EVO Shifter 4 RedLine [4 in. Wheel Version]



The EVO Shifter for RedLine is our newest edition of the EVO Shifter, AndyMark's next EVOloution of a shifting transmission gearbox for competition robots. Its design was developed from the lesso...Read More

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Product Overview

The EVO Shifter for RedLine is our newest edition of the EVO Shifter, AndyMark's next EVOloution of a shifting transmission gearbox for competition robots. Its design was developed from the lessons learned during our experience using the AM Shifter since 2004, the Super Shifter since 2007, and the Sonic Shifter since 2013.

This transmission is a two-speed, shift-on-the-fly gearbox, using an improved 4-tooth dog shifting method. For this version, the gearbox accepts up to four 775 class motors, such as the AndyMark RedLine Motor. No servo shifting is available with this shifter. This transmission is shipped assembled, but without the RedLine Motors installed, even if the motors are ordered with the gearbox.

Note: The EVO Shifter for RedLine will only be available in this ratio configuration and output shaft (which protrudes 5 in. from the output face of the gearbox,) configuration for the 2018 season. This particular configuration is specially optimized to directly drive 4" diameter wheels. AndyMark does not recommend using this ratio combination to directly drive wheels larger than 4 in. in diameter, at risk of permanent damage to the motors. If you would like to use wheels larger than 4" in diameter, AndyMark recommends using an external reduction device.

Gearing and Ratios:
Ratio A: 13.58:1 - 19.50 ft/s on 4" wheels*
Ratio B: 28.33:1 - 9.35 ft/s on 4" wheels*
*Specs derived from AndyMark RedLine Motors, assuming an 81% system efficiency.

Output Shaft:
This configuration of the AndyMark EVO Shifter for RedLine only ships with the 2 Stage EVO Shifter Long Hex Output Shaft (am-3500). If you would like to use a different EVO Shifter Output Shaft, they are sold separately for the users to install on their own:
Eleven significant improvements, not seen in AndyMark Shifters prior to the EVO Shifter family of gearboxes have been implemented in the EVO Shifter for RedLine:
  1. The dog gear now has 4 dogs on each face. This allows more material around the dog gear screw, increasing strength over previous designs
  2. A robust 1/8" diameter shoulder screw replaces the previously used #4-40 screw.
  3. The dog gear material is AMPCO® 18 Bronze. This material has similar properties to stainless steel (previously used), but has added lubricity for smooth shifting.
  4. A new, super-strong shift block assembly with a larger bearing and steel housing (and threads!) is now included.
  5. The input stage uses 32DP gears and a press fit 12T 5 mm Bore gear. This allows for an 85:12 first stage reduction.
  6. The user can swap the ratios (A to B, B to A) as needed.
  7. More encoder options are available, including the US Digital E4T (standard) and the CTRE SRXmag encoder (both sold separately)
  8. Aggressive weight reduction features have been machined into the gears and plates.
  9. All of the cluster gears have the same features surrounding the bore on both sides. This allows the user to dis-assemble and assemble the shifter without worry of correct gear orientation.
  10. Using existing mounting plate holes, it can be mounted to an AM14U family chassis or a 2"x1" box tube frame.
  11. A short, narrow air cylinder is being used, taking up less length compared to previously used cylinders.
Air Cylinder Shifting:
The EVO Shifter for RedLine only uses a pneumatic shift method.
  • A spring-extended PHD pneumatic cylinder (am-3494), powers the shift. This pneumatic shift can be done while a robot is accelerating, pushing or decelerating.
    • Extend stroke (spring extend only): 4lbs
    • Extend stroke (if air actuated, 40PSI): 21.6lbs
    • Retract stroke (if air actuated, 40PSI): 15.7lbs)
  • This cylinder extends into "Ratio A" when no air pressure is supplied. This allows a robot to continue to drive using Ratio A if air pressure is lost.
Weight Range (Without Motors):
2.9 - 3.2 Pounds

Usage, Greasing and Break-In:
All AndyMark gearboxes require grease for proper operation and long life. Use our Red Tacky Grease, 14.2 gram (am-2768). However, before applying grease, it is helpful to run the gearbox for 30 minutes without grease to allow the gear teeth to wear in. While we do design with short run times in mind, this 'break in' period for smooth gearbox operation is recommended. Once this is completed, apply grease to the spur gears periodically to ensure smooth operation. No grease is needed on the AMPCO® bronze dog gear.

Encoder Ratio:
When programming for the encoders, please know that the ratio between the Output Shaft and Encoder Shaft of the EVO Shifter for RedLine is 3:1. The Output Shaft's 20T 32DP gear mates with a 60T 32DP gear on the Encoder Shaft.

Included Hardware:
  • Shielded, flanged ball bearings
  • 1117 steel 32 DP gears, w/ 20 degree pressure angle (1st stage)
  • 4140 steel 20 DP gears, w/ 14.5 degree pressure angle (2nd stage)
  • 1/4" thick aluminum side plates, pocketed
  • US Digital encoder and pneumatic cylinder included
  • 4140 steel output shafts


  • Motor Input: 775
  • Motor Quantity: 1, 2, 3, 4
  • Ratio: 13.58:1 / 28.33:1


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