Join Date: Apr 2009
Location: Boulder County, CO
Bikes: '92 22" Cannondale M2000, '92 Cannondale R1000 Tandem, another modern Canndondale tandem, Two Holy Grail '86 Cannondale ST800s 27" (68.5cm) Touring bike w/Superbe Pro components and Phil Wood hubs. A bunch of other 27" ST frames & bikes.
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27" Rim Options (630 bsd/iso)
Classic and Vintage bikes almost necessarily means bikes designed for 27" (630) rims. While you can make 700c rims work fine with long reach brakes, or on bikes with cantilever posts, the point is that there is absolutely nothing wrong with the 27" rim standard. Which is to say that there is nothing inherently better or improved about the 700c rim.
A 27" rim is really a 630mm rim at the bead seat.
A 700c rim is really just a 622mm rim at the bead seat.
For large frames (mine are 68.5cm) you want the biggest rims you can get, even if they are just 4mm larger in radius (8mm in diameter) to keep from looking "off".
Well...Velocity may have added more rims to their 27" offerings.
Recap. Velocity offers the following rims in 27":
Dyad in 48h
(Also known as Aeroheat AT, Super stout touring/tandem duty rim, think Mavic Module 4 or Super Champion Model 58/59 w/o eyelets)
Synergy in 36h
(Good all purpose rim)
Twin Hollow in 32h, 36h, and 48h
(light duty single wall)
While Velocity had the touring/tandem rim market for 27" covered with the Dyad, at least for 48 drill, it turns out that there really was not a good 27" 40h rim on the market.
Well Velocity seems to be coming to the rescue with additions to their 27" rim line.
They will apparently now be making the Aero in 27" in 32h, 36h, and 40h
This doubles their coverage of "good" rims for 36h, adds a "good" rim to the 32h conversation, and completely owns the 40h 27" rim market.
Velocity Aero Rim
Last edited by mtnbke; 02-21-11 at 11:21 AM.