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Re: Motorcycle front-end Geometry

To: "List Land Speed" <land-speed@autox.team.net>
Subject: Re: Motorcycle front-end Geometry
From: Henry Deaton <hdeaton@verio.com>
Date: Thu, 11 Jan 2001 15:37:19 -0800
While it looks similar to a girder, it's quiet a bit different. A girder 
front end pivots on the steering stem just like telescopic forks. The 
Hossack pivots on ball joints located on the forks, not on the frame.

Henry



At 06:24 PM 1/11/2001 -0500, JAMES  CANNON wrote:
>The front end pictured is basically an exagerrated girder found on many
>sixties and early seventies choppers. They were also stock on some of the
>indians. I had one on a 69 sportster and I don't think handlig is helped at
>all with the radius you get between the frame neck and the actual fork. Good
>luck with it.
>                                                                         Jim
>from Salem VA
>-----Original Message-----
>From: Henry Deaton <hdeaton@verio.com>
>To: List Land Speed <land-speed@autox.team.net>
>Date: Thursday, January 11, 2001 5:45 PM
>Subject: Re: Motorcycle front-end Geometry
>
>
> >The bike shown uses a draglink between the front forks and the handlebars.
> >The main advantage I'm looking for is improved aerodynamics. Since the
> >forks are solid, I can use streamlined tubing. I'm also hoping to keep the
> >front of the bike lower than I could with standard forks. Ideally I'd use
> >some kind of hub-center steering, so the Hossack is a compromise that
> >should be more aerodynamic than telescopic forks and also simpler, easier,
> >and less expensive to build than a hub-center front end.
> >
> >The design has some other advantages too, like maintaining the same rake
> >and trail throughout the full range of travel and no dive when you brake,
> >things that are more important to bikes that need to turn or brake for
>corners.
> >
> >BTW, I had to ask about the steering too when I first saw this front end.
> >
> >Henry Deaton
> >SF, CA
> >
> >
> >
> >
> >At 04:18 PM 1/11/2001 -0600, Keith Turk wrote:
> >>Henry... I am throwing this opinion out there based on nothing but my
> >>concept of how to go fast and try and be semi reliable....
> >>
> >>I went to the Website and checked out the front end.... try as I might I
> >>couldn't see how the steering was applied to the front end.... nor could I
> >>see the real benefits from it over a simple triple clamp/ conventional
>Folk
> >>arrangement....
> >>
> >>I guess what I am trying to say is could you enlighten me as to the
> >>advantages of a system this complicated....
> >>
> >>Keith ( big fan of the KISS principal )
> >>
> >>----------
> >> > From: Clay, Dale <Dale.Clay@mdhelicopters.com>
> >> > To: 'Henry Deaton' <hdeaton@verio.com>; List Land Speed
> >><land-speed@autox.team.net>
> >> > Subject: RE: Motorcycle Front-End Geometry
> >> > Date: Thursday, January 11, 2001 4:01 PM
> >> >
> >> > Henry,
> >> >
> >> > I don't have much experience with "lay down" bikes but those numbers
>are
> >> > pretty close to what fuel bikes run and they're up around 230 for blown
> >> > fours and 200 for twins.
> >> >
> >> > With the limited amount of travel required, I doubt you need as
> >>complicated
> >> > a suspension as that, but if you want to play with it ...
> >> >
> >> > Dale
> >> >
> >> > Hey Dick J. is that your 300K mile bemmer in the photo?
> >> >
> >> > -----Original Message-----
> >> > From: Henry Deaton [mailto:hdeaton@verio.com]
> >> > Sent: Thursday, January 11, 2001 2:44 PM
> >> > To: List Land Speed
> >> > Subject: Motorcycle Front-End Geometry
> >> >
> >> >
> >> > I'm finally ready to start building my electric LSR bike. Here's what
> >>I've
> >> > got planned so far:
> >> >
> >> > Hossack-style front end, 1.5" travel:
> >> > http://www.eurospares.com/tfoale/mmjpg/tfbmw.jpg
> >> > solid rear end
> >> > 3.5x17 front wheel, with a 120/60ZR17 tire
> >> > 4.5x18 rear wheel, with a 160/60ZR18 tire
> >> > wheelbase around 70" (bike needs to fit on my 4x8 trailer)
> >> > weight without rider about 600 lbs, with rider around 760 lbs.
> >> > Forklift motor
> >> > CVT snowmobile transmission
> >> > 270 lbs AGM batteries, 120 volts
> >> >
> >> > Speed should be in the 150 to 175 mph range? (well, ya gotta have a
>goal,
> >>
> >> > right?)
> >> >
> >> > I was wondering if anyone on the list has any thoughts about front-end
> >> > geometry. I'm thinking of using a front rake around 40 to 45 degrees,
>and
> >>
> >> > about 8 to 10 inches of trail. That's what a guy that builds dragbike
> >> > frames recommended to me.
> >> >
> >> > Any comments or questions would be appreciated. I've done some drag
> >>racing
> >> > with electric bikes in the past, but this LSR stuff is pretty new to
>me.
> >> > Mainly looking for tips on how to build a bike for straight-line
> >>stability
> >> > at El Mirage and Bonneville.
> >> >
> >> > BTW, only 115 days until El Mirage.
> >> >
> >> > Henry Deaton
> >> > SF, CA

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