Q&A

What is the legality of cutting a support hole off on a shaft encoder? Would this fall under R22 or R23? <R22> No modifications to electronic components are allowed. Motors (including the internal PTC or Smart Motor firmware), microcontrollers (including V5 Robot Brain firmware), extension cords, sensors, controllers, battery packs, reservoirs, solenoids, pneumatic cylinders, and any other electrical component or pneumatics component of the VEX platform may NOT be altered from their original state in ANY way.
<R23> Most modifications and repairs to non-electrical components are allowed. Physical modifications such as bending or cutting are permitted and may be done to legal VEX Robotics Competitionmetal structure or plastic components.

In this QnA, link, some questions are asked about what is legal in regards to motor cartridge modification in VexU. However, it is not directly asked if replacing the casing of the cartridge with a custom casing is legal. It is only asked if making custom internals and modifying the original case would be allowed. Would a cartridge that uses fully custom parts, including the casing, be legal as well?

Hello, I wanted to make ask for clarification regarding this QnA: Q611 Here, it is asked whether making a custom motor cap to reduce the profile of the motor is legal, as shown here: image The response says yes, this is legal, and includes this caveat: “The primary motor case, internal components, etc are still considered "electronics" under R23, and may not be modified.” The main question I have here is this: does the other cap of the motor, opposite the one which was explicitly ruled legal to replace, included in this list of things which cannot be replaced? Or is replacing this cap also allowed in the same way that replacing the bottom one is. To ensure there is no confusion regarding this question, here is an example of what I am asking about: image In summary, would this motor be legal in VexU?

It was previously ruled during Tower Takeover that v5 motor cartridges could be used externally as hardware components. See for reference. Under <R23> modifications of non-electrical hardware componets is allowed. Therefore, when using a cartridge externally as hardware, would modification of the v5 motor cartridges be legal under <R23>? If so would the following scenarios be permitted:

A) Opening the cartridge and removing its internal gears and using them externally.

B) Drilling holes or slots in the cartridge to help mount it externally.

C) Fabricating custom gears out of legal material and replacing the gears within the cartridge with them.

Furthermore, It was recently ruled that vexU could replace the motor cap portion of the motor. see for reference However the stipulation was that “The primary motor case, internal components, etc are still considered ‘electronics’ under R23, and may not be modified.” Since the motor cartridge lies halfway between the motor cap and the internal side of the motor, is the cartridge considered an internal part of the motor or an external part like the cap?

Specifically, would the following situations be legal:

D) Removing the motor cartridge completely in addition to the cap so the smart motor may interface directly with a legally fabricated component. This was previously allowed for the internal gears of 393 motors. see for reference

E) If Situations A, B, and C are legal, insert a legally modified cartridge into a v5 smart motor.

In what tense, cooling devices count as decoration?

<R28> <R23>

We are seeking clarification on whether our specific LED implementation is legal under the current Override game manual.

Our Setup:

A custom-made, non-VEX-branded 3-conductor wire with the appropriate 3-wire port connector on one end, plugged directly into a 3-wire port on the V5 Brain. The other end connects to an LED via a solderless crimp - no soldering, welding, gluing, or brazing is involved at any point. The LED has no independent power source and no independent microcontroller. It is powered and controlled entirely by the V5 Brain. The intended use is as a non-functional visual decoration to provide robot state feedback to our drive team. Question 1 - Does <R28> Apply to Our Custom Wire?

<R28> restricts modifications to electronic or pneumatic components of the VEX platform, specifically including "cables" and "any other electrical component of the VEX platform." Our 3-conductor wire is not a VEX component, it was fabricated from scratch and is not a modified or repaired VEX cable. We believe <R28> therefore does not govern this wire at all, as it only addresses modifications to existing VEX-platform components.

Is this interpretation correct, that <R28> does not apply to a custom-built wire that was never a VEX component to begin with?

Question 2 - Is There Any Rule Restricting What May Be Plugged Into a 3-Wire Port?

We are not aware of any rule in the current game manual that requires the wire or device plugged into a V5 Brain 3-wire port to be a VEX-branded component. <R20> governs custom V5 Smart Cables and restricts smart port usage to legal electronic devices, but we cannot identify equivalent language restricting 3-wire port connections to VEX-branded components only. The 3-wire port is a standard physical interface that VEX designed for external connections.

