Salsa Delgado 700c Rim: Cracks?

Per (PeteCresswell):
But I am seeing a pretty-consistent "40", which the chart says is
more like 75 kg.

shb: "... more like 67 kg.
--
Pete Cresswell

On Jun 12, 7:10*pm, "(PeteCresswell)" wrote:
Per (PeteCresswell):

Gotta pull out my tensiometer, dope out the conversion table, and
measure the tension... and then find out what Salsa recommends
and compare them. * My hope would be that I erred on the high
side.

Oops.... Seems like either it's on the low side or I am reading
the tension incorrectly.

WheelSmith tensiometer.

2.0-1.8-2.0 "DT Competition" double-butted spokes.

Symmetrical wheel (Rohloff hub).

If I'm reading WheelSmith's calibration chart correctly (using
the "1.8" column) it seems like I sb seeing a nominal "60" or so
for proper tension (60=107kg, 65=122...)

But I am seeing a pretty-consistent "40", which the chart says is
more like 75 kg.

165lb , 1.8mm seems about right for a 200lb rider with a 450g rim
..

If I'm that low, one would think there would be problems with the
wheel staying true,

I'm not that one. I had no difficulties at 200lb riding 36, 304mm x
1.8mm spokes at 170lbf

but there have not been. * Broken spokes: yes

Ah, you didn't set the spokes.

Problems with staying true: no.

OTOH, I'm suspicious of my use of the tensiometer.

For starters, Wheelsmith's chart does not say anything about
double-butted spokes.

Also, the Rohloff hub might be a confusing factor bco the short
(269 mm) spoke length. * Once one side of the tensiometer is
below the rim-end butt, the other side is practically on the
crossover point.

Dunno how that plays out....


Calibrate the instrument with a test weight on one of those spokes.
Produce a new chart if necessary.

On Jun 12, 7:13*pm, "(PeteCresswell)" wrote:
Per (PeteCresswell):

But I am seeing a pretty-consistent "40", which the chart says is
more like 75 kg.

shb: *"... more like 67 kg.

Now you've torn it.

--
Pete Cresswell

On Tuesday, June 12, 2012 11:10:10 AM UTC-7, (PeteCresswell) wrote:
Per (PeteCresswell):
Gotta pull out my tensiometer, dope out the conversion table, and
measure the tension... and then find out what Salsa recommends
and compare them. My hope would be that I erred on the high
side.

Oops.... Seems like either it's on the low side or I am reading
the tension incorrectly.

WheelSmith tensiometer.

2.0-1.8-2.0 "DT Competition" double-butted spokes.

Symmetrical wheel (Rohloff hub).

If I'm reading WheelSmith's calibration chart correctly (using
the "1.8" column) it seems like I sb seeing a nominal "60" or so
for proper tension (60=107kg, 65=122...)

But I am seeing a pretty-consistent "40", which the chart says is
more like 75 kg.

If I'm that low, one would think there would be problems with the
wheel staying true, but there have not been. Broken spokes: yes
Problems with staying true: no.

OTOH, I'm suspicious of my use of the tensiometer.

For starters, Wheelsmith's chart does not say anything about
double-butted spokes.

Also, the Rohloff hub might be a confusing factor bco the short
(269 mm) spoke length. Once one side of the tensiometer is
below the rim-end butt, the other side is practically on the
crossover point.

Dunno how that plays out....

Try to get it on the thin midsection -- that's how the chart anticipates tension will be measured on a butted spoke. That may be what accounts for the low tension measurement.

-- Jay Beattie.

On 05/30/2012 09:25 PM, Jay Beattie wrote:
snip



http://velobase.com/ViewComponent.as...=107&AbsPos=14

The weight listed on that site is low. I think the nominal weight for
the Mod 58 was 565g. Your rim is 470g (?).


The spec for a Salsa Delgado rim is 515g making this rim comparable to
the mod 58 in weight.

The big difference is that the Salsa Delgado is a double wall rim and
the mod 58 was single wall - hollow box. This means the mod 58 had a lot
more material preventing the eyelets from pulling out and cracking the rim.

--

Stephen Bauman

On Tuesday, June 12, 2012 11:10:10 AM UTC-7, (PeteCresswell) wrote:

Symmetrical wheel (Rohloff hub).

Did you lace cross-2 or cross-1?

Rohloff recommends cross-2 for a rim of that diameter
and I took their advice when I built one, but if I
had to do it again I'd go cross-1. I did the math
and I'm convinced that cross-1 is adequate for torque
transmission with a 700C rim (as a single rider, not
a tandem).

Cross-2 on a Rohloff has the spokes approaching the
rim at an undesirable angle. I took Jobst's advice
("correcting the spoke line") to put a small bend in
the spokes just before where they enter the nipples.
I haven't broken any spokes in the wheel.

Did your spokes break near the nipple or at the heads?

Tom Ace

On Jun 12, 10:43*pm, Stephen Bauman wrote:
On 05/30/2012 09:25 PM, Jay Beattie wrote:
snip



http://velobase.com/ViewComponent.as...-42D6-958F-FCD....

The weight listed on that site is low. *I think the nominal weight for
the Mod 58 was 565g. Your rim is 470g (?).

The spec for a Salsa Delgado rim is 515g making this rim comparable to
the mod 58 in weight.

The big difference is that the Salsa Delgado is a double wall rim and
the mod 58 was single wall - hollow box. This means the mod 58 had a lot
more material preventing the eyelets from pulling out and cracking the rim.

--

Stephen Bauman

More likely that the rim piercings initiated the cracks and the eylets
have been used to hide the poor finish. Probably safer to get rims
with dimpled nipple beds if you are unable to examine the piercings
due to eyelets.

On Jun 12, 11:08*pm, Tom Ace wrote:
On Tuesday, June 12, 2012 11:10:10 AM UTC-7, (PeteCresswell) wrote:
Symmetrical wheel (Rohloff hub).

Did you lace cross-2 or cross-1?

Rohloff recommends cross-2 for a rim of that diameter
and I took their advice when I built one, but if I
had to do it again I'd go cross-1. *I did the math
and I'm convinced that cross-1 is adequate for torque
transmission with a 700C rim (as a single rider, not
a tandem).

Cross-2 on a Rohloff has the spokes approaching the
rim at an undesirable angle. *I took Jobst's advice
("correcting the spoke line") to put a small bend in
the spokes just before where they enter the nipples.
I haven't broken any spokes in the wheel.

It's still poor practice to have a wire spoke with an unsuppoeted
bend.
the use of washers and/or the judicious opening and/or realignment of
the eyelets is a better option when one is unable/unwilling to source
more suitable nipples or rim.

Did your spokes break near the nipple or at the heads?

Tom Ace

Per thirty-six:
but there have not been. * Broken spokes: yes

Ah, you didn't set the spokes.

Is "Set" the procedure where you lay the wheel on it's axle and
press against the rim?


Calibrate the instrument with a test weight on one of those spokes.
Produce a new chart if necessary.

- Screw a free-standing spoke into a nipple

- Throw a hitch of 600-lb-test kite line around nipple/spoke
and secure to ceiling

- Hang a known weight on "L" of hub-end of spoke

- Apply tensiometer at the same spot one would apply
it to the spoke in the built wheel

- Note tensiometer reading


Have I got it right?

(may sound inane... but the mechanical world is a mysterious
place to Yours Truly...)
--
Pete Cresswell

Per Tom Ace:
Did you lace cross-2 or cross-1?

2
--
Pete Cresswell