Herzlos

I've regularly seen claims you can't hang a bike with hydraulic brakes or oil in the suspension, because the fluids will leak out or something.

Is there any merit to it? Should I try to keep the bikes stored horizontally or does it not make any difference?

Mtracer

I have experience with Shimano hydraulic brakes only. (105, GRX and Ultegra) It's a completely sealed system, it simply cannot matter how the bike is positioned if there is no air in the system. And I've positioned my vertically as well as laid them on their sides without any issues. Normally there should not be air in the system. If there is, then the position of the bike could allow for the air to move around and cause the brakes to behave differently.

With Shimano brakes, there is a reservoir, but it is sealed and there is a flexible diaphragm/bladder that will feed the system when it needs more fluid as the pads wear and the caliper pistons gradual move out. This increases the volume of the pressurized part of the system as needed due to pad wear.

When working on Shimano hydraulic brakes (and likely most others), you attach a cup to the shift lever that has fluid in it. It will be the highest point in the system. The reservoir is then open, though full of fluid. This is part of the bleeding process. The brakes will work in this setup. I think this is equivalent to how most cars are all the time (but might be wrong on that). But with bikes, you remove the bleed cup and screw in a plug that seals. There's simply no place for hydraulic fluid to leak out form.

Again, I can't say this applies to all bike hydraulic brake systems. But it would seem really odd to me that any bike would have an open system.

Bald Paul

I guess it all depends on who you ask!

PeteHski

Nothing is going to leak out. People sometimes talk about the potential for air bubbles to get into the brake hoses from the reservoir if you turn the bike upside down, but IME it has never been a problem hanging bikes vertically. I currently have several full suspension bikes stored vertically and there have been no issues.

mattcalifornia

I hang my bikes vertically - 2 with hydraulic brakes. My town/commuter bike has relatively cheap Avid hydraulic brakes. It's been hanging vertically for 6 years, and I've never had to bleed or adjust the brakes (granted, the bike has extremely low mileage) -- the brakes still feel solid and brand new. My gravel bike has SRAM Rival brakes. They are always a problem. They have week stopping power and have been bled numerous times, both by me and professional mechanics. Nothing seems to help. No idea if it is related to hanging the bike, but I doubt it. I just replaced the calipers with Hope RX4+ 4-piston calipers and replaced all the fluid and checked for leaks. Hopefully, this will solve the problem. Not sure if this is helpful to you or not other than to tell you that I hang my bikes vertically regardless of its effect on the brakes because that's all I have room for in my garage.

rsbob 

Both of my hydraulic bikes (Shimano) have hung upside down for years and NEVER had an issue.

Kapusta

Brakes: the only issue there would be if there was already air in the lever reservoir, it could possibly work its way down to the caliper where it might have a harder time working its way back to the reservoir. But I think this rather unlikely.

The only way I can see the brake fluid leaking is if the reservoir cap was leaking, which would be rare, and you would have likely already seen it happen at some point. If you turn the bike upside down and see this happening, you need to fix this regardless of whether you store the bike upside down.

Suspension? Definitely OK. Its actually good for forks to set them upside down to get more oil into the upper bushings if a bike has been sitting for a while. As far as leaking, if your seals are so bad that they can’t hold in oil against gravity, you would have already been noticeably leaking oil from normal use. Rear shocks are made to run in all directions: piston up, down, front, back… its all OK.

Maelochs

From what I have heard, even if you have a few bubbles in the line or somewhere, several good pulls on the brakes will get the air back into solution.

Iride01 

Old myths are hard to kill. Maybe some of the very early hydraulic brake systems had an issue. (see, I might be furthering the myth!)

And of course those systems that aren't in good maintenance and already compromised, the owner might think and claim that as the reason for their issues.

RB1-luvr

for 15+ years I've had an mtb hanging by the front wheel. It rarely gets ridden. The hydraulic disc brakes (Shimano) work as they should.

jaxgtr

My bikes hang vertically, never had an issue with them. Hung up upside down for a couple of years, never had any issues.

Camilo

Ditto Sram

Maelochs

So the definitive answer is, "There is no definitive answer, but a wealth of anecdotal information."

MoAlpha

I don’t hang my bikes, but I am careful not to leave an air head in the reservoirs when I service the brakes.

Troul 

[QUOTE=Mtracer;22963211]I think this is equivalent to how most cars are all the time (but might be wrong on that). [QUOTE]
If I'm understanding your reply correctly;
no, a typical traditional hydraulic automobiles brake reservoir will have a min & max level with unused volume capacity within the reservoir.

themp

I have Hope brakes on an older mountain bicycle and hanging the bicycle by the rear wheel will cause air to enter the system and I would have spongy brakes. I switched to hanging from the front wheel and have not had the problem since.

msu2001la

I hang bikes with hydro brakes vertically and have never had problems.
My shop hangs bikes with hydro brakes upside down horizontally. I asked the owner once as he was pulling my bike down after some service, and he laughed and suggested that this was an urban legend.

Maelochs

Whenever I do anything to my bikes there is an airhead in the system ... I mostly hope I don't break anything or hurt myself, and sometimes my bikes get fixed.

I do not hang myself either right side up nor upside down.

unterhausen

I haven't looked at brake master cylinders in cars for years, but the ones I have seen could potentially have problems if you suspended the car from a hook.

The way I understand bike hydraulic brakes, it shouldn't matter. There are so many garbage sites on the web covering bikes that it's difficult to find one that is authoritative. That "Diy mountain bike" site looks to me like one that shouldn't be trusted.

seypat

I don't know if there's anything definitive, it's more like a fluid answer.

Troul 

nothings really stopping any air from being in the system if the bleed job wasn't dont right or a seal is rolled.

MarcusT

Would it be any different than laying the bike flat when it is transported/stored in a car? Then I can say no, it has no effect