SRAM Red eTAP Review

As noted yesterday, I recently had a chance to ride a new Trek Domane SLR with a SRAM Red eTAP 2×11 drivetrain.

eTap is SRAM’s new ‘wireless’ electronic drivetrain design.  I don’t know why wireless is in air quotes there–it truly is wireless.  The system works by having a compact lithium battery in each of the shifter paddles, and then detachable/rechargeable batteries on the front and rear derailleur.  The shifters and derailleurs are wirelessly linked–no cables, and no external batteries to mount.

This is the backside of the paddle–2 screws and you can access the (replaceable, but not rechargeable) lithium battery:


Removal of the batteries is a cinch–there’s a flip-toggle on the top, and then they just pop right off.  It seems pretty secure, but easy to operate.  Batteries are interchangeable front to rear.


The overall derailleur size is not hugely different from a Di2 derailleur–save for the battery on the back side.  Overall, the packaging is pretty elegant.

So there are no cables relating to the drivetrain.  There are still (obviously) brake cables.

So how’s it work?

The first function of any drivetrain is to shift.  It could be a perfectly engineered system but if it shifts poorly, then it’s a waste of time to even consider.  The eTAP shifted well under all conditions.  I was impressed by the positive nature of the shift and the very comfortable, tactile feel of the shift-toggles.  Under power, coasting, pedaling gently–it accommodated any shift you attempted very aptly.  Shifting felt confidence inspiring.

This drivetrain was set up so that the right toggle shifted down (smaller cog/faster gear) and the left toggle shifted up (larger cog/slower gear).  Pressing both toggles shifted the front derailleur.  While I had never ridden a bike set up like that before, it was intuitive and easy to pick up.  The hoods were very comfortable and immediately fell to hand.

My only criticism on the shifting was the speed of executing shifts.  It was noticeably slower than a well-operating mechanical setup and noticeably slower than Di2.  Candidly I didn’t do any stopwatch timing, but I would have to estimate that it took about twice as long as Di2 to execute a single cassette gear shift.  For a non-racer, that shouldn’t really be a huge issue…but even for a non-racer, it was noticeable.  I spent more mental energy planning my shifts than I normally would, and if I was going to go out on a sprint, I had to plan further ahead for the shifts to occur.  Once sprinting, shifting took longer as well.  I’ve been spoiled by Di2 and the instantaneous nature of the shifting.  I don’t know if there are settings that can be customized to increase the speed of the shifting, but I can say that this was unexpected and unappreciated.

That said, I like the toggle design better than Shimano–no more searching for the right ‘up or down’ button–just one big toggle that you can hit with your gloved hands and have predictable results.  I know Di2 can be configured different ways, but I really liked the ‘one toggle per side’ setup on the SRAM.

So what about wired versus wireless?  All things being equal, I think most people would prefer wireless.  No snaking wires through the frame, no worrying about wires shorting out or rubbing through, no need for a Di2 compatible frameset (or ugly external wiring) etc.  My concern is on the reliability of wireless.  When riding with 100 other eTAP riders, will my shifters continue to function reliably?  What about with age?  Those are concerns that are presently just theoretical–it functioned perfectly and I have no reason to doubt SRAM’s development of the product…but I think it’s fair to say that most consumers will have at least a moment of that thought/concern.  I have a very good wireless router at home for my wi-fi, but I still have to screw with it occasionally to make everything work right.  The Di2 on my Madone has been flawless-a few years in, I’ve never even had to adjust the derailleur.  So on this point, I’ll say…if the wireless is perfectly stable, then I’d prefer the wireless.

Too soon to tell on reliability, but SRAM has done a lot to say that they’ve tested this and it’s reliable.  They have a lot riding on the durability of this drivetrain, as they’ve put their eggs wholly into the wireless basket, and they’ve had some high profile challenges with product reliability over the past few years.  I’m hopeful and cautiously optimistic that this will be a reliable product.

What about having to maintain 2 (or 4) batteries?  Well the compact Li-ion batteries in the shifters should last a long time, and are easy to swap.  The toggles have status lights that will tell you battery status, so you’re not left stranded.  The batteries on the derailleurs are the same size and are interchangeable.  Removal/installation is a breeze, and charging 2 batteries is not much more of a hassle than charging 1.  I don’t know what battery life will be like, obviously.  One significant advantage I see over Shimano is that the batteries are interchangeable.  If you forget to charge and go out on a ride, chances are that your rear derailleur will die first–and you can stop, swap front/rear batteries, and continue your ride with a 1x setup.  That’s a huge advantage over Shimano (which defaults to 1x when the battery starts dying, but from experience, it’s not a very long window that it continues to operate).

I also think it’s a big advantage to have the batteries be external and easily accessible.  Sure, you see them more…but if my Shimano battery ever has a problem, replacement is more of a pain.  It’s also more of a pain planning for a Di2 compatible bike that can hide the battery and wiring (as I hate the look of external Di2 batteries on bikes).

For some bikes, the eTap is a no-brainer.  Bikes that aren’t Di2 compatible?  Yessir.  Bikes for travel, folding bikes and tandems (where cables are either inconvenient to set up or less reliable because of long pull distances)?  Absolutely.  I would love to run a set of eTap on the Mandem some day–that bike is screaming for this drivetrain.

So let’s do the big question: if I was building a bike tomorrow, would I go Di2 or eTAP?  Well, first I’d look into whether the shifting speed can be adjusted.  I’d really like the shifting to be more responsive than it was–and I’m thinking that something had to have been off on this particular setup, as other reviews I have read have not had this concern.

But yes, if I was buying tomorrow, I’d go eTAP.  Everything I’ve read has praised the stability and durability, and there have not been problems with cross-communication across other bikes running them in group rides.  The wireless setup is a big plus in my mind–and it opens up a range of bikes to the benefits of electronic shifting, without the detriment of trying to retrofit wires and batteries.  The feel of the toggles was great–and single toggles are better than the small buttons on Shimano, to my taste, particularly if you’re riding in adverse conditions with gloves on.

Moreover as I said recently, I’m moving from being a Shimano guy to a SRAM guy, based on Shimano’s intolerable market practices.  So yes, if I was building a new drop bar bike tomorrow, I’d put eTAP on it.  Time will tell how the reliability stacks up–I’m optimistic as noted above.  In the interim, it’s a great advance in technology that really opens up a lot of new opportunities for elegant electronic shifting.

Now I just need to make friends with someone at SRAM for some longer-term testing on the Mandem…



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