I want to store my SRAM AXS road bike upside down in the shed. I remember reading cautions about doing this do to air entering the system. Is this a real risk assuming everything in the brake system is properly sealed and functioning? I use the bike 3-4 day/week so it’s not upside for long periods.
THanks
Generally not advised because any air bubbles that may be in the system will rise to the top. This is less of a problem when the “top” is the reservoir in the shifter, but if the bike is upside down, the air bubbles can rise up to the brake caliper where they will greatly impact your braking. This just happened to a friend just a few weeks ago where his brakes were fine, and he inverted his bike to change tires (too lazy to put it on his bike stand). He left it like that for couple of days and when we went to ride on the 3rd day, he had no front brake.
Another friend hung his bike upside down for the winter and had no front brake in the spring.
And if someone tells you that you can get the front brake back by continuing to pump the lever, it’s definitely not something you can rely on. In both of the cases above, the brakes never came back until they were bled.
If your brakes are bled properly it won’t matter at all, as it’s a closed system. If they’re not bled properly or are overdue for routine service, this will be a good way to find out (test them in your driveway, not on a descent or in traffic!) It’s generally a good idea to bleed brakes once or twice per year to flush out contaminants and air bubbles anyway. You’ll thank yourself for the improved feel and function