Jump to content


Photo

Direction of rotation of F1 tyres in the 70's


  • Please log in to reply
11 replies to this topic

#1 Spa65

Spa65
  • Member

  • 88 posts
  • Joined: January 12

Posted 23 October 2014 - 23:08

It was July 1971 and I was heading home up the M1 from London in my very first car - a classic maroon and white Ford Anglia 105E rustbucket. It was a few days before practice started for the GP at Siverstone and I decided to look in to see if there was anything going on. There was.

 

No problems walking straight into the paddock and up the stairs to the top of the pits. Graham Hill was down below with the white lobster claw Brabham. He seemed sullen, barely able to raise a smile even when the famous Amateur Photographer photographer, (whose name now escapes me) lined him up for some pictures with scantilly clad young models. I wondered then if he was a Jeckyll and Hyde character as he seemed so different from the guy I had heard being so funny on numerous occasions. I suspect that Rodriguez's death in a sports car in Germany a few days before had caused his mood. There was obviously some sort of filming going on. I can't remember seeing the camera on Hill's car, but I was very surprised to hear an audio tape of high pitched racing engine revving and gear changing coming from a box on the car as it sat with engine off - that must have sounded very phony if used as the pretend background noise for the footage being shot (wonder whatever happened to that film?)

 

Others I saw were Henri Pescarolo and Derek Bell. Numerous other less well known people as well.

 

But the thing that has kept me curious these last 43 years was Pescarolo's F1 March. This was the one that was half cigar, half hunchback, with a wierd cigar shaped wing on top of the rounded nose. The model of car that first revealed Petersen to the wider world at Monaco.

 

I examined the car in detail in the paddock - nobody looked at me twice. All four tyres had an engraving saying "Direction of Rotation" with a little arrow pointing the direction. However for every single tyre, the arrow was pointing the wrong way. I felt like pointing it out to some of those involved (though as I remember I was the only one anywhere near the car) but thought there must have been some good reason. After all, getting one tyre wrong might be a mistake, but getting all four wrong suggested some sort of logic, if not collusion.

 

The only sense I could make of it was if it mattered not a jot which way round the tyres went on (in which case why state a direction on the tyre?). The car would I guess have two pairs of matched tyres. So if the Front Left was put on the "wrong" way, then so inevitably would the Front Right. Similarly with the back pair. So there would be a 1 in 4 chance that they would all be pointing the wrong way, assuming the guy fitting the wheels gave not a jot and the wheels + tyres had all been "correct" before fitting to the car.

 

The great beauty of this forum is that there will be someone out there in cyber padddock land who will know the answer, or perhaps even better I might be disbelieved, and that always leads to some entertaining bitching. But I tell you I saw it with my own eyes.



Advertisement

#2 D-Type

D-Type
  • Member

  • 9,698 posts
  • Joined: February 03

Posted 24 October 2014 - 00:02

Photographer:  Vic Blackman?

 

Tyre question:  You've aroused my curiosity so I'm awaiting an answer from someone who knows.



#3 Spa65

Spa65
  • Member

  • 88 posts
  • Joined: January 12

Posted 24 October 2014 - 01:04

Photographer:  Vic Blackman?

 

Tyre question:  You've aroused my curiosity so I'm awaiting an answer from someone who knows.

Yes, I remember the Victor first name. Not 100% sure about the surname, but you're probably right.



#4 Lee Nicolle

Lee Nicolle
  • Member

  • 11,036 posts
  • Joined: July 08

Posted 24 October 2014 - 02:44

Directional race tyres usually have the case 'woven'  so they drive better one way. Many fit the drive arrows backwards as they reckon they brake better like that. I feel directional tyres have been around since the early 60s. I feel the first directional tyres were drag tyres. Late 60s speedway adopted 'drag bags' Those tyres you can watch wind up making the contact patch longer.

Though I have seen modern speedway tyres used the 'wrong' way with little difference. I tried road race Dunlops backwards once on the front. They did not feel as sharp, possibly braked better but in all were worse. 

Even some hi performance road tyres are made like this. Though most are purely directional tread. 



#5 Ray Bell

Ray Bell
  • Member

  • 79,953 posts
  • Joined: December 99

Posted 24 October 2014 - 04:57

A lot of people got the directional tyres instruction wrong...

They thought that the arrow on the rears should point to the rear, that sort of thing. Are you sure you haven't been confused in this way?

