From: wa@raven.mcc.com (Wayne Allen)
Subject: Allsop Softride Stem review (long and windy!)
Organization: MCC ISD, Austin, Texas
Distribution: rec.bicycles.marketplace
Date: Tue, 10 Nov 1992 19:28:37 GMT



I recently acquired an Allsop Softride stem, and now offer this initial
review.  Short version:  Yyyyess!!   Long version follows...


Motivation
==========

A year ago I took my first real off-road ride (off *paved* road, that
is) 26 miles through the desert/mountain country in Big Bend N.P.,
Texas. When I got to the end, the flesh of my arms felt like it had
been flayed from the bone, and my hands clutched spasmodically like
some B-movie zombie, but man, was I pumped! I wanted to do it again,
hold the pain, please.


Why an Allsop?
==============

Cost, simplicity, reliability, maintainability, adjustability, weight,
comfort, responsiveness, high-speed performance.

When I applied each of these more-or-less equally-weighted
considerations to some popular suspension forks, the Allsop always won
(in *my* mind, at least, which some argue is a murky place, at best
=8-). If you skew priorities toward high-speed performance, one could
argue for forks being the better choice.

I also looked at the Girvin Flexstem but I felt that the Allsop would
be better because:

	- more travel (~3")
	- continuously (as opposed to descretely) adjustable on the trail
	- constant bar pitch (I thought most important)


So I Got One
============

Basic mechanics: the stem body is a pivoting parallelogram supported
by a coil spring.  One end of the spring pivots about the lower-rear
axle of the parallelogram, and the other is attached to the under-side
of the top bar of the parallelogram through a mount and threaded
screw. You can adjust the spring pre-load tension by turning the
screw. As you depress the handle bar, the spring compresses, and the
bar retains a constant pitch throughout the travel because of the
parallel geometry.

The first (!) stem I received from the All-terrain Suspension Shop
(see Sources below) was the 135mm aluminum. On this particular stem,
the pre-load adjustment screw wanted to simultaneously occupy the same
volumn of space as the fore lower pivot axle. I returned it and asked
for a 135 which had sufficient clearance, or, barring that, a 150mm.

I recieved a new 150mm stem (draw your own conclusions, but don't say
I didn't run up a flag!) and mounted it on my '90 GT K2. Replacing my
(somewhat obese) stock stem, the Allsop added 130 gm (4.6 oz) to the
total bike weight. The quality and ruggedness of construction seems
excellent. The experience illuminated a number of considerations..

1) The mounting requires that you use a cable hanger for the front
brake.  I got one of the Dia-comp hangers (nice little piece, $10).
However, the head tube on my GT was cut to fit my fork and Harra
headset with only a 3/64" washer to spare. So, since the hanger is
3/16, the headset lock nut does not really have enough threads to work
with. I plan to get the tube trimmed to fit, an estimated $10 to $20
at a local shop. One could get a smaller stack-height headset, I
suppose...  (NOT!)

2) The stems all have 1" quills, and fit oversized tubes with a shim.
The 1-1/8" shim mounted fine in my fork.

3) The stems come with several sizes of pivot-axle shims to adjust the
amount of bar rise; two rise hights for 135, three for the 150. This
requires some dis-and-re-assembly.  I did not adjust the height, so
cannot comment on the difficulty.

4) The stem design uses "friction" damping. That is, the four hollow
pivot axles are mounted with through-tube allen-head bolts and
non-slip nuts. (The nuts have a nylon insert so that they hold the
threads firmly.) This allows any amount of friction to be applied and
held constant by bolt torque. Higher damping also increases static
friction ("sticktion"). I left the damping as it came.

5) The stem allows for pre-loading of spring tension using the same
allen wrench size which adjusts damping (3mm).  I initially set mine
so that the stem depresses slightly (<0.25") when sitting in a neutral
position on the bike (I weigh 160lbs). I assume this is near the soft
end of the spectrum.

