SWB Stability?

"B. Sanders" skrev...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB stability in general.

It was on his first ride fer crying out loud. Hardly something to go by. After I learned the
reflexes I didn't notice any instability whatsoever at any speed except dead slow on my SWB. And I
attribute to balance rather than stability.

I can't rule out that some SWBs are poorly designed stabilitywise but if so it certainly hasn't been
any of those I have ridden. Old wives tale if you ask me. Maybe it was the USS? I hear USS is
horribly unstable. *cough cough* ;o) I worry more about the frontwheel of my LWB slipping to be
quite frank. Not that it does it all that much either.

Stick a kid on a bike for the first time without any trainingwheels and ask what he feels about its
stability after a few tries and we might start calling DFs unstable too.

M.

"Mikael Seierup" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"B. Sanders" skrev...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB

stability

Quoted message said:

Quoted message said:

in general.

It was on his first ride fer crying out loud. Hardly something to go by. After I learned the
reflexes I didn't notice any instability whatsoever at any speed except dead slow on my SWB. And I
attribute to balance rather

than stability.

You feel equally stable on LWB and SWB at high speeds? I don't.

Quoted message said:

I can't rule out that some SWBs are poorly designed stabilitywise but if

so

Quoted message said:

it certainly hasn't been any of those I have ridden. Old wives tale if you

ask me.

Just pulling data from my own experiences.

Quoted message said:

Maybe it was the USS? I hear USS is horribly unstable. *cough cough* ;o)

:-) USS is very stable, IMO. I loved my Ryan Vanguard. Sometimes I wish I
hadn't sold it. <sniff>

Quoted message said:

I worry more about the frontwheel of my LWB slipping to be quite frank. Not that it does it all
that much either.

Yeah, I've had that happen several times on the Ryan Vanguard. It wasn't a big deal - so much moving
mass, the wheel just skidded, and then I corrected and went on my way. No problem. When the rear
wheel breaks loose, that's a different beast.

Quoted message said:

Stick a kid on a bike for the first time without any trainingwheels and ask what he feels about
its stability after a few tries and we might start calling DFs unstable too.

I was curious about SWB's in particular. The short wheelbase does create some extremes of steering
sensitivity. I've wondered if maybe they should have steering dampers or something. Might make me
feel a little less worried on fast descents/sprints (not that there are too many of those here in
flat Illinois...)

-=B=-

Quoted message said:

Quoted message said:

I can't rule out that some SWBs are poorly designed stabilitywise but if

so

Quoted message said:

it certainly hasn't been any of those I have ridden. Old wives tale if

you

Quoted message said:

ask me.

Just pulling data from my own experiences.

I own a Bjaellby and a Streetmachine (both SWB). The Bjaellby is far less stable than the SM, which
handles really well even at very low speeds. It's all down to geometry and weight distribution I
guess. The Bjaellby is still a good bike as it's lighter and faster, but the Streetmachine is just
so sure-footed (sure-wheeled??) it's a dream.

Quoted message said:

Quoted message said:

Maybe it was the USS? I hear USS is horribly unstable. *cough cough* ;o)

:-) USS is very stable, IMO. I loved my Ryan Vanguard. Sometimes I wish

I

Quoted message said:

hadn't sold it. <sniff>

I agree - USS is more stable than OSS. I find that many OSS bikes steering twitches from side to
side as one rides along on them.

Quoted message said:

I was curious about SWB's in particular. The short wheelbase does create some extremes of steering
sensitivity. I've wondered if maybe they should have steering dampers or something. Might make me
feel a little less worried on fast descents/sprints (not that there are too many of those

here

Quoted message said:

in flat Illinois...)

Having gone down a few mountains in Nova Scotia recently on my Streetmachine (loaded with 4
panniers), I can only say that it handled very well. At 75km/h I felt no instability whatsoever and
going round the switch-backs at ridiculous speeds didn't worry me at all. You suggest steering
dampening, but perhaps just having fairly wide handlebars like the SM is all that is needed. The
only time I have felt a little instability was when I was pulling a BOB YAK which was ridiculously
heavily loaded, but even then I found I could control it - I just had to be a little more awake.

Mads

"B. Sanders" skrev...

Quoted message said:

You feel equally stable on LWB and SWB at high speeds? I don't.

Well I really wouldn't know cause even with the front fairing on the TE-clone the Velokraft can
outrun it any day. ;-) And the VK is rock solid. Even with my Radical trailer on.

