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Technical FAQ: Electronic shifting delivers a national champion

  • By Lennard Zinn
  • Published Oct. 22, 2013
  • Updated Oct. 30, 2014 at 5:31 PM EST

This week we’ll tackle more compatibility issues, this time between 10- and 11-speed drivetrains and Campagnolo compact derailleurs and cranksets, but I’m most excited to relay my experiences with electronic shifting through the first month of the cyclocross season. More on that below.

10-speed cranks in 11-speed drivetrains?

Dear Lennard,
I know you’re getting bombarded with 10/11-speed compatibility questions, but I’ve exhausted all other avenues on this one without a clear answer. Can you run 10-speed chainrings (cranks) with an otherwise 11-speed drivetrain? I’ve heard conflicting reports around the forums, and the LBS guys don’t know.
—Kurt

Dear Kurt,
Absolutely, you can. I’m doing it myself on all three of my road bikes and one of my cyclocross bikes. I have never had a shifting problem due to it, and I’ve not been able to measure a difference between the chainring spacing of the 10-speed cranks and 11-speed cranks from Shimano, SRAM, or Campagnolo. Consequently, when we build up bikes for customers, which often are equipped with cranks we make here and which I designed during the 10-speed era, we use 10-speed chainrings on 10-speed and 11-speed drivetrains.

The crankarm’s spider tab thickness is definitely the same on both 10- and 11-speed cranks. The distance between teeth on the two rings of different diameter is harder to measure, so I’m less confident of the exact measurement, but if it’s different, it isn’t by much. Finally, the fact that the new FSA chainrings that we’ve been getting from QBP are labeled “N10/11” indicates, to me, that there is indeed no difference.

Another anecdotal piece of evidence: I did this SRAM Yaw front derailleur setup both with the SRAM Red 11-speed crank the group came with, and with my own crank, both with 10-speed Praxis Works and FSA chainrings, and we do it frequently on customers’ bikes with the latter. The shift performance in the stand and while riding is exactly the same.
―Lennard

Stop the rubbing!

Dear Lennard,
I switched to a 50/36 Chorus Carbon CT crankset a few years ago (2009?), but kept my older (~2003) Record front derailleur. I’ve now changed the inner ring to 34t. Bike is 2004 Colnago C-40 Carbon, with braze-on front derailleur.

Shifting, in general, is fine, but I’ve always had some chain rubbing on the inner FD plate when on the small ring/large rear cog, but I rarely needed this combo so I didn’t worry about it. I’m now doing more mountainous riding, hence the switch to 34t, and the rubbing is driving me nuts! It now rubs when on the two larger rear cogs.

I’ve moved the lower limit screw all the way out, and loosened the cable tension to “floppy”, and no difference. The FD is just bottoming out. Would a newer FD, or a CT-specific FD, likely make a difference?
—Darrel

Dear Darrel,
I can’t remember exactly when Campagnolo offered both a “CT” (compact) front derailleur and a standard one, but your 2003 unit is likely in the realm of when the company made that distinction. It’s possible that going to a current Campy front derailleur, which works for both compact and standard chainring sizes, could make a difference. If you never had rub with your 39-53 chainrings, then it probably would.

The interesting thing to me, though, would be to find out where the derailleur is bottoming out. Is the return spring hitting the seat tube, and that’s when it’s stopping? Or is there still space between the frame and front derailleur when it’s in the small-chainring position? And it never reached this point on your old crankset? It could be that your front derailleur is hitting a wider section the seat tube that it did not before, simply because it has been slid down further on the seat tube for the smaller chainrings.
―Lennard

More on electronic for cyclocross

Dear Lennard,
Thinking back to your recent column on electronics for cyclocross, there is one other reason to be sure that your shifters are really secure with Di2: if your shifter slides even a couple millimeters, it will unplug the electronics cable and you’ll then have a single speed to ride for the rest of the race. And, the amount of movement may not be perceptible to the pilot. I did this in two races before figuring it out. I may be cute, but not very smart. The shifters didn’t unplug during practice; I never hit stuff as hard in practice as I do in races.
—Rick

