Yet another creaking BB question!

[Sunbeam]

Hi Guys,

I have a random sounding clicking, ticking sound under pressure coming from the rear of of my bike. I'm not sure exactly what is the problem, but I'd like to ask anyway.

It's a full carbon 2017 Cube 29er MTB, its 250 miles old, mostly road riding but about 50miles of trail centres involving drop offs and small jumps. I ride all the hills and never push, so I guess I put a bit of strain through the BB? The BB seems to be 30mm press fit bearings, the crank is M8000 Shimano XT.

I went right through my bike with a proper Norbar torque wernch and carbon paste from new, so I'm fairly sure bars etc are all good. I stood up while peadling and still the same sound, so it's not the seat in anyway.

I've read many posts on the net and watched countless Youtube videos on creaking. To me, my sound 'seems' to be coming from the BB or rear wheel.

I changed the chain rings for the bigger 28/38 Shimano combo, so had to buy a new Shimano chain (longer) 50 miles ago, so it can't be the chain. I checked the spokes and they all seem tight, infact everything seems correct.

The sound 'sounds like' beads on my spokes dropping down as the wheel turns as I push under load up hills, obviously I don't have beads on my bike :-0 !

Could it really be BB bearings on a bike so young? Do they really fit such cheap bearings on a high end bike? Or should I start stripping it back down and regrease and torquing everything like I did from new 250 miles ago?

I don't mind fitting new bearings if they need it, but would like to think a high end young bike wouldn't need them so quickly. So just cheacking here before I start contemplating costly bearings.

Thanks for any advice.
Rob :-)

 

[Milkfloat]

Did the noise start before or after the chain ring change? It could be those bolts.

 

[Sunbeam]

The rings were fitted from new by me, locktited and torqued up to 10Nm as per instructions on the bolt. I bought a Whippermann chain as an upgrade because I needed a longer chain going from the standard 24/34 to 28/38chain rings. The Whippermann chain was rubbish and didn't work properly even though it's meant for 11s. It was making noises. So I bought a new 11s Shimano chain and everything was back to noisless running again. The new creaking is new in the last 50miles.

I did a total degrease ( vac chamber and Ultrasonic clean) of the chain and vacuumed Squirt wax lube on the new chain. I have the tools, so I use them :-)

I reapply Squirt 24 hours before every ride as per the instructions.

 

[Yellow Saddle]

What type of BB do you have on there and what type of QR skewer do you have on the back wheel?

 

[Sunbeam]

To be honest, I don't know the actual BB? The bike is this:-

http://www.chainreactioncycles.com/...gclid=CLn_5KP3ntECFQ0-GwodZVQCbw&gclsrc=aw.ds

The rear QR is a DT Swiss boost screw in job.

 

[Yellow Saddle]

To be honest, I don't know the actual BB? The bike is this:-

http://www.chainreactioncycles.com/...gclid=CLn_5KP3ntECFQ0-GwodZVQCbw&gclsrc=aw.ds

The rear QR is a DT Swiss boost screw in job.

It appears that there's a press-fit BB in there. Plenty has been written here about that design.

The solution is easy. Live with the noise.

 

[nickyboy]

Watching this thread with a lot of interest as I likewise have a creaking/clicking sound every pedal revolution when I put reasonable force through the pedals. I'm not as pro as @Sunbeam in isolating the problem though. I've just regreased the chain ring bolts @Yellow Saddle can I ask why the interest in the QR skewer brand? Mine is a Campag (Centaur but I don't know if the QR skewers are that specific in their range)

 

[Yellow Saddle]

Watching this thread with a lot of interest as I likewise have a creaking/clicking sound every pedal revolution when I put reasonable force through the pedals. I'm not as pro as @Sunbeam in isolating the problem though. I've just regreased the chain ring bolts @Yellow Saddle can I ask why the interest in the QR skewer brand? Mine is a Campag (Centaur but I don't know if the QR skewers are that specific in their range)

Cheap skewers with open cams can't put enough clamping force on the rear wheel to stop it from fretting in the frame. A good skewer has three features:

1) High tensile steel skewer.
2) Enclosed cam
3) Steel biting teeth.

A good example of these is anything made my Shimano or Campag. Bad examples are older Zipp (perhaps newer ones but I can't vouch for that) or any other cheap wheels. You'll recognise the one-piece lever and cam that works on a flexible nylon pad. They also have fake teeth in that the grip interface is aluminium. It has to be harder than the frame to work.

Rear wheel creaking can be instantly cured by fitting a Shimano skewer. Unfortunately they weight 3 grams more than "racing" skewers and discerning customers sneer at them.

 

[Cycleops]

It would seem to be the press fit BB, problems with these are well documented. Can you change to a different type with that carbon frame?
I had a clicking problem once and it turned out to be a loose pedal.

 

[Sunbeam]

I will go through all the threads on the crank just to be sure and I'll try another set of pedals, but I think my pedals are OK as they are basically new and still feel nicly greassed with some slight greasy resistance.

 

[Sunbeam]

Sorry guys, I've not forgotten you.

I went out yesterday on an MTB trail and had a really good listen to the noise. It very much sounded like the back wheel, more specifically the 'twanging' of the spokes !!

Once I was home, I gave the spokes a squeeze where they cross over, and THERE'S the same sound :-0

I've not had time to do it yet, but I'll be spreading them with a plastic tyre leaver and running a rag between the gap to clean out any mud. I'll then put a very small blob of sticky grease at the point they touch.

I'll have another test after doing this on Monday hopefully :-)

I'll keep you posted on how it goes.

 

[Cycleops]

Maybe I'm wrong, which i often am, but the spokes shouldn't be moving against each other should they? That would indicate they are loose so maybe a slight tweak is in order. Whatd'yer think?

 

[lpretro1]

Spokes are flexing all the time when you ride - you just don't see it. If they didn't then the ride would be a bit harsh!

 

[Yellow Saddle]

Maybe I'm wrong, which i often am, but the spokes shouldn't be moving against each other should they? That would indicate they are loose so maybe a slight tweak is in order. Whatd'yer think?

No, they do move against each other but how much is a function of rim stiffness.

Two crossed spokes can have one leg standing in the load affected zone and one adjacent to it. Since spokes shorten when they're in the "zone", that means one spoke in the cross is shortening and the other stationary and hence movement at the cross. Stiff rims distribute the load affected zone to a wider section and no two spokes are simultaneously in and out of the zone.

However, the movement is extremely small. So small we never see fretting damage at the spoke's crossings, even after years and years of dusty MTB riding. Yet, it does from time to time, cause a cracking noise when manipulated by hand. That doesn't mean that's what's happening when you ride.

Would tightening the spokes help? No. Just like a wheel with high spoke tension and one with low spoke tension has the same flexibility, so a spoke that has less tension than another one - provided they are still both in tension - will move as much with each loading as the other one.

That's because the metals are flexing according to Hooke's law.

 

[Sunbeam]

Hi,

All the spokes are perfectly tight and the wheel is running perfectly true. The spokes do seem very tightly pressed together and when sqeezed do suddenly break past any muck build up and 'twang'. No, my wheels are not covered in mud.

I'm only offering this as a 'maybe', as the sound is the same. The other option is the fixing point of the spoke on the hub. Being straight pull, there is a flat part of the spoke that contacts. Maybe that point may benefit from a 'spot' of grease. That would mean removing one spoke at a time, not a fun job, so I'll leave that option till last :-)