Re: [CR] mixing spoke crosses

(Example: Racing:Jean Robic)

From: "Jon M. Schaer" <jschaer@columbus.rr.com>
To: "Brandon Ives" <monkey37@bluemarble.net>, "Joseph Bender-Zanoni" <jfbender@umich.edu>
Cc: <DTSHIFTER@aol.com>, <bikevint@tiac.net>, <sterlingcapital@mail.com>, <classicrendezvous@bikelist.org>
References: <Pine.GSO.4.20.0103221837180.8793-100000@comet.bluemarble.net>
Subject: Re: [CR] mixing spoke crosses
Date: Thu, 22 Mar 2001 22:44:33 -0500


----- Original Message ----- From: Brandon Ives <monkey37@bluemarble.net> To: Joseph Bender-Zanoni <jfbender@umich.edu> Cc: Jon M. Schaer <jschaer@columbus.rr.com>; <DTSHIFTER@aol.com>; <bikevint@tiac.net>; <sterlingcapital@mail.com>; <classicrendezvous@bikelist.org> Sent: Thursday, March 22, 2001 6:44 PM Subject: Re: [CR] mixing spoke crosses


> Joe, I'll assume you mean you use less crosses on the NON-drive side. The
> non-drive side is usually lower tensioned when both of the crossings are
> the same.

Sorry to be a stickler, but the non-driveside is ALWAYS lower in tension, regardless of the cross pattern, on normal wheels. Unless your using a symetrical hub, mixed spoke count, etc, but I don't think that's what were talking about here. Normal wheels, in 126, 130, or 135mm OLD have a pretty substantial tension differential. The lacing pattern only effects that slightly. Asymetrical rims help further.
> If you shorten the spokes on the non-drive side you increse the
> tension and equalize everything.

This is incorrect. This is a common misconception. All else being equal, reducing the cross pattern (which uses shorter spokes) decreases the per-spoke tension relative to the same driveside tension. The wheel will be slightly stiffer laterally, because the LH spoke bracing angle is shallower, but the tension overall on the LH is lower. This will ultimately mean that the likelyhood of spoke breakage from fatigue will be higher. The other potential problem with radial LH wheels (and front radials) is flange breakage. Many aftermarket lightweight hubs have had problems with flanges from radial lacing. Most won't warranty them. This doesn't mean that people can't build 3x/radial wheels that "have no problems", but generally they are inferior for most uses to other lacing patterns.
> Actually, equal tension is less
> important than equal dish. More important than both is a correctly built
> wheel

Again, unless you're using a symetrical hub (ex - the 160mm OLD hubs for Santana tandems), your rear wheel will not have equal dish (will not be symetrical), nor equal tension. Of course, you want the rim to be centered, but this is different that equal dish. Maybe the sentance didn't come out the way you intended. Tension isn't more or less important than dish; they're intertwined. Any change of tension on one side will change the dish, as well.

The term "correctly built" wheel varies a lot. That depends on the demands and expectations of the rider. Some parameters are obvious, but things like overall tension, lacing pattern, spoke count, and component choice, all depend on the end goal.

Jon Schaer