Startline confusion at Reims appears to have been a regular occurrence. In the 1956 GP there was confusion about whether Fangio or Collins was on pole, and which side of the track they started from.
This earlier thread is mainly concerned with the 1956 confusion, but does discuss the 1957 race as well. Here are two of the most relevant posts, from Tony Kaye and Roger Clark:
Not convinced by the startline snafu theory? Well, try this.............
The following year the French Grand Prix was transferred to Rouen, but a full-blown Formula 1 race was still held at Reims. This is what happened.
Fangio, as was his custom, set fastest lap in practice, 2'23.3", exactly the same time as he had recorded in the Lancia-Ferrari in 1956. This of course placed him in pole position on the pits side of the track. I checked Sheldon's black book just to make sure. Again, as in 1956, one of his team mates, Behra, made third fastest time, which put him on the left side next to the grandstands. Again I confirmed with Sheldon. What happened next was pure farce, which was well described in Denis Jenkinson's eyewitness report.
While the (starting) flag was up some of the back row were being push-started and Brabham arrived in the Cooper minus his crash hat, but with the engine running, and he joined on the back of the grid. The starter was reaching the last few seconds when the rotund Monsieur Roche, the chief organizer, realised the cars at the back were being push-started and having a yellow flag in his hand he waved to them to desist. Unfortunately he was standing in the middle of the track about ten yards ahead of row 1, and seeing a flag twitch everyone let in the clutch and roared away. Monsieur Roche ran for his life, BEING MISSED NARROWLY BY BEHRA'S MASERATI and the bewildered starter dropped the flag long after the front row had passed him.
Behra had to back off and was passed by several cars before he could get away. In fact he was lucky not to have been hit from the rear.
Now, why was Behra the victim of this coq 'up, as the French would say. Surely the most likely candidates would have been Fangio on the right or Lewis-Evans in the middle of the front row. Not so, because this was exactly the kind of catastrophe that Fangio had feared in 1956 and it was the same premonition that led him to change places on the grid with Behra in 1957. Yes, he did it two years running, first with Collins, then with Behra. Sheldon's grid is wrong. Once again, Fangio the pole man, started from the left and Behra from the right. How can I be sure? Well I have a fine videotape of the race (thanks Speedvision) and there is absolutely no doubt that Behra was on the pits side and Fangio by the grandstands. The video shows the shambles at the start and the commentary even mentions Behra's problems. It couldn't be clearer.
We are dealing here with facts. Two years running Fangio should have been on pole, but in both years he exchanged positions with a team mate who happened to have third best practice time. That's too much to be a co-incidence. And Behra's predicament just proved the wisdom of Fangio, who wasn't just fast, he was race-savvy. He had probably seen the possibility of such a situation in his earlier races at Reims and was just lucky that he had team mates who made third best time. Incidentally this also may explain why in 1956 he exchanged places with Collins, well out of the way on the far side, rather than with Castellotti in the middle.
Felix, I rest my case.
We seem to have three theories:
1) that Fangio chose to start on the left because he thought he could make a faster start from there, either bacause the road was less slippery or because he would be ligned up better for the first corner.
2) that he chose to start on the left to avoid the starter (Faroux in 56, roche in 57)
3) that his fastest lap time was disallowed in both 56 and 57 because of a change of cars.
Regrarding theories 1) and 2), I cannoit understand why nobody else chose to do the same in later years. Fangio's racing knowledge may have been enough to give him the idea, but other drivers and team managers would surely have realised what was going on. Why did nobody do the same in later years?
The start at Reims was well back from the corner, before the start of the pit area, so it is unlikely that the line for the first corner would be relevant.
Regarding theory 3) we already have some information on 1956. In 1957, Fangio set fastest lap in all three practice sessions. On Wednesday and Thursday he drove one of the cars raced at rouen, probably Menditeguy's. On Friday, three more Maseratis arrived at Reims, one of the 1956 Monza offset cars, and two V12s. Fangio drove the Monza car in Friday practice and in the race. Friday was his slowest day of the three, slower than Lewis-Evans best time. The difficulty with this threory is that Behra would appear to have started from pole, yet as far as I can see, Lewis Evans was faster than him in every practice session. The theory is only plausible if Berhra raced the car Fangio drove on Wednesday and Thursday and if the Argentinians practice time gave Behra pole.
However, we do know of other instances where practice times at Reims related to the car, not the driver.
It seems to me that we might as well put this to the vote...