Quoted message said:

Yeah, I've had that happen several times on the Ryan Vanguard. It wasn't a big deal - so much
moving mass, the wheel just skidded, and then I corrected and went on my way. No problem. When the
rear wheel breaks loose, that's a different beast.

Yep. Try S-Licks and slush for fun skidding. Nada grip. Almost crashed on level ground going 10-15
kph or so. Rear wheel just wanted to slip out under me. This on the TE-clone. Don't think the VK
would fare any better though.

Quoted message said:

I was curious about SWB's in particular. The short wheelbase does create some extremes of steering
sensitivity. I've wondered if maybe they should have steering dampers or something. Might make me
feel a little less worried on fast descents/sprints (not that there are too many of those here in
flat Illinois...)

Okay in all fairness mine all had fairly long wheelbases. 122 and 131 cm on the ones I owned. I did
testride bikes with shorter wheelbases though, a highracer among them too, with no problems. I still
feel its a question of embedded reflexes. My TE-clone feels a bit weird when I first hop back on it
after a couple of months on the VK and I can't really turn sharply on my old DF anymore cause I
never ride it.

I've seen damping on some SWB's but only FWD Flevobikes or homebuilts made after the same principle.
(Where the whole front end turns).

Mikael

Very untechnical response from me - my 2003 HepCat is the first recumbent I have ever ridden. It has OSS and is a SWB. When I first rode it, I was amazed at its stability. Maybe it's just dumb luck, but before I bought it, I rode a few others and none were as easy and confidence-inspiring as this bike. Since then, I have ridden it as fast as 44.8 mph and still felt OK. I am not a daredevil by nature, but it is so darn much FUN!!!

I never tried a LWB because there is no way for me to store it, so I didn't want to fall in love with something I couldn't have (been there, done that, but that's another story..LOL).

"B. Sanders" <[email hidden]> wrote in message news:<SYelb.605663$cF.272162@rwcrnsc53>...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB stability in general.

......

Everything you say about SWB stability I agree with in spades. After I got my Vision R40 SWB OSS I
soon discovered that it was not ideal for long road tours. And so I switched over to the LWB and all
my problems were solved. Some bikes are fine for running around in a parking lot and turn out to be
not so fine for long road tours. As far as I am concerned, LWB is the only way to go unless you are
interested only in "sporty" type of cycling.

B. Sanders and I are poles apart on politics, but in basic agreement on the lack of stability with
respect to SWB recumbents. Maybe we should should stay off of politics.

Ed Dolan - Minnesota

About the only problem I ever noticed with an SWB is (in the case of my R50) was applying too much
front brake which would throw you over the front, I had that happen once doing 5mph

No damage but felt pretty stupid

"B. Sanders" <[email hidden]> wrote in message news:SYelb.605663$cF.272162@rwcrnsc53...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB

stability

Quoted message said:

in general.

I love my 2000 RANS Rocket SWB/OSS; but it's pretty darned sporty. The

first

Quoted message said:

few rides on the Rocket didn't feel very stable. The short wheelbase

seemed

Quoted message said:

too short. The handling seemed a little too sporty and sensitive to me.

(I

Quoted message said:

had ridden other SWB's before, including a Vision R40 like Fred's). Sensitive/sporty steering is
exactly what you want when you're turning figure-8's in the parking lot, or negotiating a tricky
turn on a narrow path; but when you're going 40+ MPH on a white-knuckle descent, the sensitivity
of the SWB handling can cause some puckering of one's nether regions.

I've gotten used to the steering sensitivity; but I still have to remind myself sometimes, such as
when I'm taking a hand off the bar to swat bugs, shield my eyes from the sun, etc. If you shift
your weight suddenly, and instinctively compensate by applying pressure against one side of the
handlebars, you're asking for trouble. (BTW: This applies much more for

OSS

Quoted message said:

than for USS.) This is one of the reasons that I prefer under seat

steering

Quoted message said:

(USS). I rarely felt the same instabilities that I sense/note/experience

on

Quoted message said:

the Rocket with over seat steering.

Yesterday, while I was gliding along at 21mph or so on a smoothly-paved

bike

Quoted message said:

path, I deliberately tugged/wiggled the Rocket's handlebars at various frequencies and amplitudes,
to check stability and test the limits of handling. I could see that it didn't take much force to
upset the

steering;

Quoted message said:

but the bike did seem pretty stable within limits. Certain "wiggle frequencies" allowed much
greater steering forces than others without destabilizing the bike. This is as expected: A bike is
an inverted pendulum, basically.

