Some people!

Discussion in 'Builds & Projects' started by Borgo Panigale, Oct 19, 2012.

  1. Jon's new bikeR.jpg

    I love a funny front end... This is my 'other' two wheeler, the sort without an engine. I bought it a few years ago, and you don't see many of them about. Its very similar to the Hossack front end for motorcycles, as ripped off by BMW on the K1200RS. Things have got a little out of hand though, because now, my wife has a PRST-1, and I've got another in bits as a project.

    Im goint to experiment, by making an adjustable top steering link, so I can vary the offset, and therefore the trail, so its got more trail for downhill, and a normal setting for everything else. When will the madness end?

    Jon's new bikeR.jpg
     
  2. Brittan had a peculiar steering design too. That worked aswel .

    BRTOP.jpg
     
    #22 ducati2242, Nov 17, 2012
    Last edited: Nov 18, 2012
  3. How does it handle compared with a recent bike??
     
  4. No idea, I've not ridden anything more recent than this. I rode a Scott extensively from about 14 years ago, before I bought this, and was shocked at how rubbish the front suspension was (it was a hardtail) I thought that its only function was to rob you of all the front end feel, this is very tactile, and feels very like a normal bike, but loads better because there's no stiction. The downside is that the front axle describes a sort of J shape, moving back a little, the up. Its plenty stable enough hands off, and the ridgidity is great compared to teles. Bicycles are always going to struggle when it comes to having suspension that works, because of the sprung/unsprung masses arent very favourable (compared to something like a motorcycle).
     
  5. I was on the lookout for one for a couple of years, but never found it, enjoy!
     
  6. Things turn up on Ebay every now and again. I bought a bare frame for a PRST-1 recently, all straight with no cracks for £88, but if you buy one, make sure it comes with all the bespoke parts. The PRST-4 is better, with the Marin type rear 4 bar link on the rear suspension, but they are much rarer.

    The best thing is that you can go somewhere like Dalby Forrest, and see loads of people pointing and grinning, thinking that its over complicated rubbish, then you cruise past leaving them for dust over the lumpiest terrain.

    Its not perfect though (what is?) but its a very different compromise.

    Keep on hunting!
     
  7. If you think some of those designs for the front end have got out of hand......
     
    • Like Like x 1
  8. Straight home for a soothing pint of Optrex, I bet!
     
  9. One of the few (the only?) bikes with centre hub steering to make it into full production was the Yamaha GTS1000A and in an effort to convince the bike buying public Yamaha put them in the hands of the TT Travelling marshals in 1993 (I think) the year they were launched and well known racer, Steve Linsdell rode a heavily modified Yamaha GTS with success at the TT, praising the stability of the front end.
    1993 Yamaha GTS1000 - ADVrider

    Among the more famous hub centre steered bikes to venture onto the race tracks was 'Nessie', a Kawasaki engined endurance racer campaigned by Mead & Tomkinson with some success in the 1970's
    Bonhams 1793 : The ex-Mead & Tomkinson,1976 Laverda 1,000cc ‘Nessie’ Endurance Racing Prototype

    And the there was Di Fazio's Laverda racer... mmmmmmmmmmmm....
    Di Fazio Laverda racer.jpg

    There are lots pictures of race & street bike prototypes - with leading link front ends, feet forward bikes and also DiFazio and Tony Foale frames here Euro Spares - Graphics - New Additions scroll down a screen or two

    There is no question that the concept was well proven, but as Yamaha found out with its, by all accounts, excellent GTS1000, the public's taste was too conservative to make hub centre steered bikes a sales success


    Di Fazio Laverda racer.jpg
     
  10. Did not Rocket Ron have a Honda in the 80s with HCS?I seem to recall him scraping the front swingarm round the bends.Was it anElf?
     
  11. Good call! Of course! Completely forgot that one and any others I didn't mention.. :upyeah:

    ELF Motorcycles
     
  12. Not sure about Elf, but safety was an issue.....

    AL
     
  13. Ill get your coat for you Al...
     
  14. Just because you can don't mean you should !
     
  15. Baffles me this hub centre steering!
     
  16. I always loved the look of hub center steering set ups. I remember reading a lot about them in the 70s and 80s.

    I thought the big advantage of them was, as I recall it helped separate the suspension and steering (edit - meant braking not steering) functions, so the geometry changed less than when braking using forks. I've never ridden one so I don't know but are you not able to brake into a corner with them without standing the bike up and the stability under braking is improved?

    I thought that the big problem was reduced turning circle so the setup was good for the track but really unsuitable for road use.

    All that said like others stated, if they were that good why were they never implemented in any number. Would have thought if they were so good then we would have seen them more in racing especially.

    John
     
    #36 Old Jock, Nov 22, 2012
    Last edited: Nov 22, 2012

  17. "The sort without an engine" :) love it. We call them pedal cycles.

    You don't see many because they didn't last very long. Lifetime warranty was offered on the frames which really embarrased Whyte. They replaced hundreds at cost - one guy I know was going through them under SOG act every six months. They actually accused him of riding too much..............after the sixth frame..........now you don't see them anymore.....wonder why? :)

    A flawed (understandably) execution of a great design. It was always going to die because to engineer the reliability it needed to be heavier(better components, seals, pivots etc) then it became unrideable in any decent way. Because you had to pedal it.

    The ride was sublime for about 700/800 miles then the pivots, linkages, bushes etc. all went the way of the wind. Then it was a proper bag of shit, no handling at all. British mud was more than a match for this flimsy pile of poo. The dropouts were so fragile, wore quickly too and were never going to survive a wheel change in the field.

    I know, because I did some testing on these when they first appeared.
     
  18. Care to elaborate? Most full suss bikes are fine enough if the design parameters are met correctly and the components are of the right grade/spec. The untold millions that are sold and ridden suggest that either they work acceptably well or the majority of mountain bike riders are unknowledgeable morons who will take whatever shit the industry throws at them....................mmmmmmmmmmmmmmm maybe you are right after all :) and the latter statement is correct.
     
  19. I would be the first to admit that the Whyte bicycle isn't perfect. About 3 months after buying mine, the spherical bearing developed loads of play, where the outer part had come away from the spherical bit, and the alignment of the front caliper on the disc was such that it began to bind up. All these problems weren't anything to do with the design, but shoddy assembly and a poor component.

    Sounds familiar, a British engineering company who let their customers do their final product development for them?

    As for frame breakages, well there are lots of reports of that happening, but you can't rule out owner abuse and overloading. Im 12.5 stone, and never had an issue, it might be different if I was 17 stone, and rode 3ft dropoffs constantly, but for an all round cross country bike, its perfectly OK for what I want to do with it.

    In answer to your other question, car and motorcycle suspension doesn't have to be very 'clever' because the inertia of the sprung part of the vehicle is quite high, and in comparison the unsprung inertia is low. Its the ratio of the inertias between the sprung and unsprung part which allows the suspension of anythign to work at all.

    Some rear suspension designs for bicycles (even some very expensive ones) look as though they would make the handling worse rather than better!
     
  20. some people ...... are engineers.... :)
     
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