23 January 2008

Help for the clueless?

Avenger's front brake squeaks, where by "squeaks" I mean "emits an ear-piercing screeching noise that can be heard up and down the block and causes all the neighborhood dogs to start barking." It's done this ever since, I don't really remember, last summer maybe. I noticed that it was mostly only a problem when it was wet, but these days it's always wet, so the brake always squeaks.

I haven't considered it much of a problem because I've been thinking that if I need to stop so quickly that I'm hitting the front brake hard enough to cause it make a really annoying noise, then that's a good thing, right? There's always some delay between hitting the brakes and emitting my own annoying high-pitched squeak, so thank goodness my bike is doing it for me automatically! However, on group rides I find myself apologizing for my squeaky brake and then trying very hard not to use the front one at all. Which is madness, of course. Or is it not supposed to be madness? Am I in fact riding recklessly if I don't trust my bike to stop completely with only the rear brake?

So anyway, I keep checking and checking the brakes, which is what they tell you to do before each ride, but for some reason they never tell you what it is that you're supposed to be checking for. Are you checking to make sure they haven't magically disappeared when you weren't looking? Seriously, if the brakes aren't too loose and aren't rubbing, then what else is there that could be wrong? Which tiny screw corresponds to which seemingly alarming problem? I was instructed once to check the brake pads to make sure they're clean, so when they look really icky I wipe them off with a paper towel (or a thumb, in a pinch). But it doesn't seem to stop the squeaking. That can't be normal, or people wouldn't look at me like "Gosh, what's wrong with your brakes?" on group rides.

Maybe I should just take it back to the shop. (That would be free, right? With the winter tune-up? Or would it be like a preexisting medical condition?) The chain has also been slipping lately, even though--I think, I'm sure--I've been pretty good about keeping it lubricated. Yeah, probably time to go back to the shop. I'm pretty helpless when it comes to anything beyond adjusting the rearview mirror, and sometimes I can't even get that right. I'm terrible, aren't I.

And as long as I'm thinking about chains doing funny things, I'm pretty sure Scooty-Puff's front gear is misaligned or something. The guy who sold it to me insisted that everything was fine, but I think he might have been, well, I don't want to badmouth a community business if I don't have something in particular against them. They provide fast, cheap, adequate service right behind my office and sold me a fine bike, and as far as I'm concerned that's all that matters right now. Anyway, if there's some perfectly normal reason why a folding bike chain should make a constant noticeable grinding noise even when freshly lubricated, please let me know so I can stop worrying about it.


At 23 January, 2008 21:00, Blogger reallyboring said...

I don't know of anything to check for on brakes besides appropriate tightness to stop the bike and not rubbing. And I suck at fixing them if they start rubbing, too. Hopefully someone who knows posts a magic answer!

At 23 January, 2008 21:19, Blogger Jennifer said...

I usually get a friendly helpful post along the lines of "Try searching [some huge Web site full of DIY bike repair info].) It's a great resource!" (I realized that would probably happen just after I wrote that post.) I'm sure they mean well, but it's like someone asking me an editing question and me replying "Well, look it up in the Chicago Manual of Style." If you already know where in the CMS to find the answer to your really specific editing question, then you certainly don't need to ask me first. And if you don't, then simply referring you to a huge reference manual won't be much help.

Now, in our case, that's what the Chicago Style Q&A is for. (It's also mostly a promotion for one of UCP Books' biggest cash cows, but let's ignore that for now.) Surely there's a minor bike repair equivalent somewhere, some searchable database of questions and answers? If not, could someone please invent one? I think "How do I get my brake to stop squeaking?" would probably be among the more frequently asked questions.

At 24 January, 2008 04:46, Blogger David Johnsen said...

Google "bicycle brake squeak" and click on some of the links.

As for the chain slipping, how many miles do you have on that chain? If the chain is "stretched" (worn), it needs to be replaced. You need a tool to measure it -- we're talking about a millimeter or two in 10-12 inches of chain. If you use a worn chain too long, you can wreck the rear cogs, which are much more expensive to replace than the chain (been there). Or maybe your chain is slipping because the shifting is off a bit. Have you bumped a derailleur on anything lately?

