A few newsletters back, RBR author and contributor Coach Rick Schultz offered tips on expanding your gearing with WolfTooth’s Road Link (his article is in the form of a downloadable PDF, in case you missed it).
This week, we’re very pleased to add a related gearing tip from RBR founder Ed Pavelka. While he was recovering from hip replacement surgery, Ed recently purchased a custom Independent Fabrications randonneuring bike equipped with SRAM’s eTap wireless electric shifting components. He loves his IF and wrote to share how easy it was to go super low with his eTap gearing. Here’s what Ed wrote:
In hopes of taking strain off my new hip and my soon-to-be 72-year-old pistons, I thought it would be wise to lower the gearing on my randonnee-style bike.
The original build was with a SRAM 22-speed drivetrain – 46/36 chainrings and an 11-32 cassette. 32 is the max cog that the eTap “medium cage” rear derailleur can accept. Or so SRAM says.
I bought the WolfTooth Road Link derailleur hanger extender after reading Rick’s RBR article a few weeks ago. The plan was to us the Road Link to lower the mech so it could handle an 11-36 cassette and give me a tree-climbing 36×36 low gear. Not that that’s even remotely necessary in Florida, where I live most of the year. But, the lower the better for my annual visits to Pennsylvania and upstate New York.
Before going to work, I watched several YouTube videos about eTap installation, tips and tricks. I learned that the 32T max could be successfully exceeded even without a Road Link.
Sure enough! By turning the derailleur’s B-tension screw way in (SRAM provides a real long B screw), I got the recommended 6-mm of clearance between the top jockey wheel and the 36T. A longer chain was required, but nothing else. Shifting was spot-on in the work stand and on a test ride.
Every gear combo from small/small to big/big (in my case 36×11 to 46×36) is scrape- and rattle-free, with no need to trim the front derailleur. In fact, the eTap “yaw” movement is self-trimming, and it works.
The B screw was the key to the whole thing. SRAM makes 2 eTap rear derailleurs, a short-cage that it claims can take a max 28T cog and a “medium” cage that can take a 32T. Simply by running the B 
screw way in, on the medium-cage a 36T is easily accommodated, and it looks like a 40T might work, too, even without the Road Link. It probably won’t be too many more years before I’ll need to try that.
I guess the lesson here is not to take manufacturer limits as gospel.
However, in my case, I’m using 46/36 chainrings instead of the traditional compact 50/34. To get the chain length right I wrapped it directly around the 36T cog and the 46T ring (bypassing the rear derailleur), pulled the ends tight together and added 2 links. This meant cutting only 2 links from the new chain.
It makes me wonder what would happen if I did have a 50T big ring. Would a standard road chain be long enough to accommodate accidental shifts into the 50×36 cross-chain gear without jamming the rear derailleur? Would the chain be so long that it would overlap at the jockey wheels in the 34×11 opposite cross-chain? In other words, would rear derailleur capacity come into play?
It’s an art, not a science!
Thanks for sharing, Ed!
Jim Langley is RBR’s Technical Editor. He has been a pro mechanic and cycling writer for more than 40 years. He’s the author of Your Home Bicycle Workshop in the RBR eBookstore. Check out his “cycling aficionado” website at http://www.jimlangley.net, his Q&A blog and updates at Twitter. Jim’s streak of consecutive cycling days has reached more than 8,000. Click to read Jim’s full bio.
I have the shorter cage E-Tap derailleur and I’m using an 11-28 cassette. Do you think a 32t work with that
set up and an aggressive B-Setting?
Based on Ed’s experience I bet it will work, Rick, but the only way to know for sure with any derailleur and gearing change is to try it. Manufacturers typically put conservative numbers on their maximum sprocket sizes. And, part of whether or not a gearing change will work is the dimensions/design/shape of the derailleur hanger on the frame. I realize that you may not want to pay for a new cassette before knowing if it will work. To get around that you might see if any of your riding buddies have a cassette with a 32T you could borrow. Or, you could ask a bicycle shop to let you try one which you will return back in its packaging if it doesn’t work. That’s the best way to figure out if it’ll work. As Ed wrote, it’s more art than science. Good luck! Jim
I am running an 11-30 cassette on a short cage SRAM eTap equipped Pinarello Dogma F8 with no problems whatsoever. I haven’t tried an 11-32 but may have to do that.
Thx. Rick O, I am running 11-28 on a short cage eTap on my and my wife’s bike. She will be over the moon happy if she can go to a 30 or 32 cog. Cheers;
Great to hear from our old friend Ed!
I have a recently built custom Bill Holland Ti frame. Iit was built up with Sram E-tap medium cage. I’m running 52-36 on the front and an 11-36 on the rear. I love the ultra-wide range without having to go to a triple. The shifting has been absolutely flawless.
I have a Calfee tandem 3X10 speed, Ultegra STI + XTR, 28-37-52 and 11-34 cassette. I want to try 2X11 speed with the same or better low gear (needed!). Is this possible: 30-46 super compact, XTR rear (with TanPan), Ultegra, 11-36 cassette?