No-Weld FWD Recumbent - "The Bull"

If you want a quick-n-dirty no-weld FWD 'bent project, this could be it:

http://bsanders.net/The_Bull_FWD_recumbent.jpg

But I don't recommend it.

Why? It rides and handles well when coasting; but the pedal-induced steering is *terrible*! That's
why I call it "The Bull" - it keeps twisting, trying to buck me off; but I have a-hold of its
horns! ;-)

The front triangle is the rear triangle from a discarded 27"-wheeled steel road bike. I just sliced
it off and literally bent it back to fit (no mandrels here - put the chainstays on the floor, held
it down with my boot near BB shell and bent it over). The fork was bent open using a hydraulic jack
(carefully and gingerly). The front hub is a freewheel type, 135mm, bolt-on. It has plenty of room
for two sets of dropouts. The front triangle is surprisingly stiff with everything bolted down
tightly. The derailleur is an oddball Schwinn part that actually allows you to pre-set a gear! (It
has notches for that purpose.)

The former seat tube (now the boom tube) is bolted through the fork crown with an eyebolt (45
cents), which holds tension on a 1/4" steel clevis pin (85 cents). I just drilled a 1/4" hole
through the boom tube for the clevis pin, which threads through the eye of the eyebolt, and is held
in place with a cotter pin. With the double-dropout arrangement, the only way to get the wheel out
for tire repairs is to remove the whole triangle, and the clevis pin makes that a snap -
quick-release drivetrain!

Total time spent building: About 7 hours, including trips to the hardware store. I could build
another one in 3 hours or less. Getting the forks and donated rear triangle spread evenly was the
hardest part. Oversized steel unicrown forks don't like to bend very much!

It was a fun project; but now I know why you don't see many FWD bikes like this! Not sure how long
this bike will be intact - I think I'm going to try welding the boomtube to the head tube and do a
"twisty chain" FWD design (chain goes over idlers at head tube, twists with steering).

-Barry

 

I have had 2 of those. You just didn't play around with it enough. Turn the front fork around so
that you have as much trail as possible. I like to have at least 5 inches of trail. Front drives
need a big control spring so that you have something to push against.

Then pedal around for a while. Try pushing outward with your feet as you pedal forward. after a
while you will be riding without your hands.
--
Bill "Pop Pop" Patterson Retired and riding my Linear, my front drive low racer and our M5 tandem.

 

"Bill Patterson" <[email protected]> wrote in message news:[email protected]...
> I have had 2 of those. You just didn't play around with it enough. Turn the front fork around so
> that you have as much trail as possible. I like to have at least 5 inches of trail. Front drives
> need a big control spring so that you have something to push against.
>
> Then pedal around for a while. Try pushing outward with your feet as you pedal forward. after a
> while you will be riding without your hands.

Hey Bill! That's some great advice!

You know, I did notice the potential for hands-free steering...I mean, it's hard not to notice the
role of the feet in steering this beast! LOL!

I'm definitely going to try your suggestions. The beauty of this no-weld design is that I can turn
the fork around in about 10 minutes (or less). Today I was wondering to myself how the heck those
Flevobikes work. I mean, they're entirely steered by the feet and by leaning, aren't they?

Happy Trail,

Barry

 

"B. Sanders" wrote:

> ... Happy Trail,
>
> Barry

Pun intended?

Tom Sherman - Quad Cities USA (Illinois side) Various HPV's

 

Bill Patterson <[email protected]> wrote in message news:<3E483482.[email protected]>...
> I have had 2 of those. You just didn't play around with it enough. Turn the front fork around so
> that you have as much trail as possible. I like to have at least 5 inches of trail. Front drives
> need a big control spring so that you have something to push against.
>
> Then pedal around for a while. Try pushing outward with your feet as you pedal forward. after a
> while you will be riding without your hands.

Beware though: if you get extra trail by instead decreasing the head tube angle, a dangerous problem
develops. If you turn too far, the force no longer pushes the wheel toward the center, it instead
will spin out. This is because a wheel perpendicular to the straight ahead direction will lower the
center of gravity of the bike.

My FWD lowracer project initially had a less than 60 degree angle, and I thought it rode ok until I
crashed because of this. Adding about 10 degrees made it into the fine machine it is now, but hands
free riding requires a more balanced pedalling than I have (it exercises my arms a little to resist
the pedalling forces).

Craig

 

I have had several front drive bikes. I currently own 3, A 2 wheel drive tandem, A fully suspended
front drive low racer/off road bike, and a rigid bike similar to Barry's.

I have photos and movies of the tandem on my web site. I can get on and ride away from a dead stop
with my hands in the air.

After my back problems, I am getting rid of all the rigid bikes. Suspension is a necessity now.

