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Hi

First post so be gentle please. I'm picking up my new bike from my LBS which isn't actually very local, which means It's gonna have to go into the car. The bike will fit in but only lyiing down. Someone has said though that this might mess up the hydro brakes by letting air in. Any experts out there know whether it will be safe or not.


Many thanks

Dave

P.S it's a rockhopper with stock juicy 3's.
 

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No problem they are sealed

This was an issue with Magura Marta's of a few generations back, but your brakes are sealed and you could even do flips, if you wanted to 'get air' without compromising your brakes.

Cheers,

Kane
 

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Some brakes seem to be more prone to it than others.

I love the performance of my Marta's but they have gone a little soft over time from having the bike upside down or sideways from transporting in my car.

If you are at all concerned the tip I got from a buddy was to just put an elastic to pull in the lever around the bar while you travel with the bike. (Of course if a wheel is removed, make sure you have a spacer in between the brake pads).
 

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dont listen to the uninformed
shimano says no and allot of the other manufacturers are the same, they have vent holes in the master cylinder if you must lay the bike down for any length of time try to keep the handlebars higher than the calipers. if , after, the brakes are soft, wait a day or two and hopefully the air will work its way back into the master. if not you'll have to bleed the system
 

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dan0 said:
dont listen to the uninformed
shimano says no and allot of the other manufacturers are the same, they have vent holes in the master cylinder if you must lay the bike down for any length of time try to keep the handlebars higher than the calipers. if , after, the brakes are soft, wait a day or two and hopefully the air will work its way back into the master. if not you'll have to bleed the system
Like I said, poorly designed. Sad.
 

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Razorfish said:
Like I said, poorly designed. Sad.
not necessarily, when you move fluid from one area to another if there is no vent you create a vacuum, also with the extreme temps. you will get fluid expansion either way you need a vent and it needs to be at the master cylinder (high point) otherwise you will suck air into the system
 

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dan0 said:
not necessarily, when you move fluid from one area to another if there is no vent you create a vacuum, also with the extreme temps. you will get fluid expansion either way you need a vent and it needs to be at the master cylinder (high point) otherwise you will suck air into the system
Actually, yes necessarily. Just because it's an accepted limitation on bikes doesn't mean it's because it has to be like that. Hydraulic systems that work in negative Gs, or in a no-G environment (aka space) have been around forever. If you and bike designers think this is acceptable then fine, but laying a bike down for a while and then it becoming un-ridable as a result is lame. Would you accept tires going flat because you laid your bike on it's side for a few hours?
 

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Razorfish said:
Actually, yes necessarily. Just because it's an accepted limitation on bikes doesn't mean it's because it has to be like that. Hydraulic systems that work in negative Gs, or in a no-G environment (aka space) have been around forever. If you and bike designers think this is acceptable then fine, but laying a bike down for a while and then it becoming un-ridable as a result is lame. Would you accept tires going flat because you laid your bike on it's side for a few hours?
sure if money is no object and weight isnt an issue
did you know car, motorcycle and truck brakes have the same limitations, so what?
most things are designed with an intended purpose
as far as your flat tire analogy, ever try tubeless or for that matter even tubed tires lose air over time, according to you thats poor design?
bike brakes are designed to be used upright, if you lay your bike on its side for a few hours it propably wont matter, but leaving the master cylinder lower than the calipers will eventually induce air
but next time I want to ride my bike in space or in a negative G environment Ill give you a call and see what brakes you recommend:rolleyes:
 

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dan0 said:
sure if money is no object and weight isnt an issue
did you know car, motorcycle and truck brakes have the same limitations, so what?
most things are designed with an intended purpose
as far as your flat tire analogy, ever try tubeless or for that matter even tubed tires lose air over time, according to you thats poor design?
bike brakes are designed to be used upright, if you lay your bike on its side for a few hours it propably wont matter, but leaving the master cylinder lower than the calipers will eventually induce air
but next time I want to ride my bike in space or in a negative G environment Ill give you a call and see what brakes you recommend:rolleyes:
Whatever, dude.
 

