Hydraulic brakes and extreme cold?

[Jason Knight]

One of the things I want in my e-bike is fat tires for all-weather riding (ice/snow/mud)... but I'm concerned about the ones with hydraulic brakes and some of the temperatures I see here, where in Feb -9F is a "normal night" and double digit negatives aren't uncommon. Worse, my garage where the bike will be stored is a separate unheated building.

Cars oft have more thermal mass and fluids formulated for extremes of low temp, but it seems bike stuff just uses mineral oil and the lines are a lot thinner. Whilst "liquid" to -30F / -22C, that it tends to gel around 5F is a slight worry. A gel blob could be as disastrous as an air bubble.

Does anyone have experience with hydraulic bike brakes in cold temps, or am I worrying about nothing? I know everyone is talking up this tech, but I have serious misgivings.

 

[Jason Knight]

How cold are you going to be riding??? Below -30°F/-22°C?

Probably not riding when its that cold, but overnight lows can get down that far even when daytime temps are hovering around 30-35F, leaving components still down at those lower temps.

And I've lived in both AK and NH, so I'm painfully aware of "gelling" of oils, where until you get them moving they're not frozen, but they're certainly not liquid either.

Kind of like the truther nutters who say "jet fuel can't melt steel" when you don't need to melt it to liquid to compromise load bearing capacity. You get steel up to even two-thirds its melting point and it's a limp noodle. It's not liquid, it's not melted, but it's completely malleable. If it didn't work that way, forging would be impossible. You don't melt the steel to shape it when forging. You ever try to hammer liquid? Doesn't work.

Or the argument I use to gut "truthers" scientific illiteracy. Take three sticks of butter, leave one on the counter, one in the fridge, and one in the freezer, wait a day. Now stand on them. NONE of them are "melted", but they have WAY different load tolerances.

You have the same problem at the opposite end of the spectrum with fuels and oils. See why JP-7 and EP-7 were created, or the additives that go into home heating oil in places where gas is unsafe. Or diesel fuel for that matter. Just because they're not frozen, doesn't mean they're free-flowing.

I'm probably just overthinking this, but with the extremes of temps over seasons ranging from 105F to -20F, things like cracking and overpressure from expansion/contraction are one of the many worries I have to consider. Worries that things such as steel cables have less issues with, even if I do have to adjust the cables on my normal 26" cruiser every 3-4 months to lengthen/shorten them.

Another of the reasons I dislike derailleurs or bikes with lots of gears favoring internal hubs. Just more stuff to go out of whack when the temperature changes.

But then just a week or two ago I was explaining to a friend who came here to New Hampshire for a visit and had never left Texas before what a "Door snake' is. He was pointing at it going "what the blazes is this?"

 

[Jason Knight]

Apparently Amego ebikes are working fine in Toronto's winter temperature.

I just took a look at their site, and they're a reseller not a builder -- BUT, they sell the Aventon Aventure which is the make/model I'm looking at which prompted the question so...

I'll take that as a good sign. Thanks!

 

[Jason Knight]

Amego does have their own brands of ebikes.

Missed that on their own page, where everything I saw seemed to be other makers.

But I would say (close to) 99% of ebike companies out there are brand (distributor, etc).

And I think that's something that has me looking more and more at Aventon. They might not be actually doing the manufacturing, but they seem to be far deeper into the design process even at the frame level. I mean the bikes you just posted pictures of they're all the same bike in different colours and wattages... which honestly to me just feels sleazy, lazy, and disreputable.


Which is odd given my professed love for non-proprietary parts... but those pictures all being the exact same bike kind of set my teeth on edge, raising the hackles on my hackles.

 

[Stefan Mikes]

Jason,
Nobody expects riding e-bike at -9 F/-22 C because the battery wouldn't like it. I rode my e-bikes at 7 F/-14 C minimum. At that temperature the hydraulic brakes still worked, and the battery didn't suffer.
Generally, e-bikes are expected to be ridden at 10 F/-12 C and above, and the battery should be taken to a warm place post-ride.