TallRider

The MA3 was Mavic's "entry-level" rim, with single eyelets and non-welded rim seam construction. Despite the name, the MA3 wasn't really a successor to the MA2, which had double eyelets (a.k.a. rim sockets) and was lighter. The MA3 had machined sidewalls, which is actually a detriment in the estimation of some people. The MA3 was a solid rim by most accounts, although it had a slightly negative rep for cracking at the eyelets.

The MA3 was replaced in Mavic's 2006 lineup by the Open Sport. The only difference appears to be a wear indicator machined into the sidewall. But I'm curious if anyone knows if there are other differences between the MA3 and the Open Sport. Perhaps the OS was engineered to have less chance of cracking at the eyelets. Maybe the effective rim diameter is different (although from eyeballing, the E.R.D. is still larger than the that of the Open Pro).

Anyone know anything about this Rim? Mavic's website doesn't give you anything except the weight.

Thrifty1

I recently built a set of wheel using the Open Sport. I ordered MA-3s and received the OS instead so I don't have any experience with the MA-3. They do have the brake "wear" groove in the sidewall. The Open Sport ERD is 611.....I used 611 in spocalc to order spokes and they were the proper length. The rims built up really nice and were easy to true/dish. I think they look great....they have a slightly concave surface betwwen the sidewall and eyelet surface which IMO should add to rigidity. I laced them to Trek "no name" hubs with DT double buuted spokes in 3X pattern. Due North Daktoa arctic weather (-12), I haven't had a chance to ride them yet. I think they will be excellent wheels for my wife's light (suppoted/credit card) tourer.
Hope this helps.....
BCNU
Gary

TallRider

Okay, interesting. Thanks. Spokecalc gives the MA3 an ERD of 607.5mm - so, the Open Sport is actually closer to what I'm looking for. (My version of spokecalc didn't have the Open Sport.)

Thrifty1

I was not able to find Open Sport ERD in any of the spoke calculators.....must be too new. I measured the ERD myself......

TallRider

Yeah, the OS just came out for 2006, replacing the MA3. I just took my old MA40 (613mm E.R.D.) in to a local shop today, and compared it to an unbuilt Open Sport that I was thinking of buying. 2-3mm difference rim depth on each side, so my guess is that the Open Sport's E.R.D. is 607.5, which is the same as what's listed for the MA3 in spokecalc. Spokelengths calculated for 611mm E.R.D. may still work fine with this (spokes normally have 8-9mm of threads, so you can get away with some inaccuracies here) but I'm going to be on the safe side and build the wheel using a Sun M13II rim, which has an E.R.D. of 610mm.

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