I have a Cannondale Badboy with hydraulic discs as my winter commuter and recently something has started rubbing and for the life of me I cannot figure out what it is.

The noise is persistent even when coasting so I've ruled out anything pedal/crank/BB related, but it is a regular sound that is matching the revolution of wheels.  Pfft, pfft, pfft.  Something is rubbing.  Somewhere!

 

The rubbing noise is not present when my bike is on a stand off the ground and I spin the wheels, so is my weight of sitting on the bike affecting something?

With my bike on a stand the wheels run true as I can tell by eye and the brake pads pull back to show a sliver of clear daylight when released and wheel spinning.  Nothing caught in mudguards.  

I have Tannus tyres that are all round in good condition and nothing stuck in them.  I thought maybe it was noise of them contacting on the road, but I've had the tyres for a while and the rubbing noise is quite recent thing.

 

Is there anything else I can check or something I have overlooked?

 

Any advice greatly appreciated!

 

21 comments

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Boatsie [230 posts] 7 months ago
1 like

Lol. Mine does the same. Brake pads are clear yet front hub is a 'copter.
I guessing mine is bearing 'cos not much else. No noise with no weight.

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StraelGuy [1547 posts] 7 months ago
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Do you have mudguards? My winter bike does that when the tyre picks up a bit of sand or leaf - makes a 'tsh' noise as it goes through.

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alansmurphy [1892 posts] 7 months ago
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Loosen off a brake pad, go for a steady ride, listen. If still noisy, tighten back up and try the other.

 

It's often about eliminating a thousand things to find the one...

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ConcordeCX [886 posts] 7 months ago
7 likes

Your bike has been possessed by Satan. Time for a new one.

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evans1001 [1 post] 7 months ago
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Loose spoke/s

 

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hawkinspeter [2515 posts] 7 months ago
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Loose wheel bearings?

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Boatsie [230 posts] 7 months ago
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If it is a bearing, what's a decent material?
Reading about ceramic and harden chromoly(might be wrong).
Not sure if ceramic balls will break in not always just to roll on wheels.
Guessing from the price that ceramic very smooth.

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DaSy [841 posts] 7 months ago
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One thing I can think of that would change when you are on the bike to when it's in a stand is the front suspension. Maybe the front hydraulic hose is bowing into towards the wheel enough for it to rub on the tyre when the forks are compressed? Has a hose clip come off or moved maybe.

 

Edit to say, I just looked at a picture of the cable routing on a Badboy and it looks like it runs internally from the caliper up the fork leg, so scrub that!

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Peowpeowpeowlasers [606 posts] 7 months ago
1 like

One of the brake discs is likely out of true, but by a tiny amount too small to see with the eye.  You can easily test this by removing the pads and going for a short ride (or if it's the front wheel just reverse it, making sure it doesn't foul the fork).  You can also look on the caliper, perhaps the disc has a wavy edge that's just slightly fouling the caliper (you'll see bare metal where it's worn the paint).

It's extremely unlikely to be the bearings, but you can confirm this by grabbing the wheel rim and pushing it side to side.  Worn bearings will mean the wheel hub can move on the axle.  Ceramic bearings are a waste of money, just stick with regular steel bearings.

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StraelGuy [1547 posts] 7 months ago
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That's a downside of cartridge bearings, they don't last too well in wheels. I noticed my front wheel rocked side to side when seting out a couple of evenings ago. The bearings were toast, one was smooth but was noticeably loose. The other had got water in and rusted and was rough and seriously loose. I replaced them myself with standard SKF bearings, about £4 each. They had 1,816 miles on them and are never jet-washed.

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Boatsie [230 posts] 7 months ago
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Thanks lasers. If gt101 is same noise as mine? I haven't discs, brake pads well clear, the only expensive wheels I own, smooth as silk to spin without grounded weight yet rub, rub, rub noise once underway. I gave up trying to understand such, weird as???
Off to hand feel the spokes... I swear it's gotta be a bearing though and being sealed units I guessing it won't harm the hub.

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hawkinspeter [2515 posts] 7 months ago
3 likes
Boatsie wrote:

If it is a bearing, what's a decent material? Reading about ceramic and harden chromoly(might be wrong). Not sure if ceramic balls will break in not always just to roll on wheels. Guessing from the price that ceramic very smooth.

