Harvey Sachs wrote:
>
> I disagree. Politely, but firmly, with one of Chuck's assertions, namely that the
> concept of the BiValents was "stupid." It actually had major potential advantages
> for racing teams:
> (1) Front and rear being the same cuts down on spares to be carried.
I don't think too many wheels for a support vehicle was ever a real
problem. Also, QR wheels are held in racks on the support vehicle by
their QRs. I wonder how Bivalents are held in wheel racks since they
don't have QRs, but a lever skewer that stays with the bike.
> (2) Rear wheel changes are much faster, since you don't have to shift up to the high
> gear: the freewheel stays with the frame instead of coming off with the wheel.
The rider shifts up to the small cog before he stops with a flat so
that's not an issue. What if the freewheel is the problem? With
Bivalents it takes a wrench to get it off the bike. With a QR wheel you
just get another wheel from the support vehicle. And in my experience
the Bivalent doesn't go in and out of the drop out without some force
and some finessing to get the splines engaged. A QR wheel goes in and
out of a drop out much faster and cleaner. And the Bivalent lever
skewer has to be unscrewed; not like the flip of the QR lever. The
Bivalent lever skewer is also very vulnerable while it is fully extended
from the drop out for a wheel change; a QR is very robust and race
worthy by comparison.
> (3) For the same reason, each rider can choose a freewheel to suit himself without
> multiplying the number of spare wheels to be carried.
The choice of freewheels for a single stage by a team wouldn't differ
enough to matter during a wheel change.
> (4) Since you don't have to shift to the outside sprocket to remove the wheel, the
> bike is in the correct gear when the new wheel is installed.
The rider gets pushed by the mechanic after a wheel change while he
shifts into the gear he wants.
> Having said that, it is my understanding that two factors prevented widespread
> acceptance:
> (1) They were much more costly than Campy.
They were more expensive initially but if they had gained acceptance the
price would have been similar to a QR hub and freewheel. There is
nothing significantly different in the manufacture of a Bivalent hub and
freewheel compared to a QR hub and freewheel.
> (2) As Chuck notes, execution was not perfect. I understand that the spline set to
> hub body connection often failed on the early (3-piece) series...
Even the redesigned spine, while stronger, was subjected to the same endless movement and subsequent wear to a poor fit. This would not be a problem if you were to replace the spline on the hub and splined freewheel body periodically; costly but not hard to do. But none of this wear is present in a QR hub with freewheel. Since the Bivalent is a rear hub that can also be used for a front hub its strength is compromised by narrow flange spacing when used for a front wheel. If you ran a light rim and less spokes for a "front wheel" then you are back to carrying more wheels.
If something is truly innovative it will gain acceptance over time instead of disappearing from the marketplace. I think I've now seen four different versions of a hub with splined interface to a freewheel with the freewheel attached to the frame; two from France and two from Italy. None of them gained acceptance. Even Cino Cinelli wasn't successful in this concept gaining acceptance in the marketplace or the pro peloton. My conclusion from the above would be that there were no major advantages to the Bivalent concept but there were some serious disadvantages.
Chuck "but I still ride mine" Schmidt South Pasadena, CA
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