Saturday, September 12, 2015

SRAM eTap Wireless Electronic Groupset

A bicycle groupset is a set of matched components from a manufacturer normally including front and rear brakes, front and rear mech, front shifters, Bottom bracket bearing, Cranks, Chainwheel and Chain.

A few years ago Shimano and Campagnolo introduced the Electronic groupset whereby gearshifting is performed using electrically powered solenoids,  not a mechanical cable linkage.

At the time most Engineers grumbled that it would have better to have Engineered a wireless system, but manufacturers said they had tried, and that the technology was not reliable enough.

But in 2015 SRAM has formally announced eTAP a electrical shifting system for road bikes that is controlled using a wireless protocol

Complete Road Groupset MSRP: $2,758 €2,691* £2,059*
  • Pair of Shift/Brake Levers
  • Front Mech with battery
  • Rear Mech with battery
  • GXP Crankset
  • GXP Team English Bottom Bracket
  • XG-1190 Cassette
  • RED 22 Chain
  • Brakeset
  • Battery Charger
  • USB Stick

Is this a big deal?

It's a huge deal!

At Eurobike they had fully working set of components that I played with for over 15 minutes.

Open Secret
As noted in the Eurobike article below, the Groupset has been used by selected triathletes and pro bike teams for some months now.  It's been photographed ad nausea, just not officially announced, until now.

Entry Conditions
This is a high priced, ultra light, road groupset.  It's not for Mountain Bikes, or those without deep pockets

It's not shipping till mid 2016 so you will need to wait

System Complexity
Analysing from a Systems Design perspective, your total system complexity just sky rocketed

(+ good and - bad)
+ Potential to more precisely setup each gear shift  (but not sure how that is how it is implemented)
+ Thinner hoods, mechanically simpler
+ Less cables, i.e. no shifter cables
+ Easier to mount than a wired system or change

+ Blips are small wired switches that can be added to ends of triathlon bars to perform additional shifting

+ Individual batteries on the changers means no annoying large battery somewhere else which needs a separate mount and of course wiring.

- Coin Batteries in hoods and at front and rear mech

- Mech batteries obviously need charging, so there needs to be a charger too

= Weight at par with best Shimano/ Campag competition

= SRAM is working with Garmin and others to integrate their shift data into head units

--- Past the reduced mechanical complexity,  you've added a electrical solenoids, wireless communication, with new encrypted protocols.  Huge overall complexity increase.

Wireless How
Individual components communicate using a proprietary wireless protocol SRAM called airea.
Utilizing 128-bit encryption, eTap® shift signals are transmitted and received in accordance with SRAM’s proprietary wireless protocol known as AIREA. Each time an eTap groupset is paired, a new encryption code is generated and assigned to the components in this group to ensure complete shifting security.

I'd comment then that this is therefore none of Bluetooth, ant+, regular wifi.   I'd speculate that it may export data into ant+ format to talk to Garmin head units.  We will see.

 More Pictures
(Click to enlarge as usual)

Eurobike Writeup

SRAM RED eTAP homepage
Introducing eTap
SRAM blipbox
SRAM eTap Shifters
SRAM eTap front Mech
SRAM eTAP rear Mech
SRAM eTap brochure