#6 Spa65

Spa65
  • Member

  • 88 posts
  • Joined: January 12

Posted 24 October 2014 - 08:54

Thanks Lee for your description. Perhaps Pescarolo was trying them backwards to see how that affected braking and handling. The bearded one was there, but I did not have the temerity to tender my observations to him or his accolades in my best Froggy.

 

Ray, I most definitely did not confuse either the words on the tyre (the exact description I have forgotten over the years, but it was unambiguous). I spent a lot of time pondering whether the words should be read while at the bottom of the wheel, or at the top. I also considered the effect of switching the tyres from one side to the other. I probably considered also how the logic would stack up if the Fronts were fitted to the Rear and vice versa. I guess that would only have accentuated the hunchback appearance of this oddball car.

 

However I looked at it, they were not fitted according to the rotational guidelines on the tyre.



#7 2F-001

2F-001
  • Member

  • 4,237 posts
  • Joined: November 01

Posted 24 October 2014 - 09:21

Just to confuse matters further, some tyres are marked with 'direction' arrows (be that a matter of carcass or tread-pattern), whilst some have an arrow marked 'drive' - for which they are mounted with regard to which direction is reckoned to impart the most force on the carcass under load. Thus, at the front, braking, and thus the arrows point 'backwards'; at the rear, acceleration, and thus the arrows point 'forwards'. Or it could be other way round if you regard the arrow as the direction of force rather than the rotation of the tyre… Clear as mud, you see…

Using, for example, ACB10s, I've know Avon to recommend you ignore any arrows or directional indicators and mount them with the serial number on a particular side of the car (different front and rear) depending whether fwd or rwd.

Pleased to add some clarity here… 'not'.

Some years back I had some Yokohama A008Rs; they were not only 'directional' but 'handed' (the tread was asymmetric, being increasingly slick towards the outer edges). Thus there were two different moulds for each size. At least they might have been interchangeable front-to-rear… had I not had different sizes front and rear. (I did not find this a particularly practical proposition for a road-legal car, but they were very soft and didn't last long anyway.)

Edited by 2F-001, 24 October 2014 - 09:28.


#8 byrkus

byrkus
  • Member

  • 1,011 posts
  • Joined: October 01

Posted 24 October 2014 - 09:26

Fast forward to last year, after the British GP, with all those tyres blowing around.

 

 


...the Fédération Internationale de l'Automobile (FIA) banned the practice of swapping the left- and right-side tyres around on the cars, which teams had discovered increased the life expectancy of each tyre.

 

 

source

 

Perhaps they just re-discovered something, that was already known four decades before...?

 



#9 Concreteconrods

Concreteconrods
  • New Member

  • 29 posts
  • Joined: August 10

Posted 24 October 2014 - 09:30

Victor Blackman was a staff photographer with the Daily Express and also a columnist in Amateur Photographer magazine. Best known for a photo shoot of Graham Hill racing against Lester Piggott in formula Fords at Brands!



#10 JtP2

JtP2
  • Member

  • 452 posts
  • Joined: December 13

Posted 24 October 2014 - 09:47

The theory given out to the lesser mortals was that the direction of rotation was decided by the way the tread rubber was applied on Goodyears.The join flap on the tread rubber was supposed to be such tat the edge would not be lifted by the rotation. Firestones never seemed to have this instruction. Never seen a tread join mark on a Firestone of the era, but have on a Goodyear. There again, never had to run a tape round a Firestone and match tyres for circumference either.



#11 Cirrus

Cirrus
  • Member

  • 1,753 posts
  • Joined: February 03

Posted 24 October 2014 - 13:58

1971 was the first year of slicks in F1 and many cars were suffering from tyre vibrations in the early days. Maybe the reversing of rotation was an experiment to see if the vibration was reduced?



#12 Lee Nicolle

Lee Nicolle
  • Member

  • 11,036 posts
  • Joined: July 08

Posted 24 October 2014 - 21:27

To answer the original question. I suspect that to roll the car in the truck and around the paddock area they really did not care which way the tyres were on. They may well have been old tyres used to transport anyway. Even in those days I am sure the new tyres went on immediatly before qualifying and not before.

I have done that myself plenty of times. You only worry about the drive arrows when you are due out on the track. I once had some query me about my tyres, wets being on backwards. The same deal, used while transporting the car.