EVO Shifter

$350.00 – $360.00

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Availability: As each EVO Shifter is built to order with love and care, please allow for 3-4 business days for build time before shipping during our busiest times of the year. The EVO Shifter is ou...Read More

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Product Overview

Availability: As each EVO Shifter is built to order with love and care, please allow for 3-4 business days for build time before shipping during our busiest times of the year. 

The EVO Shifter is our next EVOlution of a shifting transmission gearbox. It's 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. Motor input can be two or three CIM or NEO motors. The transmission can be configured with two or three interior stages, and a selection of various 1/2 inch output shafts. Plates are designed for mounting either two or three motors. This transmission is shipped assembled, but without motors installed, even if motors are included on the order. 

A number of significant improvements, not seen in previous AndyMark shifters, have been implemented in the EVO Shifter.
  • The dog gear now has 4 dogs on each face. This allows more material around the dog gear screw, increasing strength over previous designs.
  • A robust 1/8" diameter shoulder screw replaces the previously used #4-40 screw.
  • 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.
  • A new, super-strong shift block assembly with a larger bearing and threaded steel housing is now included.
  • The input stage uses 32 DP gears and a 15 tooth pinion gear. This allows for a high 85:15 first stage reduction.
  • This gearbox allows users to independently pick their high and low ratios, and are no longer confined to set spreads.
  • The user can swap the ratios (A to B, B to A) as needed.
  • More encoder options are available, including the US Digital E4T (included) and the CTRE SRX mag encoder (sold separately).
  • Aggressive weight reduction features have been machined into the gears and plates.
  • 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.
  • Users can pick two or three stages for their transmission. An optional 3rd stage provides an additional C ratio choice of 1:1.14 or 2:1.
  • Using existing mounting plate holes, it can be mounted to an AM14U family chassis or a 2"x1" box tube frame.
Air Cylinder Shifting:
The EVO Shifter uses a pneumatic shift method.
  • A spring-extend pneumatic cylinder (am-4229), powers the shift. This pneumatic shift can be done while a robot is accelerating, pushing, or decelerating.
    • Extend Stroke (spring extend): 4lbs
    • Retract Stroke (air actuated @ 40PSI): 15.7lbs
  • This cylinder extends into the selected "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):
Two Stage: 2.9 - 3.2 Pounds
Three Stage: 3.3 - 3.5 Pounds

Note about Pinions:
The EVO product line utilizes an included 15 Tooth 32DP pinion gear which does not use a key. If you are are unable or uncomfortable performing the following procedures we recommend purchasing a motor with the pinion pre-installed. They are available as am-0255_15T for the CIM or am-4258_15T for the NEO.
  • When using a NEO motor a 3 ton arbor press is required to install this pinion due to the intended interference fit (0.001 - 0.002") Please follow the NEO Press Fit Pinion Guide. This press fit procedure has been tested to have a factor of safety of 3.5 on a NEO.

  • When using a CIM motor the pinion may be a slip fit or a press fit (as above) due to the manufacturing tolerances of these motors. In either case apply a few rings of red Loctite 271 to the shaft and inside the pinion, then press the pinion on using the provided aluminum spacer (am-3552) to set the depth from the end of the motor shaft (approximately 0.40"). Red Loctite 271 has been tested to a factor of safety of 4 on a CIM when let to cure for 24 hours.
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 on 2 stage versions of the gearbox the ratio between the Output Shaft and Encoder Shaft of the EVO Shifter is 3:1. The Output Shaft's 20T 32DP gear mates with a 60T 32DP gear on the Encoder Shaft.
Available Gearbox Ratios:

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 and 3rd stage)
  • 1/4" thick aluminum side plates, pocketed
  • US Digital encoder and pneumatic cylinder included
  • 4140 steel output shafts

Individual Hardware Within Two Stage Assembly (Excluding Gears from Ratio A and B):
Individual Hardware Within Three Stage Assembly:(Excluding Gears from Ratio A and B)

Gearing and Ratios:

If there is no table above this line please email support@andymark.com
  • The selection menu above allows users to select their best choice from many ratios. If the user knows their wheel diameter, then they can choose their first ratio and second ratio, and also see approximate speeds (listed in feet/second).
  • Select your ratio options:
    • Determine your wheel diameter
    • Choose Ratio A
    • Choose Ratio B
    • Verify your approximate speed, depending on the motor RPM.
Output Shaft:
Four choices of output shaft geometry are available for the 2 and 3 stage EVO Shifters. All are made from 4140 steel.

  • Short Hex: Extends 2.00" from Outside the Gearbox
    • 2 Stage EVO Shifter Short Hex Output Shaft (am-3498)
    • 3 Stage EVO Shifter Short Hex Output Shaft (am-3520)
  • AM14U Family Hex Shaft: Extends 3.75" from Outside the Gearbox
    • 2 Stage EVO Shifter AM14U Hex Output Shaft (am-3499)
    • 3 Stage EVO Shifter AM14U Hex Output Shaft (am-3522)
  • Long Hex: Extends 5.00" from Outside the Gearbox
    • 2 Stage EVO Shifter Long Hex Output Shaft (am-3500)
    • 3 Stage EVO Shifter Long Hex Output Shaft with Magnet (am-3523a)
  • Short Keyed 1/2" dia. with 1/8" keyway: Extends 2.00" from Outside the Gearbox
    • 2 Stage EVO Shifter Short Keyed Output Shaft (am-3501)
    • 3 Stage EVO Shifter Short Keyed Output Shaft (am-3521)


  • Ratio: Refer to EVO Shifter Ratio Chart


Returns are accepted within 30 days of purchase.
View our return policy here.

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