Class F

[Tony Ferrari (Nomad)]

Asking as if there is and also a specification for Trials tyres.... Then any tyre in between (In Specification) need not be listed?

Yes there is from the ACU:

Tread depth (A) must not exceed 13mm. All tread blocks in the same circumference must be of the same depth. The space between the tread blocks (B) must not exceed 9.5mm across the tyre or 13mm in a circumferential direction (C). The space between the shoulder blocks (D) must not exceed 22mm.

[Tony Ferrari (Nomad)]

Is there a specification for Road tyres?

In the Supplementary Regs:

STANDARD ROAD TYRES. For the purposes of MCC events Motorcycle Standard Road Tyres
are defined as having a gap between the tread blocks NOT exceeding 6 mm, and a maximum tread
depth of 10 mm. These dimensions will apply irrespective of machine manufacturers or tyre
manufacturer's statements.

[Stephen Bailey]

Asking as if there is and also a specification for Trials tyres.... Then any tyre in between (In Specification) need not be listed?

Yes there is from the ACU:

Tread depth (A) must not exceed 13mm. All tread blocks in the same circumference must be of the same depth. The space between the tread blocks (B) must not exceed 9.5mm across the tyre or 13mm in a circumferential direction (C). The space between the shoulder blocks (D) must not exceed 22mm.

As I said.... Those tyres between "Road specification" and "Trials specification" need not be listed as they conform. Those outside specification are the tyres that need to be listed.....