I am replacing my 11 speed chainrings on a 2014 chorus. The chain ring bolts use Torx 30, but I can;t figure out what is needed with the 5th iner bolt. It has a tab in side of it, and it seems to be Torx25, is there a special needed to remove that bolt? It is the one that also holds the spacer between the two chain rings. Once again I am regretting buying Campagnolo. Any ideas? I can't finr any reference to it online or on campy's docs.

The bolt threads in like any standard bolt... Crank arm is threaded.

I don't remember anything special to remove it. I'm using Stronglight rings on my cranks, and think I'm using all generic chainring bolts (the Stronglite 34T ring has 4 threaded holes + 1 unthreaded).

I did lose that 5th bolt once, and now am using Purple Loctite on it, so perhaps your bolt is just stuck a little bit.

Checking out that tab inside the torsx bolt further it seems to be plastic. I took a chance and took the tab out with a small screwdriver, and then was able to remove the bolt with torx. Darned if I know the purpose of that tab.

I guess I should have done more research on this. I was replacing my standard chainrings with compact chainrings but just learned that the BCD is smaller, so I need a compact crank. Now the question is what options do I have for 11 speed crankset? Will any year matter (i.e. say newer than 2011?). It does not necessarily need to be chorus, since I think the chorus is carbon fiber.

Yes, its true this vintage Campy crank does have a different BCD for full size versus compact crankset and new 4 arm Campy crank has universal spider that will fit different size chainrings. But, yYou aren't wed to this crankset. If too much hassle to change the rings, put it on eBay and buy a different crank. You can't turn a full size Campy crank into a compact for this size because of larger BCD spider.

Over 10 years ago...where does the time go?...I wrote this article on BF about chainring replacement on a Campy Chorus compact crankset you may find an interesting read:
Campy CT Chainring Options...

Still have that crankset btw. As to regret of purchasing a Campy UltraTorque crankset, you denigrate one if not thee best cranksets ever created...even if you have to replace chainrings with Campy's OEM rings and pay accordingly. They go BIG miles.

The tab was in there because Campagnolo didn't recommend that end-users change their own chainrings on the 5-arm carbon fibre cranksets - it was / is a simple anti-tamper device.


One of the difficulties of making a full carbon spider is that maintaining the run-out on the chainrings to Campag's (extremely tight) tolerance is fiendishly difficult. Every 5-arm crankset was tested for run-out and if the rings didn't come up to the standard (+/-0.125 mm), if the crankset was carbon fibre, it was custom-shimmed to compensate. The alloy cranks were / are made in such a way as the tabs were / are CNC skimmed post-forging, to produce the required tolerances - but that can't easily be done in composite.


If you take all the chainring bolts out and drop the rings off and you drop any of the shims, (on the assumption that you have a crankset that is shimmed), you will have almost no way of knowing where the shims need to replaced to, in order to guarantee the run-out on the chainrings. At the Service Centres we are aware of this and make the ProShops aware as well, so we tend to be pretty circumspect in how we take the chainring bolts out and note the presence postion of any shims - some main SCs like ourselves also have jigs so that if a mistake is made, and a shim is missed, we can correct the error easily and quickly.


Although over the years, it's been necessary to shim fewer and fewer cranksets as moulding technology has changed, Campagnolo have kept to the same policy, in part because relatively few consumers have a torque wrench and losing a chainring bolt can lead to failure of (especially the inner) chainring which in specific circumstances can wreck the crank.


All Campag high-end cranksets (Chorus and up) are carbon fibre, now. We'd recommend that you go for a model year 2015-2018 Chorus (marked FC15-CHxxxx where xxxx defines the length and chainring combo) or higher crankset, in order that the chainring spacing is a very close match to the crankset that you are replacing - current Centaur 11 and Potenza are spaced for the change in chainline that comes with Hydraulics (the chainline is actually fine with rim brake, too - it's the front mech function that will not be dead right with your levers, though it would be with the correct year of Centaur 11 or Potenza lever) and likewise, the H11 crankset will also be incorrectly spaced for your levers.

If you stick with 5 bolt CF, you can probably use either 10 speed or 11 speed Chorus, Record, or SR cranksets. There may be some minor differences, but nothing insurmountable. 110/112 BCD for the compact cranksets.

The compact CF cranksets show up on E-Bay from time to time, sometimes at a bit of a premium over the standard (135 BCD cranksets).

I haven't noted the shims that [MENTION=368670]gfk_velo[/MENTION] mentioned. Perhaps more to explore.

Thanks everyone. Lots of good detailed information. I had a campy compact (veloce) crankset on my personally built up road bike back in 2007.. When I bought my 2014 higher end road bike (custom fit/build) all of the assembly / build was by bike shop (I mentioned 2011 chorus, because I was led to believe 2011-2014 was the same for the components). I am pretty sure I saw no shims, and was pretty careful when I disassembled, just the inner chain ring bolt threw me. I am certainly regretting not going with compact now. .It only became a problem this year when I had issues with a couple of major climbs here in Vermont that I had not done in years. The 2014 bike / campy components have been flawless, for the ~6000 miles I have put on the bike so far, so I certainly love the campy components, just not the incompatibilities, as I haven't had the time to do research and my own maintenance like I did in the past.

The new 4- arm cranks were not available in 2014. I'd bite the bullet and get the new Chorus crank with ultra torque BB. You can get it for about $380. Do a google search.

If your using an English bb you can get standard overtorque cranksets for around 170 with bb from merlin. 11 speed.

Hi Campy fans, I know this is an old thread but adding a photo of the plastic anti-tamper plug, in case someone needs for future reference