[hpv] Steering head bearing loads in front-drive bike

[Tom Mallard]

I've talked with reps from IGUS about using sleeve bearings for headsets and they seem they may work for the job, self-lubricating and with a slight break-in they should be loose enough to ride no hands, he was somewhat a rider so knew what I was talking about enough to feel if I had a shop to make custom races would do it, stiction seemed it wouldn't be an issue to him & I was referencing Campy, to me there is mass contact area if truly stiction is minimal, my project a tt frame and trying to use 1" for the headtube; here's a mt. bike using them: http://www.igus.com/wpck/default.aspx?pagenr=8238&C=US&L=en

tom mallard
  
p.s. a picture of my recently finished road frame design built by A. Cooper, Cooper Works Cycle his home Chandler, AZ, based on an art frame I did that rode really well and looked alive, this one called Coyote, rides very smooth, tracks really well any speed and low drag even without the fancy  wheels ... http://www.mallard-design.com/mdc2010/media/coyote-c005.jpg
 
> From: mark at bikesmithdesign.com
> Date: Tue, 13 Aug 2013 14:18:35 -0500
> To: garrie at recumbents.com
> CC: hpv at hupi.org
> Subject: Re: [hpv] Steering head bearing loads in front-drive bike
> 
> Why not bushings? "Stiction" (STarting frICTION) 
> 
> The tiny, subconscious corrections you are always making to balance a bike require little or no friction at the start. With a bushing the force needed to initiate the movement would initially be high then suddenly drop off.  
> 
> My Raleigh Twenty folder has a bushing replacing the top bearing, with a conventional lower headset bearing.  With a steep head angle and a steerer almost as long as the blades, this is as favorable an application for a bushing as you are likely to find.  I find it "tolerable" but many who use their Twenties more than I do have converted with an Aheadset type upper bearing. 
> 
> OTOH the Greenspeed trikes get by with bushings as they don't have to be balanced.
> 
> Mark Stonich Bikesmith Design
> 612-824-2372
> 5349 Elliot Ave S.
> Minneapolis MN 55417
> www.bikesmithdesign.com
> 
> On Aug 13, 2013, at 10:37 AM, Garrie Hill <garrie at recumbents.com> wrote:
> 
> > One of the things I've pondered over the years is, "Why do we use ball or roller bearings in head sets?"  Nothing is rotating more than a couple degrees ( more than 90% of the time) plus or minus, and a good shock through the wheel into the fork can cause indentation of the balls into the races.  Use a bushing and you spread forces over infinitely larger bearing surfaces than the contact area of balls/races.  In the case of MBB FWD, bushings have the added advantage of extra drag dampening some pedal induced oscillation.
> > 
> > snip