Another day with wheels (and so on).
A customer dropped off a pair of front and rear wheels with 50mm-high carbon tubular rims.
These are wheels I built back in the day.
Front wheel: BITEX (presumably) hub, 20H, black CX-RAY spokes, radial lacing on the non-drive side,
Rear wheel: Evo hub, 24H, all CX-RAY spokes, 4-cross lacing with tied and soldered joints. However, back then I couldn't solder the joints with black spokes, so I had no choice but to use different spoke colors on each side. I apologize for that.
And of course I'm photographing the dirtiest spot—my apologies for the messy solder joints.
This is an Evo hub from the Shimano 10-speed era, but the customer had the spline machined on a lathe to convert it to 11-speed.
The customer wanted me to rebuild these wheels with a wide rim of the same height.
The original narrow rim was filled with foam polyurethane and had a construction similar to a Corum rim.
The rim height is nearly identical—around 50mm, precisely about 49.8mm for both—but the thickness of the hole wall on the inner side differs. I was able to reuse the original spokes, but had to cut them slightly shorter. Therefore, a conversion from wide rim back to narrow rim isn't possible.
Front wheel is built.
Same lacing pattern as before the rebuild.
Rear wheel is built.
I got new black spokes for the non-drive side. Reusing the tied and soldered joints wasn't feasible, so while it's possible to transfer rims if spoke lengths match, these don't, so new spokes were necessary anyway. When I removed the drive-side spokes from the hub flange, I separated the original radial and cross-pattern spokes so they'd be threaded the same way during reassembly.
↑Black tied and soldered joints
Replaced all the red nipples too.
Going back in time, here's the rear wheel before the rebuild. The customer's note shows 685g.
I weighed it. The 2g difference isn't really a problem. I'm planning to write about "the holy land of weight reduction" soon, but it's more likely due to scale variation than differences in gravitational acceleration at the measurement location. Or maybe if I'd weighed the rear wheel at this point on the customer's scale, it would have read 683g too. And since I think this will eventually be discovered, I'm writing about it preemptively:
↑Pre-rebuild narrow front rim (estimated weight around 10g)
↑Post-rebuild wide front rim
↑Pre-rebuild narrow rear rim (no weight)
↑Post-rebuild wide rear rim
The pre-rebuild rims were actually excellent in terms of height-to-weight ratio. For example, the rim on Nomu Lab Wheel No. 2 is 38mm/347g. I hope the rebuild will bring rigidity and aerodynamic benefits that offset this weight penalty, but hmm...
By the way, spoke tension was slack just before the rebuild (especially the front wheel), so the tension after tightening it up is similar to the post-rebuild tension. In other words, even if the rider thinks "it feels stiffer!" after riding the rebuilt wheels, the difference in spoke tension is likely bigger than the difference in rim stiffness. If asked to build wheels with the pre-rebuild rim that feel just as rigid as the post-rebuild wheels, I could do it. A stiff rim doesn't automatically make a stiff wheel.
Where the pre-rebuild rim is clearly inferior to the post-rebuild rim: the pre-rebuild rim's brake surface finish is more prone to heat-induced warping. The front wheel has deposits of Yellow King (you know, the caterpillar version) solder residue, while the rear has deposits from black brake shoes—probably Black Prince, but I'm not sure (the crab-light version)—but the brake zone on both hasn't warped unevenly, so they're still reusable.
Before
After
Before
After
Cleaned with acetone.
Though just the area directly under the reference tape for now. I'll do the full circumference later.
A customer dropped off a pair of front and rear wheels with 50mm-high carbon tubular rims.
These are wheels I built back in the day.
Front wheel: BITEX (presumably) hub, 20H, black CX-RAY spokes, radial lacing on the non-drive side,
Rear wheel: Evo hub, 24H, all CX-RAY spokes, 4-cross lacing with tied and soldered joints. However, back then I couldn't solder the joints with black spokes, so I had no choice but to use different spoke colors on each side. I apologize for that.
And of course I'm photographing the dirtiest spot—my apologies for the messy solder joints.
This is an Evo hub from the Shimano 10-speed era, but the customer had the spline machined on a lathe to convert it to 11-speed.
The customer wanted me to rebuild these wheels with a wide rim of the same height.
The original narrow rim was filled with foam polyurethane and had a construction similar to a Corum rim.
The rim height is nearly identical—around 50mm, precisely about 49.8mm for both—but the thickness of the hole wall on the inner side differs. I was able to reuse the original spokes, but had to cut them slightly shorter. Therefore, a conversion from wide rim back to narrow rim isn't possible.
Front wheel is built.
Same lacing pattern as before the rebuild.
Rear wheel is built.
I got new black spokes for the non-drive side. Reusing the tied and soldered joints wasn't feasible, so while it's possible to transfer rims if spoke lengths match, these don't, so new spokes were necessary anyway. When I removed the drive-side spokes from the hub flange, I separated the original radial and cross-pattern spokes so they'd be threaded the same way during reassembly.
↑Black tied and soldered joints
Replaced all the red nipples too.
Going back in time, here's the rear wheel before the rebuild. The customer's note shows 685g.
I weighed it. The 2g difference isn't really a problem. I'm planning to write about "the holy land of weight reduction" soon, but it's more likely due to scale variation than differences in gravitational acceleration at the measurement location. Or maybe if I'd weighed the rear wheel at this point on the customer's scale, it would have read 683g too. And since I think this will eventually be discovered, I'm writing about it preemptively:
↑Pre-rebuild narrow front rim (estimated weight around 10g)
↑Post-rebuild wide front rim
↑Pre-rebuild narrow rear rim (no weight)
↑Post-rebuild wide rear rim
The pre-rebuild rims were actually excellent in terms of height-to-weight ratio. For example, the rim on Nomu Lab Wheel No. 2 is 38mm/347g. I hope the rebuild will bring rigidity and aerodynamic benefits that offset this weight penalty, but hmm...
By the way, spoke tension was slack just before the rebuild (especially the front wheel), so the tension after tightening it up is similar to the post-rebuild tension. In other words, even if the rider thinks "it feels stiffer!" after riding the rebuilt wheels, the difference in spoke tension is likely bigger than the difference in rim stiffness. If asked to build wheels with the pre-rebuild rim that feel just as rigid as the post-rebuild wheels, I could do it. A stiff rim doesn't automatically make a stiff wheel.
Where the pre-rebuild rim is clearly inferior to the post-rebuild rim: the pre-rebuild rim's brake surface finish is more prone to heat-induced warping. The front wheel has deposits of Yellow King (you know, the caterpillar version) solder residue, while the rear has deposits from black brake shoes—probably Black Prince, but I'm not sure (the crab-light version)—but the brake zone on both hasn't warped unevenly, so they're still reusable.
Before
After
Before
After
Cleaned with acetone.
Though just the area directly under the reference tape for now. I'll do the full circumference later.