Campag chainrings...

For discussions about bikes and equipment.
Raph
Posts: 604
Joined: 13 Mar 2007, 8:14pm
Location: Banbury

Campag chainrings...

Postby Raph » 28 Jun 2020, 5:02pm

The question first: are ALL 10sp campag 50T chainrings 110BCD?

I've got two ultra torque cranksets... all well and good so far, really like them. I've had none of the hassles people have described (yet!)

They're both 39/53 and 135BCD. But as I'm now moving into "old codger" territory, the days of a 53T ring are over - a 50T ring is more the business but I can only find 50T rings intended for the 50/34 pairing, which is 110BCD. I'm not interested in getting a 110BCD ultra torque as I understand they don't take any old 110 rings, only campag, so I'd just be inviting more hassle!

I've replaced one of the outer rings with a TA 48T, but it took a lot of grinding to thin down the one lug that bolts to the inside of the crank, as it's approx 4mm thick as opposed to the 2.7mm or so of the campag, so since the mating surface is on the opposite side just for that one bolt hole, it's critical that the ring has to be the same thickness as the original. When I first bolted it on I hadn't noticed and it was totally wonky, though luckily not permanently bent. If that's all gibberish I'll put up a diagram of what I mean.

Hence the question: are ALL campag 50T chainrings 110BCD?

Even if I can find the right ring, the cost might mean I prefer to grind another TA to fit!

Brucey
Posts: 39500
Joined: 4 Jan 2012, 6:25pm

Re: Campag chainrings...

Postby Brucey » 28 Jun 2020, 5:11pm

Raph wrote:The question first: are ALL 10sp campag 50T chainrings 110BCD?!


I don't think so.

FWIW if you have a 'hidden fifth bolt' type crankset, and you are only ever going to use aftermarket rings with it, it may make most sense to modify the crank, which will spare you from having to modify every chainring you fit. You will need a spacer of some kind if you ever use a different type of chainring (or a campag chainring again).

FWIW you may find that using a cassette that starts with a 13T sprocket (or larger which may require a customised cassette) allows a 52/53T chainring to make more sense than with a different cassette.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
Mick F
Spambuster
Posts: 49236
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Campag chainrings...

Postby Mick F » 28 Jun 2020, 5:26pm

My Campag Chorus Triple has a "hidden bolt" behind the crank.

The outer is a different five bolt chainring, but the middle is normal five bolt.
The inner is a normal five bolt too.

53/42/30 originally, then I changed to a Spa 28 inner.
Next change is to a Spa 26 inner.

It's the outer what is different.
Mick F. Cornwall

Raph
Posts: 604
Joined: 13 Mar 2007, 8:14pm
Location: Banbury

Re: Campag chainrings...

Postby Raph » 28 Jun 2020, 5:28pm

Thanks for the reply - I'm already using modified cassettes, some starting 14T!

Come to think of it I've got a BBB cassette that starts 16T - that would mean I could leave the 53T as is. Hmmmm...

The difficulty of grinding a neat step going from 2.7mm to the c.4mm of the TA ring meant anyway I had to slightly round off the corners of the crank mating surface - but that's probably a good thing as a sharp inside corner on a DIY grinding might lead to cracks in the future.

If I can clamp the crank reliably in a sliding vice and use a milling bit on a pillar drill then I could probably get a good mating surface in the new position. I've always got on really well with TA rings and the prices don't go ballistic the way some campag stuff does, so I'll definitely consider that.

Meanwhile I'll still look for a campag 50T 135BCD if you reckon they exist, hopefully if I find one it'll be for less than stupid money.

Raph
Posts: 604
Joined: 13 Mar 2007, 8:14pm
Location: Banbury

Re: Campag chainrings...

Postby Raph » 28 Jun 2020, 5:33pm

Mick F wrote:My Campag Chorus Triple has a "hidden bolt" behind the crank.

The outer is a different five bolt chainring, but the middle is normal five bolt.
The inner is a normal five bolt too.

53/42/30 originally, then I changed to a Spa 28 inner.
Next change is to a Spa 26 inner.

It's the outer what is different.


Exactly - it's the outer I'm asking about cos that's precisely the problem - inner mating surface for the other 4 bolts, but outer for the crank hidden bolt. The inner ring can be any thickness, it's bolted from the same side all round, but it's bolted into the back of the crank through the outer, so it follows the vagaries of the outer, therefore if the outer is wonky cos it's the wrong thickness, the inner is wonky too!

Brucey
Posts: 39500
Joined: 4 Jan 2012, 6:25pm

Re: Campag chainrings...

Postby Brucey » 28 Jun 2020, 5:59pm

IIRC there were 10s triples with 40-50T big rings in 135mm BCD. However most (all?) of these were meant for the other type of 5-bolt 135mm BCD chainset, so the chain peg is in the wrong place, and maybe the thickness is different too.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

slowster
Posts: 1410
Joined: 7 Jul 2017, 10:37am

Re: Campag chainrings...

