1/8" chainring on Campag Record road cranks

[Mick F]

Thanks for the stuff about your Chorus cranks, but my problem is specifically related to Record cranks which have a different way of attaching the chainring.

Not my Chorus cranks.

Identical to Record except they say "Chorus" on them.

[pq]

Really? I've had a couple of pairs of Chorus cranks over the years and they were a standard 5 arm design, unlike the Record which have 4 arms and use the crank as the 5th. None of my Chorus cranks were very recent, maybe they adopted the Record design later.

[pq]

Yes I am using Royce Ti bolts, and you may have a point about them creaking. Ti against Ti really doesn't work well and they feel horrible when you tighten them up (fine in a steel Campag axle though). I'll dig out some steel ones and see if it cures the problem.

[Mick F]

Really? I've had a couple of pairs of Chorus cranks over the years and they were a standard 5 arm design, unlike the Record which have 4 arms and use the crank as the 5th. None of my Chorus cranks were very recent, maybe they adopted the Record design later.

Yep. The 5th arm is behind the crank like on your Record.
This is from the 2005 Campag spare parts catalogue.

[Brucey]

Titanium is notorious for picking up on surfaces and galling. If replacing Ti crank bolts with steel fixes a creak, it almost certainly means that the crank wasn't 100% secure on the BB axle with the Ti bolts fitted.

The reason for this is that whether the creak comes from the Ti bolt or within the ST interface, the crank has to be able to move slightly in order for the creak to occur.

As an experiment simply replacing the Ti bolts with steel (torqueing them partially, i.e. to about the same level as that at which they came out) , if it fixes the creak, suggests that the noise was coming from the bolts, (but NB the cranks must have been moving slightly on the taper, and probably still are, which is bad ). If the noise is still there but then quits when the bolts are tightened fully, it was the tapers themselves creaking. If the noise quits only once the tapers were disassembled then cleaned properly before reassembly, again it was the tapers.

If you wish to identify the source of the creak, it is best to do things one at a time. Taking everything apart at once, or replacing it wholesale, and curing a creak that way, I find curiously unsatisfying; the mystery isn't really solved!

With lightweight crank bolts (Ti or Aluminium) it isn't a bad idea to install the cranks using steel bolts, ride it for a while, and then to replace the bolts with the lightweight versions.

BTW pedal threads often creak. Like chainring bolts that are creaking, tightness alone is not sufficient; disassembly, cleaning, greasing of the parts is required if this is to be cured or eliminated from the enquiries.

cheers

[pq]

Mick F, Your Chorus cranks are newer than the two pairs I've had. They must have changed the design in the early 2000s.

I'm going to spend a bit more time fiddling with the existing cranks. The tapers I know are super-clean, I really went to town on them in an earlier attempt to cure the creak. I can easily remove, clean and lube the chainring bolts and experiment with steel crank bolts, but if those two things don't work, one way or another I'll be using my Record road cranks. It's likely the tapers are worn on the older set after 35 years of being moved from bike to bike.

It seems none of the 1/8 after market rings will deal with the Record road cranks fixing method, but I seem to remember TA do various sizes of 3/32 rings to suit. I'll need to figure out what chainring bolts to use, especially for the crank fixing, but that seems like an easy + cheap solution.

[Brucey]

if the Record chainring is (as I think it is, IIRC) drilled differently in the fifth position behind the crank, this means that the chainring cannot be rotated on the spider to even out the wear. Not my first choice for a singlespeed drive, that.

Good luck with the hunt, and don't forget to check the pedal threads.....

cheers

[pq]

Yes, it is drilled differently but I'm not really worried about that. The chainring I'm currently using has lasted an incredible amount of time, so if the next one doesn't do so well, it'll still be fine. Also I ride this bike a lot less since I moved to the south of France - the roads are mostly dry here, even in the depths of winter so I don't have the same need for a winter hack. Whatever solution I find for this problem will probably be the last time I have to mess with it. By the time it wears out I'll be too decrepit to get up the hills around here on a fixed.

Thanks for all the help & advice everyone, it's much appreciated.

[Mick F]

From what I can tell ............. or remember? ............. with my Chorus chainset, the five holes aren't equidistant circumferentially ........... if that's the correct expression.

It's not just the drilling. The four holes on the spider are equal, but the fifth hole on the crank is further apart .................... or that's what I seem to think. I ain't taking the outer and middle off to check.

However ......... the inner seems to have "even" holes.

[pq]

Mine look to be all on the same diameter and equally spaced. The only oddity is the machining on the hole is reversed on the one that attaches to the crank.

I have a much more recent Record compact on another bike, and that has really bizarre chainrings with the 5th hole not on the same BCD as the other 4. Can't see any reason for it.

However, for now, contrary to what I originally said, I'm having a last go at curing the creak on the old cranks. Tinkering now done, but the bike isn't rideable for other reasons, so it'll be a few days before it gets a test ride.

[Gattonero]

...The Royce bb I'm using ....

You answered your own question.
Royce BB's are high quality, but are prone to make noise if not correctly installed. Use copper-grease in between the bearings&cups, and bearings&axle contact points. Make sure the BB shell threads are correctly chased and use some low-strength threadlock at least on the Rh bb cup threads.

[Gattonero]

From what I can tell ............. or remember? ............. with my Chorus chainset, the five holes aren't equidistant circumferentially ........... if that's the correct expression.

It's not just the drilling. The four holes on the spider are equal, but the fifth hole on the crank is further apart .................... or that's what I seem to think. I ain't taking the outer and middle off to check.

However ......... the inner seems to have "even" holes.

IIRC, they made the odd positioning of the "hidden bolt" with the Ultra-torque cranks, square-taper cranks would still use a dedicated chainring but with equal BCD

[Mick F]

OK, I bow to your knowledge.
I could swear that the crank bolt is further out than the other four.

Not going to dismantle soon, but when I do, I'll check.
If I'm wrong, I will admit it.

[Gattonero]

OK, I bow to your knowledge.
I could swear that the crank bolt is further out than the other four.

Not going to dismantle soon, but when I do, I'll check.
If I'm wrong, I will admit it.

is this a race? Do you have to "admit" something?
Man, I just said "If I Remember Correctly", as such it doesn't have to be taken as an absolute statement.

[Mick F]

Of course it's not a race.
The issue is, the question that a normal chainring could fit or not.

I'm not sure at all that one would. Can't honestly say one way or another, but if I were a betting man, I would say that the crank hole is not circumferential with the rest.