Is modification to a COTS part allowed?

[Sparta3648]

With AndyMark Pneumatic tires not an option our team has opted for using HarborFreight 10 inch pneumatic tires. In order to make them compatible with our drive-train/axle system we are 3D printing compatible hubs. Are tires of this kind and modified in this manner allowed?

[theawesome1730]

Modification to COTS parts is allowed. Just keep in mind that post-modification, it is no longer a COTS part but a FABRICATED ITEM

[rich2202]

In general, modification to COTS parts are allowed. The exceptions (for safety reasons) relate to motors, motor controllers, and pneumatics. There is probably a rule regarding the roborio and related parts.

[Jon Stratis]

Originally Posted by rich2202

In general, modification to COTS parts are allowed. The exceptions (for safety reasons) relate to motors, motor controllers, and pneumatics. There is probably a rule regarding the roborio and related parts.

Details:

R30 The integral mechanical and electrical system of any motor must not be modified. Motors, servos, and electric solenoids used on the ROBOT shall not be modified in any way, except as follows:

R66 The Driver Station software, roboRIO, Power Distribution Panel, Pneumatics Control Modules, Voltage Regulator Modules, RSL, 120A breaker, motor controllers, relay modules, Wireless Bridge, and batteries shall not be tampered with, modified, or adjusted in any way (tampering includes drilling, cutting, machining, rewiring, disassembling, etc.), with the following exceptions:

R76 All pneumatic COMPONENTS must be used in their original, unaltered condition. Exceptions are as follows:

Please note that each of those rules does contain a small list of exceptions (not copied here).

[DonRotolo]

Screwing a plastic hub to a COTS item doesn't make the COTS item non-COTS, does it? Kinda like using a clamp to hold a broomstick, the broomstick is still COTS.

Of course, the OP seems to be replacing the hubs with plastic bits; this makes it non-COTS (unless the tire is available separately, which remains COTS then)

[EricH]

Well...

The COTS item is still a COTS item. However, the whole thing is now a Fabricated Item (by means of assembly) and thus no longer COTS (unless it was sold as a COTS assembly, for example a wheel and hub sold as one unit). However, if you took the two items apart, they would be COTS again.

[GeeTwo]

If your 3-d printed hubs do not require you to modify the COTS wheels, they're still COTS. As they are not actuators or control systems, you are pretty much at liberty to modify them as needed. However, if you drill or cut on them, that makes them fabricated items rather than COTS. The only difference between COTS and FABRICATED items is that fabricated parts must be made after the start of build season (a few exceptions, bumpers, and attachments), and are not exempt from bagging/withholding rules (an even smaller set of exceptions).

[GreyingJay]

Tires = COTS

3D printed hubs = fabricated item

Put together, you have a fabricated item (assembly).

[rich2202]

Tires = COTS
Gear box = COTS
Motors = COTS
Control System = COTS
Chassis = COTS

Put them all together, and you have a fabricated item.