Mountain Biking - Upside down or not?

My friend told me that a bike with hydraulic brakes or oil filled forks should not be hung upside down. But when I go to bike shops, so many of these bikes are hanging upside down. So does this really not matter?

hmm, I hang mine from the rear wheel, maybe thats why there was almost no oil in my fork(headshock) when I had it serviced! Although there were no apparent leaks either.

It'll only leak from the fork if you have bad seals. Maybe hangin it upside down could let air into the brakelines though. That depends what brakes your using I suppose.

My air sprung/oil damped fork seems to hold air better when stored upside down. I think the air valves benefit from being submerged in oil. Fox actually reccomends storing their forks upside down, as it helps the oil reach all the upper parts of the fork.

Hydraulic brakes will depend on the design. A closed system can be hung any way without worry of the introduction of air. Open systems might need more special care. There is no general rule, you'll have to see what the manufacturer reccomends.

Magura also reccommends hanging their forks upside down to circulate the shock oil (note I don't know whether this is for all models, so check your manual). Turning hydraulic brakes upside down can cause air bubbles to collect in the hose and caliper (not good), rather than in the reservoir (pretty harmless). However pumping the brakes a bit and giving the hose and caliper a bit of a shake usually sorts it out in a couple of minutes. I wouldn't reccommend riding a bike that had been upside without sorting the brakes first.

So does this really not matter?


No it doesn't matter

Your friend has outdated information. 99% of the new forks are fine. Pre-2000 and a lot of them could not be hung upside down

I was doing a little searching and on Park Tools website I found this

Hydraulic systems should be inspected at all fittings and hose connections for fluid leakage and seepage. Additionally, the bike should not be stored or turned upside down, as air may enter the brake lines. If the bike has been upside down, allow it to sit several minutes before use, and test the levers by pulling with force.
http://www.parktool.com/repair/readhowto.asp?id=126

All of my bikes hang upside down, and neither the SC (hydraulic discs and fully sprung) nor the Trek (fork only) have had any problems.

what it is, is that if there is any air in the brake cables, it will go into the caliper, which is not kosher.

Additionally, the bike should not be stored or turned upside down, as air may enter the brake lines.

How, in a closed system, would air enter the brake lines??? If there was a way for air to get into the system, then would there not be a way for oil/hydraulic fluid to leak out of the system???

I say hogwash...

By the way, I store my bike hanging from the ceiling by the front wheel in my garage.