Broken Campagnolo Pawl Spring

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Valbrona
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Joined: Fri Oct 28, 2011 3:25 am
Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

I really object to having one break after having crested a climb over 1000m - new pair of Campagnolo wheels. But I am interested why this would have happened. It must have broken on the way up the climb but went unnoticed until I tried descending and when the freehub would not rotate backwards.

Not had one of these break before, but I am inclined to think that the old design with the three separate springs was a more durable design. Perhaps there is a good reason why Campag sell replacements in packs of five.

Thanks for any comments.

highdraw

by highdraw

I have ridden Campy wheels with both freehub spring designs for decades and never an issue. Hard to say why the band style single spring broke. No doubt there have been hundreds of thousands of miles of testing on it. Hopefully it was just poor metallurgy for that example and won't happen again. If the band spring had broken on the way up, not sure you would have made it. Compression of the band is what pinches the cammed detents outboard and engages to the hub. If the band breaks the detents will slip.

The style you have below:

Image

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jekyll man
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by jekyll man

I've had quite a few break over the years on different level hubs (mirage - record, r7 etc), including one broken from new, so its definitely not an isolated case.
KT hubs had a similar design and I cobbled some of them with the campag springs.

My guess is that the grooves aren't machined too well in the pawls, and snag.

On the plus side, they're cheap, and easy to replace. Better than some gummy thing that's sealed and deteriorates further.
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Valbrona
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by Valbrona

highdraw wrote:If the band spring had broken on the way up, not sure you would have made it. Compression of the band is what pinches the cammed detents outboard and engages to the hub.


When the spring breaks the pawls stay in the sticky-out position, so forwards drive is possible. It is only when you try and turn the pedals backwards you find that the freehub does not rotate backwards properly. After the spring broke my freehub became stuck as if I was riding fixed wheel, but after some hand pressure I managed to loosen the freehub so that it would rotate backwards.

And the old style 'box of frogs' system seemed to work with more pressure/positivity.

highdraw

by highdraw

Thanks for the correction Valbrona if its true. ;) What do you suppose the physics is for holding the pawls in an extended state when the spring breaks which is designed to provide preload to that effect? I suppose centrifugal force may throw them into that position and then interference to the ratchet of the hub may keep them engaged. I have never broke one.

Valbrona
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Location: United Kingdom of Great Britain and Northern Ireland

by Valbrona

Mine broke at the 3 o'clock position, and I am inclined to think it was a case of the sharp edge inside the groove on the pawl causing the break. Not convinced the design is as good as it could be here.

graeme_f_k
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by graeme_f_k

Breakage frequency was never that high in proportion to the number made and the number of KM ridden, but the single spring mechanism does sacrifice a bit of durability for lightness and simplicity not only of assembly but also of maintenance.

We took over as main SC in 2008 and I just checked - we have done 12 of these under warranty in all that time (though I know some shops just used to do it as a goodwill thing, obviously).

The older version, used from 2000 until 2012 used a slightly lighter spring than the current and was designed so that the freewheel well could (and should) be relatively dry of grease and rotational pre-load on the mechanism would be less. Corrosion in these cases (bought about by oil / grease being washed out completely) was sometimes a cause of breakage as was defective assembly at the factory or slightly clumsy re-assembly after servicing - it was possible (and still is, although you have to try quite a lot harder) to kink the spring when setting or re-setting the pawls inside the drive ring. This could lead to breakage at that point.

In 2012 Campagnolo changed the weight of the spring as well as the material and spring rate to allow the freewheel mechanism to work with more grease, so circumventing the corrosion issues occasionally seen previously and also reducing noise (and to some extent wear and tear on the pawls & drive ring). It's very, very rare that we are asked to replace a spring under warranty now. We upgrade older hubs that come in for servicing as a matter of course.

They're in 5s because it's just not economic to sell them singly :-(

The same is true of many other Campag parts - brake springs, brake block retention springs, ball races, cups, cones are now all supplied ex-works, as examples, in multiples or as parts of kits. We still split packs though :-)

HTH
Graeme
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC
Pls contact via velotechcycling"at"aim"dot"com, not PM, for a quicker answer. Thanks!

AlanAnderson
Posts: 2
Joined: Sat Jan 28, 2017 1:22 pm

by AlanAnderson

I've had three pawl springs break in rapid succession (20 miles between each maybe) in a Campagnolo Scirocco free hub - any idea why they might be going so fast?

