Warped Cogs on Campagnolo Cassette

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AUbicycles
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Warped Cogs on Campagnolo Cassette

Postby AUbicycles » Fri Dec 01, 2017 9:15 am

I have a classic steel Francesco Moser race bike with Campy and an 8-speed cassette.

It is my bike for indoor training and the gears have always been a bit tricky - a few mechanicals in the lifespan of the bike before my time means that some of the components are not original.

It is probably time for a new chain but I notice that two of the cogs appear warped. They grind a bit though the chain is otherwise nicely aligned. I am not familiar with the ramp design of the Campag casette, can it be that shift is only accomplished or possible once per revolution?

When I observe the cassette rotating, as a specific point, both appear to be slightly curved, then they return to the 'straight' position. I have not yet been able to closely look and see if it is the teeth which are simply actually designed differently (ramps) but I an not really noticing this variation on the other cogs. I havn't ruled out that I need a new chain... I most likely do need one - so it is a question of getting a chain and cassette for my next purchase.

Anyone familiar with campy and is able to share some insights?
Are warped cogs in a cassette a 'thing'? I have only warped the front chain rings (not intentionally) and cassettes are a bit tougher to damage.

Cheers
Christopher

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Re: Warped Cogs on Campagnolo Cassette

Postby P!N20 » Fri Dec 01, 2017 11:53 am

I reckon you'd be struggling to warp a sprocket through normal use - eg; pedalling. It would have to cop a serious knock or crash, and I doubt the damage would be confined to two sprockets. Would it be possible that the cassette was damaged prior to your tenure? On a different bike? Which sprockets in the block appear to be warped?

I'm also starting to wonder if the sprockets haven't been installed on the spline correctly, but that doesn't explain that they appear to be straight for part of the rotation.

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Re: Warped Cogs on Campagnolo Cassette

Postby Duck! » Fri Dec 01, 2017 1:19 pm

Shifting teeth. All sprockets will have some specially-shaped teeth for shifting. On the smallest couple of sprockets the different shaping is more apparent and can give the illusion of bent teeth.
I had a thought, but it got run over as it crossed my mind.

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Re: Warped Cogs on Campagnolo Cassette

Postby AUbicycles » Fri Dec 01, 2017 6:19 pm

I will take a closer look and try and get photos.

It is unlikely that they are damaged though not impossible. I have ridden the bike around and on the trainer for many years and with the worsening drivetrain, is something I am noticing. Time to get the chain guage out and check the cassette for wear and damage carefully.

Thanks for the feedback.

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Re: Warped Cogs on Campagnolo Cassette

Postby AUbicycles » Thu Jan 18, 2018 8:35 pm

Small update - I checked more closely and ran a few tests and can see how the cassette teeth are shaped - the larger cogs have more shifting teeth while the smaller cogs have one - they are aligned and give the impression (while rotating) that they are moving.

That said, I still have a few shifting issues which was always a problem with this and will put in a new tech question.

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