Is there any rule that prohibits plugging a custom (non-VEX) wire into a V5 Brain 3-wire port?

Question 3 - Legality as a Non-Functional Decoration Under <R23>

Assuming Questions 1 and 2 are resolved in our favor, we believe our LED qualifies as a legal non-functional decoration under <R23>. Specifically:

It does not affect robot performance or the outcome of a match. It serves no structural function. It does not mimic field elements or interfere with opponent sensors. It is powered solely by the V5 Brain battery, no additional power source. It is controlled by the V5 Brain, no additional microcontroller. In previous years, decorative LEDs controlled by the V5 Brain and used to provide visual feedback to drive team members have been permitted to an extent. The current <R23> continues to allow non-functional decorations, and we believe this use case falls within that permission.

Is a Brain-controlled LED, connected via a custom non-VEX wire plugged into a 3-wire port, legal as a non-functional decoration under <R23>, including for the purpose of providing visual robot-state feedback to drive team members?

Our question relates to the application of <R23>; specifically, <R23> part (a), stating that "Anodizing, painting, dyeing or changing the color of any legal VEX part is prohibited."

(a) The VEX manual clearly states that some commercial off-the-shelf parts are legal, as has been standard for past seasons. Some of these parts come in color; for example, some companies sell nuts which come in color, and many teams choose to use screws with colored heads to aid in identification of screw lengths. These COTS colored parts can be considered to be outside the category of "legal VEX part", as they are not manufactured by VEX. Will these parts be legal? Broadly applied, does legal VEX part apply only to parts sold and distributed by VEX Robotics, Inc.?

(b) i. Many teams in the past have used anodized metal parts like C-channels or dyed parts like gears. Before the 2026-27 season, these parts were already dyed or anodized. The language of <R23> states that the action of anodization/painting/dyeing/coloring is not legal, but it does not state that the use of previously anodized/painted/dyed/colored parts is illegal. This part of the rule was not present before the 2026-27 season. Does <R23> forbid the action of anodizing, painting, dyeing, or changing the color of any legal VEX part from the 2026-27 season onwards, or is it meant to be applied in retrospect, overriding previous game manuals, thereby banning all parts that have been anodized, painted, dyed, or color-changed, including ones teams already owned, and that were previously legal?

(b) ii. This is a follow-up to (b) i. IF all anodized/dyed/painted/colored parts are banned. Does VEX have a plan to compensate or alleviate the financial burden on organizations which have a large amount of these parts? <R23> (a) was added to the rulebook without warning, and many teams operated under the expectation that these previously unambiguously legal parts would be continually reusable for future seasons, as is the intent with purchasing these parts; they are an investment towards students' education for the season the parts are bought in and many seasons following. How does VEX intend these teams to deal with the sudden financial burden of needing new parts?

Our team's questions are as follows, with two specific examples which we would like clarified.

(a) Rule <R23> states that “Decorations that cover or obscure identifying features of electronics and/or pneumatics parts are not legal.” Identifying features are defined following this, with "Identifying features include, but are not limited to, VEX logos, part numbers, and other distinctive colors or features of the part that allow an inspector to easily confirm it is a legal part." In some cases, modifications to VEX parts which remove material may remove the presence of VEX logos, listed as an identifying part. These modifications are not necessarily due to decorations, but they do remove the VEX logo, and may be for either functional or aesthetic reasons otherwise legal. Will such modifications be legal in general in the future?

Now, we would like to ask about specific applications of this rule.

(b) Teams have cut VEX gears for many seasons now in order to reduce drivetrain space and weight. Cutting or modifying these gears as has been standard for past seasons would potentially remove VEX logos, an identifying part. Will cutting of gears in ways that may remove the VEX logo be legal this season and in following seasons?

(c) Many teams have removed the vinyl wrapping on their air tanks and air cylinders. This does not affect the functionality of the air cylinder or air tank, and is usually made for aesthetic reasons or after damage to the vinyl wrapping. Removing the vinyl wrapping will remove VEX logos. Will air cylinders and air tanks with the vinyl wrapping removed be legal this season and in upcoming seasons? If not, how does VEX robotics plan to allow old pneumatics sets with these vinyl wrappings removed to be legal, if at all?

