We really had an excellent discussion about race car gearboxes with @RyanLewisRacing and specifically ones that are pneumatically operated and rely on air pressure to shift. https://twitter.com/RacingSpaces/status/1387227276308369416

For those that might not be familiar, many sequential racing gearboxes use a pneumatic system to change gears. This basically means that there is an air compressor that builds air pressure which is sent to a gearchange unit to mechanically change a gear once a paddle is pressed.

The unit pictured above is the P1254 IVA gearchange unit from @xtraclimited. It can be found on a variety of gearbox applications and as you can see in the image there is a pnemuatic line that is the input and a mechanical shaft that is the output.

https://www.xtrac.com/product/p1254-integrated-valve-actuator-iva-gearchange-unit/

Here is that P1254 unit in my hand for scale. In this picture it was pulled from an Xtrac gearbox that was in use on a Hyundai Veloster TCR but it can be applied to a variety of racing cars including GT cars and even sigle seaters. https://twitter.com/BoziTatarevic/status/1298681000248172544?s=20

These are often fed air from a compressor like this unit from Megaline.

https://www.mega-line.de/megaline/downloads/datasheets/0__470_111_011a__11489_Compressor_GT_uC_470_111_011a.pdf

There are variety of gearchange units and compressors depending on the application so the pieces might look different on something like an IndyCar versus a TCR or GT car.

IndyCar uses an Xtrac P1011 gearbox with some of its components pictured below.

https://www.xtrac.com/product/p1011-indycar-series-gearbox/

No matter the components employed, the basic idea is that a paddle or lever is pressed which tells a control unit to send air pressure to the gearchange unit mounted on the gearbox which then mechanically moves a gear selector inside it to change the gear.

With all of that knowledge, we can go back to what @RyanLewisRacing shared on @RacingSpaces last night on what a racing driver might experience while trying to shift gears or shift into reverse inside a race car and why it may not work.

His rough explanation last night is that a driver may attempt to shift into say reverse and not have it work on the first attempt so that driver may continue tapping the paddle in frustration which may bleed off the air pressure for the system mentioned above.

Once that air pressure is bled, the driver may have to wait for the compressor to run in order to build pressure and attempt the gear change again which can be a vicious cycle until the driver ends up in the correct gear.

So before you go criticizing from your couch about why a driver may have trouble getting a race car into gear, please take a moment to consider that there might be more at play than the shifter level that you're used to seeing in your automatic SUV.

An excellent point. https://twitter.com/AxelRipper/status/1387423842843365390?s=20