The Enviolo hubs have two types of shift splines on the axle, one in 40T and one in 44T. These sizes determine the type of interface that fits on the hub. Before MY2020 all Enviolo and Nuvinci hubs were fitted with a 44T shift spline. With the introduction of the modular axle for 142 and 148 mm axle standards, also the 40T shift spline was introduced. 

The 40T shift spline is smaller because of the design of the modular hubs and is part of the hub shaft, compared to the 44T where the shift spline is screwed on the axle. 

To simplify this Enviolo is changing all the hubs in the portfolio to 40T shift spline size. You can use this article to check which size you have and which size interface you need. 

CY2024 and earlier

*Note: the N330 hub has a 44T shift spline, but a different size spline nut. This requires a special version of our manual and Automatic interface. Don't hesitate to get in touch with our support if you need a new interface for an N330 hub. 

CY2024 overview

When you don't know the hub type

Measuring the shift spline

If you are unsure of the type of hub that you have you can also measure the size of the shift spline to determine if it is 44T or 40T. 

• 40T spline; outer spline equals a 12.9 - 13.0 outer diameter measured
• 44T spline; outer spline equals a 14.8 - 14.9 outer diameter measured

Measuring the interface

Alternatively, you can also measure the size of the interface to determine the shift spline size.

• 40T spline; inner spline equals an 11.9 - 12.0 inner diameter measured
• 44T spline; inner spline equals a 13.8 - 14.0 inner diameter measured

CY2025 and newer

From CY2025 and newer all hubs that are produced will have the 40T shift spline simplifying the Enviolo portfolio.