[email protected]
>
> http://www.calpoly.edu/~wpatters/
>
> "The Lords of the Chainring" Bike/motorcycle design text. Third edition now available
> http://www.calpoly.edu/~wpatters/lords.html
>
> Our Human Powered Helicopter "Leonardo da Vinci III"
>
> http://www.calpoly.edu/~wpatters/helo.html
>
> Remember the Pony Express
>
> http://home.earthlink.net/~aircommando1/20heliohistory.htm
>
> http://www.geocities.com/amlegnpost499/ls85.htm
>
> And remember the fighter pilot's prayer:
>
> "Lord I pray for the eyes of an eagle, the heart of a lion and the balls of a helicopter pilot."

Bozeman wrote:
>
> Bill Patterson <[email protected]> wrote in message news:<[email protected]>...
> > I have had 2 of those. You just didn't play around with it enough. Turn the front fork around so
> > that you have as much trail as possible. I like to have at least 5 inches of trail. Front drives
> > need a big control spring so that you have something to push against.
> >
> > Then pedal around for a while. Try pushing outward with your feet as you pedal forward. after a
> > while you will be riding without your hands.
>
> Beware though: if you get extra trail by instead decreasing the head tube angle, a dangerous
> problem develops. If you turn too far, the force no longer pushes the wheel toward the center, it
> instead will spin out. This is because a wheel perpendicular to the straight ahead direction will
> lower the center of gravity of the bike.
>
> My FWD lowracer project initially had a less than 60 degree angle, and I thought it rode ok until
> I crashed because of this. Adding about 10 degrees made it into the fine machine it is now, but
> hands free riding requires a more balanced pedalling than I have (it exercises my arms a little to
> resist the pedalling forces).
>
> Craig

--
Bill "Pop Pop" Patterson Retired and riding my Linear, my front drive low racer and our M5 tandem.

 

Craig, do you mean that you recommend a more vertical fork?

Barry,

I have had several front drive bikes. I currently own 3, A 2 wheel drive tandem, A fully suspended
front drive low racer/off road bike, and a rigid bike similar to yours.

I have photos and movies of the tandem on my web site. The rigid bike is in there somewhere, as
well. I can get on and ride the tandem away from a dead stop with my hands in the air.

After a little back problem, I am getting rid of all the rigid bikes. Suspension is a necessity now.

[email protected]
>
> http://www.calpoly.edu/~wpatters/
>
> "The Lords of the Chainring" Bike/motorcycle design text. Third edition now available
> http://www.calpoly.edu/~wpatters/lords.html
>
> Our Human Powered Helicopter "Leonardo da Vinci III"
>
> http://www.calpoly.edu/~wpatters/helo.html
>
> Remember the Pony Express
>
> http://home.earthlink.net/~aircommando1/20heliohistory.htm
>
> http://www.geocities.com/amlegnpost499/ls85.htm
>
> And remember the fighter pilot's prayer:
>
> "Lord I pray for the eyes of an eagle, the heart of a lion and the balls of a helicopter pilot."

Bozeman wrote:
>
> Bill Patterson <res06nh[email protected]> wrote in message news:<[email protected]>...
> > I have had 2 of those. You just didn't play around with it enough. Turn the front fork around so
> > that you have as much trail as possible. I like to have at least 5 inches of trail. Front drives
> > need a big control spring so that you have something to push against.
> >
> > Then pedal around for a while. Try pushing outward with your feet as you pedal forward. after a
> > while you will be riding without your hands.
>
> Beware though: if you get extra trail by instead decreasing the head tube angle, a dangerous
> problem develops. If you turn too far, the force no longer pushes the wheel toward the center, it
> instead will spin out. This is because a wheel perpendicular to the straight ahead direction will
> lower the center of gravity of the bike.
>
> My FWD lowracer project initially had a less than 60 degree angle, and I thought it rode ok until
> I crashed because of this. Adding about 10 degrees made it into the fine machine it is now, but
> hands free riding requires a more balanced pedalling than I have (it exercises my arms a little to
> resist the pedalling forces).
>
> Craig

--
Bill "Pop Pop" Patterson Retired and riding my Linear, my front drive low racer and our M5 tandem.

 

"Tom Sherman" <[email protected]> wrote in message news:[email protected]...
>
> "B. Sanders" wrote:
>
> > ... Happy Trail,
> >
> > Barry
>
> Pun intended?

Yes absolutely!

-Barry

PS: Can I just say it? I love this darned newsgroup.

 

"B. Sanders" <[email protected]> wrote in news:[email protected]:

>. The derailleur is an oddball Schwinn part that actually allows you to pre-set a gear! (It has
> notches for that purpose.)

Although I cannot say only based on the picture, it is most likely a very early Shimano Positron.
The earliest had two cables, one pulled one pushed the derailleur into position. The Positron II had
a single stiff wire-like cable. The "notches" are detentes for each gear. This was usually
incorporated into Schwinn's bikes that used the Front Freewheeling System. Although quite heavy, and
a bit quirky, it did work well while clean and new.

