The possibilities that electronic shifting opens up are nearly limitless. As long as a button can be pressed somewhere, a signal can be sent and the derailleurs will move to shift the bike. SRAM has shown this with their BLIPS and newer MultiClics buttons.

Now, it looks like SRAM has combined a detachable wireless BLIP with their drop bar road hydraulic brake levers to create a button-free AXS eTap shifter. And they’re doing it by making the brake lever itself the shift paddle.

To be fair, Shimano’s been using the brake levers as part of their mechanical shifting design forever. It’s called STI, for Shimano Total Integration, and was introduced in 1990, combining indexed shifters with the brake levers for road bikes. They even tried it for a year on mountain bikes, but they weren’t popular.

SRAM’s take on it is a bit different. Instead of using a lateral movement of the brake lever to pull cable, it’s simply creating a lever that pushes a button. With their Double Tap system, it only needs to push one button per side to perfectly control both front and rear derailleurs, so it works. Here’s how…

How SRAM eTap Brake Levers can pivot

sram patent for buttonless etap shifters

In this patent, SRAM explains that the brake lever is still attached to a main pivot (118, shown further below, with 94 being the axis of braking movement) that lets it pivot rearward as you grab it to activate the brakes. But that pivot point sits on a moveable member that pivots around a second axis (96) that is non-orthogonal (i.e. not perpendicular) to the braking pivot.

sram patent drawings for buttonless etap shifters

The drawings show multiple variations on the angle (96) at which the brake lever would move to create a shift…this lets SRAM angle the shifting movement however they want. It’s likely that getting the angle at which you push the brake lever sideways will be critical to having a crisp-shifting feel without also activating the brakes…and smooth braking feel without accidentally shifting.

In fact, the patent says the angle will likely be as severe as 45º to 60º so that as you pull the lever in the braking direction, “the shift-brake lever will be biased to pivot around the shift axis away from the shifting direction” to help prevent accidental shifts during braking.

If you’ve not ridden Shimano’s mechanical road levers, just know that getting distinct shifting and braking movements out of a brake lever is not only entirely possible, but also quite ergonomically functional.

patent drawings for sram etap with no shifter buttons

It sounds simple, but being able to move the brake lever in relation to the master cylinder presents a problem. While they could simply position the entire master cylinder on the rotating portion, SRAM presents a better solution that keeps the braking parts firmly mounted inside the hood. Here’s how it works:

The brake lever (22) pushes a pushrod (152) into the plunger (140), which is what moves the brake fluid into the hose. The pushrod and plunger are connected with a ball joint (154), and that allows the brake lever to have some lateral movement without requiring the master cylinder to move.

OK, so how does it shift?

The shifting activation is really simple. The brake lever is attached is to a part (110) that extends upward, creating a longer lever (102). A small shift actuator nub (11) on that lever will press a button (189, below) on a bolt-on wireless transmitter unit (Figs. 14/15 below).

That unit appears to be powered by a standard coin cell battery and is likely nothing more than a re-shaped, self-powered BLIP.

removable wireless shifter button for new sram axs etap shifter levers

The patent mentions that the position of the shift actuator is adjustable, letting them (and maybe you?) adjust the distance required to activate a shift. Regardless, the amount of brake lever movement required to initiate a shift should be very small.

The pairing/function button (194) and LED (192) relocate to the inside face of each shifter pod since there’s no longer a paddle for them to rest on.

What’s the benefit?

If you’ve ever grabbed a lot of brake, particularly on a rough gravel descent, and had the shift paddles (eTap or Di2) hit whatever fingers are still deathgripping the handlebar, and that paddle-to-finger contact limited how much braking force you could apply, then you’ll appreciate that there’s a lot more space now. This should allow deeper brake pulls. Or, at least, less encumbered braking on rough descents.

For smaller riders with shorter fingers, this should let them adjust the brake lever reach in further for easier braking, too.

SRAM’s patent also shows multiple heights for the forward bump on the hood, meaning riders could choose between different shifting module sizes if they wanted a smaller or larger protrusion on the front of the lever’s hood. Without wires, they’re simply bolted into place and easily swappable or replaceable.

Patent research assistance provided by Wheelbased.com. Check them out for deeper dives on some of these patents and more.

21 COMMENTS

    • been riding sti levers for almost 30 years now, never have considered them a disadvantage. the original 7400 series levers were and still are the best!

    • Just what I was thinking. Accidently shifiting while braking cost me so many good results racing as a kid. Tricolore 600 was so bad.

  1. I’ve always been secretely hoping that Shimano would do this at some point with di2. As much as I cherish and adore the wonderfulness of di2, I’ve always felt that there isn’t enough tactile difference between the twin shift actuating buttons behind each brake lever. Especially so with cold or numb fingers or whilst wearing thick gloves. There was an attempt to adress this issue in the current gen of di2 levers but it’s still not ideal and I’ve always yearned for di2 levers to mimic the mechanical ones with the brake lever moving laterally to activate the first shift button and a single small lever behind it that activates the second shift button.

    • This Sram lever will continue to brake on only one axis. The tiny amount of movement that the AXS levers move on Sram’s AXS groups will now be incorporated in the brake lever. People are over thinking this.

    • Exactly what I would say from a mechanical point of view. That said, I’ve been uninterruptedly using STI’s from their introduction around 1991 along with Campagnolo Ergopowers and I never found STI unnatural in any way.

  2. It’s funny. When I got my first STI bike, my immediate thought was “this is horrible”!

    Twenty minutes later, and I never thought of it again.

  3. Why not use strain gauges instead and do away with a mechanical pivot? If the brake lever is strained laterally beyond a certain limit then execute a shift.

    • strain gauge really? so lets put a power meter sensor into the leaver instead of a simple button cause why? you want this to be even more expensive?

  4. I don’t understand why, with electronic groupsets, levers are used to change gears. All I want is a button for up and button for down. Simple, lighter and cheaper. I’ve reprogrammed the secret button on my DA di2 to go one way and it works great. Had to do this as the lever actuator somehow stopped shifting. I took it apart to fix, very small and fiddly.

  5. Did you read the article? The whole point of moving the shift angle beyond 90deg was to prevents accidental shifts during braking. Don’t know if I’d swap out what I already have for this, but for those with fit issues, this could be a huge win.

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