If there are folks who don't like the sensitive/sporty handling of an SWB,

I

Quoted message said:

could definitely understand their point of view. Sometimes I think that another foot of wheelbase
would be a good thing, especially at higher speeds. For my purposes, however, the Rocket does
almost everything

right,

Quoted message said:

and I can accept the tradeoffs in its design.

-=Barry=- 2000 RANS Rocket

B. Sanders said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB stability in general.

I love my 2000 RANS Rocket SWB/OSS; but it's pretty darned sporty. The first few rides on the
Rocket didn't feel very stable. The short wheelbase seemed too short. The handling seemed a little
too sporty and sensitive to me. (I had ridden other SWB's before, including a Vision R40 like
Fred's). Sensitive/sporty steering is exactly what you want when you're turning figure-8's in the
parking lot, or negotiating a tricky turn on a narrow path; but when you're going 40+ MPH on a
white-knuckle descent, the sensitivity of the SWB handling can cause some puckering of one's
nether regions.

I happen to find the handling of the 2000 RANS Rocket fine up to 50-mph (~80 kph), at which point I
am pedaling at 150+ rpm. [1] The real problem in my opinion is having a sudden flat on the front.
The last time this happened, I ended up lying in the middle of the street [2] with road rash.

[1] Eastbound on Indiana Route 32, just before the Wabash River bridge near Perrysville.
[2] On the slight downhill section of eastbound East Main before Cottage Grove.

Tom Sherman - Near the confluence of the Mississippi and Rock Rivers

Mikael Seierup said:

... Stick a kid on a bike for the first time without any trainingwheels and ask what he feels
about its stability after a few tries and we might start calling DFs unstable too.

All single-track vehicles are unstable, since they all require rider input to create reactions
perpendicular to the vehicle's track to keep the vehicle upright.

Tom Sherman - Near the confluence of the Mississippi and Rock Rivers

Quoted message said:

"B. Sanders" skrev...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB

stability

Quoted message said:

Quoted message said:

in general.

The first time I rode a recumbent bicycle the dealer (Angletech) had me ride four styles of bikes
twice each -- CLWB, LWB, SWB w/USS, and SWB w/ASS, in that order. The route was about a mile of side
streets with stop signs and intersections. From what I had read, I expected the longer wheelbase
bikes to be the easiest for a beginner but I wobbled a lot more on them than on the SWB bikes.

When I got my bike, I rode around the parking lot at home a few times for practice. Then I rode my
new V-Rex forty miles for the first ride. I fell over once in slow motion into a grassy ditch while
practicing U-turns on a 2-lane road. It wasn't the bike's fault; the unfamiliar handling spooked me.

With a bit of practice away from traffic and exercising judgment while building new reflexes, I
believe most people would have no problem with a SWB bike. I've let several beginners try my bike
and none of them has fallen. In fact, most of them did much better than I did the first time.

Frank Calloway

In article <8yglb.198670$%h1.192605@sccrnsc02>, [email hidden] says...

Quoted message said:

"Mikael Seierup" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"B. Sanders" skrev...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB

stability

Quoted message said:

Quoted message said:

in general.

It was on his first ride fer crying out loud. Hardly something to go by.

Quoted message said:

You feel equally stable on LWB and SWB at high speeds? I don't.

I don't think one bike design is inherently more stable than another.

Beginners usually do better on a longer platform. At least that was the case with me. Did you ever
try to ride a unicycle? Yet there are those that make ballancing on one wheel seem a breeze. When
you are sitting over the front wheel, it is real easy to oversteer. This is especially true if you
are used to steering on a DF.

When I started trying recumbents, I settled on a LWB RANS Stratus because I felt the SWBs too
twitchy. Later when I learned to ride a recumbent and keep a light touch on the on the steering, I
went back and tried the SWBs again with an entirely different experience. I now own two SWBs and the
RANS Stratus is history. time for some distance

BTW I feel just as stable on a SWB at high speeds as I do on a LWB. I rode a SWB Strada this weekend
for the first time for some distance on the Skyline Drive. Within the first 8 miles, I had it up to
35mph. I would have gone faster, except that was the posted speed limit and the wind chill made my
teeth chatter above 30.
--

Cletus D. Lee Bacchetta Giro Lightning Voyager clee.orgclee.orgOpen ↗
- Bellaire, TX USA -

YMMV ... but ... I owned and rode a LOt mon a SWB P-38 and Challenge Taifun but for more than a year
I have ridden a GRR Ti Rush. For me, the LWB TiRush is FAR more satable than the SWBs.

