Rim brakes, amusing failure mode
 

So I hopped on my bike, headed down the hill from my house towards the stoplight at the bottom, and... no brakes! I squeezed hard, and all of a sudden they engaged -- hard. I didn't crash. My brakes worked fine for the rest of my ride. Next day, same thing.

I also noticed that my mirror was fogging up...

Turns out I store my bikes in the garage, which is below the house, and cool. When I get out into the humidity, water condenses on the rims, and my brakes are temporarily slippery. After the rims warm up, no more problem. Today, it was 95+ out, and quite humid, when I left my workplace. It took half a block before my brakes warmed up, and my mirror was wet for quite a while.

Not a big deal, just an amusing new thing I learned.

What brand and model pads are you running?

My guess is that you would not have noticed a thing with good wet weather pads like Koolstop salmon.


-Tim-

Ah, you got me, after that other thread. ;) They're the cheapies from Jagwire. Now I have to track down some of the Koolstop pads and make a comparison. Good thought. I'd certainly like to believe that the cheapies are as good, but I would pay a couple more bucks for better safety if it works out that way.

Those kss will likely give off that brake honking noise when used in a wet condition. Just a fyi.

I have Koolstop salmon on three bikes and don't get any noise, wet or dry.


-Tim-

Kool, but i didn't end up as fortunate when i used them. Rims were alloy too.

No noise with Kool Stop salmon on my rims when wet. I mounted them on a bike for the first time about 6 weeks ago and I love them, wet or dry.

In scenarios like this, just lightly engage the brake to shed the built up moisture and heat the rim up. Literally only takes a few seconds at best and then you’re good to go. No fancy pads necessary. Kool stop salmon compound pads are designed for use in wet weather conditions like riding in the rain. Totally unnecessary for your situation. Nothing wrong with upgrading your brake pads, just to say you don’t need to spend any money to solve this simple problem. This is like bicycle riding 101. No offence meant there, it’s just a simple problem that isn’t really a problem.

Discs.

I've had squealing issues with Koolstop dual compound (2/3 salmon 1/3 black) but they went away after I switched from cantilever to mini-v. My tandem had dual compound pads with V brakes, never squealed. It could be worse, I had flashbacks to just how terrible generic Weinmann centerpull brakes were on wet steel rims.

Try a Schwinn Varsity with chrome steel rims on a downhill in the rain, you'll never be surprised again ;)

Switch to koolstop salmon pads and this whole thread becomes moot. $12 is cheap piece of mind.

I have ave them on three bikes. They work extemely well in the dry.


-Tim-

If you switch pads to a different compound, take some scotchbrite to the rim sidewalls to clean off the braking surface first. You should do this from tile to time anyway, but it will help with your braking if you’re gonna spend the money.

It's an experiment I definitely plan on trying.

Indeed, I rode a Varsity as a teenager. The other fun fact is that no amount of rust on those rims made the braking any better. ;)

On my bike with cantilever brakes, I use Jagware black thinline pads (curved to match the rim) on the front, and Kool Stop Eagle 2 salmon pads on the rear. Can't say I notice any differences in braking. Both are good. The Kool Stop Eagle 2 and a few other KS pads have wedges that simplify toe-in to minimize squealing.

In humid or wet weather I just make it a habit to occasionally ride the brakes to lightly scrape the rims clean, or brake early.

With my road bikes' sidepull rim brakes the main problem is the cheap Sunlite brand cable housing I'm using. It's supposedly compressionless, but... nah. It compresses enough for the first several rides that I needed to adjust cable tension a few times until the cable housing finally settled in. (Note to self: Get good quality cable housing from Shimano or Jagwire. No more cheapie no-name, faux-name stuff.)

Maybe it's just me, but I thought KSS pads felt like absolute mush at the levers, not a good feeling, did not like. In fact, as someone who has the brake lever reach adjusted, and therefore less room to play with before hitting the bars, I hated the mushy feel of the KSS pads.

Back to stock hard Shimano road pads, so much better (for me).

...I'll show myself the door now.

When I start riding in the humidity, the brakes on my FX 3 squeal so loudly, people a half block away turn around to figure out where it's coming from. On a MUP, people think I'm riding like a nut because tapping the brake sounds like I'm going super fast when braking.

I tour in rain, sleet and even snow with KSS, yo. No problemo.

Reminds me of my winter mountain biking days.

The first downhill stop was fine. Before the second stop the water film from the melting snow would freeze on my rim. I don't think anybody makes brake pads for that.

I've got Koolstops on all my bikes, but they're not a panacea. My problem is either (1) getting bike out of garage and rolling it through dewy grass, or (2) rain showers. Either way, it takes a couple of wheel revolutions to dry the rims before the brakes will grab. (Note disk brakes might fix (1) if the grass is shorter than 15", but probably won't do a thing for (2).)

IME the KS shine by not picking up gravel and letting it get embedded in the pads.

Update! There were Koolstops on one of the bikes all along. They were just totally black on the outside from buildup of gunk, and I never looked at them closely. But the braking surfaces were nice and pink, not too worn down. So, both bikes had the same symptom, very similar 1980s Schwinn frames with 27" aluminum rims, one with KSS and the other with the Jagwire pads.

I'm certainly not going to worry about it, since it's a really minor issue, more a head-scratcher than anything else. I own one disc brake bike, but I still consider the rim brakes to be safe enough for my riding.

Possibly the most important thing is proper upkeep -- paying attention to gradual deterioration of the cabling, aging of the rubber, etc. Nowadays, brand new brake pads is pretty much the first thing I'd do with any bike more than a few years old that follows me home. ;)

I noticed the pad material yesterday because one of the fork ends broke off while I was out on a shopping trip. :(

This sort of thing happens to me, too. Schlepping a bike from the cool air-conditioned house to hot and muggy outdoors means that condensation forms everywhere, and my first brake or two is less effective and often squeals. Since I can't get far from my house without a minor braking event, it's out of the way soon. :)

To eliminate brake squeal toe in the front of your brake pads. Place a rubber band between the rear of your brake pad and the rim when fitting pads. That will toe in the front a little bit, which is usually enough to eliminate squeal. T here must be a youtube video on this procedure.

The first time I hit a foggy stretch of road (where the road dipped down and went across a creek with a bunch of trees along it and a cool-air reservoir at the bottom) I went to turn into a neighborhood afterwards and the braking wasn't happening. I quickly decided going straight was the better idea. So yeah, now I know to pedal against the brakes for a bit after something like that to clear the rims and pads.