Campag Khamsin

[raleighnut]

It just depends on how much grease there is in the cassette mechanism and that varies a little from wheel to wheel.
Where there is not so much grease (or the grease has begun to break down), you tend to get a louder "click".
Wheels where there is a lot of grease, the grease damps the mechanical noise of the pawls.

Until 2015, the pawl mechanism ran on oil only - Campagnolo recommended that only a very small amount of grease was used in the assembly of wheels with 3 independent pawl springs (which started to phase out of Campagnolo wheel assemblies in 1999 anyway), because grease could "stick" the pawls against the cassette body, slowing engagement down. These wheels have a characteristic, loud, freewheel action.

In 2015 the spring that drives the pawls was increased in gauge and strength and so the factory started to use grease in the drive ring well of the rear hub, as the new spring was more capable of overcoming grease stiction. Typically but not universally, when new, these wheels have a quieter freewheel action.

Grease breakdown can be mechanical (just a result of the repeated shear forces that the material is subject to) or can be caused by ingress of degreasers, detergents and / or other solvents from aggressive cleaning. Generally this area of the bike should be serviced in any case, every 5000km or so - and aggressive cleaning should be avoided.

Grease tends to harden over time but the addition of some oil tends to revitalise it.

 

[Graeme_FK]

Grease tends to harden over time but the addition of some oil tends to revitalise it.

True in some cases but not all, by any means. Depends entirely on what material is used to make the soap and what other additives are there apart from the oil and soap.

 

[HLaB]

With my older Khamsin's when the freehub started to go quiet it was a sign that the pawl springs were starting to degrade.

 

[Graeme_FK]

Older Khamsins, that had three separate springs - one for each pawl - the problem was as it is now, with the single spring - corrosion leading to failure. In the case of the old three-spring design, generally the springs wouldn't all fail at the same time so the free-wheel mechanism would stay more-or less working.
The single spring design. it depends where the spring fails. Sometimes it will still drive 2 / 3 pawls (although less "aggressively"), sometimes none of them.
Springs in this type of setting don't really degrade, as such ... it's more a case of simple failure. 9 times in 10, that's from corrosion. That in itself is usually down to insufficient oil / grease in the well of the hub. A significant part of the job that oil or grease is doing, is not actually lubrication, it is corrosion control.

 

[Apollonius]

Interested in the suggestion that you can re-rim Campagnolo wheels. I have never seen spare rims on sale.

 

[ColinJ]

Interested in the suggestion that you can re-rim Campagnolo wheels. I have never seen spare rims on sale.

You have just reminded me that I have two incomplete Campagnolo Proton rear wheels in my cellar. I think that the missing/damaged/worn bits from one could be replaced by bits from the other. I might have a go at that for a lockdown project.

 

[ColinJ]

You have just reminded me that I have two incomplete Campagnolo Proton rear wheels in my cellar. I think that the missing/damaged/worn bits from one could be replaced by bits from the other. I might have a go at that for a lockdown project.

I haven't done that, but I did find the front Proton which turns out to be in good condition so I have put that on my best bike. (The rim on the Neutron which it replaced got a bit worn after me foolishly riding it through a mucky winter. I'll keep that wheel for a spare now.)

 

[Ajax Bay]

Interested in the suggestion that you can re-rim Campagnolo wheels. I have never seen spare rims on sale.

In what way does the non-availability of 'Campagnolo' rims stop one re-rimming 'Campagnolo wheels'? It's the freehub that defines whether a wheel is C or S. Or this just an aesthetics (must have a 'CAMPAGNOLO' on the rim) thing?

 

[Apollonius]

In what way does the non-availability of 'Campagnolo' rims stop one re-rimming 'Campagnolo wheels'? It's the freehub that defines whether a wheel is C or S. Or this just an aesthetics (must have a 'CAMPAGNOLO' on the rim) thing?

Not at all. I probably don't know what rims are available. I presume generic rims which would work with Campagnolo wheels can be purchased. I didn't know that. I would like to know where they can be obtained.

 

[ColinJ]

Not at all. I probably don't know what rims are available. I presume generic rims which would work with Campagnolo wheels can be purchased. I didn't know that. I would like to know where they can be obtained.

My Campagnolo rear wheels have asymmetric rear rims so finding replacements for those could be a problem! The spokes are offset from the centre to reduce the difference in spoke tensions from one side to the other. It may be that disk wheels have it done on the front as well?

 

[Ajax Bay]

I would like to know where they can be obtained.

Google/Yahoo are your friends.

finding replacements for those could be a problem!

Like this one, perhaps? https://www.wiggle.co.uk/dt-swiss-rr-411-asymmetric-18mm-road-rim/

 

[ColinJ]

Like this one, perhaps? https://www.wiggle.co.uk/dt-swiss-rr-411-asymmetric-18mm-road-rim/

I have no idea whether that would be suitable.

Anyway, I have 2 partial rear Protons and both rims are in good order so I can probably rebuild one wheel and have a rim in reserve. (Or get a friend who knows more about such matters to do it for me!)

 

[Apollonius]

I can do most things with a bike, but would not know which rim to buy, nor how to fit one. And I do feel reassured if things say Campagnolo on them.