Zipp is a big name in the world of road wheels, and its first mountain bike wheel, the 3Zero Moto, is suitably unconventional for a newcomer to the market.
Zipp’s radical single-wall carbon rims are designed to flex vertically and twist along the circumference of the rim thereby improving comfort and reducing the risk of pinch flats.
Most MTB rims use a box-section design, meaning they have a hollow D-shaped cross section comprised of the rim bed and the sidewall. Zipp’s 3Zero Moto rims are essentially a flat piece of carbon, which is broad laterally but very shallow in the vertical direction.
For the same reason that an I-beam or a plank of wood is stiff in one direction but not the other, this should allow the rim to flex radially (up and down) while still being stiff from side to side.
Zipp’s 3Zero Motos are designed to flex vertically and twist along the circumference of the rim. Georgina Hinton
But there’s more. Zipp claims that the rims also twist along the axis of their circumference, thereby allowing them to conform to the terrain when rock strikes impact one rim bead harder than the other, or even when cornering. Zipp calls this twisting action “ankle compliance”.
When I compared a 3Zero Moto rim to a regular carbon trail rim (SRAM Roam 60), it flexes noticeably more when pushed against the ground. It even twists in the hand relatively easily, whereas a regular carbon rim feels totally solid in this test.
The single wall rim has a flat cross-section. The rim on the left is an early prototype, while the right is the final rim shape. Rupert Fowler/SRAM
As a complete wheel, they are of course far more solid due to the pre-tension of the spokes. However, when I rested one rim bead on a block of wood and pushed down on the wheel hard, the rim still twists a little. Far more than any other enduro wheelset I subjected to the same test.
In box-section rims, there’s a physical separation between the spoke heads and the rim tape, so when the rim flexes radially towards the hub, there’s room to ensure the spokes never poke through the rim tape from inside. With this single-wall design, there’s no gap between the spokes and the rim tape, so Zipp relies on a thin but tough Kevlar strip between the airtight rim tape and the rim bed. In theory, this stops the spokes poking through when the rim flexes towards the hub.
The rim is designed to twist along the axis of the spoke bed, helping to prevent punctures. Zipp
Zipp claim these wheels weigh 1,910g in 29in (1,875g in 27.5in), but my wheelset weighs 1,998g in 29in including tape and valves. That makes them heavier than some alloy wheels costing half as much, so you’re not paying for lightness.
Another interesting selling point is the integrated TyreWiz pressure sensors. These send precise tyre pressure measurements to your phone or bike computer. Also, LEDs flash to tell you if your tyres are under-inflated (slow red flash), over-inflated (fat red flash), or within the pressure window you’ve specified in the TyreWiz app (green flash). That means you can ride knowing your tyres are in the right ballpark at a glance.
Complete wheelsets are shipped with integrated TyreWiz pressure sensors. Dan Hearn/SRAM
Zipp 3Zero Moto ride impressions
The crux of my testing involved back-to-back runs down three well-known test tracks, which included hand-buzzing hardpack and rough rock gardens. I swapped between these and competitor wheelsets (carbon and alloy) between runs and made sure the bike setup and tyre pressures were identical.
Interestingly, the hand pain and buzz I experienced was similar to all but the harshest carbon wheels, and if anything, I found some alloy wheels to be marginally comfier.
After plenty of testing the wheelset does seem seems to reduce the risk of punctures and take the sting out of jarring rock hits. Rupert Fowler/SRAM
There were occasions where I was convinced the wheels smoothed-out bumpy turns, but whenever I tested back-to-back against other wheels I can’t say I noticed a consistent difference in traction.
I never felt any vagueness or unwanted flex either, except for on one occasion when recklessly cutting into a hardpack berm the rear wheel made a loud pinging sound and I could feel it flexing and springing back into shape. This was a one-off after months of testing, but these wheels probably aren’t for the careless cutty crowd.
They do seem to take the sting out of the very harshest impacts where the tyre bottoms-out on the rim, but it’s hard to test this repeatably because it’s only when things got wild that I perceived the benefit. On the other hand, despite several such impacts over months of hard riding, I’ve yet to puncture a tyre.
The integrated TyreWiz pressure sensors are a handy feature. Rupert Fowler/SRAM
On one particularly brutal impact, a spoke poked through the Kevlar strip and rim tape causing a slow flat. Though inconvenient, this does at least prove the rims flex towards the hub, and the tyre was fine.
The fact that the rim sidewall measures a whopping 3.5mm wide where it contacts the tyre no doubt spreads the load of impacts, further helping to keep the tyres intact.
The wheels use 32 J-bend spokes on Zipp ZM1 hubs. Georgina Hinton
If riding down several rough tracks testing 14 different wheelsets has taught me anything, it’s that tyre pressure is the most important factor concerning hand-buzz and traction. The integrated TyreWiz pressure sensors make it a little easier to tune that factor, and it seems these wheels do let you get away with lower pressures without pinch flats.
Zipp 3Zero Moto reliability
The rims remain damage-free despite months of low-pressure abuse and they’ve stayed true and tight with no need for a spoke key.
Since re-taping it’s been leak free. Georgina Hinton
However, the rear hub did start to creak slightly when cranking hard in the low gears after just a couple months of use. I sent the wheel back to Zipp, where, apparently, it just dismantled the hub, cleaned it out and reinstalled the bearings. Since then, they’ve been creak free.
Since re-taping the wheel with a hole in the rim tape, it’s been leak free.
After a few months of use the hub has started to creak. Georgina Hinton
Price per rim: £670 / $700 / €750
Price per set: £1,875 / $1,999 / €2,099