I received an Open Pro UST tubeless rim from a customer.
So far, it seems that most samples are lighter than the stated weight of 430g.
The Open Pro traditionally comes with double eyelets, but the original inventor of the double eyelet design was Mavic. So they may have some attachment to that feature.
However, the Open Pro UST has single eyelets. They probably couldn't make it double eyelets because of the need for a circular depression in the center of the rim. Current Mavic MTB wheels use hookless rims with no internal hook on the bead, but this rim does have a hook, albeit a thin one. The bead area is noticeably thinner, so it seems more susceptible to brake wear. However, there's a separate rim called the Open Pro UST tubeless disc for disc brakes, which has machining in the brake zone, so this is a rim brake model. The weight reduction from thinner ear flange and single eyelet (especially the latter) is greater than the weight increase from wider rim profile, so it's only natural that this rim is lighter than the traditional Open Pro.
I have a bad feeling about this, so I'll mention it upfront: I wouldn't recommend using tire levers with narrow bead hook contact area on this rim.
Built it up. This rim comes in 32, 28, and 24 hole counts—releasing a 24 hole option was a bold decision.
Front wheel: HB-9000 24H CX-RAY Italian 4-cross lacing. The customer wanted tangent lacing, so I went with 4-cross.
Rear wheel: FH-9000 24H semi-comp 4-cross lacing with spoke crossings tied together.
↑This red sticker is only on one side of the rim, but I'm ignoring that
and using the laser-etched marking orientation as my guide instead—making sure it reads correctly from the right side. As a result, the red sticker ended up on the left for the front wheel and the right for the rear wheel. The rim is labeled with an internal diameter of 589mm, but unlike typical Mavic rims, the actual measurement differs significantly. With my rim diameter gauge, which gives readings in 0.5mm increments relative to a 580mm baseline, I measured it at plus 11mm—that is, 591mm. The actual radius I use for calculations is 295.5mm.
The nipples are flush with the rim surface when finished building.
The rim's machining is clean.
The thinness of the bead hook (brake zone) is concerning—it's similar to Stan's Grail, which is disc brake only. As I mentioned earlier, narrow tire levers aren't recommended for this rim. But Mavic's road tubeless tires (UST tubeless tires, not regular tubeless) install and remove so easily by hand that tire levers aren't necessary anyway.
So far, it seems that most samples are lighter than the stated weight of 430g.
The Open Pro traditionally comes with double eyelets, but the original inventor of the double eyelet design was Mavic. So they may have some attachment to that feature.
However, the Open Pro UST has single eyelets. They probably couldn't make it double eyelets because of the need for a circular depression in the center of the rim. Current Mavic MTB wheels use hookless rims with no internal hook on the bead, but this rim does have a hook, albeit a thin one. The bead area is noticeably thinner, so it seems more susceptible to brake wear. However, there's a separate rim called the Open Pro UST tubeless disc for disc brakes, which has machining in the brake zone, so this is a rim brake model. The weight reduction from thinner ear flange and single eyelet (especially the latter) is greater than the weight increase from wider rim profile, so it's only natural that this rim is lighter than the traditional Open Pro.
I have a bad feeling about this, so I'll mention it upfront: I wouldn't recommend using tire levers with narrow bead hook contact area on this rim.
Built it up. This rim comes in 32, 28, and 24 hole counts—releasing a 24 hole option was a bold decision.
Front wheel: HB-9000 24H CX-RAY Italian 4-cross lacing. The customer wanted tangent lacing, so I went with 4-cross.
Rear wheel: FH-9000 24H semi-comp 4-cross lacing with spoke crossings tied together.
↑This red sticker is only on one side of the rim, but I'm ignoring that
and using the laser-etched marking orientation as my guide instead—making sure it reads correctly from the right side. As a result, the red sticker ended up on the left for the front wheel and the right for the rear wheel. The rim is labeled with an internal diameter of 589mm, but unlike typical Mavic rims, the actual measurement differs significantly. With my rim diameter gauge, which gives readings in 0.5mm increments relative to a 580mm baseline, I measured it at plus 11mm—that is, 591mm. The actual radius I use for calculations is 295.5mm.
The nipples are flush with the rim surface when finished building.
The rim's machining is clean.
The thinness of the bead hook (brake zone) is concerning—it's similar to Stan's Grail, which is disc brake only. As I mentioned earlier, narrow tire levers aren't recommended for this rim. But Mavic's road tubeless tires (UST tubeless tires, not regular tubeless) install and remove so easily by hand that tire levers aren't necessary anyway.