simplify

The Open Sports are the new "entry level" rims that replace the MA-3, but they might have a different ERD. They're shaped differently than the MA-3, but not as deep as the Open Pro. I can't find the ERD anywhere on Mavic's site or elsewhere, does anyone know what it is? I think it's still too new to appear in the database of the spoke calculators online, at least the ones I've checked. Thanks!

coyotecrust

you dont always want to believe the databases, anyway. you should back it up with your own measurements. you can find a spokecalc where you can enter your own measurements.

bostontrevor

I'm really curious about this. I'll be wicked annoyed if it's different than the OP. Giving them the same ERD provides a simple upgrade path and makes things easier on the builder.

Why NOT make them the same?

Fisty 'O Toole

Because the wheelbuilder would reuse spokes?

bostontrevor

Scandalous.

Thor29

The ERD is 607mm.

I had a hard time finding it. It's not on the Mavic website. i asked www.speedgoat.com since they sell the rims, but they didn't know. Then I asked Excel Sports of Boulder, CO since they also sell it, and they told me 607. I don't know where they got the number, but the spoke length that I calculated using 607 turned out perfect, so it must be correct.

I don't understand why the ERD numbers are so secret sometimes. In my opinion, the rim manufacturers ought to include it right on the rim decals. I mean, they put the number of spokes on there (at least Mavic does on the Open Sport) rather than make you count all the holes...

coyotecrust

mavic is known to be secretive. they have a specs site but you have to have a dealer password to get in.

ivan_yulaev

Not as deep as the OP? The OP is not very deep at all...

bostontrevor

Yeah, I don't know why they're so tight-lipped. They'll tell you up front what the weight is, which is really the only thing that would likely turn a customer from one rim to another.

The target build tension, ERD, and spoke offset should be right on the sticker. And their website. Why is it some sort of deep corporate secret?

Thrifty1

I am currently building a set wheels with Mavic Open Sports. The ERD per my measurement is 611. Is used this ERD to calculate spoke lengths on Spocalc and DT Swiss calulators...must have been accurate because the recommended sp[oke were exact length. I lace the Open Sport to Trek "no name" hubs with 14-15-14 DT spokes in 3X pattern. FYI for this component combo the spoke lengths are 229 front, 297 drive side rear, and 298 non-drive side rear. The 297s protrude about 2 threads beyoynd the nipple on the drive side....296 would be an option for the drive side.

Thrifty1

Edit my last post typo.....the spoke length for the fron is 299 .....not 229.
297 drive side rear
298 non-drive rear

white lobster

I've spent a lot of time trying to get ERD's from rim manufacturers and the two reasons why nobody seems willing to give that info out are:

1) They don't know it. More often than you'd imagine, rim manufacturers don't actually make the stuff they sell, and for some reason, they don't bother to figure out the spoke-end diameter of their own rims. This definitely isn't the case with Mavic, but I've had rim "manufacturers" send me samples to measure just because they couldn't figure out how to measure the ERD on their own.

2) The ERD actually changes pretty often. Aluminum rims are made by smooshing aluminum bars through a die (much like the old Play-Doh Fun Factory), and this die slowly wears down, making the ERD on an early rim significanly different from a later rim. Strange, but true.

You can measure ERD pretty effectively with a tape measure and some guesstimation. I find that the tape measure method gets me close enough to the Wheesmith rods/Bike-alog Rimometer measurement. It's not ideal, but it'll do in a pinch.

HillRider

One method for actually measuring the ERD of any rim is to thread nipples onto two spokes and drop them into two opposite spoke holes in the rim. Measure the gap between the spoke ends then measure the distance between the base of the nipples and the ends of the spokes. Add these three distances together to get the ERD.

OutgunRacing

I build wheels for a living and have a brand new one here that I am building up for a friend. I measured it in two different places, 90° apart, and it is 610 mm in both places. It is 700c silver and was purchased in 2011.

mrrabbit 

Aiming for the flat of a 12mm standard profile nipple:

ERD = 606mm

Folks using top of 10mm standard profile nipple as aiming point would probably report:

ERD = 609mm

=8-)

Um...folks...posting ERD's without noting an aiming point and nipple type make the number meaningless and untrustworthy. Try to get in the habit of providing a reference.

=8-)

Mr IGH

6 year old dead thread.....

mrrabbit 

Shall we bring back to life the one about rim label orientation?

=8-)

OutgunRacing

My measurement was to the bottom of the screwdriver slot. I always use the formula from Jobst Brandt's book and now that the set is built the spoke ends came exactly to the bottom of the slots.