Which slicks?

[AntA35]

I need to put some slicks on my Gp1 Dolomite Sprint for racing in the JD Classics series this season, yet I have never used slicks before and I haven't a clue which brand, which compound and type that I should be looking at.

The regs don't subscribe us to use any particular tyre, however one would assume I should be looking for a radial slick of a medium to harder compound for use in endurance racing that would suit the car.

Any suggestions, or does anyone have any experience of trying different types/brands/compounds?

[Mike Bell]

Originally Posted by AntA35

I need to put some slicks on my Gp1 Dolomite Sprint for racing in the JD Classics series this season, yet I have never used slicks before and I haven't a clue which brand, which compound and type that I should be looking at.

The regs don't subscribe us to use any particular tyre, however one would assume I should be looking for a radial slick of a medium to harder compound for use in endurance racing that would suit the car.

Any suggestions, or does anyone have any experience of trying different types/brands/compounds?

I would ring BMTR and speak to Peter in their Motorsport dept. They are UK Avon suppliers and should be able to advise what is available, which is more important these days than what you actually want. They also service a lot of the race meetings, which is very handy. Most historic touring car series require crossply slicks, so would be nervous about fitting radial in case not acceptable at some point. Dunlop also supply, btw.

[AntA35]

Thanks Mike, I will be sure to give them a call. As for the regs on cross ply or radial, it just seems to say tyres according to App K.

App K says:

"Unless otherwise specified in Appendix K and within the limits of availability and practicality, the width, external diameter, general appearance and tread pattern of tyres must be consistent with those fitted to the car or similar cars during the relevant period. All relevant regulations in respect of bodywork and rims must be respected and competitors are responsible for ensuring that the tyres chosen are compatible with the rims used."

Furthemore specific to the period:

8.2.5: Periods H1 and HR onwards may use slicks and wet tyres. T, CT, GT, GTS and GTP cars may also use tyres marked with «E» or «DOT» approval in accordance with the appropriate standard of the country in which the competition is taking place with a minimum external diameter as set out in Article 8.4.2.

The period in question is Period I, through to the end of 1981. The question I guess becomes, were crossplys or radials used in Period? Or maybe both?

[SAMD]

I 'think' (although I do stand to be corrected) that radial slicks are a fairly recent fenomynone.

[phoenix]

Originally Posted by SAMD

I 'think' (although I do stand to be corrected) that radial slicks are a fairly recent fenomynone.

I believe the phenomenon that is the radial racing tyre dates back to the 70s when Pirelli introduced the P7 - first as a treaded road tyre and then as a competition tyre in slick and treaded patterns. Lancia certainly used them for Group 4 rallying/racing (Stratos) in the mid 70s, Group 6 racing later in the 70s and Group 5 in the early 80s. I think Porsche used them too for the first Turbo race cars.

[Mike Bell]

Looking back at the thread discussing JD Classic series, the date radial slicks were introduced into racing was questioned. Peter M thought they were used in F1 from early 80s. It may be worth asking scrutineer John Hopwood via MRL for clarification, but my 'gut' feeling is that for touring cars the requirement for period profile, appearance and width will mean crossplies. Always happy to be proved wrong though....

[FastDB2s]

Originally Posted by phoenix

I believe the phenomenon that is the radial racing tyre dates back to the 70s when Pirelli introduced the P7 - first as a treaded road tyre and then as a competition tyre in slick and treaded patterns. Lancia certainly used them for Group 4 rallying/racing (Stratos) in the mid 70s, Group 6 racing later in the 70s and Group 5 in the early 80s. I think Porsche used them too for the first Turbo race cars.

The 1st possible use of radial tyres is some 20 years before in the 1950s, Dunlop Duraband tyres were tested & raced ?? on the works D Type.

[phoenix]

Originally Posted by phoenix

I believe the phenomenon that is the radial racing tyre dates back to the 70s when Pirelli introduced the P7 - first as a treaded road tyre and then as a competition tyre in slick and treaded patterns. Lancia certainly used them for Group 4 rallying/racing (Stratos) in the mid 70s, Group 6 racing later in the 70s and Group 5 in the early 80s. I think Porsche used them too for the first Turbo race cars.

Correction to the above, Renault raced on Michelin radials, including slicks, in sports prototype racing - including Le Mans - as early as 1974.