Road Gear

Technical FAQ: Gearing compatibility, tubeless tips

Lennard Zinn address questions about mixing and matching drivetrain parts, how to seat tubeless tires while traveling, and more.

Dear Lennard,
Because of the terrain I frequent on my gravel/cross bike, I need a pretty wide gearing selection, but the surfaces are such that having a clutched rear derailleur would be fantastic. I think the following set-up would work properly, but thought you’d know for sure.

[related title=”More Technical FAQ” align=”right” tag=”Technical-FAQ”]

I want to use Shimano R785 shifters, road junction boxes, Absolute Black ovalized 42t ring on Ultegra crank, no FD, XT Di2 medium cage RD, SRAM 10-42 cassette.

This will give a great range, and I can easily swap rings or cassettes if needed for a particular ride.

I wish I could run a double up front, but my understanding is that, as of right now, the only way to make the XT rear work with those shifters is if no front is installed.

If this is all a pipe dream, I’ll probably just get a 32/48 crank and deal with the chain bouncing/rattling all over the place.
— Carter

Dear Carter,
I’ll bet that will work just fine. Depending on the length and/or angle of your derailleur hanger, you may have to tighten the b-screw in fully (maybe even reverse it) or get a Wolf Tooth RoadLink (formerly Lindarets RoadLink) to get it to run smoothly on the 42T cog.

And yes, you must either run an XT Di2 front derailleur or no front derailleur; a road Di2 front derailleur will not work with Di2 road levers and a Di2 MTB rear derailleur.
― Lennard

Dear Lennard,
My wife’s current main bike is Ultegra Di2. I don’t like the Shimano cassettes ranges; she has the standard 11/28. She in no way ever needs an 11. I would rather have a 12/xx. Either fill in a gap or give a 29 cog. I ride Campy Chorus 11 Mechanical with a 12/29.

If I put on a Campy rear wheel with a 12/29, will the shifting of the Di2 work with a Campy-spaced cassette, or is there a reasonably-priced option for a 12/29 Shimano cassette.
— Jeff

Dear Jeff,
Yes, the Campy rear wheel and cassette will work fine. The cog spacing is the same on 11-speed Campagnolo, SRAM, and Shimano cassettes.
― Lennard

Dear Lennard,
Through Lasco Concept, I can have my Ultegra 11-32 11-spd cassette machined to work with a 10-speed freehub. My question is: Will a 10-speed wheel work in a frame designed for the 11-speed setups? Yeah, the frame is carbon fiber and not ‘adjustable’ (cold setting the rear dropouts).
— Rich

Dear Rich,
Yes, the wheel will fit into the frame just the same. The rear axle “overlock” dimension (same as what the face-to-face spacing between dropouts on your frame should be) for road rim-brake quick-release wheels, whether 10-speed or 11-speed, is 130mm. And for road disc-brake quick-release wheels, the rear axle overlock dimension, whether 10-speed or 11-speed, is 135mm.
― Lennard

Dear Lennard,
I prefer to use friction shifting on my tri/TT bike, so I still use Dura-Ace 7800 bar-end shifters and derailleurs. My question is about using 11-speed wheels with this. Can I simply swap out my 10-speed chain for an 11-speed chain to make this work as long as I stick to friction mode? Or will I still have compatibility issues with things such as the pulleys? I don’t want to have to swap an 11-speed cassette for a 10-speed one every ride when switching between my Ultegra 6800 road bike and my 7800 (friction) TT bike. There’s not room in the budget for two rear aero wheels.
— Glen

Dear Glen,
Yes, that will work fine. The only changes you’ll need to make is to install an 11-speed chain and tweak the rear derailleur limit screw(s).
― Lennard

Feedback on previous columns

Regarding mounting tubeless tires while traveling with only a hand pump:

Dear Lennard,
I’m surprised you didn’t mention the homemade tubeless inflator option, such as this one: Make Your Own Tubeless Inflator.

There’s also a ready-made option called Airshot. I have no personal experience with either of these (yet), but it seems you would able to get enough air in one with a decent frame pump, and it would be small and light enough to travel with, certainly smaller than a double-chamber floor pump.
— Michael

Dear Michael,
Thanks for that! I received a number of emails about both homemade and commercial canisters for rapidly inflating tubeless tires that you can fill yourself with a pump, and yours was the only one that combined both of them.

I had forgotten about the Airshot as well as the SKS RideAir, slated for April availability, which comes in two versions, one of which includes an integrated cable lock for securing your bike. Both versions fit in a bottle cage and are marketed as environmentally-friendly take-along units to replace CO2 cartridges for dealing with flat tires while out riding.

The utility of any of these units as an air tank that you can fly with (depressurized, of course) and then mount tubeless tires with at your destination is obvious. I’m going to start including one of these in my bike case.

I also received email pointing out that, in the same column, I did not mention mounting tubeless tires with a compressor at a gas station, using a Presta/Schrader adaptor. That, however, was not an oversight; I intentionally did not mention that. When I’m traveling in Europe and end up via public transportation at a hotel, I want to be able to ride out of there. I don’t want to lug my bike around, with two flat tires, to a gas station that may or may not offer compressed air to its customers. I can rarely think of when I’ve been in hotels in European cities where I even noticed a service station close by.
― Lennard

Dear Lennard,
I’ve not had the direct problem the recent article addresses, but my experience as an early user of Stan’s conversion kit on MTB tires makes me believe that using a rubber rim strip could help.

I find that the tire “seals” to the rim strip quite nicely such that when I change tires on my MTB, I’m required to peel off the rim strip. I keep using the rim strip for this reason despite the newer rim interfaces not making it necessary to obtain a seal, as it seems to prevent tire burping.
— Bill

Dear Lennard,
I was thinking, when reading your latest Tech FAQ, I’ve been using American Classics wheels for a couple of years now, and the tire beads are really hard to get off the rims when switching or fixing flats. As you probably know, the AC tubeless have an extra little hook built into the profile that keeps the bead in place. I literally have to wrestle the tires to unseat them every time. I’ve used Shimano and Stan’s tubeless rims before, and beads always pop off once the air comes out.

There are probably other companies with that rim feature that would work the same, but I just thought that would be one option to keeping tubeless installed and deflated for packing.
— JF

Dear Lennard,
I was pleased to find that I am able to fit 32mm tubeless tires into my Co-motion soft case without fully deflating them. I suspect this would work with the S&S backpack soft case as well. I’ve never had any damage using a soft case. Co-motion even recommends them over the hardshell case. Perhaps other folks traveling tubeless would have an easier time with a softer case?
— Doug

Regarding using a 10-speed wheel with an 11-speed drivetrain

Dear Lennard,
In your Technical FAQ you responded to a question from Jonathan about using an 11-speed cassette on a 10-speed Shimano freehub. There is a fourth option you didn’t mention. I have been using 11-speed conversion cassettes from Edco for the past couple of seasons. They work great, are available in a number of configurations, and are a much less expensive option than replacing a perfectly good 10-speed wheelset.

Here is a link to the Edco site. The cassettes are also available in the U.S. from several vendors.
— Ted

Dear Ted,
Great suggestion! Thanks!
― Lennard

Regarding stuck Campagnolo levers

Dear Lennard,
I can attest to the problem of Campy shifters jamming up on you. It’s certainly user error, mostly happens in the winter wearing heavy gloves that rest on lever while resting on the hoods, which then prevents actuation of the button shifter, i.e., using them both at the same time. I have gotten used to the error and have learned to correct it pretty quickly, even at 30 degrees.
— Alan