drivetrains – MTB Weekly

The wireless tech boom stops at nothing and, for better or worse, it is coming to mountain biking in 2019 with a bang. We’ve seen early signs in the past years, but with the introduction of Sram’s AXS platform, things are about to speed up and we will probably see other manufactures follow suite with their wireless solutions.

What are the wireless innovations coming in 2019 and where are they going to take mountain biking?

1. Wireless drivetrains

Drivetrains are going through a bit of a revolution lately. I’ve already covered the 1x v 2x debate in a previous post. Now, there are more changes coming with Sram dropping its fully wireless AXS system. It’s a 1×12 drivetrain that looks just like any other, expect there are no wires and the actuation happened electronically at the press of a button. This is the first time, as far as I can tell, that a manufacturer is bringing a mass market ready wireless drivetrain system. We will have to see how others respond, but my hunch is that we will see more wireless systems come out soon.

Shimano does have the Di2 system, which is about 4 years old. It is electronic, but not wireless, so you have to run a physical wire between the shifter and derailleurs. Despite this, it brings innovation in a different way, with its Synchro Shift system — a 2×11 that combines the simplicity of a 1x system with the gear range of a 2x one, bringing the best of both worlds. It does this by automatically adjusting the front derailleur based on the gear you choose in the back.

2. Wireless dropper-posts

Dropper-posts are another obvious component that can be stripped of wires. I believe Magura eLect was the first to introduce a wireless dropper post and now Sram has added the RockShox Reverb to the AXS platform.

There are a few advantages to a wireless dropper post. First, it has a nearly instantaneous response. With a hydraulic dropper, like the RockShox Reverb, it’s also less prone to issues, since the hydraulic system is enclosed in the seat post. You can also swap these dropper posts between bikes easily, since there are no cables to guide through the frame.

3. Wireless fork & shock controls

Being able to remotely control your lockout on both fork and shock is very useful. There are plenty of cable solutions out there, so you’d think the logical next step would be to make these levers wireless. But Fox decided to skip that altogether and introduced the Live Valve system, which adjusts the damping on both your fork and shock automatically. It takes 3 milliseconds to unlock your suspension when it senses you are going to hit an obstacle for the first time. It then keeps the suspension unlocked for a defined amount of time. And this period changes depending on if you are climbing or going down. It uses a 3-way accelerometer to figure this out. If you are going down, it will keep everything open for a longer period of time, if you are climbing, on the other hand, it will lock out much faster, so you don’t lose momentum.

Cannondale had a similar prototype a few years back, but only for the fork and it was much more complicated than what Fox introduces. Still Live Valve is very expensive at the moment and probably only useful to performance riders.

What about wireless breaks?

This one is a bit tricky and apart from a really rough prototype that came out a few years ago I haven’t seen anyone taking this on. The obvious issue is, that breaks have to work at all times. Whereas a drivetrain that runs out of batteries is still bad, but allows you to get home in one piece, a break that simply stops working when it runs out of juice is a show stopper. The trick is to develop a failsafe that allows the break to operate in some limited mode at all times.

The second challenge is that we’ve become really accustomed to modularity in breaking with hydraulic breaks. A wireless system would have to have the same modularity in order to get adoption.

With that said, it’s not completely unthinkable, so let’s see if someone comes up with wireless breaks.

A fully integrated system?

I think there is a lot of potential in an integrated system. Imagine your seat post dropping, your fork lockout opening up and gears getting into a sweet spot for descends at the press of a button. Sure, some will say that there are situations when they need an unlocked suspension but the seat post up. All that should still be possible. I think it will come down to how well the interface is designed. It has to be simple enough to actually make riding better, and yet modular to work in edge cases. But the potential is there.

Sram is particularly well positioned, because it owns RockShox and other component manufacturers. The batteries on the new AXS system are actually the same for the drivetrain and the dropper post. Maybe it’s a sign of more to come.

Diagnostics and riding recommendations

Another benefit of a fully integrated electronic system is its ability to collect data and serve you with diagnostics and riding recommendations. For instance, it could tell you to adjust your shifting or give you suggestions on how to tweak your suspension based on your riding style much like Quarq’s ShockWiz. Since Quarq is owned by Sram, this could be the next addiotion to their AXS platform.

