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RE: Motorcycle front-end Geometry

To: "'Henry Deaton'" <hdeaton@verio.com>,
Subject: RE: Motorcycle front-end Geometry
From: "Clay, Dale" <Dale.Clay@mdhelicopters.com>
Date: Fri, 12 Jan 2001 07:58:48 -0700
Why aren't you going to use a fairing?  Even if the fork is relatively more
streamlined than a tele (not so sure), remember, you're sitting behind it.
This could have better compliance than a tele at 450 and it could be
somewhat lower, but again you'll be sitting behind it.  

With the limited travel and long wheelbase you will have I doubt the
geometry issue and anti-drive will have much effect.

Not trying to talk you out of building it, just making some observations.
I'd also seriously consider some streamlining.

Dale
-----Original Message-----
From: Henry Deaton [mailto:hdeaton@verio.com]
Sent: Thursday, January 11, 2001 3:44 PM
To: List Land Speed
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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