Forget 53x11
dave a
or
Why is his fork backwards?
What PEDS did he use? (just to make this qualify for rbr)
- dave a
Beloved Fred No. 1
It would have worked if they'd used a Ferrari.
H. Fred Kveck
wrote:
> http://clubroadster.net/vb_forum/showpost.php?s=cbe0cc85f5b5a62de20a7765cae4fa
> ...&p=578228
>
> or
>
> http://tinyurl.com/2a3f6c5
>
> Why is his fork backwards?
I'd say it's set up like that to increase the trail, thereby making the bike a bit
more stable. Think of it like the front wheels on a shopping cart. It'll want to
track better than if the fork was the normal way.
Carl Sundquist
> In article <iasetf01...@news6.newsguy.com>, dave a <blkcatREMOVET...@gmail.com>
> wrote:
>
> >http://clubroadster.net/vb_forum/showpost.php?s=cbe0cc85f5b5a62de20a7...
> > ...&p=578228
>
> > or
>
> >http://tinyurl.com/2a3f6c5
>
> > Why is his fork backwards?
>
> I'd say it's set up like that to increase the trail, thereby making the bike a bit
> more stable. Think of it like the front wheels on a shopping cart. It'll want to
> track better than if the fork was the normal way.
That makes sense, but looking at pictures of Fred Rompelburg's and
John Howard's bikes (did you know that Howard beat Rompelburg over the
Gavia in a snowstorm to win the Tour of Bonneville?), they both have
forks with generous head tube angle and a slight forward rake.
The bike behind the Porsche looks like you typical stayer bike.
--D-y
I've read that trail "doesn't care" if the offset is ahead of or
behind the head tube. Having it behind gets the rider a little closer
to the wind break. At least that's what I've read <g>.
--D-y
H. Fred Kveck
Carl Sundquist <carl.su...@gmail.com> wrote:
Now I'm not an expert on this, so take it for what it's worth.
Trail is defined as the distance between a line drawn through the steering axis to
the ground and a vertical line through the center of the wheel. So on a bike like
Howard's [1] and Rompelberg's [2], where the headtube angle is tipped back pretty
far, the line extending to the ground will naturally land further in front of the
vertical line through the wheel. That means more trail. On a bike with a more normal
headtube angle, turning the fork around moves the wheel further back, increasing the
trail. Turning the fork around on a little kid's first bike is a trick I've seen used
to good effect - the small wheels mean the bike is pretty minimal on trail from the
get go. The backwards fork moves the wheel back, increasing trail and making the bike
a lot less squirrelly.
One interesting thing I see is that the Colnago of Rompelberg has a lot of fork
offset. That moves the wheel forward in relation to the steering axis, which reduces
trail. Perhaps Colnago wanted the bike to steer more like a regular bike. Howard's
bike does not appear to have much fork offset at all.
[1] <http://www.fixedgearswitzerland.com/wp-content/uploads/saltlake_speedbike.jpg>
and:
<http://davesbikeblog.squarespace.com/storage/Speed04.jpg?__SQUARESPACE_CACHEVERSION=1
218068584515>
[2] http://www.blingcheese.com/image/code/0/fred+rompelberg.htm
A. Dumas
> John Howard's bikes (did you know that Howard beat Rompelburg over the
> Gavia in a snowstorm to win the Tour of Bonneville?),
Haha. (sob)
--D-y
> In article <8a65e528-dd31-4058-b9c1-536a22cba...@p1g2000yqm.googlegroups.com>,
>
> and:
> <http://davesbikeblog.squarespace.com/storage/Speed04.jpg?__SQUARESPAC...
> 218068584515>
>
> [2]http://www.blingcheese.com/image/code/0/fred+rompelberg.htm
Here's one example, although the straight fork kinda interferes with
"the picture", comparing forks curved ahead or behind the steer tube:
<http://i32.photobucket.com/albums/d7/k4drd/Bicycles/
RakeandTrail-1.jpg>
Noting, briefly, effect of smaller front wheel:
http://davesbikeblog.blogspot.com/2007/05/stayers.html>
Dave says "not too much more trail" than a normal track bike (which,
in spite of steeper angles, might tend to run a little more trail than
road-pattern frames, so they don't "twitch") and then I'm reminded of
the old "Bicycling Science" book where a trail experiment was carried
out which indicated that too much trail was unstable and IMS, less
desirable from a handling ("ability to control the bicycle")
standpoint, than instability caused by too little trail.
