Rules
This page contains some key information and rules for racing with NSMXC. These rules
must be adhered to in order to ride with us.
Classes and accepted ages
Ages are determined by the riders date of birth on 1 January. Riders may continue
to ride in a class for which they have reached the maximum age until the end of
that calendar year. Riders wishing to ride in a class above that which they are
eligible to ride with by age may apply for an upgrade from the sports governing
body (The ACU). No rider may race before his/her sixth birthday.
| Class Name | Min Age | Max Age | Max Bike Capacity | Max Wheel Size |
| Auto | 6 | 8 | Maximum50cc 2 Stroke or 4 Stroke Automatic | 12 Inch Rear, 15 Inch Front |
| Junior 65 | 7 | 10 | Maximum 65cc 2 Stroke or 110cc 4 Stroke | 12 Inch Rear, 14 Inch Front |
| Small Wheel 85 | 9 | 12 | Maximum 85cc 2 Stroke or 150cc 4 Stroke | 14 Inch Rear, 17 Inch Front |
| Big Wheel 85 | 11 | 15 | Maximum 85cc 2 Stroke or 150cc 4 Stroke | 16 Inch Rear, 19 Inch Front |
| Schoolboy 125 | 14 | 17 | Maximum 144cc 2 Stroke or Minimum 200cc 4 Stroke or Maximum 250cc 4 Stroke | 19 Inch Rear, 21 Inch Front |
| Adult Under 35 (Riders Under 17)* | 15 | 17 | Maximum 250cc 2 Stroke or 450cc 4 Stroke | N/A |
| Adult Under 35 (Riders Over 17)* | 17 | 34 | Any Machine Capacity | N/A |
| Adult 35 and Over | 35 | 100 | Any Machine Capacity | N/A |
* Riders in classes Marked with * ride in the same group but the ACU regulations
on bike capacity are different.
Noise Limits
All bikes MUST meet the noise level limit of 96 Decibels
which is set by the sports governing body (The ACU)
Noise testing will be carried out at random or at the discretion of the Noise officer
or clerk of the course.
Noise levels will be tested according to the guidance of the sports governing body
(The ACU) and shall be done at RPM levels decided by the capacity of the machine
(rather than the piston stroke).
RPM Testing Levels
| Capacity | RPM Level |
| Up to 85cc | 8000 |
| over 85cc up to 125cc | 7000 |
| over 125cc up to 250cc | 5000 |
| over 250cc up to 500cc | 4500 |
Temporary silencers, bypass pipes or the inclusion of temporary parts to achieve
silencing requirements are prohibited.
The Clerk of the Course may exclude or penalise any rider of a machine which exceeds
the maximum permitted sound level, or which in his/her opinion is deemed to be excessively
noisy.
Marshalling
It is the rule of the club that all riders MUST be able to provide a marshall for
all meetings entered. This means a marshall for every rider. Excuses will not be
accepted. Your entry to the meeting is taken as your agreement to supply a marshall.
Any riders not able to provide a marshall will not be allowed to race.
Numbers
Number plates will be 3 in number on all machines and it is the riders responsibility
to ensure that the numbers are clearly visible. No metallic or reflective colours
may be used in any circumstances. Plates and numbers must comply with the following
requirements:
Plates must measure a minimum of 285 x 235 mm in size with a minimum of 50mm rounded
corners. Each machine must be fitted with one forward facing number plate and two
further plates, one to each side. The minimum dimension of numbers should be (height)
140mm, (width) 80mm, width of stroke 25mm and the space between two figures 15mm.
The required colours are detailed below:
| Group Name | Background Colour | Number Colour |
| Auto | Black | White |
| Junior 65 | Black | White |
| Small Wheel 85 | Red | White |
| Big Wheel 85 | Green | White |
| Schoolboy 125 | Black | White |
| Adult Under 35 (Riders Under 17)* | White | Black |
| Adult Under 35 (Riders Over 17)* | White | Black |
| Adult 35 and Over | White | Black |