From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.racing
Subject: Re: Spinergy Wheel Failure Causes Broken Back
Date: 22 Sep 1998 22:09:21 GMT

JV anonymously writes:

> I would like to comment on Jobst Brandt's comment regarding Spinergy
> failures; as he stated, he has been consulted on many cases where wheel
> failure has caused injury and he feels that documented cases regarding
> Spinergy failures appear to be misreported. I understand this to be
> true--that more often than not, it was cyclist error that ultimately
> caused the breakage of Spinergy wheels. But the issue should be that
> Spinergy wheels are not acceptable for cycling because of the
> catastrophic events resulting from such error.

I fully agree with that conclusion.  My point was that the
circumstances under which these failures occur may not be what they
seem in the reports.  As I said, I do not use such wheels because I
feel there is no margin in them for unusual overloads.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Spinergy X-beams
Date: 2 Oct 1998 01:04:32 GMT

David Ryan writes:

> That is in fact what happens [spokes goinfg slack].  But I haven't
> seen any of the Spinergy Failure posters mention failure under that
> type of loading.  Isn't there something in the rim construction that
> compensates and supports the wide area between spokes?  Many riders
> report being able to ride (limp along) with a pair of spokes
> missing.  Do wire rims lose tension under similar loads but just not
> have the spoke surface area to make noise?

Wire spoked wheels are metal and do not change even if you leave them
in the back of a closed car with the sun shining on them.  They just
get too hot to touch and the tire blows out.  THat's an old failure
and why track riders prefer to partially deflate tires when they are
through.

I suspect that most of the Spinergy failures we hear of are such
compression failures in which the pair of spokes between hub and
ground go slack.  It takes only a light side load to collapse a wheel
when that happens.  Spinergys are no different from wire spoked wheels
in that respect.  They stand on the bottom spokes and when these go
slack, there are NO spokes between the road contact patch and the hub
to hold the wheel laterally.

Thermal aging of these wheels seems to relax their tension.  In any
case, I have felt wheels with practically no tension.  You can check
this by squeezing the spokes together.  They should have substantial
resistance.  I am surprised that Spinergy hasn't offered a
tensiometer, a calibrated spoke squeezer.  These guys seem to be
asking for a bunch of liability claims from what I have seen.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Spinergy X-beams
Date: 1 Oct 1998 21:27:53 GMT

Richard Hopkins writes:

> On a couple of local TT courses there are small sections of tarmac where the
> surface is beginning to degrade in a manner I rarely see elsewhere. I ride
> both sections of road very regularly - both racing (on the Spinergys) and
> training on more conventional wheels.

> The suface degredation is barely noticeable on training wheels, but
> with good tubs and a lot of pressure on the Spinergy's, is felt as a
> high frequency 'buzz'. This buzz became worse after I fitted the
> X-beams in one of my wheels, and lessened again when I removed them.

I believe that wearing ear plugs would have the same effect but for a
far less expense than the wheels you ride.

The more important issue is that these devices are covering a fatal
error in these wheels, and that is that the spokes become slack under
certain loadings because they have lost their preload.  Just as with
wire spoked wheels, the Spinergy relies on pretension to support
loads.  When you hear the wheel make noise on bumps, it's because the
spokes are flapping in the breeze.  That is not far from wheel
collapse.

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.tech
Subject: Re: Spinergy X-beams
Date: 2 Oct 1998 02:11:21 GMT

Richard Hopkins writes:

>> I believe that wearing ear plugs would have the same effect but for
>> a far less expense than the wheels you ride.

> Er, I did use the word *felt* as a high frequency buzz, not *heard*. Maybe I
> could have phrased it more clearly, but the implication was clear enough,
> especially in the context of the thread.

I also meant ear plugs because I believe that the sound influences the
impression of things one cannot feel.  If they do this to the extent
that you feel it in your hands, then the spokes are looser than I
thought.  Ride no further unless you want one of those sudden
collapses that have been reported.

> Ear plugs will have no damping effect whatsoever on the increased
> amount of vibration felt through the bars, which is what I was
> commenting on...

Have you squozen the spokes together to assess their tension in
comparison to a new set at your local bike shop?

Jobst Brandt      <jbrandt@hpl.hp.com>

From: jbrandt@hpl.hp.com (Jobst Brandt)
Newsgroups: rec.bicycles.misc
Subject: Re: Rolf, Spinergy, ?
Date: 3 Mar 2000 20:58:45 GMT

Michael D. Paul writes:

> After years of breaking spokes, re-truing regularly, and having
> wheels rebuilt, I bought a pair of Spinergy rev-x wheels.  I'm very
> happy with the feel of them, except when there's a cross wind they
> get squirly.  The wheels have been great - no problems (except with
> the wind).  But ever since I viewed the information at the following
> website

>    http://home.interlynx.net/~pjdu/

> I have never felt safe on them.  I don't know if the information
> there is accurate or phony, but it's always in the back of my mind.
> I am currently considering Rolf wheels.

I find the introduction to the web site factual and balanced but the
"Engineer's report" that follows is so strongly biased that it causes
the opposite to his conclusions to seem plausible.

His words:

"Personally, I don't like Spinergy wheels and would not ride them,
especially off-road."

This isn't a personal matter but one of technical accuracy.  The
entire report is presented in the above tone, largely losing its
credibility.  I have made up my own mind on why these wheels can be
unsafe.  They, like ordinary spoked wheels, rely on tension for
strength, tension that is difficult to control with the inelasticity
of the material.  Through small changes, all preload can be lost,
leaving the wheel with no strength.  These wheels have no means
of tensioning the four spokes.  From monitoring comments on the net,
it seems that loss of preload is accelerated by heating the 'spokes',
typically in a closed car with the sun shining on them.

The spokes, constructed lying flat in the central plane of the wheel,
are tensioned by spreading the center of the four bladed web halves by
inserting the hub spool.  This causes a radial change in length of
about 1mm, about half the displacement of tensioning a conventional
wheel with wire spokes and aluminum rim.  Spoke tension in Spinergy
wheels cannot readily be measured nor can it be adjusted.  Spokes that
make a rattling/rumbling sound in use are going through zero tension
and are dangerously close to failure.  Under tension they do not
change shape and therefore, make no audible sound.  In contrast steel
spokes and aluminum rims do not creep or lose tension with time or
temperature and have ductility by which to absorb damaging blows,
something that Spinergy wheels do not do well.

Jobst Brandt      <jbrandt@hpl.hp.com>