SPOKE choice for light WHEELS

Everything about building wheels, glueing tubs, etc.
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wally318
Posts: 475
Joined: Fri Feb 21, 2003 1:00 am

by wally318

I'm not sure if i'm posting on the right forum but ... here goes.
This summer during holidays I got to ride on the velodrome in
Seattle & Portland and the bug hit me.
So I decided after many years to build up a track bike.
I got a Cinelli Vigorelli frame good deal from Planet X.
An will use a few things that have been sitting around.
So I need a bit of advice on wheels. I have a Saavedra turbo rim
314 grams for the front and a Sun 19 352 grams for the rear.
Both rims are 32h. Hubs will be Novatec high flange track/fixed.
What I had in mind for the spoking was: 15/16 ga. double butted
spokes X3 for the front, and 14/15 ga X3 for the drive side Rear
and 15/16 X3 ga. non drive side, alloy nipples all around.
I weigh 155 lbs. and won't be doing any racing. Just plan on playing around
mostly at the indoor velodrome in Vancouver which has 47 degree banks
as well as a few of the near outdoor ones.
Will these rims and spoke choice be a pair of flexy noodles or will they be at least
stiff enough to have a bit of confidence when bombing down off the steep banking.
and when doing shorter personal time trials or an all out flyer for a lap.
I know we have a few wheel builders here, and maybe some track riders.
So hoping for some input.
AEROLITUS-defender of the faith

eric
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Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
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by eric

These days they make light spokes with 2.0mm elbows and threads (14g in old speak) and 1.5mm center sections (17ga?).
I prefer those to spokes with 15g elbows since the elbow is usually where they break.

I.e. http://www.sapim.be/spokes/butted/laser

Sapim CXrays are Lasers with flattened center sections They're aero and stronger (some DH bikes use them) but cost 3x.

I get Sapim spokes from BikeHubStore. Lasers ought to be fine for 32h wheels and the better hub geometry ought to make the rear stronger than a road wheel. You can put Race (1.7mm center section) on the DS.

bm0p700f
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by bm0p700f

Sapim Lasers all round is what I would do. 2/0/1.5/2.0

wally318
Posts: 475
Joined: Fri Feb 21, 2003 1:00 am

by wally318

You don't think there will be too much spoke wind up using the Laser spokes
on the rear drive side?
How about the choice of rims? Bad/good/OK?
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Zen Cyclery
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by Zen Cyclery

I doubt that a rim that light could be too stiff, but I've never worked with them so I really couldn't speak for those.

I'd say go Cxrays though. Those are used on DH race rigs all the time with no issues at all. They only come in at 4.8 grams w/ nipple.

eric
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Joined: Tue Nov 11, 2003 9:47 pm
Location: Santa Cruz, California, USA
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by eric

By wind up we usually mean the spoke twists while tightening the nipple. It's an issue when building or truing the wheel but not while riding.

You're talking about hub wind up, or the wheels' torsional stiffness. High flange hubs and spoke patterns that have the spokes at around 90 degrees to the hub maximize torsional stiffness. Jobst Brandt's wheelbuilding book has equations to calculate it and also says that in a 42x21 gear it takes about 5200 N (more than half a ton) of force to make a large flange hub wheel wind up 1 degree.
(I assume he means 32h 3x since he's not a fan of low spoke counts)

I have built wheels on small flange road hubs with 1x DS and 2x NDS and not noticed hub wind up even when hammering up very steep grades in super low gears.

But if you're worried you can get Jobst's book and calculate it. Jobst notes that small flanges have plenty of torsional stiffness and the large flanges of track hubs are not for stiffness but are to allow easy spoke replacement without removing the cog.

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