metropical

been out the last few days on my CAAD9, all has been well.
Got on today, there is a ratchet kind of sound coming off the crank when my left peddle is in down stroke, from like 9:00 to 7:00.
I can actually slightly feel the vibration.
Only under torque. On the bike stand or in the air, it's quiet.

cny-bikeman

In time with crank rotation is pretty much always crank/BB, but multiple possibilities after that - remove, clean tighten pedals, cranks, BB, chainring bolts.

metropical

thanks very. guess I'll need to get that Shimano tool.

Bigbus

I'd start with the pedal and work my way in, but my money is on the BB.

AnkleWork

Chain rubbing front derailleur, maybe due to cross chaining? Occurs in which gears?

metropical

nah, occurs all the time.

metropical

until I get the Shim tool, am I OK to ride it or ........?

cyclist2000

which tool are you planning on getting? crank tool?, bottom bracket tool?, pedal tool?, chainring tool?

metropical

Shimano crank-arm/cap tool, TL-FC16

cyclist2000

you'll probably need bottom bracket tools too.

cpach

Creaks clocked to drivetrain torque are very difficult to diagnose because you're also twisting the whole frame to some degree. Start with the easy things and work your way down the list: replace pedals, tighten rear QR(tight!), ensure that crank is preloaded appropriately and that bb bearings are in good shape, check chainring bolts, install new BB.

Kovkov

taz777

I have exactly this type of sound on my fatbike (Cannondale Fat CAAD 2). It feels like the chain rubbing on the front mech but I'm not too sure about that. It only happens in some gears for me and only sometimes when pedalling.

The noise is like the ratcheting sound of a wrench, so I'd be interested if the OP solves this.

metropical

any particular BBT to get?

and new to self-maint, so a couple q's.

bb vs BB - I assume ball bearings vs Bottom Bracket?
"ensure that crank is preloaded appropriately " ?
OEM chainring and chain. Even though they are 8 or so yo, they appear to be in good shape. I don't think the bike has but 1000 miles on it ....... if that. I was off the last few years after I messed up my knee a bit.

Thanks.

metropical

is the bolt on pedals always the same size? Special Park tool or crescent wrench do the job?

taz777

Most pedals will require a 15mm pedal wrench if they have hex flats at the point where the pedal meets the crank arm. Pedal wrenches are just a bit thinner than regular spanners so you can get them into the narrow gap easier.

Some pedals, particularly lighter ones, don’t have hex flats to fasten them. For those you’ll need an 8mm hex wrench imserted from behind the crank arm and into the 8mm hex socket on the end of the pedal spindle to draw the pedal into the crank arm.

By the way, I have a similar sound coming from one of my bikes. I think I’ve found the issue. When I drop down a gear or two and my pedalling cadence rate is slower than required for my current speed, I can hear the pawls on the rear hub during the slower part of the pedal stroke. This may not be your issue at all, but the sound you described was similar to the sound the has baffled me for months.

metropical

yea, looks like mine have the hex flat. Fon't think I have a wrench with a long enough handle for real leverage, but I'll try. If not, the tools seems pretty reasonable. Hopefully that'll be it.

blamester

Do the pedals spin freely under no load?
Can you hear the bearings inside? It may just need lube. Grab it hard with your hands and load it like you where pedalling is it rough now.
Same thing with the bb. Don't be afraid to pull and twist it. Get the chain out of the way.
Check the chain gap against the fd in every gear.
How close does it get?
Possible brake rub on one side,

metropical

I'll try those ideas blamester. I tried loading it by hand , got nothing. I have noticed at the start of the ride, pretty quite. After going thru front and rear a few times the sound and vibration shows up.
Chain gap looks good and I recognize the rub sound. This is more cyclic and there is a small vibration with the cycle,

taz777

Apologies if you've already checked this.

Something else to consider: I found one loose chainring bolt that I discovered today. I was lucky enough to have a chainring screwdriver to hold the nut as I tightened the bolt using a hex wrench. It was a bit of a pain checking and tightening the bolts in situ but it was manageable.

Initial tests show my ratcheting noise to have been eliminated but I need a few more test rides to be sure.

metropical

mentioned earlier, but I still haven't really checked them one by one. thnaks though

jp911

After generally inspecting for chain rub, missing chainring bolts, and any other mechanical items that you could visually inspect, I would do the following...

On the non drive side (left) with Shimano cranks the first thing I would check is the torque of the two bolts that secure the crank arm to the spindle. If that checks out (not loose), then I would get the Shimano crank arm tool, remove the crank arm, pull the crank, clean and re-pack the BB and crank spindle with grease, put it all back together and test. Sounds complicated, but It's pretty simple with the right tools.

metropical

by Shimano crank arm tool, you mean this correct?

And is this just a fancier version?

jp911

Yup, that's the one. There's a fancy metal one made by Park Tool, but the plastic Shimano version works fine.