The first few builds with the HED Belgium+ Eroica are out the door and we feel knowledgeable enough about them to put up a review. You can find all of our build options here.
First the specs. Average weight for 700c is 456g (we actually haven't done any 650b builds yet). Depth is 24mm, and 700c rims are available in 24, 28, and 32 hole drillings, with 650b available in 28 and 32. Drilling is centerline (no offset).
Internal width is 25mm, external width is 30mm. Max pressure is 80psi (more in this in a bit). The difference between the external and internal widths is somewhat wide for an alloy rim, and that owes to the small lip on the outside of the external rim (see photo below). These are disc only.
The lip adds a bit of meat at the point where your rims are most likely to get dinged bottoming out on a stray rock or root, and provides some bearing surface to prevent pinch flats, and it's a nice idea. We'll see how it does in practice, but it's solid logic.
With the 25mm inner width, most people are probably going to use these with 35mm tires or bigger. The 80 psi pressure limit doesn't tell you a whole lot, since there's no guidance as to what size tire that's applicable to, but these are gravel rims and not your aerodynamically optimized "105% rule" road rims. We set this pair up with Donnelly MSO 36s, and they look great to us. Curiously, the tire sets up at exactly 36mm wide (it's a new tire) at 50psi (we use that pressure for the compression test), but it should grow a bit. But the actual 36mm tire looks great on the rim, and is probably about the minimum overlap you'd want in order to maintain tire suspension and cornering knob traction.
The tubeless setup is great. Just like the HED Belgium+ rims (and it's going to get confusing since these are officially Belgium+ Eroicas, which we're just going to call Eroicas), there's no bead lock lip, yet the tire installs and inflates easily and stays put down to low pressure. We're using two wraps of 1" wide tape, and that works just wonderfully.
The build quality is par for HED, which is to say brilliant. With rim tape on, you'd have no hope of finding the joint, and we can get them to human hair levels of true with very even spoke pressure. Spoke tension loss under tire compression load is slightly less than with the regular Belgium+ (by a small amount) and I can't really account for that since the depth and vertical shapes are so similar. The dish moves a little toward the drive side as the tire compresses the rim, which is in line with how things happen these days.
As with all rims/hubs/spokes, who puts them together and how is easily as important as what the parts are.
At $175/rim retail, they're not cheap, but in the grand scheme of things it's not that bad. One of the things about having custom wheels built is that smart builders are able to price things well using the inherent margin in the products. With very inexpensive products, the money that we need to make to do the work and provide the service and keep the lights on gets pretty evident, whereas with slightly more premium products we're able to blend our costs into the margin some more and create great value.
We'll review some of the other new rims in this category in the coming weeks, but for now these are a wonderful new addition to the landscape.