Thoughts on Cycle Genius STX?

Tracer said:

I have a chance to buy one reasonably priced.($400).Any thoughts for a
beginning recumbent?

While I have not ridden one [1], the price is reasonable in comparison
to competing bikes.

My only real caution would be is that the STX comes in only one size,
and will either not fit or have to much weight on the real wheel if the
rider is much over 6 feet (0.183 m) tall [2].

[1] <http://www.cyclegenius.com/stx.htm>.
[2] Assuming normal range body proportions.

--
Tom Sherman - Behind the Cheddar Curtain
Post Free or Die!

Johnny Sunset aka Tom Sherman said:

Tracer wrote:
....
My only real caution would be is that the STX comes in only one size,
and will either not fit or have to much weight on the real wheel if the
rider is much over 6 feet (0.183 m) tall [2].
....
[2] Assuming normal range body proportions.

Yes but is a lightly-loaded front wheel on a recumbent so bad of a
thing? During emergency braking much of the total weight shifts to the
front wheel, and people frequently note that they crash because their
front wheel begins to slide. Tires slide because either they are
overloaded for what traction they have, or because they are overinflated
for conditions.

It seems logical to have weight distribution proportional to where the
CG of the bicycle lies but in real-world terms it may be useful to have
an "underweighted, underloaded, underinflated" front wheel in
anticipation of making emergency stops.

Cruising down the road with most of your weight on the rear tire doesn't
hurt anything, but crashing when your front tire slides out under hard
braking does. And certainly any bicycle can brake hard just fine on
/clean pavement/,,,, it's when you need to brake hard while turning on
a patch of gravel or sandy pavement that is the test.
~

DougC said:

Johnny Sunset aka Tom Sherman said:

Tracer wrote:
....
My only real caution would be is that the STX comes in only one size,
and will either not fit or have to much weight on the real wheel if the
rider is much over 6 feet (0.183 m) tall [2].
....
[2] Assuming normal range body proportions.

Yes but is a lightly-loaded front wheel on a recumbent so bad of a
thing?

On a RANS Tailwind, I can amuse myself by doing power wheelies from a
dead stop. 😉

Too little weight on the front wheel can make handling during low speed
riding, especially climbing difficult, particularly if the front wheel
comes off the ground, as it did with every pedal stroke on my RANS
Rocket when climbing the steeper part of this road. [1] [2] The late
Gardner Martin reportedly did not put a larger than ISO 451-mm wheel on
the front of Easy Racers, since obtaining proper weight distribution
would have made an already long bicycle even longer.

Quoted message said:

During emergency braking much of the total weight shifts to the
front wheel, and people frequently note that they crash because their
front wheel begins to slide. Tires slide because either they are
overloaded for what traction they have, or because they are overinflated
for conditions.

As long the the coefficient of friction remains relatively linear, the
increased loading will produce a similar increase in traction.

Quoted message said:

It seems logical to have weight distribution proportional to where the
CG of the bicycle lies but in real-world terms it may be useful to have
an "underweighted, underloaded, underinflated" front wheel in
anticipation of making emergency stops.

Assuming adequate braking power, one of two things will happen at the
limit: the bike will rotate about the contact patch of the front tire
or the front tire will slide. As long as the CG is some combination of
far enough rearward and low enough that the front tire will slide under
braking, no further improvement in braking will occur by moving the CG
further rearward.

Quoted message said:

Cruising down the road with most of your weight on the rear tire doesn't
hurt anything,

It will increase rolling resistance due to the greater deformation of
the rear tire casing and resultant energy loss through hysteresis. The
tire deflection could be reduced by increased tire pressure, but this
is limited by tire blow-off and rim strength factors of safety, and
ride comfort on non-suspended bicycles.

Quoted message said:

but crashing when your front tire slides out under hard
braking does. And certainly any bicycle can brake hard just fine on
/clean pavement/,,,, it's when you need to brake hard while turning on
a patch of gravel or sandy pavement that is the test.

Generally, experience shows that LWB bicycles with lightly loaded front
wheels are worse on loose surfaces than SWB bicycles with more heavily
loaded front wheels.

[1]
<http://terraserver.microsoft.com/image.aspx?T=2&S=12&Z=16&X=581&Y=5541&W=2&qs=%7cperrysville%7cin%7c>.
[2] The front wheel would likely have stayed on the ground if I had had
a lower gear than the stock 39/28 or a 2001 or later RANS Rocket which
has longer chain stays.

--
Tom Sherman - Behind the Cheddar Curtain
Post Free or Die!

Johnny Sunset aka Tom Sherman said:

Assuming adequate braking power, one of two things will happen at the
limit: the bike will rotate about the contact patch of the front tire
or the front tire will slide. As long as the CG is some combination of
far enough rearward and low enough that the front tire will slide under
braking, no further improvement in braking will occur by moving the CG
further rearward.

.....

Generally, experience shows that LWB bicycles with lightly loaded front
wheels are worse on loose surfaces than SWB bicycles with more heavily
loaded front wheels.

As to the first point--on some bents it is possible to do this (lift the
front wheel in low gears) but the "problem" of being able to lift a
front wheel when your cranking up a hill in low gear isn't likely to
cause you to crash to the extent that you get seriously injured. It's
limited in scope (in that it's only a problem at VERY low speeds and on
very steep hills) and is more of an annoyance than an actual danger.

If you try to make an emergency stop and your SWB either lifts its rear
off the pavement, or the front wheel slides out from under you--you are
much more likely to be hurt.

-------

As to the second point--that's because most people seem to overinflate
their front tires, regardless of what style bent they ride. They tend to
go for the max pressure to minimize rolling resistance, but the tire
ends up way overinflated for the actual load that is normally upon it.
If you inflate your car's tires to 50 PSI, they'll slide around a lot in
gravel, too. If you take one of those "poor handling LWB's" and air its
front tire down to 50%-70% of whatever the rear is at, you'll probably
find the loose-surface handling drastically improved.
~

"DougC" <[email hidden]> wrote>

Quoted message said:

[...] If you take one of those "poor handling LWB's"

In order of loose-surface handling, I rank mine from
best to worst

CLWB BikeE (wide tires)
LWB Tour Easy (moderately wide tires)
LWB Tour Easy (moderately narrow tires)
Volae Sport (narrow tires)

In addition to the (obvious) tire width aspect, the low-bottom
bracket/upright seating may play a role.

Quoted message said:

and air its front tire down to 50%-70% of whatever the
rear is at, you'll probably find the loose-surface handling
drastically improved.

Increased contact area may help if the issue is lateral traction loss.
Suspension may also improve
contact.