any normal speed is balance and body weight, and countersteering is very rare in practice (I very rarely do it and watching other people I very rarely see it. I never used to notice it, but now I often notice myself starting a turn by countersteering. For some reason it's much more noticeable on the Street Machine that it used to be on my ATB. Perhaps it's more necessary on a bent than on a wedgie. [1] It was my 30th birthday present from my Dad. I downloaded a 2.84MB movie of it in action from URL:http://www.taiyoedge.com/, but it appears to no longer be there. Instead, it should be temporarily possible to get it from he URL:http://www.speedy5.freeserve.co.uk/z-freestyle.mpg -- Danny Colyer (the UK company has been laughed out of my reply address) URL:http://www.speedy5.freeserve.co.uk/danny/ "He who dares not offend cannot be honest." - Thomas Paine |
#18
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"Simon Brooke" wrote in message
... in message , Doki ') wrote: Mark South wrote: The problem is that to turn away from an obstacle you have to steer towards it. This means that situations can arise where it is not possible to avoid the obstacle with rear steering but it could have been avoided with front steering. I'm afraid I don't really *get* countersteering. I must do it, but I've never noticed myself do it. Probably all bunged away in the brain stem and never consciously thought about. It's not countersteering, with a rear-steer vehicle that is *steering*. Countersteering is one of those things about cycling which people have religious beliefs about. But on a rear-steered vehicle you have to swing the rear towards the object you are trying to avoid. Fact, not religion. In practice you can steer a bike by starting the turn by turning the handlebars the opposite way, in order to get the wheels out from under the CoG, but it isn't necessary or even common. If you had a radio controlled bike with a rigidly mounted crash test dummy this would be the only way to steer it. But 90% of bike steering at any normal speed is balance and body weight, and countersteering is very rare in practice (I very rarely do it and watching other people I very rarely see it. Which probably tells you that humans are not well adapted to it as a balance control mode. Mind you, cycling theorists will tell you this is impossible. And that wheels stand on spokes and that steering is a matter of gyroscopic precession, and all sorts of other things which are indeed partly true or true under some circumstances, but which True Believers recite as mantras of universal truth. This is all a bit uncalled-for. There is no myth about what I said relating to rear-steering recumbents. Nor have I claimed that any of the false statements above are true. -- "You need to declare a jihad on your own ignorant ass." - Ed Dolan in alt.rec.bicycles.recumbent |
#19
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in message , Ambrose Nankivell
') wrote: In , Simon Brooke typed: in message , Peter Clinch ') wrote: Doki wrote: Does anyone make a FWD / rear steer recumbent? FWD, certainly. Zox and Flevo are the obvious examples, plus the Very Serious Speed machinery used at the likes of Battle Mountain is sometimes FWD (well, it's not like they have to go round hairpin bends...). The Flevo is an interesting exception to the usual rules: it doesn't steer at either wheel but has a hinge in the middle of the bike, and can be ridden completely no hands as far as steering goes (though bars are provided to mount brake and gear levers) Can you post a URL: All I find on the Flevobike site URL:http://www.flevobike.nl/indexmodellen.html is a very nicely finished and interesting looking velomobile (come to think of it, it's reviewed in the latest VeloVision). http://home.hccnet.nl/Mark.Maier/rec...evoracer99.jpg There's one, it's a Flevoracer. Ahh! Interesting. Questions: Are the handlebars attached to the forward chassis, or to the rear chassis? Are the handlebars rigidly attached, or is there a linkage? What is the mechanism of the link - does it have bearings like conventional headset bearings, or something more robust - and are there mechanical problems at the link in practice? Has anyone here ridden such a thing and if so how did it ride? Front wheel drive without twisting the chain line has a lot to be said for it. -- (Simon Brooke) http://www.jasmine.org.uk/~simon/ Tony Blair's epitaph, #1: Here lies Tony Blair. Tony Blair's epitaph, #2: Trust me. |
#20
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On Mon, 21 Jun 2004 23:15:13 +0200, Mark South wrote:
"You need to declare a jihad on your own ignorant ass." - Ed Dolan in alt.rec.bicycles.recumbent Has The Troll of arbr discovered a sense of humour? Maybe I should rescue him from the killfile.... Mike |
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