I assume I'm not fitting them right as the free hub itself is clean and well lubricated, but don't know how they are supposed to go in apart from, slip them into the groove. I can't see a place for the hook at the end to catch and I can't tell if the spring needs fitting in a particular direction.

Help!

Thanks!

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jekyll man
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Location: Pack filler

by jekyll man

AlanAnderson wrote:I've had three pawl springs break in rapid succession (20 miles between each maybe) in a Campagnolo Scirocco free hub - any idea why they might be going so fast?

I assume I'm not fitting them right as the free hub itself is clean and well lubricated, but don't know how they are supposed to go in apart from, slip them into the groove. I can't see a place for the hook at the end to catch and I can't tell if the spring needs fitting in a particular direction.

Help!

Thanks!


Look for the hole where the tail of the spring sits? Should be facing towards ie to the hub body.
If its not located, the spring will rotate, resulting in it ending where a pawl sits.


Edited for me talking cr@p :oops:
Last edited by jekyll man on Sat Jan 28, 2017 6:16 pm, edited 1 time in total.
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AlanAnderson
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by AlanAnderson

Thanks! I'll do that....

davidgreyling
Posts: 1
Joined: Tue Apr 18, 2017 6:59 am

by davidgreyling

Good morning

I have a similar issue to the gentleman below with new 2017 Scirocco wheels. They were trouble free for over 4000kms and have now broken two springs in 50km. Both springs broke exactly where they exit the back (non-engagement edge) of the pawl. I'm installing the third spring now but am worried there is another issue somehow. Is there anything specific I should be looking out for?

Unfortunately I can't warranty these as they were purchased on international online store and shipped here so local dealers understandably won't warranty.


graeme_f_k wrote:Breakage frequency was never that high in proportion to the number made and the number of KM ridden, but the single spring mechanism does sacrifice a bit of durability for lightness and simplicity not only of assembly but also of maintenance.

We took over as main SC in 2008 and I just checked - we have done 12 of these under warranty in all that time (though I know some shops just used to do it as a goodwill thing, obviously).

The older version, used from 2000 until 2012 used a slightly lighter spring than the current and was designed so that the freewheel well could (and should) be relatively dry of grease and rotational pre-load on the mechanism would be less. Corrosion in these cases (bought about by oil / grease being washed out completely) was sometimes a cause of breakage as was defective assembly at the factory or slightly clumsy re-assembly after servicing - it was possible (and still is, although you have to try quite a lot harder) to kink the spring when setting or re-setting the pawls inside the drive ring. This could lead to breakage at that point.

In 2012 Campagnolo changed the weight of the spring as well as the material and spring rate to allow the freewheel mechanism to work with more grease, so circumventing the corrosion issues occasionally seen previously and also reducing noise (and to some extent wear and tear on the pawls & drive ring). It's very, very rare that we are asked to replace a spring under warranty now. We upgrade older hubs that come in for servicing as a matter of course.

They're in 5s because it's just not economic to sell them singly :-(

The same is true of many other Campag parts - brake springs, brake block retention springs, ball races, cups, cones are now all supplied ex-works, as examples, in multiples or as parts of kits. We still split packs though :-)

HTH
Graeme

by Weenie


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graeme_f_k
Shop Owner / Manufacturer
Posts: 611
Joined: Mon May 26, 2008 12:21 pm
Location: UK
Contact:

by graeme_f_k

davidgreyling wrote:Good morning

I have a similar issue to the gentleman below with new 2017 Scirocco wheels. They were trouble free for over 4000kms and have now broken two springs in 50km. Both springs broke exactly where they exit the back (non-engagement edge) of the pawl. I'm installing the third spring now but am worried there is another issue somehow. Is there anything specific I should be looking out for?

Unfortunately I can't warranty these as they were purchased on international online store and shipped here so local dealers understandably won't warranty.


Try thoroughly cleaning, or changing the pawls as well (FH-RE113). Sometimes, if the spring does not seat all the way down into the pawl and can get "nicked" by the drive ring, leading to failure.

When we have wheels returned under warranty with pawl spring failure and we suspect this, we swap new pawls in automatically. It's a benefit of using the warranty system, the SCs and to a lesser extent the ProShops are made aware of these types of possibilities.

The warranty operates irrespective of where the parts are bought, geographically, by the way - SCs are obliged to service warranty regardless of the location of the vendor, provided the general conditions of warranty are upheld.
A Tech-Reps work is never done ...
Head Tech, Campagnolo main UK ASC
Pls contact via velotechcycling"at"aim"dot"com, not PM, for a quicker answer. Thanks!

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