Grinding noise on road bike with Campagnolo drivetrain.

[Cippo]

I have a 2008 Colnago carbon frame with Record 10 speed. For past few months when descending especially there is a grinding noise when freewheeling which I thought was coming from BB area. When I pedal the noise goes away. We replaced crankset bearings and noise was still there. To date we have replaced chain, serviced Mavic hubs, freewheel body, replaced pedals, serviced Chris King headset, tried a different front wheel, checked the entire frame for cracks especially in BB area. I'm at a loss as to what the problem could be. Noise is there well into a ride, on CTCT it happened while descending Chappies and Suiker. Anyone with any advice please, thanks in advance.

Edited April 10, 2023 by Cippo

[FirstV8]

You  mention your hubs serviced but often the techies dont check each ball bearing  . If they are the old type ball bearing with cones it could possibly them . One damaged ( cracked ) ball causes a grinding noise which reverberates through the frame . I had this a few weeks ago and found that to be the cause . 

[madmarc]

Well if the grinding is only happening when you freewheeling then it can't be the BB as its not turning - maybe i misunderstand your post.

During freewheeling the only things turning are the wheels and i would hazard a guess it's got to do with your hubs. When you say you serviced them, did you replace the bearings ?

 

[Cippo]

6 minutes ago, madmarc said:

Well if the grinding is only happening when you freewheeling then it can't be the BB as its not turning - maybe i misunderstand your post.

During freewheeling the only things turning are the wheels and i would hazard a guess it's got to do with your hubs. When you say you serviced them, did you replace the bearings ?

 

Hubs were sent to Dragonsports (Mavic agent) for servicing. I could not find a rear wheel to match my casette when changing wheels. Mavic changed their freewheel body specs for newer Mavic wheels so couldnt switch my freebody to borrowed wheels. The front wheel however was eliminated as cause. There is no tyre rubbing either on fork as thought this was the case with weight shifting on descending. Im am running 24mm Specialized tyres and before that 23mm tyres.

Edited April 10, 2023 by Cippo

[Cippo]

6 minutes ago, FirstV8 said:

You  mention your hubs serviced but often the techies dont check each ball bearing  . If they are the old type ball bearing with cones it could possibly them . One damaged ( cracked ) ball causes a grinding noise which reverberates through the frame . I had this a few weeks ago and found that to be the cause . 

Mavic Kysiriums and they were serviced by Dragonsports.

[madmarc]

Not sure which frame you riding, but 24mm tyres are very tight older NAGO frames frames, especially the gap between the tyre and the seatpost - Nevertheless if it was tyre rubbing it would happen all the time, not only when freewheeling.

Find out from Dragon Sports if they replaced the bearings or simply cleaned and re-greased.

Cup & Cone each ball needs to be cleaned and inspected - I use a magnifying glass - In fact i mostly just replace them - the races have to be cleaned and inspected for damage, if there is any damage they are Kaput - these cup and cone bearings emit a fairly loud friction noise when they are damaged - Also from overtightening.

Same applies for cartridge bearings, if they removed the seals, cleaned and re-greased without checking the balls and races and they still have friction noise - then thy need to be replaced.

Hub service = new bearings, especially if they are the older type 

[Cippo]

2 minutes ago, madmarc said:

Not sure which frame you riding, but 24mm tyres are very tight older NAGO frames frames, especially the gap between the tyre and the seatpost - Nevertheless if it was tyre rubbing it would happen all the time, not only when freewheeling.

Find out from Dragon Sports if they replaced the bearings or simply cleaned and re-greased.

Cup & Cone each ball needs to be cleaned and inspected - I use a magnifying glass - In fact i mostly just replace them - the races have to be cleaned and inspected for damage, if there is any damage they are Kaput - these cup and cone bearings emit a fairly loud friction noise when they are damaged - Also from overtightening.

Same applies for cartridge bearings, if they removed the seals, cleaned and re-greased without checking the balls and races and they still have friction noise - then thy need to be replaced.

Hub service = new bearings, especially if they are the older type 

Had the issue with my 23mm tyres as well. Fitted the 24mm from Specialized before DC. The frame is the Extreme Power. Will check with Dragonsports.

[betaboy]

I’d strip the hub, do some digging, could be a small bit that made its way into the hub mech, and when it engages freewheel it’s touching metal upon metal. Sometimes a misalignment on a leaf spring is the result. You see with alot of packed grease it can go unnoticed. Worth a second look in my opinion. Let us know if you come right.👍🏻

[Madone69]

Change the rear hub bearings and freewheel bearings....you can do this yourself.

Experienced this myself but on a powertap hub assembly 

[ChrisF]

1 hour ago, Cippo said:

Hubs were sent to Dragonsports (Mavic agent) for servicing. I could not find a rear wheel to match my casette when changing wheels. Mavic changed their freewheel body specs for newer Mavic wheels so couldnt switch my freebody to borrowed wheels. The front wheel however was eliminated as cause. There is no tyre rubbing either on fork as thought this was the case with weight shifting on descending. Im am running 24mm Specialized tyres and before that 23mm tyres.

 

I would have a specialist check Dragons work ....  I have had to send stuff back to them in the past, after they did not do the repairs properly

[DJuice]

https://www.velonews.com/gear/technical-faq-noisy-mavic-freehubs/
 

Happened twice with my set before I retired them.

 

[Cippo]

1 hour ago, DJuice said:

https://www.velonews.com/gear/technical-faq-noisy-mavic-freehubs/
 

Happened twice with my set before I retired them.

 

Very interesting article thanks.

[DJuice]

26 minutes ago, Cippo said:

Very interesting article thanks.

Pleasure, the first time they lubed mine, good for 3 weeks, second time replaced, simple part, the broken one probably still in the parts bin. 

[Barry]

Two or three drops of Shimano mineral oil in the rubber seal and it should sort the problem. 

[RobertWhitehead]

Stop freewheeling! It's your bikes way of telling you to stop slacking 

[OVERDRIVE]

I know nothing about Campagnolo, I always ask @Jewbacca. But the day i saw this bill for shifters I knew I would never use them. Hope you get sorted.