Technical FAQs: mix of Campagnolo 11 and 12-speed components, tubeless road safety, back surgery

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Have a question for Lennard? Please email us at [email protected] to be included in the Technical FAQ.

Dear Lenard,

I want to use a Campy Super Record 12 crankset on a Campy Record 11 speed drivetrain.
How will this work? Will it perform as well as an 11-speed crankset? I use a cable Campy Record band.

-Walter

Dear Walter,

If Campagnolo was asked, the official answer would be “no”, of course. Campagnolo does not generally design or test backward compatible systems, and unless it does, it will not recommend it.

It can work quite well, but there are several 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 perfect front derailleur setting can be tricky. It would not fall within the design range of the 11-speed front derailleur, as the chainrings are closer together. It will also depend on all the other variables already determined with the positioning of the frame and front derailleur hanger to be brazed.

The wider 11-speed chain could also prematurely engage the shift ramps on the large chaining when pedaling in the small chainring while chained to the smaller cogs. This is nothing new, however. This can sometimes be a problem anyway with compact chainrings (i.e. 34/50t) on a bike with short chainstays originally specified with standard 39/53t chainrings, even when both 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 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 Lenard,

Regarding your recent article on improving road tubeless safety through better standardization of diameters, 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 stroke my tubular tires.

I’ve only ridden tubulars on the road for many years and have reached the point where their perceived hassle just doesn’t seem that important to me. However, I recognize that times change, and so I wondered about the evolution of tubeless road and if I needed/should consider it. It seems that the general situation is improving; however, it also seems like you have to be careful and know which tires and rims are not only compatible, but safe together. Frankly, I’m not sure how to feel confident in this area, so maybe you could give us some “rules of thumb”? Finally, have you ever tried slippers like the one Vittoria makes in road tubeless? Per BRR there is virtually no increase in RR, and they provide some security/retention and limp ability if you have a flat.

–Scott

Dear Scott,

Hmmm. Basic rules. A rule of thumb might be to go with a combination of brands that you know have always stuck to the ETRTO 622mm (BSD) bead seat diameter, like Continental for tires and DT Swiss for wheels ( and the supplied rim tape). There are, of course, many more, and I have no way of producing such a list based on actual measurements of a large sample of products from each manufacturer.

Another rule of thumb would be to use the tubeless inserts you mention; these make tire burping nearly impossible by holding the tire beads outward against the rim walls. Since tire burping is the methodology (other than a massive puncture caused by a large sharp object or an explosion from a worn tire carcass, both of which are hazards equally shared by non-tubeless tires) that ‘a tubeless tire suddenly experiences a drastic loss of air pressure which endangers the rider, the elimination of burping essentially eliminates any decrease in the safety margin of a tubeless tire compared to a tubed tire air.

I haven’t personally tried the Vittoria Air-Liner tubeless inserts you mentioned. However, the fact that Florian Vermeersch finished second in Paris-Roubaix 2021 with these inserts leads me to believe that they are reliable and worth using.

-Lennard

Dear Lenard,

I had a belt break (Gates) this year while on a dirt tour in the Swiss Alps. My belt was eight years old and tens of thousands of miles. I couldn’t find a spare belt in the Alps, so I hired a bike for the last three days of our tour.

I could never have approached the belt life of a chain. When I rode the Great Divide with my Rohloff hub, the chain lasted (only) about 1200 miles. As far as breakage goes, the belts are very light, and I’ve since learned to only carry a spare belt with me “just in case”.

I agree that it’s not a good idea for a runner to use a Rohloff because it’s about 1.5 pounds heavier and it’s also a bit less efficient. But it’s a great option for a long-distance traveler.

–Larry

Dear Larry,

Thank you for pointing out the durability of Gates belts, as well as their lightness to carry. As for a spare, however, carrying one only makes sense for a rider carrying a bag or strapping a large enough bag to the bike. A belt is definitely too big to fit in a jersey pocket or in a spare wheel bag under the saddle.

-Lennard

Dear Lenard,

In regards to today’s VeloNews post about riding after back surgery, I too have had two back surgeries at the same location in my lower back, one at age 30 and another at 35 year. I’m 54 now. After my second surgery, I moved my saddle forward a bit and moved my bars so they were just below the saddle. My body tells me what is too low. I’m lucky to have had Tom Kellogg build me a bike seven years ago with a tall head tube. My mountain bike has a similar setup. I think my earlier position, with low bars and the saddle way back, as was the rage in the 80s, got me in.

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

– Kevin

Dear Kevin,

Indeed, raising my bar and increasing the length of my head tube as I got older has been part of my ability to continue riding comfortably.

-Lennard


Lennard Zinn, our longtime tech writer, joined VeloNews in 1987. He is also a custom frame builder and supplier of huge non-custom bikes , a former U.S. National Team rider, co-author of “The broken heart” and author of numerous books on cycling, including “Zinn and the art of road bike maintenance,” “DVDas good as “Zinn and the Art of Triathlon Bikes” and “Zinn’s Introduction to Cycling: Maintenance Tips and Skill Building for Cyclists.”

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

Follow @lennardzinn on Twitter

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