Bicycle Mechanics - Bike storage with hydraulic brakes: Right side up or upside down?

When I bought my bike with hydraulic disc brakes my local bike shop said don't turn the bike upside down because air can get in the brake lines and cause spongy brakes. A friend of mine stores his bike upside down in his garage and his LBS said it wouldn't harm anything. I posting this question to get the mighty Bike Forum gurus opinions on this. I personally hang mine from the garage ceiling right side up on a homemade rig

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When I bought my bike with hydraulic disc brakes my local bike shop said don't turn the bike upside down because air can get in the brake lines and cause spongy brakes. A friend of mine stores his bike upside down in his garage and his LBS said it wouldn't harm anything. I posting this question to get the mighty Bike Forum gurus opinions on this. I personally hang mine from the garage ceiling right side up on a homemade rig

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I think it depends on the brakes. I have XTR's and am always flipping the bike upside down for cleaning/adjusting/changing tires etc
and have never had a problem. I read some reviews on some high end Avids (Sram XX I believe, that were on sale on chainlove) that seemed to need to be bled
everytime they turned upside down. I guess you would have to try and see if yours have an issue.

I've been told that the only reason you get air in the brake lines when you flip over the bike is because the person filling them up didn't do a good job bleeding them in the first place.

If air was to get into the brake lines, it would have to replace brake fluid, which means you'll see brake fluid leaking from the bike.

If air was to get into the brake lines, it would have to replace brake fluid, which means you'll see brake fluid leaking from the bike.
Not necessarily. I think all bicycle hydraulic systems are sealed off from the atmosphere (the ones I've seen are, at any rate). This doesn't mean the reservoir has no air in it, though I doubt very much whether it would enter the master cylinder if the bike is upside down. I simply cannot believe the brake manufacturer didn't plan for bikes being shipped, flipped or dropped.

Don't take my word for it, or the LBS either. The best info regarding whether you can hang the bike upside down will come from the brake manufacturer.

The best info regarding whether you can hang the bike upside down will come from the brake manufacturer.
Call them, or send an email, then post the answer. Until then, I'd keep it wheels down.

aFAIK,
The expansion reservoir has a bladder to let the fluid expand
as the disc friction heats it.

If it's got leaks air can get past the bladder.

Magura's Rim-brake is a closed system , the heat goes elsewhere than the fluid.