Gear
Campagnolo five-arm cranks have an unusual BCD...

Technical FAQ: Finding Campy-friendly chainrings

Lennard Zinn answers questions about off-brand Campagnolo-compatible chainrings, infrared motor checks, and nitrogen for tire inflation.

Regarding Campagnolo compact chainrings

Dear Lennard,
TA makes rings for the goofy sorta-110 pattern, called “Nerius.” Peter White has them.

I don’t know how they compare to Campy rings in quality, cost, or availability, but they apparently exist. There is a nice explanation of Campy rings here.

Thanks for your very informative (as always) column. A couple of years ago, you had a letter from a fellow who had an allergic reaction to “hypoallergenic” (NOT!) baby wipes. I later saw the same thing in medical literature. I had the same problem, and I pulled up your article in my dermatologist’s office to show him. He didn’t know about it, either. That letter saved me a lot of trouble.
— Jon

Dear Jon,
Glad that came in handy. I’ve given up trying to predict what topics might end up being useful to include here. I’ve found that subjects that seem way out of the ordinary to me often can be just the information somebody needed and are grateful to have come across.
― Lennard

Dear Lennard,
There are two French makers of Campy compatible chainrings: Stronglight and Specialities TA. They’ve been around since the 1940s (maybe earlier). This link is to French web retailer Xxcycle. The link takes you to a page for an inside ring for Campy five-arm 110/112 mm ring — black — where you can select chainring teeth. Scroll down the page for all tech info, including Stronglight’s website. TA has a similar range of Campy rings to Stronglight. Over the years I’ve bought many chainrings from them, both Campy 110 and 135 as well as 110 and 130 non-Campy. They mail all around the world (I live in Ontario, Canada). I prefer the CT2 rings as they last longer. Prices are in Euros but payment is made in U.S. dollars. Currency is not an issue (I pay in Canadian dollars. Mailing is inexpensive for a flat package and delivery is quick.
— Cliff

Dear Lennard,
Miche makes 110mm chainrings with an oval hole to allow use on both regular 110mm bolt circle cranks and Campagnolo 110/112mm bolt circle cranks; see Compact and Super 11. I believe BBB has a similar solution.

Also, your statement that the clocking of shifts would be off with other 110mm chainrings because of the 36-degree offset does not make sense unless shift clocking is asymmetric with respect to the right and left legs. You really should be rotating the chainring by 180 degrees by putting the hole which would be opposite the crank arm on a traditional crankset behind the crank arm of a Campagnolo (or new SRAM) crankset. This looks like 36 because 180 = 72 + 72 + 36. There can still be the issue of the chain-drop pin being in the wrong position. Miche makes the pin removable by unscrewing and the pin can usually be knocked off other chainrings.
— Jay

Dear Jay,
Yes, you are correct. Since your point is functionally identical to this one regarding SRAM 22 rings, I’m including it, too.
— Lennard

Dear Lennard,
Regarding the tech question posed by Matt regarding 11-speed SRAM rings on his SRAM 10-speed crank, a couple notes. First, if the hidden-bolt rings were mounted 180 degrees from their intended position, the ramps would actually be where they are supposed to be. Secondly, their rings now come set up for both hidden-bolt cranks and non-hidden-bolt cranks. They have two catch pins, with the intent that you plier off the one not in use. They even supply a pointless rubber plug for the exposed hole.
— Gregory

Dear Gregory,
Flipping the SRAM 11-speed hidden-bolt road chainring so the pin is opposite the crankarm on a crank with a standard spider would indeed clock the chainring properly to shift as intended. Similarly, mounting a standard ring with the pin opposite the arm on a hidden-bolt crank would likewise ensure proper orientation of the shift ramps.

However, regarding the break-off pin, two weeks ago I bought a 50T SRAM Red 22 chainring from QBP, and it definitely has only one catch pin, no removable pins, no rubber plug, and no secondary pin hole. So after clocking the ring so the pin is opposite the crankarm, there is no pin to catch a dropped chain with this chainring.