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I transport my bike to the trail in a pickup. The bike is laid on its side with the calipers on top so technically my rear brake should be bled more often then the front because the master cylinder-lever is lower than the caliper when driven to the trail in my truck.

How often do hydraulic brakes need to be bled? And compared with other makes, how do Avid's reservoirs fair with preventing air from entering the MS when the caliper is level with or above the MS?
 

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A properly designed hydro will have a flexible bladder to allow for fluid expansion without leaving the system open to air. You do realize DOT fluid is extremely prone to moisture contamination? Therefore there should be no fluid/air interface anywhere in the system. It should be fully closed to the atmosphere.

If you need to bleed because of brake orientation that means there's a leak somewhere in your system or that you have air trapped in the resevoir (underneath the bladder). Either way you have some maintenance to do...

Shimano uses mineral oil which has no moisture problems. So maybe their master cylinders do leave themselves open to air leakage. Dumb idea if that's the case.
 

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Deme Moore said:
A properly designed hydro will have a flexible bladder to allow for fluid expansion without leaving the system open to air. You do realize DOT fluid is extremely prone to moisture contamination? Therefore there should be no fluid/air interface anywhere in the system. It should be fully closed to the atmosphere.

If you need to bleed because of brake orientation that means there's a leak somewhere in your system or that you have air trapped in the resevoir (underneath the bladder). Either way you have some maintenance to do...

Shimano uses mineral oil which has no moisture problems. So maybe their master cylinders do leave themselves open to air leakage. Dumb idea if that's the case.
from the shimano tech doc
• Be sure to use only oil from a freshly-opened container, and do not re-use oil which has been drained from thebleed nipple. Old oil or already-used oil may contain water which could cause vapor lock in the brake system.• Be careful not to let water or air bubbles to get into the brake system, otherwise vapor lock may occur. Be
particularly careful when removing the cover of the reservoir tank.
• Vapor lock may occur if the brakes are applied continuously. To relieve this condition, momentarily release the lever.
When turning the bicycle upside down or on its side the brake system may have some air bubbles inside the reservoir tank which are still there when the reservoir tank cover is replaced, or which accumulate in various parts of the brake system when it is used for long periods. The M755-DH disc brake system is not designed to be turned
upside down. If the bicycle is turned upside down or on its side, the air bubbles inside the reservoir tank may move in the direction of the calipers. If the bicycle is ridden in this condition, there is the danger that the brakes may not operate and a serious accident could occur.
If the bicycle has been turned upside down or on its side, be sure to operate the brake lever a few times to check
that the brakes operate normally before riding the bicycle.

as you can see mineral oil does have moisture absorbsion just as dot oil, and shimano brakes also have a bladder
the bottom line is again, do it at your own risk, its not recommended, doesnt matter how many people post and say they did it or do it, if you can avoid it , you should. even in a perfectly sealed system you can get air bubbles just from the fluid heating up, eventually they make their way up to the master cylinder, flipping the bike will allow those bubbles to migrate back into the system causing poor braking
 

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DanO, does this Shimano Tech. document apply to the new XT 775 brakes as well?

So a Fox fork owner must choose a brake that can be turned upside-down because Fox recommends storing the bike this way in order to keep the fork’s bushings lubed.
 

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bwalton said:
DanO, does this Shimano Tech. document apply to the new XT 775 brakes as well?

So a Fox fork owner must choose a brake that can be turned upside-down because Fox recommends storing the bike this way in order to keep the fork's bushings lubed.
every shimano doc Ive seen says the same,
I have the xtr 970 series and theyre the same, it depends on how much air has acumulated as to how long you can invert. I used to store my bike overnight upside down occasionally as per fox, untill my brakes got soft. I havent had any problems with my fork in several years of not inverting it, but i lube the stancions now and then
 
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