Spoke length for Mavic Open Pro vs Mavic CXP33

Thanks.
--
Marty

According to Spocalc:

CXP33: ERD = 596mm
Open Pro: ERD = 605 mm.

From that you can calculate the required spoke lengths based on the
number of spokes, cross pattern, and hubs used.

Art Harris

DT has a spoke length calculator on their site, so does Sapim, and you
can download Spocalc, an excel macro for the same task. Be forewarned
tho, some say the values (OLD, etc...) provided with the macro can be
wrong, which can result in up to a .5 mm difference in the
calculation! Horrors!

D'ohBoy

Yes, by a good bit. I built up one 4x with some long spokes intended
for an OP type profile in order to take up the slack on one side.
Whooboy--ugly, not recommended, as I crossed the heads....but whaddaya
gonna do on a Sunday?

At any rate, just plug your stuff into spocalc:

http://www.sheldonbrown.com/rinard/spocalc.xls

and you'll get your figgern done for you.

You'll need a spreadsheet proggie. Any one will do that opens basic MS
stoff. I use Gnumeric, but Openoffice.org or Staroffice works great.

Damon Rinard's SpocCalc says ERD's are 598 vs 605

Check it out for yourself at "http://www.sheldonbrown.com/rinard/
spocalc.htm"

MW

Art, D'oh, Landotter, and Wolff,

Thanks!!!
--
Marty

I think that there are two issues here: Regarding the 0.5 mm
discrepancy, then it can be caused by whether the spoke calculator
gives raw geometric values or whether it subtract a small 0.5 mm fudge
factor from the final results. The 0.5 mm number stems from
wheelbuilder Roger Musson who claims that standard swaged spokes
elongate and rims compress when under tension and that 0.5 mm is a
good fudge factor to use for this phenomenon. So his spoke calculator
subtract this number from the final results:
http://www.wheelpro.co.uk/spokecalc/

I am pretty sure that Spocalc gives the raw numbers, anyway it just
uses macros so its internal workings are fully accessible for those
who want to check how its results are calculated. The online spoke
calculators from DT Swiss and Sapim are black boxes that just spits
out results without telling how they reached it.

The other issue is that there may be errors in the Spocalc database,
which may results in deviations far larger than 0.5 mm.
Mavic are using the term "Spoke Support Diameter"(SSD) which isn't
identical with ERD. The SSD for the CXP33 is 595 mm. People sometimes
confuses this number with ERD like this vendor:
http://www.starbike.com/php/product_info.php?lang=en&pid=1625

Other uses the 598 mm number that can be found in the Spocalc db that
claims that the ERD for a Mavic CXP33 is SSD + 3mm = 598 mm.
http://www.wheelbuilder.com/closeup.asp?cid=58&pid=118&offset=0

The DT Swiss calculator claims that the CXP33 ERD is 599 mm.

Allgemeiner Deutscher Fahrrad-Club e.V. says the ERD is 596 mm:
http://www.fa-technik.adfc.de/Komponenten/Felge/Felge622.html

According to my own notes I have measures the CXP33 ERD to be 596 mm
too.

So one can find a spread of numbers from 595 mm to 599 mm regarding
the ERD of the Mavic CXP33. The spoke calculators results will of
course wary depending of which number one uses.

--
Regards

I use 597 for the CXP-33 and 603 for OpenPros...measured with
Wheelsmith rods.