I've never ridden a stayer bike; closest I've come is finishing a race
after an accident that left my front fork "altered" to the point of
extreme toe/front wheel overlap. I was too busy to notice anything in
particular IRT handling changes.
--D-y
Michael Press
> http://clubroadster.net/vb_forum/showpost.php?s=cbe0cc85f5b5a62de20a7765cae4fa...&p=578228
>
> or
>
> http://tinyurl.com/2a3f6c5
>
> Why is his fork backwards?
So when the front wheel bumps into the roller on the tow vehicle
it does not force the front wheel to yaw.
> What PEDS did he use? (just to make this qualify for rbr)
Valium.
--
Michael Press
Michael Press
What happens when the front wheel jams into the roller on
the tow vehicle? With forward fork offset the wheel wants
to yaw. With backward fork offset as, on the pictured bike,
the collision with the roller acts to keep the front wheel straight.
Later exploits of this nature mounted a bumper on the bicycle
frame at the head tube for bumping into the tow vehicle.
--
Michael Press
Plano Dude
> In article <YOURhoward-AF4437.17333403112...@news.giganews.com>,
> "H. Fred Kveck" <YOURhow...@h-SHOESbomb.com> wrote:
>
> > In article <iasetf01...@news6.newsguy.com>, dave a <blkcatREMOVET...@gmail.com>
> > wrote:
>
> > >http://clubroadster.net/vb_forum/showpost.php?s=cbe0cc85f5b5a62de20a7...
>
> > > or
>
> > >http://tinyurl.com/2a3f6c5
>
> > > Why is his fork backwards?
>
> > I'd say it's set up like that to increase the trail, thereby making the bike a bit
> > more stable. Think of it like the front wheels on a shopping cart. It'll want to
> > track better than if the fork was the normal way.
>
> What happens when the front wheel jams into the roller on
> the tow vehicle? With forward fork offset the wheel wants
> to yaw. With backward fork offset as, on the pictured bike,
> the collision with the roller acts to keep the front wheel straight.
>
> Later exploits of this nature mounted a bumper on the bicycle
> frame at the head tube for bumping into the tow vehicle.
>
> --
> Michael Press
Michael,
Have you ever motorpaced behind a vehicle, either with or without a
roller? You can smash into them pretty hard without any yaw problems.
In fact, if you're motorpacing behind an unprotected rear bumper and
keep hitting it, your front tire can grind through it pretty fast.
Michael Press
<ebb159ed-32bc-4ba1...@k22g2000yqh.googlegroups.com>,
Plano Dude <tx.was...@gmail.com> wrote:
> On Nov 4, 4:41 pm, Michael Press <rub...@pacbell.net> wrote:
> > In article <YOURhoward-AF4437.17333403112...@news.giganews.com>,
> > "H. Fred Kveck" <YOURhow...@h-SHOESbomb.com> wrote:
> >
> > > In article <iasetf01...@news6.newsguy.com>, dave a <blkcatREMOVET...@gmail.com>
> > > wrote:
> >
> > > >http://clubroadster.net/vb_forum/showpost.php?s=cbe0cc85f5b5a62de20a7...
> > > > ...&p=578228
> >
> > > > or
> >
> > > >http://tinyurl.com/2a3f6c5
> >
> > > > Why is his fork backwards?
> >
> > > I'd say it's set up like that to increase the trail, thereby making the bike a bit
> > > more stable. Think of it like the front wheels on a shopping cart. It'll want to
> > > track better than if the fork was the normal way.
> >
> > What happens when the front wheel jams into the roller on
> > the tow vehicle? With forward fork offset the wheel wants
> > to yaw. With backward fork offset as, on the pictured bike,
> > the collision with the roller acts to keep the front wheel straight.
> >
> > Later exploits of this nature mounted a bumper on the bicycle
> > frame at the head tube for bumping into the tow vehicle.
>
> Michael,
>
> Have you ever motorpaced behind a vehicle, either with or without a
> roller?
No.
> You can smash into them pretty hard without any yaw problems.
> In fact, if you're motorpacing behind an unprotected rear bumper and
> keep hitting it, your front tire can grind through it pretty fast.
There goes another perfectly good theory.
--
Michael Press