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Tech & Wearables

Technical FAQ: mixing and matching SRAM drivetrain components; more on Campy crank bolts; racks on carbon frames

Mixing 11- and 12- speed SRAM eTap shifters and derailleurs, 11-speed chainrings on 10-speed drivetrains, and mounting a rack on a carbon frame.

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

Dear Lennard,
Can SRAM AXS eTap MTB shifters work with 11-speed SRAM Red eTap derailleurs?
—Nick

Dear Nick,
No: 12-speed AXS shifters cannot communicate with 11-speed eTap derailleurs.

The only way to use 11-speed eTap derailleurs on a flat-bar bike is to use 11-speed Blips coupled with a Blipbox as the shifters.
― Lennard

Dear Lennard,
I’ve got a Campagnolo Record 10 UT compact crank on my only road/cross/gravel bike. I damaged the drive side of the crankset. Compact Record cranksets are unobtanium. Are there other compact or ultra-compact cranksets I could substitute that would be compatible with the rest of my Campy 10 drivetrain? (Really I have been on the ‘net a bunch trying to find such a thing and can’t).
— Tom

Dear Tom,
Most 10-speed cranksets (and even 11-speed ones) would be compatible with your drivetrain. I used to have Campy 10-speed drivetrains on my own personal road and cyclocross bikes with either Shimano, FSA, or Praxis chainrings mounted on Zinn 205mm cranks. They always worked fine together.

Back when Campy 10 drivetrains were current, we sold lots of our bikes with FSA, Shimano, or other chainrings on our own custom cranks paired with Campy 10-speed derailleurs, shifters, chains, and cassettes without experiencing any shifting problems. We almost always swap in our own cranks into all sorts of different drivetrains, because both our Zinn custom-bike brand and our Clydesdale stock-sized titanium bike brand are focused on tall riders, and the bikes are generally built up with cranks in the 190mm-215mm length range, which, of course, are not available from the drivetrain manufacturers. It has worked fine in each generation, with 9-speed, 10-speed, and 11-speed drivetrains. They always worked fine.

The thickness of the spider tabs on most cranks has not changed significantly since the days of 9-speed cassettes. We do get chainrings matched to cog count, but this is often not critical, either; we’ve found 9-speed and 11-speed chainrings to work with 10-speed drivetrains, for instance.
― Lennard

Attaching a rack to a rear thru-axle. Photo: Lance Holmberg
Mounting a rack to a carbon frame with an attachment point on a dropper-post. Photo: Lance Holmberg

Regarding putting a rear rack on a carbon frame:

Dear Lennard,
I put a rack on a carbon fiber mountain bike from Canyon. I used a Robert thru-axle and cobbled an extension to accommodate 29-inch wheels. The rack does not touch the frame. I had to accommodate the width of the axle as the rack is made with tubes and it cannot be bent like racks made with solid rods. I attached it to a dropper-post with a post clamp, not a frame seat post clamp. Since weight is directly on the axle, the rack can support much more weight than if attached to seat stays.
— Lance

Dear Lance,
That’s a great way to do it!
― Lennard

Dear Lennard,
I just read your latest Technical FAQ concerning the fixing bolt for Super Record Cranks. Yes indeed, it is a left-hand thread for titanium spindle as you state.

Less well known is the Super Record crank was initially released with a steel spindle and a conventional right-hand thread, matching the Record version.

I think the titanium spindle first appeared circa 2011. I think it was even an option for a while. Thus, an old enough Super Record may be either…

So, unless he knows the spindle material, it may be either way. But I suppose the answer remains “Turn it the other way!”
— Brian

Dear Brian,
Thanks! I had forgotten that the first generation of Super Record Ultra-Torque cranks had a steel spindle, and it came with right-hand thread.
― Lennard

Dear Lennard,
Regarding Shimano Synchro shift: Thanks for raising that caution, and for presenting a solution. I meant to note that my bike is a triathlon bike, and the Di2 bar-extension shifters do not permit the front shift that you describe, which would indeed be disastrous. I should also have warned against the automatic adjustment sequence in the e-tube firmware, which tries to force big-to-big. It didn’t break anything, but I had to remove my chain in order to remove the jam!
— Matt

Dear Matt,
That’s indeed the issue I was trying to warn against!
― Lennard

Dear Lennard,
I’ve read with interest the articles about skin sensitivity, and here are a few observations.

If skin redness appears, see a dermatologist. I had my annual skin exam yesterday and I discovered that what I thought was a chafing or dry skin problem where the suspenders of my bibs cross my shoulders was actually a minor skin fungus called tinea versicolor. It also tends to discolor the skin, making it lighter or darker. I’ve had it before in other places, chiefly my arms and on my trunk where moisture gathers. It’s easily treatable with a ketoconazole shampoo or (my favorite) tablets, taken once a week for two weeks. The latter works best if taken about an hour before a workout, as perspiration expresses it more deeply from within the skin. But in either case, see a dermatologist first. The drug is prescription-only and misuse can cause side effects or other problems. Another person may have something else that looks similar, so that’s why it’s important to see a dermatologist. The condition is more frequent in humid climates, but sitting around in wet, used clothing after rides can promote its spread.

Re: cleaning clothing, I used to have problems with odor caused by residual organisms (probably bacteria) as well as some skin reactions. This happened even with cleaning products that were advertised as effective for workout gear. I saw a tip on a cycling site, I can’t remember where to wash with a hypoallergenic detergent free of additives and scents (often concentrated these days) and a cup of vinegar with it. Then an extra rinse to get it all out. The result is no more stinky clothes and no irritation. I can hold my clothes in a hamper in the garage and wash this way when I have a good-sized load. The extra rinse also eliminates an issue I’ve seen with washer longevity — vinegar can degrade rubber seals if left intact. Also, leave the lid or door on the washer open so it dries out thoroughly or fungus can develop on the rubber parts. I use a detergent called Boulder Clean, available at Costco.
— Larry


Lennard Zinn, our longtime technical writer, joined VeloNews in 1987. He is also a custom frame builder (www.zinncycles.com) and purveyor of non-custom huge bikes (bikeclydesdale.com), 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 Bikesand 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.