I didn’t notice the product photo at the time I ordered that ring, but now the product photo on QBP of SRAM 22 outer chainrings, whether 53T or 50T, shows the two opposing pins, just as you describe. So I assume that in the future, they will be that way, and I must have gotten an earlier version with only a single chain-drop pin. Thanks for pointing that out.
― Lennard

Dear Lennard,
Regarding the compact Campy chainrings, I rode with compact Rotor rings on a Campy Chorus crank. I’m not much of a wrench, but the wizard that is didn’t seem to have much of an issue mounting them. Of course, that didn’t stop him from complaining about Campy … I think that’s part of the training to work on their stuff.

Trust me — I accidentally cut a derailleur wire (you get why I don’t wrench) to my new EPS setup, which caused quite a bit of “only Campy” type discussion.

— Robert

Dear Robert,
A Campagnolo mechanic once explained to me that Shimano patented wires that plug into the derailleur, and Campy thus couldn’t see a way around having wires coming off of EPS derailleurs. Yes, you don’t want to cut one.
― Lennard

Dear Lennard,
I’ve used Campy 10- and 11-speed compact cranks for a long time. A few years ago, I acquired a used Ultra Torque Chorus crank with an aftermarket 46T chainring that had been drilled to work, although it didn’t look quite right. I was able to buy a Stonglight 48-tooth ring with Campagnolo pattern that worked well and is still on the bike.
— Jim

Feedback regarding infrared photos

Dear Lennard,
In hopes of providing a little clarity on Ben’s motorized doping question from last week. When I watched the full 20-minute video from the Italian and French journalists’ joint investigation, it is clear (even without speaking French) that the FLIR photo you referenced in your response to Ben was not from a race. Rather, it was an example of a known, commercially available motor in a test bike, which was used to illustrate the FLIR technology.

The use of that particular “smoking gun” image (as many outlets used at the top of their stories) does paint a terrible picture for cycling. The areas where the FLIR images from the actual racing showed heat (debatably) were inside the BB or in the rear hub area, which to your point I think, wouldn’t be explainable by electronic group sets, but also aren’t a slam dunk indictment of cycling (at least to my untrained eye). Take a look, I’m curious if you think friction could be responsible for the actual heat signatures shown in the investigative video.
— Brian

Dear Brian,
Awesome! Thanks for clarifying a misleading photo spread all over the Internet!
― Lennard

Dear Lennard,
Or you could simply take some pictures (heat signature) of bikes that have been altered already.  Like the one that LeMond showed on YouTube?

Side-by-side comparisons with the shifting batteries and the tabloid article would be awesome!!!

I, for one, would love to see that from a technical level.
— Craig

Dear Lennard,
What amazed me with the pro race infrared camera footage is, why weren’t those riders stopped? Why didn’t the cameraman bike zoom up (or back) to a commissaire and say, “Hey, you need to pull over these riders RIGHT NOW and check their bikes!” Why didn’t that happen?

That doesn’t make sense to me at all.
— Jonathan

Dear Jonathan,
Well, as we saw above, that’s apparently because the particularly compelling photos weren’t from a race!
― Lennard

Dear Lennard,
“There also appears to be a relatively warm area where the bottom of the seatpost is as well; that might well be the shifter battery. ― Lennard”

Now that you mention it, there should be heat from the motor’s battery right? Those motor kits are as big as the heat signature area, but there’s no battery heat.
— Randall

Dear Randall,
Yes.
― Lennard

Regarding putting water in tires

Dear Lennard,
My background is in motorcycle racing. Controlling tire pressure gain is one component that motorcycle racing and, it appears, bicycle racing, at least while descending, have in common. In this regard, less moisture, not more, is the answer. As you presumed, moisture inside a tire retains heat and heated water vapor greatly contributes to pressure gain. Inflating tires with a dry gas is something that many motorcycle racers do to help keep things under control. Bottled gas is the easiest way to get this done and it happens that nitrogen is cheap. That’s why you read about nitrogen use in racing, because it is dry, not because it has “larger molecules.” At least for motorcycle racing, using a dry gas to inflate tires results in predictable and controllable pressure gain.
— Mark