Warbling C64 Sound from Front Wheel

[andybesy]

Hello Folks,

Just looking for people's thoughts on a funny sound my bike developed from the front wheel area last week.

To me it sounds like a warbling, oscillating sound; my mechanic described it as sounding like a commodore 64 loading.

It's obvious, loud, consistent and easy to reproduce; not sporadic or intermittent. It's quiet up to around 25mph then it starts and remains up to around 90mph.

It's consistent with road speed, increasing in pitch as road speed increases. It's not in any way linked to engine RPM; it remains unaffected when I pull in the clutch lever and coast. If I brake then it decreases with road speed, but doesn't immediately disappear under braking pressure.

My first thoughts were wheel bearings, but my mechanic and I have had the front wheel off and inspected them and they look good and feel smooth. They were last replaced with OEM ones about 20k ago.

My next thought was the speedo drive, but it looks intact. It was replaced with the upgraded part after the original finally failed about 2k ago.

I've of course confirmed that tyre pressures are exactly correct (36 psi front 42 psi rear), that the front sprocket area is clean, and the front sprocket is secure. We've also adjusted the chain.

I've also had the callipers off, cleaned them and checked for foreign objects, and also checked for anything between the front tyre and the mudguard. Bike is otherwise generally all good and well serviced.

My mechanic's theory is that the large spacer in between the bearings inside the wheel hub is rotating, as we noticed when checking the bearings that when he rotated the bearing on one side the other bearing on the other side rotated too. Is that normal?

He very slightly drifted the bearings back out a bit to release pressure of the centre spacer (he described it as "1mm if that") and the noise was indeed gone for a few hundred miles, but has now returned.

Has anyone experienced problems with the centre spacer rotating? Is that normal? Any suggested remedy? Or do you think it might be something else? Would you just change the bearings even though they seem good?

Any advice or similar experiences very welcome, as always.

Thanks, Andy

[darrsi]

Don't s'pose you've done anything recently with the rear wheel at all?

[BBROWN1664]

I used to get a noise like that. it was the tyre and down to the way the tyre had worn even though it was perfectly legal.
Once the a new tyre was fitted, it went away.

[andybesy]

Hi Both,

Thanks for your replies. Only thing done to the rear has been new tyres, Bridgestone BT023 Front + Rear, fitted around 2k miles ago.

I'll consider the tyres and take a closer look at wear patterns but I'd be surprised if they'd gone bad quite so soon?

Andy

[BBROWN1664]

Mine hadn't gone bad, as you put it, it was just a noise they made due to wear. I put up with the noise, which was more noticeable if I ducked down out of the wind noise, until the tyre needed replacing. The noise went at the same time.