giraurd wrote:Pitstops of some sort were there since the start of racing due to the cars' fragility and the need to fix them once ina while. Even the "modern" style pre planned refueling/tyre change strategies were common in the 1930's already.
That is certainly true, as reflected by the development of the "knock off" wheel fixings in the 1950's and 1960's that allowed for quicker tyre changes.
That said, although pit stops were not uncommon in that era, it is not something that you would have wanted to undertake multiple times in a race given that stops were relatively slow. For example, in the 1951 British GP, the deciding factor in that race was the fact that Alfa Romeo had to stop twice to refuel in that race (the engines were producing a prodigious amount of power for that era, but at the expense of extremely high fuel consumption), whereas Ferrari could get away with just one stop. Refuelling was undertaken in later years, but was something teams tried to avoid where possible given that it was comparatively slow, laborious and dangerous work.
One example from the 1970's would be the 1974 Spanish GP, where drivers pitted to change from wet tyres to slicks midway during the race - it took around 35 seconds for Ferrari to get Lauda in and out of the pits on new tyres, although that was a comparatively fast stop for the time.
That race was also famous for the spectacularly farcical pit stops that Lotus made, which I think is worth recounting to show how badly pit stops could go in that era.
When Peterson came in for his stop, one of the mechanics tried to jack the front of his car up, only for the jack to break and for the mechanic to fall over onto his back. A junior mechanic, thinking that the neighbouring Surtees team weren't paying attention to one of their jacks, promptly grabbed it and ran back with it to the Lotus pits - however, Surtees's chief mechanic noticed this and ran over to grab it back.
Upon reaching the pits, he promptly tried to yank the jack out from underneath the car - however, not realising that the car was still being supported on the jack, the car promptly fell off the jack and pinned it underneath it, leading to the two mechanics shouting at each other as they argued how to lift the car off it.
By this point in time, Ickx was now in the pits and lining up behind Peterson's stuck car, and angrily revving the engine to get the attention of the mechanics. Borrowing jacks from other teams, the mechanics managed to get Ickx's car off the ground and changed the wheels - however, the rear jack man dropped the car to the ground before the rear left jack man had finished tightening up the new rear tyre.
Thinking that was the sign for him to go, Ickx naturally dumped the clutch and floored it - unfortunately, the mechanic at the rear still had his wrench attached to the rear wheel and was still holding onto it. Now, to speed up the tyre changes, the wrench had a very long lever arm to help the mechanics undo the wheel nuts - that, coupled with several hundred horsepower from the engine, ended up throwing the poor mechanic a reportedly quite impressive distance down the pit lane before striking the ground and damaging the rear axle, probably contributing to Ickx's retirement a few laps later.
To add insult to injury, one of the mechanics had tried to switch off the engine in Peterson's car to prevent it from overheating (having been sat still for several minutes by now). Unfortunately, in the midst of this confusion, he accidentally flicked the switch for the fire extinguisher system instead, which promptly discharged its contents into the engine intake (hence why he is listed as having retired due to engine problems)...
With regards to making multiple tyre changes per race, I would say that effectively came in during the 1980's as Brabham developed the air gun technology that made it possible to speed up changes. That started to drive teams towards changing tyres more frequently and also meant that the tyre manufacturers could put more emphasis on outright performance at the expense of higher wear rates, whereas beforehand wear rates were more of an issue.