At 24 January, 2008 08:44, Blogger Web said...

Whether coming from the chain or elsewhere, a grinding noise is not normal. Either the chain is rubbing against another part of your bike or a bearing has grit in it. If your bottom bracket has grit in the bearings, this will prematurely wear out the bearings.

Rather than attempt to sort this out, take the bike to a good local shop. It shouldn't cost much and you'll be back in business faster.


At 24 January, 2008 10:07, Blogger Dingbat said...

Hi Jen, from your upstairs neighbor (cube 411I)--as it turns out, the hugest friendliest DIY biking website on the web has a page on Creaks, Clicks, and Clunks but brake squeaking is part of the brake adjustment page.

That said, squeaking is generally due to one of a couple of things. First, squeaky pads. Some pads are just squeaky, thought they work fine. This usually isn't a groaningscreamingsqueak though, just a friendly little "mmmm, yeah, we're stopping ya."
Second, loose canti arms or pads. If the pads are loose, they'll grab the rim, wiggle to the end of their range, then let go of the rim and spring back, then grab again. At 660 times per second, that gives you a high E.
Third, pads aren't aligned totally happily. If they're aligned so that the first part to touch the rim is the "leading" corner of the pad, as opposed to the trailing flat, then again, it can grab and wiggle and groan (oh yeah).
Fourth, worn out pads. If you wear out the pad past the best braking material you get into something that doesn't grip the rim smoothly.

ANY of these things should be taken care of by the good folks at Rapid Transit, and it's most definitely a normal part of your winter checkup.

The grinding on the chainring is a little odder; it should be soluble but I'd have to hear it. Which I'll happily do any of these days.

At 24 January, 2008 11:49, Blogger Fritz said...

The easiest thing is probably just to get new brake pads.

The real problem is probably the toe in adjustment. Here's one online resource that discusses toe in, squeaking, and adjusting toe in. Can you say what kind of brakes you have? I can't remember what kind of bike you have, but if you don't know the brake style but tell me the bike you have I can work from there.

At 24 January, 2008 13:12, Blogger J/tati said...

(I tried emailing you, but kind of guessed the address. Sorry!)

Hi there,

A customer forwarded your blog entry in the hope that I could help a little.

Regarding your squeaky brakes, this sounds like a classic toe-in problem. Alternatively, it could be that the pads are unevenly worn and/or of an inappropriate compound for our climate. Clay/salmon pads work best in the wet stuff. If you're ever around 55th & S Hyde Park, feel free to wheel it in for a (free)diagnosis. I can show you how to handle toe-in yourself.

As for your folder... is this a Breezer, or something older? Folding bikes classically have chainline problems and truth be told, even nice ones almost always rub somewhere, because the frames are inherently flexy. But again, feel free to wheel it in for a (free) diagnosis.

At 24 January, 2008 13:17, Blogger J/tati said...

Also, although there are thousands of online bicycle resources -- you've probably already discovered that most are riddled with inaccuracies or unfounded opinion/bias. There are several (printed) guides for home mechanics that are pretty good, but the truth is that the two symptoms you've described are classic bicycle voodoo -- things that even experienced folks can misdiagnose or miss altogether when the bike is on a workstand. It's best to just have someone (whether it's a friend or shop) whom you trust address the problems head-on and in the flesh.

At 24 January, 2008 13:48, Anonymous RecumbentKen said...

Take the front wheel off and clean the rim. Alcohol should do it. Then take some fine sandpaper and remove any glaze (shiny part) from the part of the pad that contacts the rim.

If that doesn't do it you will have to adjust the pads or have it done. It's not difficult but getting it just right can be tricky. The front part of the pads should contact the wheel rim before the rear part. The pads shouln't rub on the tire.

Check out Sheldon Brown's site.


Ken (from GITAP)

At 24 January, 2008 14:47, Blogger Jennifer said...

Oh wow, thanks everyone! Let me get some more Real Work done and then I'll sort out all your various questions and try to figure out what's up with my herd.


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