6) Maintenance entails relieving the spring tension with the pre-load
screw, un-screwing each of the four pivot axle bolts, and greasing the
eight bearings. Requires only the one allen wrench. Should probably be
done every (pick one): 100, 1000, 1000000 miles. (Your guess as good as
mine.)

After mounting, I rode down a local hilly back-road, composed of
caliche, exposed limestone, and much loose rock. Having ridden this
bone-jarring road many times with my stock stem, I was able to make a
preliminary assessment:

	Aaaahhhhhhhhhhhh!!!


*Subjective* Impressions and Random Blither
===========================================

There was no detectable steering flex - the bar seemed as firmly
connected to the fork as ever.

There was a small amount of dive on braking. I did not adjust the
pre-load to test it's effect on dive.

Jumping or hopping the bike required a little anticipation, since the
stem rise stop is rubber, and compresses slightly when you jerk up on
the bar.

Subjectively, the front of the bike seems like it's "flowing" over the
ground.  At the low level of pre-load I used, the small bumps (high
frequency) were simply gone, and the large bumps were just a gentle
up-down. When you *watch* the stem work (a risky business at best,
similar to *thinking* about counter-steering while doing it ;-), it's
flexing constantly, and the front wheel and frame move up and down.
When riding normally, you're completely un-aware of this activity. I
suppose the constant bar pitch contributes to this effect.  Also,
the vertical movement at the front does not translate into much
movement at the saddle or pedals, because they are so much closer to
the point of rotation (rear axle).  I'll pull out my geometry book for
the next report.

With the original stem, the front of the bike would bounce wildly when
the going got rough at speed. The front wheel would actually bounce
off the ground from the springiness of the fork and tire. This is
because my arms could not effectively dampen the blows *and* maintain
a grip on the bar (this is the *flayed flesh* effect =8-).  With the
Allsop, the inertia of my body applied through the stem spring acts as
a damper so that the wheel stays on the ground rather than bouncing.
So while the frame still moves, there is detectably less
high-frequency movement than with the stock stem. I assume this
translates into better steering traction, etc., but cannot objectively
verify it.

I have ridden a few fork-suspended bikes. The Trek 8000 with the DS2
fork, for example, feels rigid at low speeds (air shocks typically
have high sticktion - MBA). It's at high speeds on rough roads that
the fork action becomes effective. The effect of the Allsop is
apparent at all speeds. I'll speculate that the combined low sticktion
and long travel of the Allsop allows a wider dynamic response than
most forks. There are probably exceptions, like the AMP and Cannondale
forks.


Summary
=======

*Very* effective. I can't think of any other bucks I could have spent
which would make as big an impact on my riding enjoyment. 

If COMFORT is your bag, this stem is probably better than forks, since
it has such a wide dynamic range. If PERFORMANCE is your bag, this
stem *should* let you go faster, but I doubt it performs as well as a
good fork at the limit.  


Next Report
===========

The basic question I hope to answer next is how the stem compares with
forks in feel and function on a real side-by-side ride. I'll play with
the pre-load settings, and I'll also see if we can quantify some of
the differences in the fork vs. stem approaches. 

Anyone out there in central Texas have a fork-sprung GT?  If so, give
me an e-buzz.


Sources
=======

	Cambria Bicylcle Outfitters
	(805)927-5510  $200

	Bike-Pro  1-800-bike-pro
	$200 alum, $148 Chromo

	All-Terrain Suspension shop, 880 Spartan Court., #218,
	Lexington, KY.,40504. information= 606-253-9312, ordering=
	1-800-932-4931
		Alum= $189.88
		Chromoly= $149.

	I think it's also available out of the Performance catalog for
	about $225.



 wa | Wayne Allen, wa@mcc.com
    | MCC/ISD, 3500 West Balcones Center Dr, Austin, Tx 78759 (512)338-3754
    | I really really really really really really really like girls!!!! Oh yeah
    | I really really really really really really really like girls!!! I like'm
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