Digging through patent documents can sometimes offer hints at what we might be riding in a few years' time. Many of the weird and wonderful designs don't see the light of day, but even then it's interesting to see what ideas the bike industry's brains are working on. Here are a few that we've spotted lately from SRAM that all relate to AXS electronic shifting components.
SRAM's Axle-mounted AXS battery
A patent filed by SRAM in 2021 called "power supply in a bicycle" shows a battery housed in a thru-axle that could be used to power an electronic derailleur or other electronic components. The patent art shows the axle battery connected to the derailleur in several different ways, but all the drawings show a style of direct mount derailleur like the one we saw here
and which was patented earlier in 2021 - we covered that patent here
Some embodiments (possible versions) have an external wire connecting the axle to the derailleur's "bracket" - the cage which extends down from the frame and is separate from the rest of the derailleur. Others show how the wiring could be routed inside the bracket with a charging port on the back.
The advantages? The patent mentions that the axle battery could supply power to more than just the derailleur, for example, "a derailleur, seat post, bicycle lighting, an air pump, a GPS transponder, a shock, or other component." So, perhaps, one battery could power multiple devices. Also, the patent goes on to say that the internal location protects the battery from water and dust ingress, as well as impacts. It may also have a larger capacity than external batteries, which it says "may be limited in size to reduce unbalanced weight or reduce likelihood of impacts". Finally, the document says the battery may be charged without removing it from the bicycle (something which isn't possible with current AXS batteries). "Alternatively," says the patent, "the power supply may include disposable batteries that may be replaced by the user."
Solar spare battery charger
Another SRAM patent filed in October 2020 describes a solar spare battery charger. The small solar array could be mounted to a fender, bottle cage, or elsewhere on the bike, and would be connected electronically to a mount for a spare AXS battery. It wouldn't be able to charge the battery while it's in use but would slowly charge up a spare and keep it charged. This is potentially useful because batteries slowly lose charge over time, so a spare battery stored long-term on the bike might otherwise be useless by the time it's needed.
In low light conditions, a capacitor could store energy from the solar cells and periodically discharge this energy into the battery, thereby allowing the battery to trickle charge even without strong sunlight. Presumably, it would take a long time to charge up a battery unless you ride in the desert (theoretically, a 10*10 cm solar panel could charge a 2.2Wh AXS battery in a couple of hours in ideal conditions, but with trees, mud, and clouds it will take a lot longer), but there is value in just stopping the battery from going flat over long periods of time.
Self-charging (& self-shifting) derailleur
If solar charging wasn't enough how about this: SRAM could be working on an electronic derailleur that charges itself as the rider pedals, and maybe also shifts gears automatically.
, filed in May 2021, was brought to our attention once again by an article on Bikerumor
. It shows a derailleur which houses a small generator in the cage assembly, which is powered by the rotation of the upper jockey wheel via a mechanism of gears and pulleys which step up the rotation speed. Potentially, this could mean never having to recharge or replace the battery. Indeed, the drawings don't depict a removable battery or a charge port.
The obvious drawback of this approach is that the energy required to do the shifting will come from the rider and not a battery. But this is true of a mechanical system too, except there the energy comes via your thumb instead of your legs. Besides, the energy requirements will be very
A current SRAM AXS battery contains 2.2Wh of energy and lasts for around 20 hours of riding. That means an AXS derailleur is drawing on average about 0.1 Watts of electrical energy. So if this system is 50% efficient at generating electricity (which isn't great - electric cars can recover over 80% of their kinetic energy during braking), you're still talking about 0.2 watts or so, on average. It will be more if you're shifting frequently, but potentially less if you're not. The point is, you're probably not going to notice any drag.
Also, the electronics for shifting the gears seem to have been moved from the back of the derailleur body to the derailleur cage - a bit like SRAM's electric road derailleurs.
More interestingly, the patent mentions the possibility of automatic shifting. The pulley wheel generator could act as a chain speed sensor which, along with information about the chairing size, could tell what cadence the rider is using in real time. Potentially, it wouldn't be so hard to have an automatic shifting algorithm (perhaps configurable to your tastes in an app) to keep you in a sensible cadence automatically, much like Shimano's XT Di2 drivetrain
is meant to do.
Will it see production? I suppose that hinges on how many riders find it a chore to remove a battery to recharge it after every few rides. For forgetful types or those who like multi-day rides in the wilderness, it could be very appealing.
I thought you Br'ish blokes were good at the sarcasms?
We're as good at sarcasm as Americans are at school shootings
good day, old boy!
ask me about the number of $350 cassettes I have seen destroyed on Ebikes because the owner only uses the top 3 gears. lol
And yet, I haven't broken one yet either.
I’d be real surprised if you actually did either of those things by laying your bike, unless you mean in a crash.
If you weren’t twisting der and hangers in the heyday of 9spd, then you’re not doing any damage to current 12s stuff.
Seems like user error on your part dude. ;-)
cavaleri bikes / effigear does it. Only that they work with a not very known motor brand and that I already pre ordered two of their non e-bikes and both of the models disappeared on the webpage after a few months and I got refunded.
Seems like no one is capable to build a payable, reliable gearbox and obvsly no Gearbox motor.
Pinion are leaking quite often (can see it in our shop) plus they are terrible in sandy conditions and so far they don't seem to work with a motor company, even though they have some patents pending.
Panasonic tried it but people have the option to shift themselves so they never shift and the motors melt...same story as with the 3 top gears.
