TSB #169 - Incorrect Chamfer on Helix Race E*Spec Avinox Chainrings

Chris Costello
  • Updated

 

TECHNICAL SERVICE BULLETIN #169.1

March 16, 2026

Provided By:  e*thirteen Technical & Engineering Dept.

Direct Questions To:  support@ethirteen.com 

INCORRECT CHAMFER ON HELIX RACE E*SPEC AVINOX CHAINRINGS

THIS TECHNICAL SERVICE BULLETIN IS INTENDED FOR: 

  • Distributors, Dealers, Riders 

PRODUCT INCLUDED

  • CR5ERA-114 thru 119 - Helix Race e*spec Avinox Chainrings in all colors and sizes with production date codes of 40R thru 52R and 01S thru 02S. 

PRODUCT NOT INCLUDED 

  • Helix Race e*spec chainrings with date codes other than those specified above.
  • Helix Race e*spec chainrings for non-Avinox motors
  • Helix Race e*spec cranksets for Avinox Motors

BACKGROUND & ISSUE

  • e*thirteen manufactures e*spec direct mount chainrings for Avinox motors. Early production batches of these rings were manufactured correctly and functioned as intended. Several more recent production batches unfortunately include a chamfer at the start of the splines. This chamfer results in the chainring installing too deeply into the ring mount splines on Avinox M1 motors and can contact the motor seal and create drag.
  • Rings with chamfer have no fitment issues on Avinox M2 and M2S motors.  

RESOLUTION

  • e*thirteen will replace any Helix Race e*spec ring with the incorrect chamfer.

KEY POINTS

  • Recent production batches of Helix Race Avinox Direct Mount e*spec rings have an incorrect chamfer at the start of the splines. The use of these rings can cause excess seal contact and drag on Avinox M1 motors but have no issues when used on Avinox M2 and M2S. 
  • These rings can be identified by the presence of a chamfer or the associated production date code within the range of 40R thru 52R and 01S thru 02S. .
  • e*thirteen recommends against using these rings and will replace them at no charge for distributors, bike shops and riders. 

TECHNICAL & IDENTIFICATION INFORMATION

  • The impacted rings can be identified by inspecting the production date code of the ring which is laser etched at the location shown in the image below. 
  • The impacted rings can be identified by the presence of a chamfer at the start of the splines as shown in the images below. 

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About e*thirteen:

A global organization of expert designers, engineers, developers, manufacturers, marketers, sales teams, and customer service players, e*thirteen builds bold, best-in-class bicycle solutions. After 20 years of building unique solutions across a variety of industry needs, e*thirteen leads by providing bike retailers and riders with high-performance products with one goal – fearless engineering for the best and most reliable ride.  ™


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