Did a tire swap, and the brakes flaked out.

Jason Knight

Active Member
Region
USA
City
Keene, NH
I wanted to switch to some lighter weight whitewalls on my Aventure. Easy enough a task when I have a rack I can mount the bike upside-down on in my garage. But after I was done I found the front brake barely engaged, and the rear just up and did nothing.

EXACTLY how the bike behaved when I got it from Aventon.

So I grabbed my bleed kit, did the front first and got a LOT of air out of it, which is odd as I had checked it previously and it passes a pressure check... and it was working fine before I flipped it over. Got it back to being filled with fluid instead of air, and move on to the rear.

Opening the fill I was welcomed by the overwhelming odor of death. The stench of cadaverine, a smell I regretfully am all too familiar with.
I put the bleed kit on and black-green foam was foaming up as the oil went in!!! I immediately wheeled the bike outside and using a small hand-pump ran a hot water wash through the hose. The line was filled with a green slime that smelled horrible.

I'm a computer guy. I've seen this behavior before in liquid cooling loops. Bacteria was growing in my brake lines! I know how to handle that, it's just very odd to have to do it to a bicycle.

After a good power wash, pressure flush, and ajax soap in the sink, I did a long deep soak in my sonar cleaner drowning everything in IPA, All the parts checked out so I re-assembled and filled with clean oil, brakes good to go.

But it leaves me with nagging questions -- and even more distrust for this fiddly finicky hydraulic brake stuff. The liquid is supposed to mostly be just mineral oil, what was in there from Aventon and/or the brake maker that would allow growth like that? Did someone fill it along the way with water instead of oil? Did some sort of water left over from parts cleaning remain in the system from the factory? Brake oil should not be a growth-friendly environment.

The front had no such issues with growth, but both stopped working when the bike was flipped over. Could that be where/why so many people have problems with the brakes on the Aventure? Could it be as simple as "if the bike is flipped upside down in shipping, this design of brake needs to be bled and refilled?" Is that actually a thing with hydraulic bicycle brakes?

It's a very odd situation all-around.

It looks nice though now that it's complete and working. It also feels like it rides better which is funny since these are cheap Zinghang or whatever "wanda" / WD $80 a pop tires. Which apparently $80 each is cheap for fatties. A quick measure shows I'm at 68 pounds for the bike total, so that's 3.1 pounds less from my starting point. Pretty good since that's 4 pounds below the factory weight without rear rack and panniers. But again I took a lot of weight off when I swapped from the cast iron pretending to be "forged" cranks and pig iron chainring off.

It's funny, but the white-walls make the bike look less... I dunno... absurdly oversized. It changes the lines of it. Running the various cables and hoses through some cheap plastic conduit cleans up things nice as well.

whitewalls1.jpg


Suspension post, comfortable seat instead of unrideable butt-floss, headlight that's not a pathetic weak joke, Whole different beastie now.

Next up to get a longer fork since it feels to me like the bike doesn't have enough "rake" and like everyone else I'm bottoming out these cheapo's. Also want to find a longer front fender because the existing one does nothing to stop your shins-down from getting covered in gunk... or the down-tube for that matter which I hadn't noticed had gotten so grotty until I flipped it over.
 
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Jason Knight

Active Member
Region
USA
City
Keene, NH
Oh, side note. I will say I had some trepidation about doing the swap on the rear since it's been 25+ years since I took apart a bike with a derailleur, and never done one with a motor. Easy-peasy lemon-squeezy. The screw together connector and single cable to the motor were no hassle, derailleur didn't fight me at all, Off, deflate, swap, inflate, back on, 15 minutes flat. Not too shabby for a fifty-something cripple. Not even sure what I was worried about.

Couldn't find my stupid little plastic shims for tire removal even though I should have like twenty of the blasted things by now, but I have a set of pushrods from an old lawnmower engine that are 1/4" diameter with rounded ends that did the job just fine and no risk to the tube or rims.

So at least something went right with the process. :D

Also forgot that with new larger tires, inflate, ride, inflate again as you'll "lose" about 5 pounds of pressure just from the tube settling into the tire. Not something you deal with on 2.25's / narrower a whole lot.
 

dodgeman

Well-Known Member
Region
USA
City
Macomb, Illinois
I know growth can occur in diesel fuel, often if it’s partly biofuel and if there is some moisture in the fuel. I assume that’s what you got.
 

harryS

Well-Known Member
About six years ago, when I got nt first bicycle with hydraulic brakes(and also disk brakes), I had read that some of them will leak if turned upside down. My SHimano Mt200's don't do that, nor do the cheap HB100 zooms.
 

ETH

New Member
Region
USA
Oh, side note. I will say I had some trepidation about doing the swap on the rear since it's been 25+ years since I took apart a bike with a derailleur, and never done one with a motor. Easy-peasy lemon-squeezy. The screw together connector and single cable to the motor were no hassle, derailleur didn't fight me at all, Off, deflate, swap, inflate, back on, 15 minutes flat. Not too shabby for a fifty-something cripple. Not even sure what I was worried about.

Couldn't find my stupid little plastic shims for tire removal even though I should have like twenty of the blasted things by now, but I have a set of pushrods from an old lawnmower engine that are 1/4" diameter with rounded ends that did the job just fine and no risk to the tube or rims.

So at least something went right with the process. :D

Also forgot that with new larger tires, inflate, ride, inflate again as you'll "lose" about 5 pounds of pressure just from the tube settling into the tire. Not something you deal with on 2.25's / narrower a whole lot.
Are you just flipping the bike over to help w/ the tube change or do you have/recommend a bike repair stand that can support the Aventure. I need to change out my rear tubes, too, but was thinking about just trying to elevating it on a large enough tree branch or something with some rope to get it off the ground to make it easier for me.
 

Jason Knight

Active Member
Region
USA
City
Keene, NH
Are you just flipping the bike over to help w/ the tube change or do you have/recommend a bike repair stand that can support the Aventure. I need to change out my rear tubes, too, but was thinking about just trying to elevating it on a large enough tree branch or something with some rope to get it off the ground to make it easier for me.
Because I switched to cruiser bars, I can just change their angle to point straight up. I have the two pieces of foam from the packaging the bike came in that I layer atop each other, and put the bike upside down atop that. The foam is mostly there to keep by bar ends and saddle from getting scratched up. With the stock straight bars, I'd likely find some other solution.

I do have a wall mount that I use for my conventional bikes, but it's just too weaksauce to handle the aventure.

You don't really "need" to flip it over, I just did the fork swap without doing so. I just wanted to get a better look at what was going on. You could easily just elevate the bike from the middle with a short stool, so long as you have it secured in a way that it won't rock around / fall over.

My personal rule of thumb is that if I'm working on just the front end, I don't bother flipping the bike. If I'm working on the rear end, it's easier to see what you're doing AND to get things back together with the bike inverted.