On any SWB I must focus very carefully on what I am doing . That includes my test rides on the
Bacchetta Aero.

On my GRR LWB I relax and enjoy the scenery. For me, starting after a dead stop, especially uphill,
is a piece of cake on the GRR and relatively hard to do on the SWBs.

Gator Bob Siegel

"Cletus Lee" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

In article <8yglb.198670$%h1.192605@sccrnsc02>, [email hidden]

says...

Quoted message said:

Quoted message said:

"Mikael Seierup" <[email hidden]> wrote in message
"]news:[email hidden]...

Quoted message said:

"B. Sanders" skrev...
> Fred's recent crash on a SWB Vision stirred my thinking about SWB

stability

Quoted message said:

> in general.

It was on his first ride fer crying out loud. Hardly something to go

by.

Quoted message said:

Quoted message said:

You feel equally stable on LWB and SWB at high speeds? I don't.

I don't think one bike design is inherently more stable than another.

Beginners usually do better on a longer platform. At least that was the

case with me. Did you

Quoted message said:

ever try to ride a unicycle? Yet there are those that make ballancing on

one wheel seem a

Quoted message said:

breeze. When you are sitting over the front wheel, it is real easy to

oversteer. This is

Quoted message said:

especially true if you are used to steering on a DF.

When I started trying recumbents, I settled on a LWB RANS Stratus because

I felt the SWBs too

Quoted message said:

twitchy. Later when I learned to ride a recumbent and keep a light touch

on the on the

Quoted message said:

steering, I went back and tried the SWBs again with an entirely different

experience. I now own

Quoted message said:

two SWBs and the RANS Stratus is history. time for some distance

BTW I feel just as stable on a SWB at high speeds as I do on a LWB. I

rode a SWB Strada this

Quoted message said:

weekend for the first time for some distance on the Skyline Drive. Within

the first 8 miles, I

Quoted message said:

had it up to 35mph. I would have gone faster, except that was the posted

speed limit and the

Quoted message said:

wind chill made my teeth chatter above 30.
--

Cletus D. Lee Bacchetta Giro Lightning Voyager clee.orgclee.orgOpen ↗
- Bellaire, TX USA -

My physics instructor says, "This is funny thread!"....

"B. Sanders" <[email hidden]> wrote in message news:<SYelb.605663$cF.272162@rwcrnsc53>...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB stability in general.

<snip>

Quoted message said:

Yesterday, while I was gliding along at 21mph or so on a smoothly-paved bike path, I deliberately
tugged/wiggled the Rocket's handlebars at various frequencies and amplitudes, to check stability
and test the limits of handling. I could see that it didn't take much force to upset the steering;
but the bike did seem pretty stable within limits. Certain "wiggle frequencies" allowed much
greater steering forces than others without destabilizing the bike. This is as expected: A bike is
an inverted pendulum, basically.

Nope. A bicycle does *not* rotate around the tire's contact patch. It rotates around the center of
gravity of the bicycle and rider.

Going into a turn, the rider steers the contact patch to one side, say, to the left. Gravity tries
to pull the rider to the ground. In order to prevent this, the rider steers *to the right* until
centrifugal force balances the pull of gravity. To recover from the curve, the rider steers *harder*
to the right, and increased centrifugal force straightens him/her up. This is called
"countersteering"... and every two wheeled vehicle balances this way.

Try it sometimes- while on a smooth area (preferably away from traffic), *push* sharply on your
right handlebar. You'll find that you'll recover by turning *right*- opposite the way you'd expect.

Quoted message said:

If there are folks who don't like the sensitive/sporty handling of an SWB, I could definitely
understand their point of view. Sometimes I think that another foot of wheelbase would be a good
thing, especially at higher speeds. For my purposes, however, the Rocket does almost everything
right, and I can accept the tradeoffs in its design.

-=Barry=- 2000 RANS Rocket

Other experiments: compare handling sensitivity when your back is in contact with the seat vs.
leaning forward. You'll find that the additional mass of your torso helps damp the twitchy feeling.

FWIW: I've had my SWB Lightning past 55mph- and it felt capable of more. I was spun out, though.

