kehoe@reed.UUCP (Dave Kehoe) (07/18/85)
I just re-read "Bicycle Wheels" by Jobst Brandt. The book
is excellent, and I recommend that anyone building or buying
a new pair of wheels read the book. But, for those of you
who aren't going to read it, here is a summary of the book's
conclusions. Anything surrounded by (parentheses) is con-
sidered an inconsequential benefit or disadvantage.
Benefits Disadvantages
heavy spokes cheaper weaker
(easier to true) heavier, greater wind drag
(stiffer) (goes out of true sooner)
light spokes stronger** expensive
lighter,less wind drag (harder to true)
**"The elastic action of butted spokes reduces peak forces
and lowers stress changes by distributing loads over
several spokes."
high flange (reduced spoke failure at hub)
(torsionally stiffer) (increased spoke failure at rim)
low flange (lighter) (won't work with 40 spokes,5x,etc.)
radial spoking lightest no torsional strength
goes out of true sooner
(can break hubs),(no aero advantage)
1-2 cross much stronger than radial (breaks more spokes at hub)
3 cross most common
4-5 cross (torsionally stiffer) (heaviest)
(reduces spoke failure at hub) (breaks more spokes at rim)
more spokes stronger rarely any need for greater strength
less spokes lighter, (less wind drag) weaker
tighter spokes (stiffer wheel) rim and spoke failure
looser spokes longer wheel life laterally weaker
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Notes: 1) High-low flanges offer no advantage.
2)The strongest wheels have all the pulling spokes on the inside.
This is because when hill-climbing in low gear outside pulling
spokes cause the spokes the flex out in the derailleur.
3) 6- and 7-speed wheels are laterally very weak, but bicycle
wheels rarely undergo lateral stress, even in cornering.
Lateral stress only occurs when the tires leave the ground
while cornering (and return to the road).
4)Flanges should be as far apart as possible for lateral strength.
5) I can build symmetrical 5-speed rear wheels by re-spacing the
hub and moving the freewheel to the outside. This can make
shifting onto the 13-tooth sprocket difficult, but it makes a
very strong wheel.
6) Alloy nipples save over two ounces, but you must leave the
spokes fairly loose (aluminum is more ductile than brass and
more easily damaged).
7) The best rim strips are made by Kool Stop. Use the wide
ones on narrow rims and the narrow ones one wide rims.
8) Spokes can be shorter than is usually recommended. I've
put hundreds of miles on wheels with a couple spokes
"hanging on by a thread".
9) Be sure to lubricate the spoke threads -- I find dipping them
in motor oil to be best.
My opinions on hubs:
Campagnolo, Gipiemme: heavy, axles bend and break under heavy riders,
otherwise very dependable
Phil Wood: bearings have too much play, flanges too close together
Hi-E: My favorite -- very light and very strong.
Shimano, Helicomatic: I like the cassette freewheel, but I also like
to use Ultra-6 freewheels.
--
"Why my thoughts are my own, when they are in, but when they are out
they are another's." -- Susanna Martin, executed for witchcraft.
Dave Kehoe tektronix!reed!kehoe (503) 230-9454craig@hp-pcd.UUCP (craig) (07/23/85)
Spokes with alloy nipples do not need to be any more loose than brass nipples. I've seen crashed wheels that had the spokes break before the nipples pulled out and I've never had the treads strip out of a alloy nipple. The disadvantages are its easy to round off the nipple if your not careful with the spoke wrench and nipple and spoke can weld themselves together if not properly lubed. Oil is NOT ok because it washes out after wet rides and time. I use NeverSeize.