GEL 280 rims 36H suitable for 180 lb rider?

On 29 Oct 2004 13:10:15 GMT, (Qui si parla
Campagnolo ) wrote:

carl- Can you give us some idea of what kind of distance, grades,
and elevation gains are involved in Super Jamestown, Cold
Creek Canyon, Ward, Magnolia, and Flagstaff? Are they paved
hairpins snaking up vast faces? BRBR

Paved, hairpins, grades of 8 to 15%, lengths from 5 or so miles to about
15...elevation rise of about 5ooo feet for some.

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

Dear Peter,

When I fool around with the TerraServer topo maps, here's
what I estimate for the Magnolia road:

http://terraserver.microsoft.com/ima...=5533&z=13&w=1

From where a rider enters the mouth of the canyon at the
edge of Boulder at about 5400 feet, it's about 3.6 miles up
a 3.5% grade next to the river to where you turn off at
Silver Spruce at about 6062 feet to head for Magnolia.

From there, the actual Magnolia road runs only 3.6 miles to
where it tops out at 8400 feet. After the first steep
stretch to Magnolia at 7230 feet, there's a short flatter
stretch to 7413 feet, and then another steep stretch. Both
steep stretches average a bit over 12% grade.

I count maybe 9 curves that are arguably hairpins between
Silver Spruce and where the road tops out, but that's
stretching the definition of hairpins.

It looks like a short, steep road, but it doesn't look like
a long, challenging Alpine pass full of hairpins that's
going to heat rims up dangerously.

Maybe I didn't pick the best example from your list?

A table of rough estimates follows.

Carl Fogel

total abs gain avg
miles mile elev elev grade

0.0 0.0 5400 0 0.0% Canyon Boulevard
3.6 3.6 6062 662 3.5% Silver Spruce turnoff
5.4 1.8 7230 1162 12.3% Magnolia
6.0 0.6 7413 183 5.8% flatter stretch
7.2 1.2 8200 787 12.4% road tops out

From the mouth of the canyon to where the road tops out:
7.2 miles
2800 foot elevation gain
7.4% average grade

From Silver Spruce turnoff to where the road tops out:
3.6 miles
2138 foot elevation gain
11.2% average grade

Ok, so back to the orginal post. If he really wants a good rim to race then
the 280 is not that rim. It's not as fast as any semi-aero rim even if it
weighs twice as much, and it's less durable for the unseen bumps you get in
a race. It's fine for casual riding but don't you think we should let him
know the pluses and minuses?

And 36 spokes on such a light rim are needed due to it's very low torsional
rigidity, yet you can't use high spoke tension as the spokes will pull out
of the rim holes. One of the many reasons rims like that are no longer
popular or even produced. (we already discussed the heat issue which you
finally admited without actually saying you were wrong).

Bruce

"Qui si parla Campagnolo " wrote in message
...
David- So if the same energy is put into a rim weighing 3/4 as much, why
would
there not be a 4/3 as high rise in temperature? BRBR
Obviously a higher rim temperature increases the risk of melting glue.
BRBR

Must be the season to wonder about things that really don't matter. Back
to OP,
and would GEL 280s, 36h work for race wheels...Sure they would and I
wouldn't
really worry about heat buildup when braking...

He's not racing in the Alps, BTW...

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

On 29 Oct 2004 13:10:15 GMT, (Qui si parla
Campagnolo ) wrote:

carl- Can you give us some idea of what kind of distance, grades,
and elevation gains are involved in Super Jamestown, Cold
Creek Canyon, Ward, Magnolia, and Flagstaff? Are they paved
hairpins snaking up vast faces? BRBR

Paved, hairpins, grades of 8 to 15%, lengths from 5 or so miles to about
15...elevation rise of about 5ooo feet for some.

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

Dear Peter,

Would "Cold Creek Canyon" be "Coal Creek Canyon," where
Colorado Highway 72 runs east from Wondervu?

http://terraserver.microsoft.com/ima...=5523&z=13&w=2

Carl Fogel

Bruce- Ok, so back to the orginal post. If he really wants a good rim to
race then
the 280 is not that rim. BRBR

That wasn't his question. He asked if the GEL 280 could be used for a
infrequent race wheel on the rear, using 36 spokes. And I said yes, just like
some other really light rims could and have been used. Like Fiamme yellows. It
is the best choice? nope and I think he lnows that.

Is it a bad choice because of 'excessive heat buildup when braking'? Nope, not
the best because it is a really light rim.

Bruce And 36 spokes on such a light rim are needed due to it's very low
torsional
rigidity, yet you can't use high spoke tension as the spokes will pull out
of the rim holes BRBR

garbage. I have built many fronts with rims this light and use the same tension
as the right side rear...about 100 kgf.

Bruce-
(we already discussed the heat issue which you
finally admited without actually saying you were wrong). BRBR

I did????

I'll say it again, 30% hotter cuz it's 100 gram lighter?...My Aunt Matilda's
mustache.....


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