Still expensive, but prices will eventually drop

Wireless and electronic systems are still very expensive. The top of the line Sram AXS XX1 will set you back $2000 and the X01 sitting one level below is only $100 cheaper. Shimano’s Di2 is about the same price.

Dropper posts are expensive as well. The AXS Reverb is a whopping $800 easily making it one of the most expensive dropper posts.

You also have to factor in the cost of batteries, that will lose their capacity over time and will need to be replaced.

With that said, much like with any other tech that catches on, prices could drop. The question is, whether Sram or Shimano, will be able to persuade enough people to purchase the expensive early models and justify further development.

Security concerns

As with any other wireless tech, people have already voiced concerns around security. Besides reliability, there is also hacking. This can be a particular concern for pro race teams, with rivals hacking into the wireless systems of other riders. I know it sounds far fetched, but we thought mechanical motors hidden in the frames of bikes were far fetched before they became true. Hopefully all manufacturers are investing into the security of their solutions.

How will this change mountain biking?

Just like with other tech advances, you inevitably start thinking about how it’s going to change things. For me, mountain biking is about unplugging from tech. I don’t wear a heart rate monitor, I rarely track my trip on Strava and my bike has 0 electronics on it. Don’t get me wrong, I’m not a tech hater, it’s just that I need a place and time to disconnect, and mountain biking gives me just that.

And yet, when I was thinking about wireless components I found myself excited about the possibilities. Sure, you have to worry about additional batteries to charge, as if charging our phones, headphones, watches, computers, and tablets was not enough. But, there are obvious positives too. It declutters your bike, it’s easier to maintain and I believe that with time it will bring additional benefits, like a fully integrated experience across components and diagnostics. So the jury is still out for me. I’ll try to get my hands on a bike with wireless components, to fully experience it and I’ll report back.

When I was buying my latest bike I had to chose between a 2x and 1x drivetrain. With almost all manufacturers offering both options in their lineup, it’s another hard choice you need to make. So which one is better a 1x or 2x drivetrain?

The short answer is – it depends. It comes down to the type of rider you are and the terrain you will be riding most. 2x gives you a wider range and makes it easier to tackle steep climbs, while the 1x is much easier to operate and is less prone to chain drops. Let’s look at both options up close to find out which one is right for you.

What does 1x and 2x mean?

The number refers to the number of gears you have. For example, a 1×11 drivetrain will have 1 gear in the front and 11 in the back.

Why chose a 1x drivetrain?

The main advantage of 1x can be summed up in one word — simplicity. Because you only have a rear derailleur, you can free up space on your handlebars and use it instead for a dropper post lever. You shift gears with one hand, leaving the other free to drop your post, break or just enjoy an energy bar.

The biggest advantage is probably how a 1x drivetrain lets you focus on your ride, instead of constantly adjusting gears. It’s also less likely that your chain will drop off the front since it’s fixed to one chain ring.

All this does come at a price. There is a noticeable drop between gears, meaning you might not be able to find the right gear every time. You also have less range on a 1x setup. This means that you might be riding on a harder gear up a steep hill then you’d like to.

Pros: weight and space savings, shifting with one hand, less prone to chain drops, easier for new riders

Cons: smaller range of gears making it harder to climb steep ascents, bigger drops between gears make it hard to find the optimal gear

Why is 1x so popular these days?

1x has gained a lot of popularity among riders in the last few years. Fueled by the rise of Enduro racing and technological advances making it possible to attain a working 1x setup. But the 2x system has still a lot of fans. In fact, Shimano did a survey recently and found out that it’s really 50/50 among riders.

However, I ran a small survey in the r/mountianbiking subreddit and the results were more in favor of 2x, again just showing there is no clear winner.

Why chose 2x drivetrain?

If what you are after is better performance on climbs, a 2x is a better option. The main advantage of having a front derailleur is the wide gear range it offers and a smoother transition between gears. The end result is an easier climb on steep ascents. It’s also gives you more confidence to explore and tackle unknown terrain.