Postby slowster » 28 Jun 2020, 6:47pm

I think MickF has a square taper chainset, and I thought that the 'hidden bolt' square taper Chorus and Record chainsets used the same Campagnolo outer chainrings as the contemporary Centaur, Veloce and Athena chainsets which did not have a hidden bolt. If so, it sounds like the Ultra Torque chainsets and chainrings are different.

With regard to modifying a TA outer chainring, TA list three different models for 135 BCD Campagnolo chainsets: Vento, Horus and Tivano. It looks to me like the Vento model is the same pattern as the chainrings for Campagnolo square taper chainsets, the Horus is designed for 11 speed chainsets and has no recess/shoulder in the bolt hole that faces the inside of the crank arm, and the Tivano is - I suspect - the model designed for your type of Ultra Torque chainset, with a much thinner section where it presses against the inside of the crank arm (just about visible in the image below). TA only offer the Tivano in black and not in 50t, but they do list 47t, 48t and 49t, and their website currently shows 47t and 48t chainrings as in stock.

Image

User avatar
Mick F
Spambuster
Posts: 49236
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Campag chainrings...

Postby Mick F » 28 Jun 2020, 6:57pm

Yes, square taper.
Identical to the Record except it says Chorus on the cranks.
You can save a fortune if you buy the next version down.

2006 vintage Chorus Triple.
Screen Shot 2020-06-28 at 18.54.57.png
Mick F. Cornwall

Brucey
Posts: 39500
Joined: 4 Jan 2012, 6:25pm

Re: Campag chainrings...

Postby Brucey » 28 Jun 2020, 7:03pm

slowster wrote:I think MickF has a square taper chainset, and I thought that the 'hidden bolt' square taper Chorus and Record chainsets used the same Campagnolo outer chainrings as the contemporary Centaur, Veloce and Athena chainsets which did not have a hidden bolt. If so,.....


The chainrings are different because the chainring pegs are in a different place. Having said that, it isn't difficult to refit the peg elsewhere if you really want to.

cheers
-------------------------------------------------------------------------------
~~~~~~~~~~~~~~~~~~~~~~Brucey~~~~~~~~~~~~~~~~~~~~~~~~

User avatar
Mick F
Spambuster
Posts: 49236
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Campag chainrings...

Postby Mick F » 28 Jun 2020, 7:16pm

Pegs?
Please explain.

The outer chainring on mine is different because the hole for the bolt into the back of the crank is different.
Mick F. Cornwall

slowster
Posts: 1410
Joined: 7 Jul 2017, 10:37am

Re: Campag chainrings...

Postby slowster » 28 Jun 2020, 7:20pm

It looks like Stronglight is the answer, but you'll have to find a retailer selling the particular chainring you need. The chainrings are available in silver with 50 teeth. Type B "for the crank sets Ultra Torque Centaur Carbon, Veloce, Mirage, Fulcrum R" and Type C "for the crank sets Ultra Torque Record, Chorus, Centaur Alu, Fulcrum RS or RRS "

slowster
Posts: 1410
Joined: 7 Jul 2017, 10:37am

Re: Campag chainrings...

Postby slowster » 28 Jun 2020, 7:42pm

Brucey wrote:
slowster wrote:I think MickF has a square taper chainset, and I thought that the 'hidden bolt' square taper Chorus and Record chainsets used the same Campagnolo outer chainrings as the contemporary Centaur, Veloce and Athena chainsets which did not have a hidden bolt. If so,.....


The chainrings are different because the chainring pegs are in a different place. Having said that, it isn't difficult to refit the peg elsewhere if you really want to.

I hadn't considered the peg. TA have addressed the issue by having two holes 180 degrees apart for the peg in the TA Vento chainring, which seems to confirm that the Campagnolo square taper chainrings are otherwise the same pattern.

Image

User avatar
Mick F
Spambuster
Posts: 49236
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Campag chainrings...

Postby Mick F » 28 Jun 2020, 8:09pm

That picture of that chainring wouldn't fit my chainset.
Peg holes or otherwise.
All five holes are the same.
Mick F. Cornwall

Raph
Posts: 604
Joined: 13 Mar 2007, 8:14pm
Location: Banbury

Re: Campag chainrings...

Postby Raph » 28 Jun 2020, 8:52pm

The TA ring I bought and had to modify only needed thinning down to 2.7mm (I've already forgotten the exact thickness! ...but I can check), the bolt positions were all exactly right, and it had one different hole with no rebate for the bolt - so it must have been intended for a hidden bolt design... but the wrong thickness.

User avatar
Mick F
Spambuster
Posts: 49236
Joined: 7 Jan 2007, 11:24am
Location: Tamar Valley, Cornwall

Re: Campag chainrings...

Postby Mick F » 29 Jun 2020, 8:48am

Not going to take mine off .....................

Tell you what, I will.
Back to this later.
Mick F. Cornwall