Technical FAQ: Shimano, Garmin, and a new book

Lennard Zinn addresses a question about using Shimano XTR Di2 and a Garmin, and then discusses the latest edition of one of his books.

Shimano XTR Di2/Garmin compatibility

Dear Lennard,

I recently purchased a Shimano XTR Di2 upgrade kit on sale. While they did permit the change from an XTR 11-40 to an XT 11-42 to preserve my low gear, I did not get the 9051 display unit but a 9050 one.

I have a Garmin 520 and am contemplating suspension upgrades, and would like to change the shift pattern to avoid that large-large gear combo in synchro shift mode. Do I have to get the 9051 unit or is there a way to update firmware and the rest of the LE Bluetooth functions for less money? Like adding the road part? This gear works so well that I actually shift gears much more often. I really wish for shifter buttons like my mechanical shifters. Thumb for easier and first finger for harder.
— Mike

Dear Mike,
You cannot get the SC-M9050 digital display to gain Bluetooth connectivity through any firmware updates. You either have to buy the SC-M9051 display or you have to get the D-Fly transceiver — either the EW-WU101 (both ports on the same end) or the EW-WU111 (one port on either end). Yes, those are generally used on road bikes.

Once you have either piece of hardware, you can connect it wirelessly to your smartphone or tablet and program whatever changes you want into your synchro shift mode. Some of the steps are not intuitively obvious, and I described exactly how to do it in this column.

Getting your Bluetooth working provides the platform for you to set up a dedicated page on your Garmin to monitor your Di2 with like this one I made on my Garmin:
— Lennard

‘Zinn & the Art of Mountain Bike Maintenance’

Dear Lennard,
I saw you have a new edition of “Zinn & the Art of Mountain Bike Maintenance” out. I have an earlier version. Why would I want to get the new one?

— Dave

Dear Dave,
Ha! Good question! I cover a lot of new stuff in this edition. After all, the prior edition was eight years old, and there has been a lot of development on mountain bikes over that time! The 6th edition is now almost 500 pages long and has more than 750 detailed illustrations and exploded views, including 150 new or revised illustrations, to make following each step crystal clear. The illustrations focus on only the relevant parts to a given procedure without the distraction of other items, as would have happened if I’d chosen to instead use photos.

Here are some things that are new in “Zinn & the Art of Mountain Bike Maintenance, 6th Edition:”

— Inspired by questions like the above one on Di2, I have written an entirely new chapter on electronic shifting. I believe it is the most complete guide to maintenance, service, repair, and troubleshooting of all Shimano electronic shifting groups anywhere. Determining how to install your system and route the electric wires is clearly described and illustrated. It also includes how to program your electronic shifting system for personalized shifting and how to display its status in real time and record shifts on a computer head unit like a Garmin.

— And when it comes to cable-pull shifting systems, I’ve added a lot more to cover modern, low-profile, and other wide-range rear derailleurs, including servicing and adjusting rear-derailleur clutches. Furthermore, “one-by” systems were not a thing when I wrote the 5th edition eight years ago, and this one goes into great detail on them — such as how and why the SRAM X-Horizon 1X rear derailleur and X-Sync 1X chainrings work in both 1×11 and 1×12 drivetrains. I’ve also updated the table illustrating compatibility between various shifters, rear derailleurs, and cassettes — answering the kinds of questions I frequently get in this column. [related title=”More Technical FAQ” align=”right” tag=”Technical-FAQ”]

— Since fat tires, tubeless tire technology, and rim and hub designs have changed so much over the past decade, I split wheels into a separate chapter from tires. New procedures for mounting and sealing tubeless tire systems are accompanied by revised usage guidelines for tire sealants to prevent flats for mountain bike and fat bike tires.

— The 6th edition now has detailed step-by-step instructions for overhauling thru-axle hubs, both loose-ball and cartridge bearing. It also goes into detail of completely overhauling a much wider range of freehub types.

— I separated the brake chapter into separate chapters on rim brakes and disc brakes. The disc brake chapter covers installation, adjustment, maintenance, service, and repair of all hydraulic and mechanical systems, along with various, detailed methods of bleeding hydraulic ones. I’ve added more on selecting and installing the correct disc brake mounting adapters as well.

— I’ve expanded the service and upgrading sections on pedals.

— I have complete installation, service, and bleeding instructions for dropper posts, which were in their infancy when the prior edition came out.

— I’ve completely rewritten the wheelbuilding chapter. The detailed, and extensively illustrated, step-by-step wheelbuilding instructions follow a completely new wheel-lacing pattern for building disc brake-specific wheels. I also give a number of methods for working with wheels that have thru-axles in a standard truing stand meant for quick-release axles.

— I have included many more detailed instructions on maintaining, servicing, rebuilding, and upgrading front-suspension forks and rear shocks in this book. These are accompanied by many new illustrations. I’ve also expanded the front and rear suspension tuning guides, including more detail and determining and setting preload, compression, rebound, and sag.

— I describe and have exploded illustrations of all the numerous bottom bracket “standards” and go into the details of installing the latest bottom brackets, including on fat bikes and 1×11 and 1×12 systems.

— For those starting with the basics, you can become the star among your friends on removing, installing, and adjusting thru-axle wheels. Adjusting the depth of thread engaged so that the lever points straight up the fork when fully tightened becomes a snap. You’ll understand why you might have had so much trouble removing a thru-axle wheel from a Manitou fork. The detailed series of illustrations and accompanying instructions provide a full education on how the system works so that you can envision what is happening inside when you install and remove the wheel from the key-interlock system. And installing a wheel on a Cannondale Lefty fork? No problem!

— In the back section of the book, I’ve updated and revised the troubleshooting tables, torque tables, and now have gearing charts for bikes with 26-inch, 27.5-inch, and 29-inch wheels with a wider range of cog and chainring choices.
― Lennard