Ordinary steel bearings are perfectly fine for bikes.

Ceramic bearings are very expensive and are probably only worth it if you plan on running them without lubricant. I'd be surprised if ceramic bearings have more than a tiny advantage.

Here's Road.cc's article about them: http://road.cc/content/feature/175644-ceramic-bearings-pros-and-cons

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gthornton101 [170 posts] 7 months ago
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Thanks everyone.  Have checked underside of mudguards, a bit dirty but no debris caught in there.

Rear wheel has not long been replaced (due to a series of broken spokes that ended up being cheaper just to replace the wheel) but I'll check the spokes on the front.

Front wheel bearing is solid, no movement there.

Didn't see any hose clips loose etc, but going to give a more thorough investigation at the weekend with some of these ideas in mind to find the culprit!

If nothing looks awry I'll remove the pads and see if the rubbing goes with it and identify a rotor out of true!  I'll keep you posted...!

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No Sweat [36 posts] 7 months ago
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It's unlikely, but check the frame for cracks around the bottom bracket, and the chain-stays and the seat-stays - it is just possible that a crack could open up under your weight and cause the rear wheel to move enough to rub against a brake disc. I hope this isn't the case!

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SpikeBike [111 posts] 7 months ago
1 like

Clothing? Something was driving me nuts for weeks and I finally found it to be my long laces slapping against my shoe as I pedalled.

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Boatsie [230 posts] 7 months ago
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SpikeBike wrote:

Clothing? Something was driving me nuts for weeks and I finally found it to be my long laces slapping against my shoe as I pedalled.

Dude, that's gold.

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DaSy [841 posts] 7 months ago
1 like
SpikeBike wrote:

Clothing? Something was driving me nuts for weeks and I finally found it to be my long laces slapping against my shoe as I pedalled.

 

I chased a tick-tick-tick sound on my bike for weeks once, which I accidentally found to be a loose memory cleat bolt plate in one of my shoes. I had removed and tested just about every part of my bike, when finally I found the source as I picked up my shoes to move them and heard the now haunting tick sound. My shoes had the memory cleat option but I use SPD-SL so nothing was screwed into it, so it would fly forward and make the tick on every pedal stroke on just one foot.

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Boatsie [230 posts] 7 months ago
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DaSy wrote:
SpikeBike wrote:

Clothing? Something was driving me nuts for weeks and I finally found it to be my long laces slapping against my shoe as I pedalled.

 

I chased a tick-tick-tick sound on my bike for weeks once, which I accidentally found to be a loose memory cleat bolt plate in one of my shoes. I had removed and tested just about every part of my bike, when finally I found the source as I picked up my shoes to move them and heard the now haunting tick sound. My shoes had the memory cleat option but I use SPD-SL so nothing was screwed into it, so it would fly forward and make the tick on every pedal stroke on just one foot.

 1 if two on the peak of the podium should bronze stand where silver would be?

Another thread mentioned noisy hubs? Could it be that?

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gthornton101 [170 posts] 7 months ago
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No Sweat wrote:

It's unlikely, but check the frame for cracks around the bottom bracket, and the chain-stays and the seat-stays - it is just possible that a crack could open up under your weight and cause the rear wheel to move enough to rub against a brake disc. I hope this isn't the case!

I do hope not, but will investigate only to rule it out and put my mind at rest now you've mentioned it!

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gthornton101 [170 posts] 7 months ago
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SpikeBike wrote:

Clothing? Something was driving me nuts for weeks and I finally found it to be my long laces slapping against my shoe as I pedalled.

I had something similar a while ago where I heard a little "tink tink" every now and then, especially when I leaned forward which made me think it was coming from front wheel area...

Turned out to be the keys in my chest zip pocket...  The jacket was a loose fit and when I leant down on to the drops my thigh would touch against the pocket (which hung forward with weight of keys) every stroke! 

 

Not clothing this time though, definitely something on the bike.

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SpikeBike [111 posts] 7 months ago
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Ok one last guess for me. Worth a check is whether there is anything sticky between your inner tube and tyre. This could cause the noise to coincide with wheel tuning and weight on that part of the tyre/tube (or as the wheel rotates and weight comes off). Its an easy check.