jyl

Well, don't I feel stupid.

My commute bike, an old road bike, had developed a very tiny, but irritating, "bump" sensation during the pedal stroke.

I checked the chain for stiff links, saw none but found it rather worn, put on a new chain. Still there. I checked the derailleur alignment and adjustment, thinking the chain or the crank were ticking the cage or something. Still there. I cleaned the drivetrain, pulled and regreased the bottom bracket. Still there. Finally I saw that the chain was hesitating momentarily when meshing onto the big ring, and always at the same spot. I felt the teeth and felt a slight roughness on the side of one chainring tooth. Like I'd nicked it on something. Three strokes with a flat file and problem solved.

Well, on the bright side I now have a shiny new chain and a very clean, well adjusted drivetrain. And since I've been commuting on the leg breakingly heavy cargo bike rather than suffer - suffer I tell you - from this irritation during my daily riding, I expect to have wings for legs when I get back on the road bike tomorrow.

Andrew R Stewart 

Don't feel stupid. Instead understand that you've learned something. And have a smooth running andclean bike too boot. Andy.

RandomTroll

There's an old joke about a guy who takes his rough-running car to a mechanic. The mechanic lifts the hood, listens, adjusts a screw. He bills the guy $51. The guy asks, '$51 just to turn a screw?'; the mechanic replies, '$1 to turn a screw, $50 to know which screw to turn.' (Inflated from the $11 when I first heard it 50 years ago.)

I've screwed up a few repairs on my bike/pickup/home/etc. over the years and figured out it would have been cheaper to hire a pro, but the experience was worth it. A couple of times I've had small nicks on rims that made a noise and caught on the brakeshoe that required a swipe with a file.

Continuity

Nice one. It's *great* when you finally get there isn't it?

Rubato

OP is studying at UHN. University of hard nocks....

HillRider

Uhh, UHK. Unless you are discussing archery, "nocks" is spelled with a "K".

FBinNY 

Sorry to hear that you feel stupid over this. However, consider that even pros who charge for parts and labor make similar mistakes. At least you're only out for some parts you maybe didn't need, and a slightly bruised ego.

I say this so often it hurts. DIAGNOSE the problem, and try to confirm the diagnosis before taking stuff apart or spending dough. Of course this isn't always possible but, as your case shows, some extra effort early on, can save lots of wasted effort later.

I wouldn't be posting an "I told you so" but I hope to hammer the point home, so that others may benefit from your experience.

Rubato

It's an old joke-and depressing how many people don't get it...

North Coast Joe

Doesn't matter how long it took to do. It's done and YOU did it. You figured it out and got it done.

The real shame of the situation is how much worse off your bike is with a new chain and freshly greased BB.

Good job! Got a few minutes to look at a problem on my bike? Should be a quick fix!

Juha

This. And try and explain the misery to a non-cyclist.

You did well.

--J

TimmyT 

I'm going to use that knowledge. Every time I get a noise from the bb area, I assume it's the bb, but it could be either derailleur, the cassette, the chain, the crankarms, or the pedals. I was in the LBS recently, and a guy came in with a creak in the bb. The two mechanics and I rolled our collective eyes --- creaks are impossible to diagnose. I never heard of the teeth being the problem, but I will look next time there is a noise.

Thanks!

1 Miyata Biker

Don't feel stupid about staying on the problem and performing any repair/solution on the bike until you discovered the cause and fixed it to your satisfaction! There's lots of people who would have kept on riding until whatever the "bump" was, either fixed itself or did enough damage that it would be obvious what the cause was. Congratulate yourself on your fortitude and expertise to find and repair the cause!

Dave Cutter

My Dad was a mechanic by training. His ultimate insult for a mechanic who skills he thought to be unsatisfactory... was to call him a "shade tree mechanic". By Dads definition a shade tree mechanic was one that merely replaced parts. A shade tree mechanic would replace parts until the problem was fixed... without any diagnostics.

Many worse things than a little shade tree tinkering.

FBinNY 

I agree, which was why I wasn't aiming criticism at the OP. However, there are too many shade tree mechanics working in bike shops today. They've gotten too used to modern hardware that just about needs only to be hung and they're read to go. (not quite, but close these days).

Again, what's OK for someone working on his own bike isn't for some who charges for his work.

But, whether a pro or amateur mechanic, knowing the problem is key to knowing the solution.

Dave Cutter

Yeah... I love wrenching [for fun]. But no one would be foolish enough to pay me for those services. I am way too slow and despite my repair book, forum reading and searches, and all those YouTube videos.... sometimes I have no idea what I am doing. But... I always have fun. Cycling is my passion... wrenching is my hobby.

jyl

It may just be my OCD, but I have decided my drivetrain is noisier with the new chain. In a gear with straight chain line, bike on the stand, when I turn the pedals by hand I hear more mechanical noise than I think there should be. Sort of a clickety-clickety chain-gear-meshing sound.

Adjusting the (friction) derailleurs doesn't eliminate it. The chain is not rubbing the front cage or visibly misaligned in the pulleys. The rear cage is straight. Everything is clean and lubed. The upper pulley is not too close to the cogs.

The cogs don't look too worn, but maybe the combination of new chain and somewhat worn cogs is causing this? Or using a 9 speed chain on a 7 speed freewheel is inherently noisy? Searching for ideas . . .

FBinNY 

New chains are often noisier than the one they replaced on the same freewheel. The old chain was well matched to the worn sprockets, and the rollers on the new chain touch the tips of the teeth as they engage. A narrower chain can make this a bit worse as can changes in the shape of the plates which can touch as they engage.

Changing lubes also makes a difference, some do a decent job muffling the chain noise, some not.

jyl

I normally use Chain-L and my drivetrain used to be practically silent after a lubing. Arrgh.

Perhaps I could put the old chain back on, but the new one is so shiny and pretty.

So the prescription is to apply some Chain-L to the new chain, insert some plugs into my ears, wander down to the co-op to see if they happen to have a used but nearly unworn freewheel, and if all that fails to just HTFU? A slightly clickety-clickety drivetrain is, I suppose, kind of a first world problem.

FBinNY 

Since you have it and have been using it all along, why not start there and see how it goes.