The NuVinci Continuously Variable Planetary (CVP) hub is the first and only bicycle drivetrain on the market that offers infinite gear-inch choices within an overall range of 350%. From NuVinci:
NuVinci CVP technology combines continuously variable ratios with the advantages of a conventional planetary gear set. A set of rotating spheres arranged around a central “sun” is used to transfer torque between two “rings.”
Tilting the spheres changes their contact diameters on the rings, permitting an infinite progression of speed ratios. The result is smooth, seamless and continuous transition to any ratio within its range, maximizing overall powertrain efficiency and ride quality.
For the past couple of weeks I’ve been riding a Surly Long Haul Tucker outfitted with a NuVinci CVP hub. The LHT was set-up by The Bicycle Business in Sacramento with upright bars, MTB levers, a single chainring, and the NuVinci hub/shifter combo.
Details & Impressions
The NuVinci hub is extremely smooth and quiet, much like a high quality internal gear hub. Its gear range is also similar to internal gear hubs such as the Shimano Alfine 8 and SRAM i-Motion 9 (see chart below). The amount of resistance created by the CVP is insignificant for its intended use on commuters, cruisers, and e- bikes, though subjectively I’d say it introduces slightly more drag than the Alfine or i-Motion.
The twist shifter’s “gear” indicator relates drive ratios to terrain: a flat line indicates level ground (high gear-inches) and a curved line indicates hills (low gear-inches). It takes 1.25 turns of the twist shifter to move through the entire range. The long throw on the shifter is good for fine tuning the ratio, but quick shifts from high to low are difficult to execute; somewhere under one full rotation of the twist grip would probably be better for most people.
Like internal gear and single speed hubs, the NuVinci CVP requires either horizontal dropouts, sliding dropouts, or a chain tensioner (our LHT used for the test was set-up with a chain tensioner). Removing the rear wheel is relatively simple and no more difficult than removing the rear wheel on bikes set up with internal gear hubs.
It took a while to get over the old habit of spinning up before making a shift, something that’s completely unnecessary with the NuVinci. With the CVP there’s no need to hesitate making adjustments because there are actually no “shifts”. In other words, each miniscule adjustment of the shifter results in a minuscule adjustment in gear-inches. Eventually I ended up using the twist shifter almost like a throttle, constantly changing the ratio to match cadence and pedal pressure depending upon the terrain and wind direction.
The NuVinci CVP’s main audience is likely to be newcomers who are intimidated by triple chainrings and derailleurs, or commuters who want a bullet-proof drivetrain with an industry-best 6-year warranty. It may also be a good fit for hybrid electric bikes where the hub’s substantial 8 lb. weight would be mitigated by e-assist. Unfortunately, having 8 lbs. concentrated at the rear axle on a lightweight bicycle is enough to alter the handling and may make it a tough sell on those bikes. Even so, I think CVP is a cool technology with a future, particularly if NuVinci can get the weight down into the 4-5 lb. range and hit a price point that is on par with competing products such as the Shimano and SRAM internal gear hubs.
User-friendly for novices
Quiet and smooth
Infinite “gear” ratios within a 350% range
Ability to change ratios while stopped, coasting, or under power
Heavy (approximately 8 lbs.)
Relatively expensive (approximately $450)
Long throw on twist shifter
The LHT used for this review was provided by The Bicycle Business. Stop by their shop in Sacramento to test ride the NuVinci CVP.
Disclosure: The Bicycle Business is a sponsor of this website.