 

"rorschandt" <[email protected]> wrote in message
news:[email protected]...
> "B. Sanders" <[email protected]> wrote in news:[email protected]:
>
> >. The derailleur is an oddball Schwinn part that actually allows you to pre-set a gear! (It has
> > notches for that purpose.)
>
> Although I cannot say only based on the picture, it is most likely a very early Shimano Positron.
> The earliest had two cables, one pulled one pushed the derailleur into position. The Positron II
> had a single stiff wire-like cable. The "notches" are detentes for each gear. This was usually
> incorporated into Schwinn's bikes that used the Front Freewheeling System. Although quite heavy,
> and a bit quirky, it did work well while clean and new.

Exactly right! I'm impressed. I had a salvaged Schwinn 24" girls 10-speed a couple of years ago with
the front freewheel system (the freewheel is in the BB - chain keeps moving during coasting). It was
interesting.

The derailleur came from a pile of old Schwinn parts, wheels and frames that I hauled away (for
free) from a garage sale last summer. It has been handy for these kinds of projects, where weight
isn't a priority, 9-speed STI is a distant dream, and spindly "Schwinn approved" caliper brakes with
age-hardened pads are good enough for around-the-block test rides.

-Barry

 

Bill Patterson <[email protected]> wrote in message news:<[email protected]>...
> Craig, do you mean that you recommend a more vertical fork?
>

Yes, I do. I don't know at what angle other problems start to counteract this phenomenon (has anyone
tried a bike with a 90+ degree head tube angle?) (problem gets worse as distance from 90 degrees
increases in either direction), but for larger wheels and lower head tube angles it can be quite a
problem. Also, this problem is not unique to FWD, it is just that these bicycles prefer more trail,
and lowering the head tube angle is one way to get it.

I'll try to explain more clearly: when the wheel is straight, the front axle is R off the ground,
where R is the wheel radius. However, when the wheel is turned 90 degrees, the front axle is about
R*sin(head tube angle) off the ground. The height varies continuously between these extremes,
because the point of contact moves forward as the wheel is turned from straight ahead. The
anti-centering force is proportional to W*dh/d(theta) where W is the weight on the front wheel, h is
the height of the front axle, and theta the steering angle.

> Barry,
>
> I have had several front drive bikes. I currently own 3, A 2 wheel drive tandem, A fully suspended
> front drive low racer/off road bike, and a rigid bike similar to yours.
>
> I have photos and movies of the tandem on my web site. The rigid bike is in there somewhere, as
> well. I can get on and ride the tandem away from a dead stop with my hands in the air.
>
> After a little back problem, I am getting rid of all the rigid bikes. Suspension is a
> necessity now.
>

Are you selling them? Too bad I just left California

Craig

 

THanks,

I get you now. In my book that effect is called K1. It is the anti centering spring that is most
noticed at low speed. That effect is why I suggested that the BikeE2 be built with a vertical
headtube and a bent back fork for trail.

quote
================

I'll try to explain more clearly: when the wheel is straight, the front axle is R off the ground,
where R is the wheel radius. However, when the wheel is turned 90 degrees, the front axle is about
R*sin(head tube angle) off the ground. The height varies continuously between these extremes,
because the point of contact moves forward as the wheel is turned from straight ahead. The anti
centering force is proportional to W*dh/d(theta) where W is the weight on the front wheel, h is the
height of the front axle, and theta the steering angle.

--
Bill "Pop Pop" Patterson Retired and riding my Linear, my front drive low racer and our M5 tandem.

 

Barry,

Did you try turning the fork around to increase the trail ? If so , how much did it change the way
pedaling affected your bikes handling ?

What other changes did you notice?

Thanks Robert

"B. Sanders" <[email protected]> wrote in message
news:<[email protected]>...
> "rorschandt" <[email protected]> wrote in message
> news:[email protected]...
> > "B. Sanders" <[email protected]> wrote in
> > news:[email protected]:
> >
> > >. The derailleur is an oddball Schwinn part that actually allows you to pre-set a gear! (It
> > > has notches for that purpose.)
> >
> > Although I cannot say only based on the picture, it is most likely a very early Shimano
> > Positron. The earliest had two cables, one pulled one pushed the derailleur into position. The
> > Positron II had a single stiff wire-like cable. The "notches" are detentes for each gear. This
> > was usually incorporated into Schwinn's bikes that used the Front Freewheeling System. Although
> > quite heavy, and a bit quirky, it did work well while clean and new.
>
> Exactly right! I'm impressed. I had a salvaged Schwinn 24" girls 10-speed a couple of years ago
> with the front freewheel system (the freewheel is in the BB - chain keeps moving during coasting).
> It was interesting.
>
> The derailleur came from a pile of old Schwinn parts, wheels and frames that I hauled away (for
> free) from a garage sale last summer. It has been handy for these kinds of projects, where weight
> isn't a priority, 9-speed STI is a distant dream, and spindly "Schwinn approved" caliper brakes
> with age-hardened pads are good enough for around-the-block test rides.
>
> -Barry