Have just changed wheels & tyre setup and the new sizes aren't listed on the tyre pressure plate, so was wondering what's the general consensus on correct pressures? Tyres are 275x35x19 & 235x40x19 on a F32 430d M Sport Thanks in anticipation. Frank
Continental Data Book list those tyre sizes for a 4 series. They suggest 35psi front & 46psi rear. Sounds a tad high to me - but you have 'upsized' a fair bit.
Thanks, i'm obviously looking in the wrong place, couldn't find anything in those sizes for the F32 4 series. Sounds a tad high to me too, i'm currently on 35psi for all 4, but might look at upping the rears a couple of psi?
I would say these are too high sound more like run flat pressures - https://www.tyrerunner.com/find-tyre-pressure/bmw/4-series I would expect something like 38-40 rear, 32-34 front as a start
Just found this: https://tiresize.com/pressure-calculator/ which could be quite a handy tool, however, not sure i'm happy with the 31psi it suggests for both front and rear? I know with larger tyres the pressure is supposed to be lower, but for now i'm sticking with 34 front & 36 rear. The tyre/wheel specialist set them to 34 for all 4, so maybe they weren't far off the mark.
Somewhere about 32 or 33 all round seems about right for non run-flats; it’s the recommended pressure for an M4 when carrying no more than 2 people. If carrying 4 people add 1 or 2 psi to the front and 4 or 5 to the rear. I’m guessing those pressures (32psi) are for an ambient temperature of 20 degrees C. If you set those pressures at 20 C, they would drop by approximately 3 degrees at freezing, and rise by 3 degrees at 40 C. Similar proportions for 40psi - drop by 4 at freezing and rise by 4 at 40 C. Or to rephrase that, if you set them at 32psi one really cold morning, they will be too high later in the day. And of course, many owners don’t bother to check them until a warning light comes on, but I could almost guarantee they’ve never ridden a quick bike.
