Robotics Education & Competition Foundation
Inspirando estudiantes, un robot a la vez.

The Q&A is closed for the 2021-2022 season. Any rule changes or clarifications pertaining to the 2022 VEX Robotics World Championship will be included in the April 5 Game Manual Update. Teams attending VEX Worlds who wish to pre-submit questions for the driver's meeting should have received a contact form via email; if not, please contact your REC Foundation Team Engagement Manager for more information.

Official Q&A: VIQC 2021-2022: Pitching In

Usage Guidelines All Questions

Rubber band size


Judy Peng (Event Partner)
hace 7 meses

According to VIQC rule R(8), teams are allow to use rubber bands either directly purchased from VEX or has the same dimension specified on VEX website.

However, it comes to our awareness that there are significant dimension difference between the website and the rubber band in our warehouse. How would you suggest we address this during the events?

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R8  
Answered by committee

Per the VEX website, the expected dimensions for VEX IQ rubber bands are as follows:

Rubber Band #32 (275-1089)

  • Length: 3" (76 mm)
  • Width: 1/8" (3 mm)
  • Thickness: 1/32" (0.8 mm)

Rubber Band #64 (276-3990)

  • Length: 3.5" (89 mm)
  • Width: 1/4" (6 mm)
  • Thickness: 1/32" (0.8 mm)

Although it is tough to tell, it appears that the rubber band in the attached image meets the nominal dimensions for a #64 size, and would therefore be legal.

In general, the reason why rubber band sizes are referred to in nominal terms (e.g. #32, #64) is because it is impossible to guarantee a rubber band's exact dimensions with 100% certainty. Rubber may expand or contract due to temperature, humidity, repeated over-stretching, etc. If students are raising concerns about the legality of their official VEX rubber bands, this could serve as a "teaching moment" to explain material properties, tolerances, etc.

The intent of R8-c is to clarify that although off-the-shelf rubber bands are permitted, searching for "the perfect rubber band" should not be a part of the design challenge. Inspectors may request measurements of rubber bands that appear to be grossly outside of the expected sizes, but measuring to millimeter precision should not be necessary.