Solve the following bike noise puzzle...

greg66_tri_v2.0

I spend a lot of my time on the 15 tooth of my cassette.

Bike 2 now has an annoying click-clickclick. Almost a tick-ticktick. Things to note:
1. It happens in or out of the saddle.
2. It happens pedalling one legged (doesn't matter which one).
3. It is not synchronised with the pedal stroke. So the first click appears when the NDS crank arm is at 9pm. Then at 2pm. Then at 8pm. And so on.
4. It terminates completely if I shift to the 14, or the 16.
5. It can be reduced in intensity by backing off the force on the pedals (quite a bit; almost to just above freewheeling).

From this, I have diagnosed an issue with 15t sprocket. Maybe it is worn and clicking on the chain. Maybe it is moving on the freehub. Maybe it has put some nice little dents in the freehub and is moving on them. I won't know til I take it to pieces.

Thing is, when I have had a worn sprocket previously, it usually manifests itself by the chain jumping. Any bright sparks able to tell me *precisely* what is going on?

nicklouse

what "position" is the 15T cog? and in both (all) crankset rings?

daddy0

Derailleur jog wheel hitting sprocket maybe? Tighten cable?

tgotb

If you're going to be a proper triathlete, you should resolve this issue by replacing the bike; at the very least, take it to a fancy bike shop (none of these small local ones) and get them to fix it for you. You can buy some new sleeveless tops while you're there :-)

Have you checked that the locknut on the cassette is still tight?

I had to take the "good" road bike yesterday after breaking my commuter on the way home. Haven't ridden it for a few weeks, but was fine last time I did...
First time I went over a bump I could hear the jangling of loose sprockets, which I rapidly traced to a missing spacer. Rode back home, found a spacer, put it all together again and set off on a much quieter bike. I was still getting a bit of the same noise, much quieter, but every time I stopped and wiggled the sprockets they felt fine. Problem was clearly related to chain tension, because it was quieter on the big ring. Anyway, 30 miles and 12 hours later the problem was getting worse. I got home, and took off the wheel, to find the locknut perfectly tight and no loose sprockets. Gave the bike a quick rattle and discovered that all 5 chainring bolts were half-undone :shock:

zx6man

check all links of chain. I had the similar and noticed a bent link which seemed more prominent when in a certain gear, probably due its alignment with cassette and front rings. It snapped a few hours later :-)

Ride hard

As others have suggested it might just be the RD needing adjustment.

I confusingly get the 'chink, chink, chink' noise on my 15T cog even though the other gears have been set up perfectly and make no noise. As you're probably aware that noise on the cassette is the chain momentarily juming up then down, or vice versa but without changing gear properly because the RD is too far left/right. As I say its confusing how this happens as you would assume a RD (Ultegra in this case) moves a predefined amount, so the fact when the RD seems to move more/less when in the middle of the cassette doesn't make sense.

Anyway, mine only does this a few times so a bike stand and a few turns of the barrel adjuster in either direction should sort it out.

jonginge

It's yer knees *QI KLAXXON*

I was going to say what zx6man said although the 15 is probably near the middle of the cassette so less likely, I suppose.

graeme_s-2

TGOTB wrote:

Have you checked that the locknut on the cassette is still tight?

I had a similar problem with my road bike last year while I was commuting a long way every day on mud splattered roads and this was the cause of my problem. I'd been using Purple Harry's Bike Floss to clean the cassette at the weekends, and I think the back and forth motion had loosened the lock ring off slightly.

tgotb

So what was it?

greg66_tri_v2.0

nicklouse wrote:

what "position" is the 15T cog? and in both (all) crankset rings?

4th in from the pointy end of the cassette. Seems to make the tick/click when on the small ring at the front too.

Daddy0 wrote:

Derailleur jog wheel hitting sprocket maybe? Tighten cable?

Nope, no contact there.

TGOTB wrote:

Have you checked that the locknut on the cassette is still tight?

On the list for tomorrow.

TGOTB wrote:

Gave the bike a quick rattle and discovered that all 5 chainring bolts were half-undone :shock:

Checked them, and they are all fine. Have shed chainring bolts before, and that tends to have the chain jumping sideways. This is tick/click.

zx6man wrote:

check all links of chain. I had the similar and noticed a bent link which seemed more prominent when in a certain gear, probably due its alignment with cassette and front rings. It snapped a few hours later :-)

Thought of that, but a visual doesn't disclose kinking or bends.

Ride hard wrote:

As you're probably aware that noise on the cassette is the chain momentarily juming up then down, or vice versa but without changing gear properly because the RD is too far left/right.

I am (regrettably) familiar with that noise. This isn't it. This is less constant.

TGOTB wrote:

So what was it?

Dunno. Yet.

TGOTB wrote:

If you're going to be a proper triathlete, you should resolve this issue by replacing the bike; at the very least, take it to a fancy bike shop (none of these small local ones) and get them to fix it for you. You can buy some new sleeveless tops while you're there :-)

You're thinking on the right lines. I'm thinking a wetsuit might cure the problem.

itboffin

If I ever see you in a sleeveless top will slap you with one of your own dirty slip on tri shoes.

Oh and I'm guessing its your bottom bracket.

walkingbootweather

itboffin wrote:

If I ever see you in a sleeveless top will slap you with one of your own dirty slip on tri shoes.

Oh and I'm guessing its your bottom bracket.

What have you got against sleeveless tops? I always thought they were 'armless enough. :roll:

Greg T

Sounds like you are injured, this gives you an ideal excuse not to do it.

Do you hear a strange gurgling noise that sounds like "elp mi" when you are open water swimming - that's right you are drowning - stop it.

greg66_tri_v2.0

Greg T wrote:

Sounds like you are injured, this gives you an ideal excuse not to do it.

Do you hear a strange gurgling noise that sounds like "elp mi" when you are open water swimming - that's right you are drowning - stop it.

It can't possibly be that bad. First 200m of the swim: swim over other people. Then find someone's ankle to hang onto for the rest of it.

Bike: those aerobars are a great mount for a tray. Bacon cheeseburger, fries, milkshake (with malt). Twice.

Run: well, how bad can it be? 26.2 miles in honour of a Greek chappie who dropped stone dead at the end when he did it. And they didn't even have bikes back then!

What can possibly go wrong?

Greg T

Greg66 Tri v2.0 wrote:

What can possibly go wrong?

My wish list is coming along nicely

I'm holding out for you getting Trout Flu.

itboffin

What about those barbs worm things that swim down the tubes of your old fella, surely that's on your wish list. Oh and one of those flies that lays maggots that burrow inside you arms and legs, do they have those over there?

Greg T

itboffin wrote:

What about those barbs worm things that swim down the tubes of your old fella, surely that's on your wish list.

Naturally, however it would need to be a very small specimen to make it through other Greg's teeny man. Me, you could get a pencil down there nay drama, sideways.

will3

Have a good look at your chain for cracked side plates.

UndercoverElephant

How worn out are your jockey wheels?

Mine may have started making a similar noise this morning, they're near enough sharks' teeth.