Changes to the Approved Tyre List Groups Na, Nb, Nc, Sa, Sb and Sc to create an Approved tyre list which details approved tyres and sizes.

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1 Page 1 of 6 Bulletin Number: B13/085 TECHNICAL BULLETIN 5 th CATEGORY APPROVED TYRE LIST REFERENCE: CAMS Online Manual of Motor Sport; 5 th Category Historic; Approved Tyre List Groups Na, Nb, Nc, Sa, Sb and Sc RATIONALE: Changes to the Approved Tyre List Groups Na, Nb, Nc, Sa, Sb and Sc to create an Approved tyre list which details approved tyres and sizes. ACTION: APPROVED TYRE LIST GROUPS Na, Nb, Nc, Sa, Sb and Sc This approved tyre list relates to tyre characteristics applying at the date of publication. If In the event of a tyre manufacturer makes changes to effecting reformation of an approved tyre (particularly in respect of aspect ratio, tyre pattern or grip levels of compound) this such reformation normally will normally result in the approved status of the tyre lapsing. Any historic racing tyre, street-legal tyre, treaded race tyre or standard road tyre that meets these guidelines may be included on the list after application and approval. Slicks and tyres that are designed to have minimal tread pattern after limited use are not acceptable. The Approved Tyre List will be maintained by CAMS will maintain a list of tyres approved for each of these groups. Approved tyres for these groups and may be updated by the Historic Production Based Eligibility Committee. Consult the CAMS National Office or the CAMS website to obtain the current list of tyres and section sizes. For Group Na the minimum aspect ratio permitted is nominally 65%. For Groups Nb, Nc, Sa and Sb the minimum aspect ratio permitted is nominally 60%. For Group Sc the minimum aspect ratio permitted is nominally 60% unless the vehicle in question was originally fitted with tyres of a lower aspect ratio by the manufacturer, in which case this shall be the minimum permitted aspect ratio. The aspect ratio will be based on the manufacturer s published dimensions and calculated by the following formula: Overall diameter, minus rim diameter, divided by two, divided by the tread section width. ((OD-Rim Dia)/2)/SW=AR.

2 Page 2 of 6 Bulletin Number: B13/085 Where a manufacturer s published dimensions differ from the actual dimensions and the tyre therefore falls below the minimum aspect ratio requirements, the tyre will not be acceptable. Any historic racing tyre, street-legal tyre, treaded race tyre or standard road tyre that meets these guidelines may be included in the Approved Tyre List after application and approval. Dedicated rain tyres or wet compound tyres are not acceptable for Group S. Where the Approved List indicates an approved model of tyre, only the individual sizes that meet the minimum aspect ratio requirements are acceptable. Slicks, semi-slicks and tyres that are designed to have minimal tread patterns after limited use are not acceptable. Tyres may not be fitted to rims wider than recommended by the tyre manufacturer as per Schedule E section 2 Tyres. An application to add a new tyre to the approved list must be made to the HPBEC and shall include the following information: Manufacturer s information sheets showing tyre make and model identification. Tyre dimensions (overall diameter, section width and recommended rim widths). Illustrations of the tread pattern. Section sizes available in the model range. Where the tyre is produced in multiple compounds the range and the method of identification must be provided. Any other relevant information that would be required in identifying the tyre at an eligibility check. The ongoing supply of specific tyre types and sizes will be essential in order for a tyre to remain on the tyre list, which will be reviewed regularly. Include indications of the likely availability of tyres in the short-to-medium term.

3 Page 3 of 6 Bulletin Number: B13/085 60% ASPECT RATIO INFORMATION Groups Nb, Nc, Sa, Sb, Sc 65% ASPECT RATIO INFORMATION Group Na Make Model Make Model Avon CR6ZZ Avon CR6ZZ CR28 CR28 ACB9 Yokohama AO32R Bridgestone RE55S Hoosier Vintage TD RE11S Speedster Yokohama A032R, A021R Dunlop D83J A048 A050 CR48 (R6) CR65 Michelin TB15 R5 Hoosier Sports Car DOT (Bias) Pirelli P6 Vintage P600 Dunlop D84J, D93J DO1J DZ02G DZ03G CR65 CR82 CR311 Goodyear Blue Streak G12A(K) G12 American Racer Silverstone Toyo KK-704TM FTZ RR (T5 compound only) Proxes R888 Proxes RA1 Kuhmo V70A C03 V700

4 Page 4 of 6 Bulletin Number: B13/085 APPROVED TYRE LIST GROUPS Nb, Nc, Sa, Sb and Sc Make Model Size imperial Size metric Approved Rim Size in" American Racer M / /70x Pass Perf DOT 215/60D Pass Perf DOT 235/60D KK-704TM G / KK-704TM L / Pass Perf DOT 265/60D Pass Perf DOT 285/60D Pass Perf DOT 305/60D Avon CR6ZZ 165/70R /60R /60R /60R CR28 185/60R ACB9 5.0/ / / / Bridgestone RE11S 205/60R RE55S 205/60R Dunlop D01J 205/60R DZ03G 175/60R D84J 185/60R /60R D94J 165/70R CR65 450M M M M M M M M CR82 135/ / / / CR /530R

5 Page 5 of 6 Bulletin Number: B13/085 D93J CR48 (R6) DZ02G Goodyear G-12A Blue Streak G G G G G-15A 26.5x G-15A 26.5x Hoosier x x /60R Sports Car DOT /60D Bias /60D /60D /60D /60D /60D Vintage & Hist. TD / (stiff sidewall) A Kumho V70A 175/60HR V700 C03 Michelin TB15 16/ /60R / /65R Silverstone FTZRR (T5 comp. only) 205/60R Toyo Proxes RA1 Proxes R /60R Yokohama A021R 185/60R A032R 165/70R /60R A /60R /60R /60R A /60R /60R

6 Page 6 of 6 Bulletin Number: B13/085 END