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Discussion Starter · #1 ·
trying to figure out the best way to bring my fat bike on our family camping excursions. Not a fan of the tailgate pad (ok for my kids bikes, but the fat bike doesn't sit well on it. We have a kayak door with some storage in the back of the TT, but the bike is so damn long it's not totally feasible. I thought of taking the front wheel off and flipping it upside down. I have tie downs to stop it from tipping. Any other reason I'm no thinking of that could harm the bike?
 

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why upside down?

it's going to be sitting on the levers. depending on how they're adjusted, maybe even on the master cylinders of the brakes. why would you want to do that to beat up on stuff? Why aren't you considering attaching a fork mount to a piece of wood, and then using your straps to keep the bike in place?
 

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I've always been under the impression that inverting a bike with hydraulic disk brakes risks introducing any air bubbles trapped in the reservoir into the master cylinder and hence into the brake circuit. Granted, it is merely a risk in normal inversions, but it might be something different when it is inverted for a good amount of time plus being vibrated and jostled in the course of automotive transportation.

I don't see any bike rack/transportation gear manufacturers ever resorting to the inverted carry, so I would assume there might be a reason.
 

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I've always been under the impression that inverting a bike with hydraulic disk brakes risks introducing any air bubbles trapped in the reservoir into the master cylinder and hence into the brake circuit. Granted, it is merely a risk in normal inversions, but it might be something different when it is inverted for a good amount of time plus being vibrated and jostled in the course of automotive transportation.

I don't see any bike rack/transportation gear manufacturers ever resorting to the inverted carry, so I would assume there might be a reason.
if that's a problem, then your brakes needed to be bled, anyway.
 

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if that's a problem, then your brakes needed to be bled, anyway.
I dunno about that. There's a difference between having a bubble in your reservoir and having it trapped in the circuit. I really haven't encountered any reservoir with a bleed fitting (like the one you would find on the caliper) that would actually keep a bubble from being induced when you cap it with the fill screw.
 

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I dunno about that. There's a difference between having a bubble in your reservoir and having it trapped in the circuit. I really haven't encountered any reservoir with a bleed fitting (like the one you would find on the caliper) that would actually keep a bubble from being induced when you cap it with the fill screw.
I stand by my statement. My brakes don't have those shimano-style fittings that open/close the port on the calipers and it's not that hard to get the air out.

Putting the bike vertical and jostling it around will move any air that's in there, as well. With a fresh bleed, it's not an issue. Later on when the system needs to be bled, it might be. Racks to transport bikes vertically would do this same thing. If air is moving through the system when the bikes get oriented like this, your brakes need to be bled.
 

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If you're going to take the front wheel off anyways, why not just buy some cheap fork skewer/TA mounts and slap them on a 1x4 to stabilize it. Then you can just lay the 1x4 in your rv without any permanent changes or damage to your bike levers.
 

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Discussion Starter · #8 ·
why upside down?

it's going to be sitting on the levers. depending on how they're adjusted, maybe even on the master cylinders of the brakes. why would you want to do that to beat up on stuff? Why aren't you considering attaching a fork mount to a piece of wood, and then using your straps to keep the bike in place?
No - none of my controls will be touching the ground - even my grips have a metal ring so the rubber won't be touching either. I thought upside down would be better than the fork on the ground, no? I suppose I could put a blanket or something under the fork...

if I keep the wheel on the bike protrudes past the bathroom door - this can be an issue if it shifts I'm afraid the bars will go through the door. I could try to get it more stable - just looking for options...
 

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No - none of my controls will be touching the ground - even my grips have a metal ring so the rubber won't be touching either. I thought upside down would be better than the fork on the ground, no? I suppose I could put a blanket or something under the fork...

if I keep the wheel on the bike protrudes past the bathroom door - this can be an issue if it shifts I'm afraid the bars will go through the door. I could try to get it more stable - just looking for options...
Do this:

If you're going to take the front wheel off anyways, why not just buy some cheap fork skewer/TA mounts and slap them on a 1x4 to stabilize it. Then you can just lay the 1x4 in your rv without any permanent changes or damage to your bike levers.
Could even stick rubber pads onto the bottom of said board to minimize the potential of scuffing the floor of the RV even further. I see no good reason to put the bike upside down on its handlebars and saddle instead of doing it this way.
 

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It's fine. I've done this before many times. Just make sure your controls aren't touching anything because if the front lever gets depressed without the rotor in it could push the brake pistons out.

As to air bubbles, etc., just make sure you turn the bike right side up a little while before you go ride, and maybe give the brakes a few squeezes to make sure bubbles migrate back to the top. I do think this is unlikely to be a major issue unless you're storing your bike upside down for long periods of time (like days). I also agree that properly bled brakes aren't really going to have this issue.
 

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i frequently lay my bike over when trail side. always on the non drivetrain side....like a good boy. that orients the initial take off of the front brake line exactly vertical. not once has it ever been an issue. i suspect everyone's experience on here would be the same. if it is, the issue is an overdue or bad bleed, not gravity, on your fluid. which brings to mind all of the slopestyle guys, flipping bikes, introducing excessive g forces on their brakes....none of them ever has an issue braking.....
 

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Shimano brakes dont like being upside down as it seems to make the wandering bite point issue worse but I've never had SRAM brakes change after being left upside down for extended periods

Either way it doesnt really matter, after about 30 minutes of use the brakes will return to normal as the air travels back up the hose to the lever.
 

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Yeah, with some seatposts, lke the bikeyoke, extended time upside down and vibrating can cause the air to mix with the oil. It's easy to reset though, so that's not a huge issue. A bigger issue that applies to more bikes IME is air bubbles in your lever will migrate to the caliper and you may be left with very little, or no brakes, if you transport upside down. This is kind of hit-and miss, but it's also pretty difficult to have absolutely no air in the system, especially when it's been a while since you bled it. Then you get "surprised" by the lever going to the bar when you get your bike out at the destination.
 
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Discussion Starter · #17 ·
ok - thanks all, I'm sold on trying to keep it upright. I will take the front wheel off - that should help me stabilize it a bit better and not block the bathroom door, should we need it in transit...
 
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