Re: [CR]Spoke tension recommendations?

(Example: Racing)

Date: Sun, 31 Jul 2005 16:45:25 -0400
From: "Steve Maas" <stevem@mail.nonlintec.com>
To: <classicrendezvous@bikelist.org>
Subject: Re: [CR]Spoke tension recommendations?


The basic principle is that you want to make them as tight as possible short of warping the wheel or breaking something. Usually, the rim is the limiting factor. If it starts to warp--like a potato chip--it's too tight. Most modern rims will easily handle 100 KGF, but older ones may not. The rims on my Carlton (ultralight steel) warped at something considerably less than 100; I can't remember the exact value. So, in general, I make the front spokes 100 KGF if the rim can take it. The rear is more of a problem--often, I find that 100 KGF on the right side means that the left must be down around 40 (I'm going from memory here, so the numbers may not be exactly right), which seems awfully low. I then make the right side 120, which puts the left at about 50. I'm afraid to go much higher on the right, especially with older rims, for fear that the spokes might pull out of the holes.

You can check Brandt's book for the yield strength of the spokes. These numbers should be comfortably below the yield point for both 2.0 and 1.8 MM spokes. I don't think you will reach the yield point without damaging the rim, but fatigue--the REAL reason spokes break--is much worse near that point.

Whatever else you do, don't neglect to stress relieve the spokes!

Finally, before anyone suggests it, making the tensions high makes the wheel stonger but NOT stiffer.

Steve Maas
Dublin, Ireland


---------- Original Message ----------------------------------
From: Jerome & Elizabeth Moos
Date: Sun, 31 Jul 2005 12:56:43 -0700


>Although I've built quite a few wheels over the years, I don't do it on regular enough basis to remember all the details without consulting notes, books, etc. One thing which seems to be conspicuously absent from most books and from the manuals of wheelbuilding equipment is the recommended spoke tensions. This may be partly because of the many possible spoke gauges, shapes, materials and spoking patterns, but I suspect fear of liability may play into it as well.

\r?\n>

\r?\n>Can anyone recommend tensions in Kg (that's the units on the conversion chart with my new Park tensionmeter) for front wheels? Rear drive side? Rear off side? I'm talking about classic wheels here. 2.0 or 1.8 or 2.0/1.8 butted round spokes, DT if I am building new wheels. 700C or 27" alloy rims, sewup or clincher, 3 or 4 cross.

\r?\n>

\r?\n>Regards,

\r?\n>

\r?\n>Jerry Moos