F1 insights: Which driver has to race the F1 test chassis and who gets a new one?

At JA on F1 we have always tried to help the fans get closer to the sport and from time to time that means channeling a question in a reader post to F1 team insiders to get an authentic answer.

We had just such a question this morning on the F1 testing analysis post from a reader called OffCourse.

While I know that an F1 car comes apart and goes back together on many occasions and of course all the parts won't be the same, especially the PU and gearbox after testing but do you know who in each team gets the test car chassis etc… or are they effectively retired and each driver gets everything new?

Answer: First of all nowadays it is not like a few years back when there were differences between chassis and drivers would try a couple over a season and find one better than the other (although we have seen examples of a team replacing a chassis for a driver during the year if things are not going well).

Composite production is much better controlled now with laser cut pre-preg sheets and detailed ply books describing the lay up of the composite material in huge detail. That being said there is often a small weight difference between chassis which you normally attribute to a little excess glue not being cleaned up here and there and the amount of filler and paint used in the final finish.

In terms of the chassis number then and the choice for the drivers – practicality tends to dictate things; for most teams in the recent years they tend to shake down two chassis in the two winter tests (or across filming day or full-car dyno and the first winter test).

There are several reasons for this – firstly the production happens in series so the second one often comes out once the program at the track or dyno for the first chassis has started.

Secondly if you have an upgrade package for the second test it makes sense for your factory to build the second car with those new bits so all of the pre-fit is done in the factory with all the right people, before you send it on to the track for the second test.

Thirdly it gives you a chance to ‘shake down’ both chassis :– nowadays the build is so precise that there aren’t many things that you would expect to go wrong – potentially a bracket here and there which mounts on a ‘bag surface’ rather than a mould surface (and the accuracy of positioning therefore isn’t quite as good so you would prefer to check everything fits) or a hole which has been missed out in production, etc, so nothing major but it pays to check before you get to the race.

In terms of who gets which chassis – it varies and it's common to have ‘pick a number from a hat’ scenarios as well as situations where one driver is heavier driver than the other so the team have given the very slightly lighter chassis to that driver.