(d) Hypothetically, if a team was to remove the VEX logo from parts for little to no gain, like shaving off the VEX logo off new aluminum C-channels or sandblasting the surface of a VEX gear or sprocket, how would this be ruled?

(e) In the past, teams have been known to use rubber bands or zipties to connect the VEX V5 Smart Motor cap and body, in order to improve maintainability and serviceability in the middle of a competition. This is commonly referred to as allowing a motor to be "hotswapped". However, in some cases, these zipties or rubber bands can cover the VEX logo on these motors, which are electronic parts. Will such hotswapping setups be allowed in this season and onwards? If not, <R23> also states that the appropriate way to address this is to "remove the decoration if possible". Would this removal be only for inspection, or would it be for the duration of the competition? Broadly applied, since the intent of this rule is to aid in inspection, do restrictions on decorations potentially obscuring VEX identifying features apply only during inspection, or through the full duration of the competition?

(f) Finally, what are some general guidelines our team can apply to decide the legality of modifications which remove identifying features in the future? We ask this on an understanding that not every edge case can be covered here, but the manual is vague on these guidelines as well.

<R23>

Decorations that cover or obscure identifying features of electronics and/or pneumatics parts are not legal. i. Teams will be asked to either replace the electronics and/or pneumatics part entirely, or remove the decoration if possible. ii. Identifying features include, but are not limited to, VEX logos, part numbers, and other distinctive colors or features of the part that allow an inspector to easily confirm it is a legal part.

Question: Over the course of normal use, the plastic protective wrapping/labeling on V5RC pneumatic reservoirs and cylinders can become frayed, damaged, or fall off entirely, removing the VEX logo and part number. If a pneumatic part is otherwise identical in form and function to an official VEX part but is missing its factory label/logo due to wear and tear, is it still considered legal for competition use and furthermore, what secondary identifying features should a team point to during inspection to "easily confirm" the part is legal if the primary logo is missing?

<R23> reads:

Anodizing, painting, dyeing or changing the color of any legal VEX part is prohibited.

Our team has many RoboSource "Color Coded Star Drive Screws" where the screw heads have been painted by the vendor.

Related to this, we also have many RoboSource "Color-Coded Standoffs" which are anodized aluminum.

Technically, none of us painted or anodized the part ourselves - it came brand new painted and/or anodized from a well-known reputable vendor.

Are either or both of these two types of products legal?

Thank you!

<R23> Hello REC Foundation, we hope you are doing well. We would like to request clarification regarding the rules for non-threaded spacers.

According to the rule that allows commercially available nuts, washers, standoffs, and non-threaded spacers up to 2.5" in length, we understand that the length is restricted but the outer diameter is not mentioned.

Is there any outer diameter (OD) limit for plastic spacers? For example, can a plastic spacer have a diameter larger than 2.5", as long as its length is within 2.5" and it fits legal screw sizes?

If a plastic spacer is cut, drilled, or modified (e.g., adding a hole or reshaping it), does it still count as a “spacer” or does it become a “plastic sheet” under the separate plastic-sheet rule (12 uses)?

We would like to confirm whether modified spacers remain classified as spacers, or if any cutting/drilling reclassifies them as plastic sheets.

Thank you!

<R23>

R23c State "Any commercially available nut, washer, standoff, and/or non-threaded spacer up to 2.5" long which fits these screws."

Does this include wing nuts?

Can a team use a wing nut to secure a licence plate for quick switch over between matches?

Could you please tell me if this commercially available plastic rivet shown in the picture can be used as a compliant construction material for robots in the junior and senior high school categories?<R23>

Concerning vexu's ability to use custom sensors and electronics, as well as rule <R23> as follows

<R23> One or two Controllers per Robot. No more than two (2) VEX V5 Controllers may control a single Robot. No physical or electrical modification of these Controllers are allowed under any circumstances. Attachments which assist the Drive Team Member in holding or manipulating buttons/joysticks on the V5 Controller are permitted, provided that they do not involve direct physical or electrical modification of the Controller itself. No other methods of controlling the Robot (light, sound, etc.) are permissible. Using sensor feedback to augment driver control (such as motor encoders or the Vision Sensor) is permitted.

As we are allowed to make custom sensors, could we connect them to a controller and act as a secondary controller.

For example, could we plug a big red button into an arduino, which mimics a controller and plugs into the primary controller?