Many modern bikes use high-tech electronics to enhance your ride, ranging from derailleurs to dropper posts and even active suspension systems.
When they’re working, the performance these systems enable you to achieve is unmatched by mechanical alternatives, but their Achilles heel is once they’ve run out of battery power, they are useless. They can even become a hindrance.
The best way to avoid disaster is to make sure your batteries are fully charged before you go riding, but if you find yourself on the trail with a dead electrical component, here are the best ways to cope.
Heed the warning signs
It’s worth keeping an eye on your charge levels while you're on the trail. SRAM AXS components display a green light when they're over 25% charged, a solid red light when the battery is between 10 and 25% full and a red flashing LED when battery power drops below 10%.
This indicator isn’t always the easiest to see, especially on derailleurs and seatposts, but if you stop for a rest trailside, it’s worth having a scan to see your charge levels.
On Shimano Di2 derailleurs, although 11-speed doesn't have an LED, it is possible to see the battery level on 12-speed Di2, but you will have to stop and press the function button. If the LED is red, the derailleur has less than 25% charge remaining.
Once the charge level drops, it’s prudent to be mindful of gear selection because your battery may give out without further warning. This means not shifting into the lowest or highest gears unless absolutely necessary.
If you stay around the middle of the cassette, when your battery dies you’ll at least be stuck in a fairly ubiquitous gear suitable for the widest range of terrain.
Plan your exit
If you’ve run out of juice in a key component such as your dropper post or gears while on a ride, make life easy for yourself by taking a breather and working out if you can optimise your return route.
Finding a flatter, more direct route back will minimise the need for gear shifting, or dropping your seatpost. This is especially applicable to eMTB riding, because mountain bike trails are typically rough and undulating.
Some bike parks and trail centres have access routes for service vehicles, which are not rough or challenging like the trails themselves. These are often signposted, so it can be worth searching around for one of these to travel on if you’re in any difficulty.
Swap batteries around
SRAM AXS systems all use the same battery. This includes RockShox Reverb electronic dropper posts, suspension equipped with Flight Attendant and AXS derailleurs.
If your Reverb dropper post battery dies while riding, you can swap in the battery from your derailleur each time you want to put it up or down. It’s a hassle, but at least you can still raise your saddle before climbs and drop it before descending.
If your AXS derailleur battery runs out, you can swap in the battery from your Reverb dropper and continue using the gears, leaving your dropper post in position.
A flat battery on your RockShox Flight Attendant is the least likely to ruin your ride. When the battery runs out, the LED indicator will flash yellow and the suspension will automatically switch into ‘Open’ mode.
You will lack the use of ‘Pedal’ and ‘Lock’ modes, but your suspension will still perform at its best for technical riding, meaning you can enjoy the descents as normal. Therefore AXS batteries can be swapped from Flight Attendant suspension and into either your dropper post or derailleur if they run out.
Likewise, batteries from the Fox Live Valve Neo suspension system can be swapped with those from Fox Neo dropper posts because the architecture is the same.
Unlike the SRAM AXS suite of components, though, Shimano Di2 and Fox Neo batteries are not interchangeable, even though they are very similar, so you can’t swap batteries from a Shimano Di2 derailleur into a Fox Neo product, or vice versa.
The best way to avoid having to swap batteries is to carry a fully charged spare with you. This is an extra piece of kit to organise and carry, but given they’re small (around 3.5 cubic centimetres) and light (circa 25g), it could be worth the peace of mind.
AXS button hack
SRAM AXS Pod Controllers are universal across AXS products and can be programmed for various uses including shifting, activating the dropper and changing suspension modes.
AXS Pod Controllers use coin-style non-rechargeable batteries that last ages. To check them, you can hold the AXS button on the controller and it will show green (6-24 months' life left), red (1-6 months left), or flash red for a critically low battery (less than 1 month life left).
If you’re unlucky enough to run out of battery power from your AXS controller during a ride, SRAM has built in a clever hack to help you out.
If you lose functionality from the remote, AXS products have a button on the body of the product itself so you can activate its functions. This includes derailleurs (front and rear), dropper posts and Flight Attendant suspension.
With derailleurs, it’s not practical to reach down every time you want to change gear, but at least you can change out of the biggest or smallest cogs into something more around the middle of the block. Doing so is simple: to shift into a harder gear, press the derailleur’s AXS button once, or to shift into an easier gear, double-tap the derailleur AXS button quickly.
An AXS-equipped dropper is even simpler – press the button next to the battery pack to open the valve (freeing the post to move up or down). Once the post is at the correct height, press the button once again to close the valve and lock the post in place.
For suspension equipped with Rockshox Flight Attendant, when the suspension loses connection with the Pod Controller, it will automatically default to the ‘Open’ fully-active mode.
While your pedalling efficiency may suffer for the rest of the ride, your bike will still give you maximum traction and should respond consistently to bumps. Alternatively, use the button on the Flight Attendant equipped component to cycle through the modes until you reach the one you want.
Other electronic derailleurs, such as Shimano Di2 and TRP E.A.S.I, do not have an override function built in, so if your shifter batteries go flat, you’ll have to make your way back to civilisation as best you can in the gear you’re in.
Navigation tips
If your bike computer goes flat while you’re out riding, it can be anxiety-inducing.
The best way to combat a flat GPS or phone battery is to carry a powerpack. Some can be quite compact and light, so it’s worth shopping around for an easily portable one.
If you don’t have a powerpack, one of the best ways to get out of trouble and charge your GPS or phone is to find a cafe, community hub or kindly bike shop where you could use a plug socket.
If you know your GPS or phone battery isn’t always up to the task, take a hard copy of your map in a plastic bag/case as a back-up and make sure you understand how to use it before setting off.