I guess a reliable option that is customer proof would need to be fully automatic, shifting only after 90 crank rpm, needs to be sealed like crazy and, and, and.
A package like this would probably cost more than an E-Bike of these days.
I still hope that we are going to see some tinkering hero who has the knowledge and patience to build a gearbub in to the frame similar to the high pivot design of zerodes G2 DH-Bike.
If you'd run a Shimano Motor and a Nexus/Alfine Di2 hub that would pretty much tic all the mentioned boxes above.
If only I won the lottery and knew how to weld.
But let's hope the industry hears us...
I dont just throw my bike driveside down out of the back of a pickup into a pile of bricks after every ride.
I have working drivetrain components on old bikes from the 90's. I can't imagine any of the electronic stuff lasting a fraction that long. It's like the old household appliances that used to last 20+ years, but now you're lucky to get 5 out of the washing machine that has an app and tweets you when your laundry is done.
Problem is most derailleur impacts are not a sideways only motion, typically the rider's forward momentum provides the force, so the AXS movement doesn't really help a lot.
AXS haver here, just felt it would be fair to compare apples to apples on that aspect. Without AXS having that feature, it would have been *worse* than a standard derailleur in terms of impact, that feature puts it in line.
Yes! I don't understand why people want every device in their home to be a smart device...making it more expensive, more buggy, more things to go wrong.... I wouldn't care so much, except it's difficult to find items now that aren't "smart".
I have AXS on two bikes. It's nice. But...I'm not sold on it being the greatest thing ever. I still want a cable on my commuter and my trail bikes. It's kind of a bummer knowing that my Dura Ace equipment roadie, with external cables, can't be upgraded to a top tier group set without going wireless.
Anyway, you can build extremely durable mechatronic systems if you're willing to spend the money. Another good example are electronics in cars, which we often complain as being a source of unreliability. Ever compared the electric connectors of an average car to those in a , say, Valtra tractor ? Or even to those in a Leopard tank ? We're just not willing to pay tractor or tank level prices for our car, but still want the electronic gimmicks. So it's not necessarily an issue with the electronics
Hopefully this is getting better with the new design...
On an MTB I can only see disadvantages in electronic shifting. Don't get me wrong, I'm not against electronics in MTB, I ride all the time with a Garmin and a powermeter, and couldn't do without them, but mechanical has also the advantage to control the pull and that's a good thing in MTB when you're grinding or maybe suddenly find yourself in a harder gear than you should. These scenarios just don't happen on the road when you're always at much higher cadences.
The shifting is dead perfect, EVERY.SINGLE.SHIFT. always, unless something is bent/broken. So you know immediately if you need to address it. There is no cable/housing to compress, get gunked up and degrade over time. The mech doesn't rely on a spring that slowly loses tension over it's life, for shifting.
Yes, it's expensive. but the performance difference is absolutely quantifiable.
Can I look forward to being a curmudgeon SS rider?
Cheers for all the replies, good starting point.
I’d love the climbing ability and range of the first 10 gears combined with reliability that comes from the thicker materials and lower tolerances of less gears. Lasts longer not as prone to skipping due to tiny misalignments etc.
"I found this one the web for "Siri shift 3 to my higher ears please"
PS all you daft bastards who actually buy these ridiculous electronic derailleurs etc are probably part of the reason we don't have proper gearboxes yet, why would they change things when they've got all these pay piggies spending 700$ a pop on what are essentially consumable parts...
I sometimes get the feeling that some just like to pretend like Pinion doesn't exist just to act frustrated and "against the Man"
As for charging on the bike, no thanks. I like that I can take those batteries off and conveniently leave the bike where it is without having a dirty bike in a hallway or trying to buy some 6 metre USB charging cable to reach the bike. Disclaimer, live in an apartment now with no lift, no garage, and a cozy kitchen living room. We have enough stuff jammed in here without trying to eat dinner with a bike leaning on us at the table. I'm about to install a Knog Scout to try and not looking forward to charging it.
Except broken axels happen.
I suppose there’s going to be a DUB wheel axel standard now to make this work, hubs will be the new BB when it comes to ….is this the right one that will work with what I have .
Would have figured a direct contact would have been nicer than a cable
I don't remember no one complaining about that issue...I mean, does not looks a market demand.
Especially with electronic shifters.
Electronic shifters remove a bunch of potential mechanical failure modes pertaining to precise shifting during a ride.
Cables that stretch and need adjusted over a length over time.
Sheathings that can get kinked or otherwise damaged in a way that may inhibit to prevent smooth cable actuation and cable return(which is the important bit).
For someone like me who might get 2hrs max a week riding, that is a very valuable thing to have... Shifting that is repeatable and not dependent on a cable and sheathing during a ride and requires no maintenance ither than keeping the derailleur clean and charging a battery (or not with the self charging one) Ensuring shifting is repeatable and has little failure modes during a ride is more important to me than being able to replace a cable or sheathes in the garage at another point. Time constraints....bad shifting ruins a ride that i wont get to do for nearly another week or more and pisses me off.
Even the idea of a self charging derailleur battery is something i can get on board with, but as with anything it has to be implemented correctly and maintained.
Im not at this stage yet, im still on purley mechanical 11spd gears but i did kink a gear cable last ride in a crash and i still haven't had the chance to fix it yet. But if i had the money i do see the value in investing in axs.
There is perceived value in AXS in the eye of the beholder who has the right set of riding requirements that AXS satisfies.
The majority of pinkbike commenters most likely do not fall into this category.(this is a big potentially egregious assumption..20/30 something..single...alot of spare time)
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