I don’t know what the measurements are but recall three scenarios. (FYI, I have installed maybe 100 or so tires, so while no expert, I’m not totally clueless either.)

1) I got a BBS RS lip that appeared to have a presta sized valve stem hole in it, like you’d see on a higher end bicycle or a road bike. My $700 mountain bike has presta valves. You have to unscrew a bit before putting air in or taking it out. I think I traded or sold this pair of BBS RS lips, but always assumed I was going to have to drill the holes bigger to use standard valve stems.

2) standard Schrader valves are what we normally have on our cars, and my BBS RS and most early bundt wheels see to use metal re-usable valve stems which I like a lot. You can tighten them down and loose the them up just like a TPMS valve stem, and you don’t have to cut them out the way you have to with rubber valve stems. I’ve got a massive bag or two of these rubber ones I bought and left at rwd4evr ‘s shop because he lets me use his tire machine. (I buy wheel weights too.)

3) I bought a cheap “scrappin’ trailer” that has mobile home style axles and 14.5” tires/wheels. I bought new wheels (really just hoops that the big 5-star hub crudely attaches to) and tires for it, and discovered that the valve stem holes are LARGER than standard schrader valve stems that every car rim seems to use. I think they might have been 1/2” or even larger. These wheels need to be run at 80-90 PSI and they DO NOT have the hump for the bead seal. The dry old tires I had for these kept popping off the “bead” because they would leak and have nothing to hold them in place. I can’t tell you how many times I put bead sealer on them and sprayed starting fluid into them and then tried to get air compressor air in them while batting out flames to try and get these damn tires back on the rims with no bead seat. I really wanted to install tubes in these, and will consider it if I ever have to use those old tires again. Anyway, I bought special fat-neck rubber valve stems for those mobile home rims.

Aside from the BBS hoop mentioned above in 1, I’ve never seen a presta-sized valve stem used on a car. I believe they do exist though.

__________________
Past mb: '73 450sl, '81 280slc stick, '71 250, '72 250c, '70 250c, '79 280sl, '73 450sl, parted: '75 240d stick, '69 280s, '73 450slc, '72 450sl,