The disadvantage is the extra complexity that a front derailleur introduces. For starters you have an extra lever to think about and adjust. It also creates extra clutter and adds weight to your bike. You also run a higher risk of chain drops with this setup. This can be minimized with the addition of a chain guide, but again — that’s more weight and complexity. You also need to tune and maintain an additional derailleur.

Pros: Better gear range and smoother gear transitions resulting in better climbing performance.

Cons: Extra complexity with the maintenance of front derailleur, additional gear shifter on handlebars and a higher chance of chain drops.

To get a better idea of the gear range a 2x offers, let’s compare it to popular 1x setups:

Which drivetrain manufacturer is better?

There’s a lot of drivetrain manufacturers, but the biggest by far are Sram and Shimano. If you are buying a mountain bike from any major brand, they will offer both Shimano and Sram options. So what’s the difference?

First off, I think it’s great we have two big names in the game. The end result is constant competition and pushing what’s technologically possible. We benefit every time.

There are a few differences between Sram and Shimano. Most noticeably in the shifting actuation, meaning the distance between shifts in relation to the lever index.

Shimano has a 1:1 ratio — the cable and derailleur move further between each shift. The end result is crisper shifting with a better feel and sturdiness in muddy terrain.

Sram on the other hand has a 2:1 ratio which creates smoother shifts with less effort.

The second difference is in the way you shift. Shimano lets you shift with both your thumb and your forefinger, whereas Sram is thumb-operated only. Sram also offers Gripshift with all their setups, letting you shift gears by turning the handlebar grip. It’s available throughout the range and is very popular with performance riders.

Sram is committed to the 1x setup and has only a few 2x options left in the low end spectrum of their lineup. Shimano still offers 2x setups in their high-end and flagship lineup.

Day to day life with Sram & Shimano

There’s more to it than just ratio difference. I tried to outline a few differences that matter in day-to-day life:

Sram is easier for unmounting the rear wheel: Sram has a unique system that allows you to lock the rear derailleur effectively removing all the tension from the chain and making it easy to unmount the rear wheel.
Sram has a positive click: when you shift on a Sram system you will hear a loud click – some riders like the “positive” click sound giving them a better connection with their bike.
Shimano allows you to shift 2 gears at a time: when going to a harder gear, Shimano lets you shift 2 gears at a time. Sram can only shift 1 gear at a time going to a harder gear. Both systems let you shift multiple gears when going down.
Shimano makes it easier to change the derailleur cable: If you are doing your own cable maintenance, Shimano has easier access to the cable housing and is simpler to work on.

Don’t get me wrong — both systems are great. There are small nuances that make them different and it’s really up to you, which one hits closer to home. Let me know in the comments which is your favorite and why!

Understanding the lineup

Both manufacturers have a different approach to their lineups. Sram is usually the more progressive brand, bringing innovation to market sooner, while Shimano has more options on the higher end of the spectrum.

What’s the future of drivetrains?

Technology is making its way into every part of mountain biking and drivetrains are no different. The two main manufacturers Shimano and Sram are fighting this one off with two different approaches to electronic drivetrains.

Synchro shifting from Shimano

Shimano’s approach is the Di2 system, which comes in 3 flavors: It can be a 1×11 setup which operates the rear derailleur electronically rather than with a cable-actuated system, or a 2×11 system with individual controls for the front and the rear derailleur. Shimano also offers their Synchro Shift system — a 2×11 that combines the simplicity of a 1x system with the range of a 2x one, bringing the best of both worlds. It does this by automatically adjusting the front derailleur based on the gear you choose in the back.

Wireless shifting from Sram

Sram has taken a different route with the just announced Eagle AXS system — a fully wireless electrical drivetrain. It’s a 1×12 setup that completely removes the clutter since there are no cables to run.

Conclusion

As with many other things in mountain biking (or life in general) it really comes down to your personal choice. If you are a rider that enjoys climbs and will seek steep hills to climb a 2x drivetrain is a better option for you. If you endure the climb up only to shred downhill, the 1x is a wiser choice. Whatever you pick, don’t forget to enjoy every ride, because that’s what it’s about!