Join Date: Feb 2006
Location: Cody, WY
Bikes: Specialized Mountainbike & Surly LHT
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Spoke Tension on Rear Wheel
Recently I completed building a rear wheel. The components used were a new Velocity Dyad 40-hole rim, new Wheelsmith double-butted spokes (2.0/1.7/2.0mm), and I reused the original Suntour hub (the bike is a mid-80s Miyata used for fully-loaded touring).
To get the wheel dished properly a large difference in tension exists between the drive-side and the left-side spokes. Per my Park Tools spoke tension meter the average tension on the drive-side spokes is 135kg, and the average tension on the left-side spokes is 75kg [note: all spokes came within 5% of these average values]. Velocity recommends a spoke tension of 100kg to 110kg for this rim.
In his article "Wheelbuilding" <http://www.sheldonbrown.com/wheelbuild.html> Sheldon Brown wrote:
Average freewheel-side tension should be up to shop standards for the type of spokes and rim being used. More important is that it be even. Don't worry about the left side tension on rear wheels. If the freewheel side is correctly tensioned, and the wheel is correctly dished, the left side will be quite a bit looser. You should still check the left side for uniformity of tension.
I'm wondering if the tension I have on these spokes is reasonable -- or if they are too tight. I pretty much split the difference, making half the spokes too tight and the remaining spokes too loose compared to the range Velocity recommends. If I understand what Sheldon wrote it seems that I should reduce the tension on all the spokes -- but I'm worried that this would make my left-side spokes too loose. Should I stay with the wheel as it currently is or does it need to be changed?
P.S. When I used "spocalc" to determine the spoke lengths for this build the difference between the drive- and left-side spokes the software gave was 1.5mm. The source that I purchased the spokes from didn't think that it made much difference if the spokes I used varied by 1mm or 2mm, and ended up giving me spokes that differed by 1mm. In retrospect it appears as though I should have asked for a difference of 2mm. Agreed?