Jeff

The way I solved some of that sensitive feel on my 2002 Rocket was to change the stem and the
handlebars to the Terracycle 55 degree, 44cm bars sold at Hostleshoppe.com. My hands are more in the
position as if driving a car. What a big difference at higher speeds. I'm sure these bars or the
Evolution bars would benefit most OSS bikes. I wish I would have done this a thousand miles ago.

Rans Rocket EZ-1

"B. Sanders" <[email hidden]> wrote in message news:<SYelb.605663$cF.272162@rwcrnsc53>...

Quoted message said:

Fred's recent crash on a SWB Vision stirred my thinking about SWB stability in general.

I love my 2000 RANS Rocket SWB/OSS; but it's pretty darned sporty. The first few rides on the
Rocket didn't feel very stable. The short wheelbase seemed too short. The handling seemed a little
too sporty and sensitive to me. (I had ridden other SWB's before, including a Vision R40 like
Fred's). Sensitive/sporty steering is exactly what you want when you're turning figure-8's in the
parking lot, or negotiating a tricky turn on a narrow path; but when you're going 40+ MPH on a
white-knuckle descent, the sensitivity of the SWB handling can cause some puckering of one's
nether regions.

I've gotten used to the steering sensitivity; but I still have to remind myself sometimes, such as
when I'm taking a hand off the bar to swat bugs, shield my eyes from the sun, etc. If you shift
your weight suddenly, and instinctively compensate by applying pressure against one side of the
handlebars, you're asking for trouble. (BTW: This applies much more for OSS than for USS.) This is
one of the reasons that I prefer under seat steering (USS). I rarely felt the same instabilities
that I sense/note/experience on the Rocket with over seat steering.

Yesterday, while I was gliding along at 21mph or so on a smoothly-paved bike path, I deliberately
tugged/wiggled the Rocket's handlebars at various frequencies and amplitudes, to check stability
and test the limits of handling. I could see that it didn't take much force to upset the steering;
but the bike did seem pretty stable within limits. Certain "wiggle frequencies" allowed much
greater steering forces than others without destabilizing the bike. This is as expected: A bike is
an inverted pendulum, basically.

If there are folks who don't like the sensitive/sporty handling of an SWB, I could definitely
understand their point of view. Sometimes I think that another foot of wheelbase would be a good
thing, especially at higher speeds. For my purposes, however, the Rocket does almost everything
right, and I can accept the tradeoffs in its design.

-=Barry=- 2000 RANS Rocket

Sprawling said:

The way I solved some of that sensitive feel on my 2002 Rocket was to change the stem and the
handlebars to the Terracycle 55 degree, 44cm bars sold at Hostleshoppe.com. My hands are more
in the position as if driving a car. What a big difference at higher speeds. I'm sure these
bars or the Evolution bars would benefit most OSS bikes. I wish I would have done this a
thousand miles ago.

Rans Rocket EZ-1

What is a "Rans Rocket"? 😉

FWIW, I have cut down (16" wide vs. 19" stock) RANS T-bars on my Sunset and it is stable at
high speeds.

Tom Sherman - Near the confluence of the Mississippi and Rock Rivers RANS "Wavewind" and Rocket,
Earth Cycles Sunset and Dragonflyer

Jeff Wills said:

... Going into a turn, the rider steers the contact patch to one side, say, to the left. Gravity
tries to pull the rider to the ground. In order to prevent this, the rider steers *to the right*
until centrifugal force balances the pull of gravity. To recover from the curve, the rider steers
*harder* to the right, and increased centrifugal force straightens him/her up. This is called
"countersteering"... and every two wheeled vehicle balances this way....

According to my physics texts, centrifugal force does not exist (this can also be shown with a free
body diagram).

Tom Sherman - Near the confluence of the Mississippi and Rock Rivers RANS "Wavewind" and Rocket,
Earth Cycles Sunset and Dragonflyer

Tom Sherman <[email hidden]> writes:

< snip - sensible comment from Jeff Wills >

Quoted message said:

According to my physics texts, centrifugal force does not exist (this can also be shown with a
free body diagram).

Tom Sherman - Near the confluence of the Mississippi and Rock Rivers RANS "Wavewind" and Rocket,
Earth Cycles Sunset and Dragonflyer

Please explain so that the rest of us may be enlightened.

"Tom Sherman" skrev...

Quoted message said:

According to my physics texts, centrifugal force does not exist (this can also be shown with a
free body diagram).

That would be why its called a fictitious force I suppose. You get this in noninertial reference
frames. Heres my kind of free body diagram: kmmod.comcschifferOpen ↗

M.