Dear Rick,
That’s a very good point. Glad I didn’t have this problem, too! On Campy EPS levers, the wire wraps around in little grooves in the lever body to take up slack, so it won’t unplug if the lever slides down.
―Lennard

Electronic shifting delivered a national champion

Dear Lennard,
We have a national champion because of electronic shifting. At the 2013 cyclocross national championships, Steve Tilford went down and tore his rotator cuff. He never went in the pit after the crash because he could not shift gears with that arm. His pit bike was not Di2, and the bike he was on had Di2. If he would have not had electronic shifting, there is a good chance he never would have won the race.

From Tilford’s blog:

I don’t think I did anything wrong. I just got unlucky. And maybe if I wouldn’t have fallen so hard on the second lap, I would have been fine the rest of the race. When I fell, my gloves were totally, completely soaked. And every other time I fell they just got re-soaked. So, my hands were pretty useless the last couple laps. I was thinking about making a bike change, but wanted to stay on my bike with Di2, electronic shifting. I’m pretty sure I couldn’t have shifted mechanical shifting.

—Jeff

Dear Jeff,
I can well imagine that. I crashed a half-dozen times in my race at nationals on the same morning as Tilford. And my gloves also were completely soaked and my hands also did not work well. Electronic shifting would have been nice then (but braking predictably with numb hands on such a treacherously slippery course was a bigger problem for me). Finally, on my last crash, I broke my right lever body so that the shifter no longer worked and released all of the cable: I only had my 12-tooth cog for the last section of the course and had to run the last hill. That’s when I got passed and lost the top-eight finish that would have, if I understand the rules correctly, secured an automatic front-row spot for the upcoming nationals here in Boulder, Colorado. Oh, well. I suspect that my EPS electronic shifter still would have worked if the lever body were cracked the same way, since it does not require significant leverage off of pivots in the lever body.

Even without cold, wet, or a torn rotator cuff, I discovered once again in racing the Boulder Cup last Sunday what an advantage electronic shifting can be. The course was set in a much more challenging layout than had ever been done at Valmont Park (the upcoming nationals venue), and there was one particularly steep, rough, and fast downhill heading straight down a hillside with a buttonhook right turn at the bottom, sending riders straight back up the grassy (weedy) hillside. Over the knoll dropping into the descent, I wanted to be pedaling hard in a high gear, but as soon as the hill started really dropping, I needed to be pulling the brakes hard and hanging on for dear life. It would have been very hard to shift a mechanical system in those conditions but I could just hold my EPS downshift lever inward while pulling the brakes and pedal a turn or two when I had a chance to get it to go from the smallest to the biggest cog and be ready for the steep uphill after negotiating the hairpin at a super slow speed. There were some other places on the course leading into barely-rideable sections straight up the hillside after sharp corners where I was glad to have electronic shifting as well.

The amazing thing is that, if I hadn’t been having some heart problems this summer and fall, I might never have discovered for myself what an advantage electronic shifting can be on dry courses. I built my disc-brake/electronic-shift bike specifically for the mud I expected at masters ’cross worlds in Louisville, Kentucky, last January, as well as for gravel-grinder events like Dirty Kanza that I wistfully plan to do someday. Our flood a month ago notwithstanding, we rarely race in mud here in Colorado, so I figured I would rarely race the bike in ’cross, since, despite being made out of the same magnesium tubing and having top-shelf components, it weighs three pounds more than my cantilever-brake/mechanical-shift ’cross bikes.

