I second everything discussed here and the rationale. I have used lower crosses on the drive side for years. I think that good rear wheels are best achieved by achieving the most uniform spoke tension between drive and non-drive side. Another way to achieve this is to have less spokes on the non-drive side as on my vintage Rovals.
Joe
At 04:45 PM 3/22/01 -0500, Jon M. Schaer wrote:
>----- Original Message -----
>From: <DTSHIFTER@aol.com>
>To: <bikevint@tiac.net>; <sterlingcapital@mail.com>;
><classicrendezvous@bikelist.org>
>Sent: Thursday, March 22, 2001 10:06 AM
>Subject: Re: [CR] mixing spoke crosses
>
>
>>
>> The LH spokes of a (multi-speed) rear wheel do very little to effect
>torque
>> transmission, due to their inherently lower tension........
>
>The LH spokes in a standard wheel do transmit some torque to the rim, though
>it is much less than the RH, but it has nothing to do with the lower tension
>or shallower angle relative to the hub. As long as the spokes don't go
>slack, either from vertical or tortional loading, they all transmit torque
>the same (as a rigid column). The LH spokes transmit less torque because the
>hubshell is absorbing the tortional load (actually twisting slightly).
>Fatter rear hubshells (like Parallax) transmit torque better because of the
>larger diameter.
>
>>
>> Spring effect of the left has no "real world" relationship with stress and
>> power transmission for the RH spokes. If it did, we would never see the
>LH
>> spokes of a rear wheel radially laced........
>
>I didn't see the original post, so I don't know what you mean by "spring
>effect". But in regards to radially-laced RH spokes, I believe you should
>look closely at the Mavic Ksyrium wheel. It is laced radially on the RH
>spokes, and the idea has some merits. The radial spokes do actually transmit
>some torque - they become very slightly non-radial - but a larger proportion
>of the tortional load is caried by the LH spokes (this helps the overall
>stability of the low spoke count wheel in accepting tortional load). Also,
>the radial RH design (along with the particular spoke/hub interface of the
>Ksyrium) helps minimize the differential tension (also helps the overall
>stability of the low spoke count wheel).
>
>>
>> Torque is more efficiently transferred with a 4x pattern (drive side) as
>the
>> lever arm (spoke) is 90o to the hub axis. 3x is also very good, and these
>> days with materials being so much better that 20-30 years ago, there
>really
>> is no need for 4x (and 36o hubs!) wheels except tandems and fully laden
>> touring bicyles.
>>
>
>In principle, 4x does transmit the tortional load better because of the load
>path of the spokes. But in practice, it's overkill on anything accept a very
>low geared tandem. Even on loaded touring bikes or mtb's, no one person can
>exert enough force on the pedals to significantly stress a well-built 3x
>rear wheel.
>
>
>> Your argument against fewer crosses on the LH side is not supported by the
>> reference to 8-10 speed wheels...."...radial non-drive pattern on 8-10 sp
>> wheels actually works pretty well." By "works pretty well" I am assuming
>you
>> mean "does not collapse"? I think I have addressed why they do not
>collapse,
>> but consider the following: We never see the RH spokes laced radially as
>> they would have no wind-up under load (pedaling) and the fatigue factor
>would be enormous.
>>
>
>Again, look at the Mavic Ksyrium wheel. Similarly laced wheels could be
>built from standard parts, as well. But the risk of flange failure from the
>RH radial spokes isn't worth it, in my opinion. I do strongly recommend a 2x
>RH, 3x LH pattern for most wheels I build for people, as a long-term use
>wheel, and 1x RH, 2x LH pattern for the lighter riders or more limited use.
>This is especially pertinent to Campy hubs because of the wide left center
>dimension on their rear hubs. I only do the "race lace" 3x/radial for
>limited use, and I explain thoroughly why it makes a bad wheel overall. It
>does make the rear wheel stiffer laterally, but the differential tension is
>WORSE, contrary to popular belief.
>
>>
>> As I mentioned in my previous response to Sterling, I generally do 4x on
>the
>> RH (rear) whenever I am able to do so. Small flange hubs are not well
>suited > for this, but it can be done with a little care. I do the LH
>spoking (3x;
>> 2x; 1x) in whatever I feel like and by what spokes I happen to have on
>hand.
>
>That's actually backwards. Large flange hubs are less well suited to 4x
>lacing. For a given spoke count and lacing pattern, the larger the flange
>diameter, the closer to tangent the spoke leaves the flange. This causes the
>spokes to overlap the head of the next spoke. But large flange hubs don't
>need the higher cross lacings as much because the tortional load is lower.
>This is why tandems still use (and benefit from) large flange hubs. On track
>wheels, it's mostly just tradition.
>
>> I like to do 4x/2x as I like the pattern as viewed from the right-side to
>the
>> left-side of the wheel, and I think that 4x looks more "classical".
>>
>
>Assuming the rim and spoke count are appropriately chosen, that pattern will
>work. But from the mechanical standpoint, it's not optimum. There's just no
>reason to have the RH 4x, and why risk the spoke head overlap? Lacing the
>LH side fewer cross is only useful for a miniscule weight savings and
>lateral stiffness gain, and possibly looks. But for the best combination of
>durability and performance, it's the opposite of the best chioce.
>
>Jon Schaer