Technical FAQ: Mixing Campagnolo 11- and 12-speed components, road tubeless safety, back surgery

Have a question for Lennard? Please email us veloqna@comcast.net to be included in Technical FAQ.

Dear Lennard,

I want to use a Campy Super Record 12 crankset on a Campy Record 11-speed drivetrain.
How well will that work? Will it work as good as a 11-speed crankset? I am using a Cable operated Campy Record groupset.

― Walter

Dear Walter,

If one were to ask Campagnolo, the official answer would be “no,” of course. Campagnolo doesn’t generally design or test systems to be backwards compatible, and unless it has, it’s not going to recommend it.

It may work well enough, but there are a few reasons why it won’t work as well as an 11-speed crankset. The 12-speed chainline is a millimeter wider; it is 43.5mm for 11-speed cranks and 44.5mm for 12-speed cranks.

Another difference is that the chainring spacing is narrower for the narrower chain, and getting the front-derailleur adjustment perfect might prove elusive. It would not fall within the design range of the 11-speed front derailleur, since the chainrings are closer together. It will also depend on all the other variables already determined with the frame and braze-on front-derailleur mount positioning.

The wider 11-speed chain could also prematurely engage the shifting ramps on the large chaining when pedaling in the small chainring while cross-chained to the smaller sprockets. That is nothing new, though. This can sometimes be an issue anyway with compact (i.e., 34/50-tooth) chainrings on a bike with short chainstays originally specced with standard 39/53-tooth chainrings, even when the two cranks are designed for the same number of gears as the bike’s drivetrain.

The 12-speed crank on the 11-speed drivetrain may work just fine, but since the design specs are different, and since I haven’t tried it, I can’t say what your experience will be. If you try it, let me know how it works.

― Lennard

Dear Lennard,

With respect to your recent column about the improved safety of road tubeless due to improved diameter standardization, I have a few thoughts and questions. I for one was certainly alarmed by the initial/previous article and went out to my garage to pet my tubular tires.

I have only ridden tubulars on the road for many years and have reached the point that their perceived hassle just doesn’t seem that great to me. However, I recognize that times are changing, and so I had been wondering about the evolution of road tubeless and if I need/should consider it. It sounds like the overall situation is looking better; however, it also sounds like one will need to be careful and aware of which tires and rims are not just compatible, but safe together. Frankly, I’m not sure know how to feel confident in that arena, so maybe you could provide some “rules of thumb”? Lastly, have you tried liners such as the one Vittoria makes with road tubeless? Per BRR, there is essentially no increase in RR, and they offer some security/retention and limp-along ability if you have a flat.

– Scott

Dear Scott,

Hmmmm. Rules of thumb. One rule of thumb might be to go with a combination of brands that you know has always adhered to the ETRTO 622mm bead seat diameter (BSD), like Continental for the tires and DT Swiss for the wheels (and supplied rim tape). There are, of course, many others, and I have no way of producing such a list based on actual measurements of a wide sample of each manufacturer’s products.

Another rule of thumb would be to use the tubeless inserts that you mention; those make tire burping next to impossible by holding the tire beads outward against the rim walls. Since tire burping is the methodology (other than a massive puncture from a big, sharp object or an explosion of a worn-out tire carcass, both of which are dangers also shared by non-tubeless tires) for a tubeless tire to suddenly suffer a drastic loss in air pressure that endangers the rider, eliminating burping essentially eliminates any decrease in safety margin of a tubeless tire relative to a tubed clincher tire.

I have not personally tried the Vittoria Air-Liner tubeless inserts you asked about. However, the fact that Florian Vermeersch placed second in the 2021 Paris-Roubaix with those inserts leads me to believe that they are reliable and worth using.

― Lennard

Dear Lennard,

I did have a (Gates) belt break this year while dirt touring in the Swiss Alps. My belt was eight years and tens of thousands of miles old. I wasn’t able to find a replacement belt high in the Alps, so I rented a bike for the last three days of our tour.

I would never have been able to get anywhere near the life of the belt out of a chain. When I rode the Great Divide with my Rohloff hub, the chain lasted (only) about 1200 miles. As for breakage, the belts are very light, and I have since learned to just carry a spare belt with me “just in case”.

I agree that it is not a good idea for a racer to use a Rohloff, as it is about 1.5 pounds heavier, and it is also a bit less efficient. But it is a great option for a long-distance tourer.

– Larry

Dear Larry,

Thanks for highlighting how long the Gates belts last, as well as how light they are to carry along. Regarding a spare, however, carrying one along only makes sense to a rider wearing a pack or attaching a large enough pack on the bike. A belt is definitely too big to stuff in a jersey pocket or in a spare-tire bag under the saddle.

― Lennard

Dear Lennard,

In regard to today’s VeloNews post concerning riding after back surgery, I too have had two back surgeries in the same spot in the lower back, one at age 30 and another at age 35. I am 54 now. After my second surgery, I moved my saddle a little forward and moved my bars so that they are just below the saddle. My body tells me what is too low. I am fortunate that I was able to have Tom Kellogg build me a bike seven years ago with a tall head tube. My mountain bike has a similar set up. I think my prior position, with low bars and the saddle way back, as was the rage in the 80’s, did me in.

I enjoy your articles and refer to your repair manuals often.

– Kevin

Dear Kevin,

Indeed, raising my bar and increasing my head tube length as I age has been part of my being able to continue to ride comfortably.

― Lennard

Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder and purveyor of non-custom huge bikes , a former U.S. national team rider, co-author of “The Haywire Heart,” and author of many bicycle books including “Zinn and the Art of Road Bike Maintenance,” “DVD, as well as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Cycling Primer: Maintenance Tips and Skill Building for Cyclists.”

He holds a bachelor’s in physics from Colorado College. 

Follow @lennardzinn on Twitter