Then I discovered that in order to have both derailleurs work properly, neither my planned 36-40 Rotor Q-ring chainring setup for ’cross, nor my planned 36-52 Rotor Q-ring chainring setup for road would work. I tried to knock a pound or so off of it by removing the front derailleur and running a single chainring, but the Campy EPS rear shifter would go to sleep in under a minute after the last shift if the front derailleur was disconnected. I was left with the 36T-Rotor-Q/50T-round-chainring setup described in the answer to Valeriano last week. Turns out, I never use the 50T in ‘cross, so it just serves as an outer chain guard, and now the only thing to change when switching from ’cross to road is the tires. Now that’s a versatile bike!

And what does my heart have to do with this bike? My heart issues have inspired a new, lower-key approach to cyclocross racing for me. I now am only doing races that I can ride to. I don’t bring multiple bikes or spare wheels, and I have no stress about remembering to throw everything I might need in the car, nor am I driving to the venue in a panic because I didn’t allow enough time to get all of that extra stuff together. If I flat, I have a spare tubular in my pack that will get me home (this happened on Saturday when pre-riding the Boulder Cup course on my ride home after the Colorado Cross Classic!). And since I am just doing it for sheer joy and am unconcerned about the results, then of course I’m going to ride my new bike with all of its bells and whistles, whatever the extra weight! Also, my single-chainring ’cross bikes don’t have a high enough gear for efficient road riding in varying terrain, and this bike with a 50×11 top gear is perfect for getting to the races.

Consequently, I’m learning a lot about racing ’cross with disc brakes and electronic shifting, and I like it, especially on technical courses! I also end up getting in a lot of relaxing miles; between racing and riding to and from the venues on our big UCI-race weekend in Boulder October 12-13, I rode 3.5 hours on Saturday and 2.5 hours on Sunday!

Thanks to my more laid-back approach, I’m also trying other things I normally would never try for fear of a failure during a race. One example is sticking my ’cross tubulars onto the rims without glue and instead with prototype Effetto Mariposa gluing tape. It’s way faster and cleaner, and it allows me to change tires the night before a race (like the night before the Boulder Cup when I flatted on my ride home from the Saturday race). I have no concern about rolling them; they’re totally stuck onto the wide Enve 29er XC rims, in part because they have such a deep gluing channel that adhesion at 25psi is much less of an issue. I used an earlier prototype of the Effetto Mariposa tape on the road all summer without problems, but I haven’t tried either generation on narrow rims with ’cross tires yet. …
―Lennard

Get back to cloth tape to keep clean

Dear Lennard,
Saw your advice regarding handlebar tape and cyclocross bikes. If you’re looking for tape that will stay clean despite mud, sludge, and pressure washers, I’d suggest hopping in the way back machine and going with cloth tape covered with shellac. everal great reasons to do this:
1) Cheap;
2) Great grip — I haven’t found anything as grippy as shellac tape — no need to worry about your hands slipping provided you don’t put on too much shellac;
3) Impervious to weather;
4) Durable, takes a pretty hard spill to tear it up — usually it just scuffs which can easily be touched up with fresh shellac; and
5) Light (it always seems odd that people spend hundreds of dollars to shave a few grams off their stem or bars but then put on relatively heavy bar tape).

Downside is the complete lack of padding, but it’s cyclocross, not the RAAM. Tough it out. And those fancy schmancy carbon bars and forks are supposed to magically absorb all those bumps, right?

Cloth tape and the Cinelli plastic saddle are the two retro items that still have a place on modern ‘cross bikes.
—Chris

Dear Chris,
Wow, another use for Shellac in cyclocross! But a Cinelli Unicanitor plastic saddle? Wow. Not sure I want to go there again. …
―Lennard

FILED UNDER: Bikes and Tech / Technical FAQ TAGS:

Lennard Zinn

Lennard Zinn

Our longtime technical writer joined VeloNews in 1987. He is also a framebuilder, a former U.S. National Team rider, and author of many bicycle books, including Zinn and the Art of Mountain Bike Maintenance and Zinn and the Art of Road Bike Maintenance, 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 degree in physics from Colorado College. Readers can send brief technical questions to Ask LZ.

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