Bontrager was one of the pioneers of mountain bike and then road tubeless technology on both tyres and wheels.
Its TLR system uses a hard plastic sealing strip that snaps into place (be patient when fitting) rather than tape. This adds around 30g but it provides a much more secure seal, which is less prone to accidental damage from tyre levers or from over pressuring. That’s particularly pertinent as the rim shape does create a tight tyre-fitting squeeze that sometimes needs over-pressuring for a consistent tyre fit.
On the plus side, once they’re on and sitting evenly, that keeps them reliably airtight right down to teen psi cyclo-cross pressures. The 18.5mm wide internal trough also means they’re wide enough to support tyres up to 30mm well and manage 33mm too.
The OCLV carbon rims are hand-built at the Trek factory in Wisconsin and, interestingly, they’re the same between rim and disc-brake versions. However, Trek feel the disc versions are more likely to be used aggressively than the rim-brake versions and having the same reinforcement is useful when you’re rimming out on a rocky path at low pressures.
The latest rounded D3 profile gives easy handling in all wind conditions
I used them extensively off-road without any issues, I can’t fault the logic unless you’re after the lightest wheels possible, but even then they’re still lighter than equivalent wheels from Zipp, Easton and Enve. It also means you could use them in a rim-braked bike in an emergency though that will obviously scuff up the otherwise clean gloss rims.
Bontrager was an early adopter of the wider, blunter rim trend for aero wheels and the latest rounded D3 profile gives easy handling in all wind conditions. The 35mm deep section still has enough drag reducing advantage to feel over a shallower or flat-faced rim too and 50mm versions are also available if you want to amp up the aero or build a mixed depth set similar to the ENVE 4.5s.