12 replies to this topic

[DeadSquare]

I wonder how may sets of tyres the French team needed for the 24 hours.

[RichMPiBlue]

I wonder how may sets of tyres the French team needed for the 24 hours.

 

This is what the stratosphere of "ai" says on a quick search;

 

"The 1966 Mini Marcos at Le Mans needed at least 16 tires, which includes four for the race and 12 for spares. The car was noted to have used two sets of magnesium wheels for the 24-hour race, and a full set of tires would have been needed for each wheel plus several spares to cover punctures and other issues during the event. 

 

Race tires: A full set of four tires is needed to race, and since the 1966 Mini Marcos had two sets of wheels, it would have needed a second set of tires for backup during the event.

 

Spare tires: It's standard practice in endurance racing to have a sufficient number of spare tires available for potential punctures. A common setup for a 24-hour race involves carrying several spares, bringing the total number of tires to a minimum of 16."

[DeadSquare]

Thank you.  Good find.

 

Presumably, to be prudent, in case it was wet, that could be doubled.

[RichMPiBlue]

Presumably, to be prudent, in case it was wet, that could be doubled.

 

Easily I would say. 

[RichMPiBlue]

While on subject, and not knowing much about the history of the Marcos' at the '66 Le Mans, this archive footage is good to watch. 

 

[DeadSquare]

While on subject, and not knowing much about the history of the Marcos' at the '66 Le Mans, this archive footage is good to watch. 

 

Thanks again.  Some shots there of it raining, so they did need 'wets'.

[PoolGuy]

 

While on subject, and not knowing much about the history of the Marcos' at the '66 Le Mans, this archive footage is good to watch. 

 

Thanks again.  Some shots there of it raining, so they did need 'wets'.

 

Were wet and dry tyres different in '66? 

[DeadSquare]

The early 60s Dunlop R7 was replaced with the Cross-ply Racing CR65 in 1965.  They introduced a softer 'High Hysteresis' Compound, developed by or with Avon, which had magically more grip in the wet, and they altered the angle of the ply in the carcase, so that a deflated tyre actual had a concave tread that became flat when inflated.

 

Now you are testing my memory. 

 

The softer compound wore more quickly, especially in the heat of summer, which didn't help the cost of Club Racing, and I think it was in 66 that they introduced the same carcase with a slick tread that was definitely better in the dry.  It looked as though someone had stuck the tip of a Phillips screwdriver into it, all round, as a gauge to judge tyre wear.  I can't be certain, it might have been 67, Firestone definitely had a wide Dry tyre in 68.

 

In the rain, I used to race on Avon Weathermaster tyres, which had a deep wavy winter tread.  I borrowed a Hot-iron that recuts the tread in lorry tyres, and modified the edge of the tread to let more water out.

[DeadSquare]

It has just come to me.  The dry tyre was called CR70, but I know that I was racing on them long before 1970.

[PoolGuy]

It has just come to me.  The dry tyre was called CR70, but I know that I was racing on them long before 1970.

Ah of course, the current Mini Se7en tyre. I think they use the CR65 as their wet.

[r.tec]

 evolut10.jpg   50.03K   1 downloads

[r.tec]

 I can't be certain, it might have been 67, Firestone definitely had a wide Dry tyre in 68.

If I may quote a part of the Marshall/Frazer-book:

 

"At about this time (When Dunlop brought out their CR70) the Firestone company produced their Mini racing tyre, the Super Sports Indy, a 600x19.3x10 tyre in 118 compound, which proved very successful both on the 1300 racers and on smaller-engined models.
.
.
Firestone at this time (1972) brought out their new Mini tyre, the Super Sports GP, slightly wider than the 6.5x13.3x10 but now moulded in IB19 rubber although some were produced in IB24."

 

 Firestone Indy.jpg   29.17K   0 downloads Firestone Indy tread pattern

Edited by r.tec, 24 November 2025 - 06:35 AM.

[DeadSquare]

@  r.tec.   Thank you for the pics and info.

 

It is good to find that the memory still works.  Just a shame that I can't remember what the wife asked me to go to the kitchen and get. Lol.