Spoke Questions

Hello,
I've built myself a set of tandem wheels (26" Bontrager Clyde Rims 36h, 14g DT
spokes and Phil Wood tandem hubs). I have two concerns.

1) The spoke tension seems quite high. There is a little flex left in the
spokes but feels much tighter than any wheel I've ever built before. Is there
an easy way to test it?

2) How short is too short when it comes to spoke length? I'm assuming that
perfect length the spoke would be long enough to reach the bottom of the
screwdriver slot in the nipple.

Thanks in advance!
Maurice Miller

"Bike Camano" wrote in message
...
Hello,
I've built myself a set of tandem wheels (26" Bontrager Clyde Rims 36h,
14g DT
spokes and Phil Wood tandem hubs). I have two concerns.

1) The spoke tension seems quite high. There is a little flex left in the
spokes but feels much tighter than any wheel I've ever built before. Is
there
an easy way to test it?

The only way the spoke would be too tight would be if there was too much
windup when trying to tighten the spoke, you're rounding off the nipple or
if the wheel tacos from over-tension. It doesn't sound like you have any of
these conditions so you're probably fine. You won't break spokes from too
much tension. Remember to properly stress-relieve the wheels and you should
be good to go.


2) How short is too short when it comes to spoke length? I'm assuming
that
perfect length the spoke would be long enough to reach the bottom of the
screwdriver slot in the nipple.

Actually, pefect for me is exactly flush with the high point of the nipple,
or the top, not the bottom, of the slot. However, bottom is pretty good as
well. How short is too short?? Well, I've built wheels with threads
showing below DT nipples, but I haven't felt good about it. The wheels
didn't have any problems, but that doesn't mean you won't have any. Maybe
the guy I built them for was lighter, softer on his wheels, low mileage etc.
In the immortal words of my mentor, if a job's worth doing, it's worth doing
right. So if you're not somewhere between the bottom and top of the nipple
slot, think about replacing them.


Thanks in advance!
Maurice Miller



Good luck,

Scott..

S. Anderson wrote:

The only way the spoke would be too tight would be if there was too much
windup when trying to tighten the spoke, you're rounding off the nipple or
if the wheel tacos from over-tension.

Depending on your definition of "too much windup", you *can* get a spoke
too tight. I ran into this recently when I was trying to retrue a wheel
after replacing a couple of spokes. At one point, further tightening of
the drive side spoke resulted in the rim moving the *opposite*
direction. This elicited the classic "huh?" response, then I realiized
that I must have exceeded the spokes' maximum tension and they were
beginning to elongate. Probably not much further and they would have
popped. I backed off and since I'd bought a bag of spokes anyway,
re-spoked the entire drive side and started over. As stated in The
Bicycle Wheel, the post stress-relief taco warning only applies to rims
up to a certain strength. Heavier/stronger rims can be tensioned past
the spoke's limit. I was working on a T-520.

S. Anderson wrote:

"Bike Camano" wrote in message
...

Hello,
I've built myself a set of tandem wheels (26" Bontrager Clyde Rims 36h,

14g DT

spokes and Phil Wood tandem hubs). I have two concerns.

1) The spoke tension seems quite high. There is a little flex left in the
spokes but feels much tighter than any wheel I've ever built before. Is

there

an easy way to test it?


The only way the spoke would be too tight would be if there was too much
windup when trying to tighten the spoke, you're rounding off the nipple or
if the wheel tacos from over-tension. It doesn't sound like you have any of
these conditions so you're probably fine. You won't break spokes from too
much tension. Remember to properly stress-relieve the wheels and you should
be good to go.

You can get them so tight that they pull out of the rim or the rim
stress cracks around the holes (the last is typically a Mavic problem).
If you don't have access to a tensiometer I'd go to Sheldon's page and
in the wheel building section there's a link to a page that gives the
musical note that's approximately the pitch that the spoke should give
when plucked -- it'll let you know if you're in the ballpark. But, on
the good side, if you're basing your concern on machine built wheels --
they're almost always undertensioned. Another thing that you could do
is if you LBS has someone who builds a lot of wheels, they'll usually be
happy to give you an opinion .

David

bikecameo- I've built myself a set of tandem wheels (26" Bontrager Clyde Rims
36h, 14g DT
spokes and Phil Wood tandem hubs). I have two concerns.

1) The spoke tension seems quite high. There is a little flex left in the
spokes but feels much tighter than any wheel I've ever built before. Is there
an easy way to test it? BRBR

'Easiest' is to take it to a bike shop and have them check with a
tensionometer...

2) How short is too short when it comes to spoke length? I'm assuming that
perfect length the spoke would be long enough to reach the bottom of the
screwdriver slot in the nipple. BRBR

All the threads of the spoke should be engeged by the threads of the nipple...

Peter Chisholm
Vecchio's Bicicletteria
1833 Pearl St.
Boulder, CO, 80302
(303)440-3535
http://www.vecchios.com
"Ruote convenzionali costruite eccezionalmente bene"

(Bike Camano) wrote:

Hello,
I've built myself a set of tandem wheels (26" Bontrager Clyde Rims 36h, 14g DT
spokes and Phil Wood tandem hubs). I have two concerns.

1) The spoke tension seems quite high. There is a little flex left in the
spokes but feels much tighter than any wheel I've ever built before. Is there
an easy way to test it?

Yes, by sound. See Sheldon's wheelbuilding pages.

This method has a few drawbacks, mostly that a spoke, especially in a
crossed pattern, does not resonate very clearly. But the pitch is
dependant only on tension.

An instrument known as a tensiometer is better, but spendy for the
occasional wheelbuilder.

2) How short is too short when it comes to spoke length? I'm assuming that
perfect length the spoke would be long enough to reach the bottom of the
screwdriver slot in the nipple.

You assume correctly.

--
Ted Bennett
Portland OR

Thanks to all who replied!

I rebuilt the wheel with longer (now perfect length) spokes and the tension
(unscientific feel method) feels more in line with the other trouble free
wheels I've built in the past.

Hopefully I didn't do any damage to the hub or rim with the original build.
It was never ridden Thanks again!

Maurice Miller