What is Crownring?

Crownring is a bicycle chainring that is so named for its unique opposing "crowns". The crowns, their size, and their timing are all factors in the Crownring's efficiency. The crowns provide two radii per rotation. Crownring is the only bicycle chainring that can claim dual ratios within a single stroke. It is akin to changing gears mid stroke to maximize your power, but it does so transparently without the need of any hardware beyond the Crownring itself.

Why Is it More efficient?

The straight knee posture throughout the second half of a stroke is stronger than the bent knee posture in the first half of a stroke. By timing an increase in radius to align with the increase in strength there is a boost in speed. The rider has little notice of the change because the crown is nearly equal to the rider's increased strength.


How is that more efficient?

The round chainring possesses the same dynamics as Crownring. The differences come from the chainring demanding the same force from the weaker bent knee as it does from the stronger straight knee. They share the same radius. Crownring lowers the bent knee radius and thus the force requirement. The lowered radius benefits casual riding where applied force is less. Crownring retains low radius through the center stroke where leverage offers the best mechanical advantage for uphill travel.


More so, the round chainring has little cultivation of the straight knee strength because it depends on reduced leverage to raise the ratio. By the time the leverage and leg posture are prime for power input the pedal is no longer traveling down but has increased resistance by traveling backwards. Crownring raises the ratio while leverage and straight knee strength are both near optimal during a phase of continued downward pedal travel. Crownring uses your peak strength whereas a round chainring does not.


Why doesn't the increased radius become harder to pedal?

It is kinetic energy that moves your bicycle. Pedaling only overcomes resistance.

Speed increases kinetic energy. As you accelerate, your force overcomes the resistance of going faster. Kinetic energy is still powering your bicycle. In fact you are adding energy to energy. The more speed you have the easier it is to go faster.

Crownring offers more speed for less effort. It is literally faster and easier by using strength you didn't know you had. Combining your straight knee strength with the crown you gain a boost of speed while completely unaware that you are doing so. More speed increases kinetic energy. Kinetic energy powers your bicycle. Every stroke is feeding more kinetic energy to the following stroke making resistance easier to overcome.


Wouldn't Crownring make it harder to go up a hill?

On the contrary. The radii align with your strengths. When your leverage is at peak mechanical advantage the radius is low giving you more climbing power. Thereafter the crown rises with your straight knee strength while there is still significant leverage advantage. Crownring improves uphill travel two ways; it provides a lower gear ratio at peak leverage, and it takes advantage of increased strength to increase speed. The reason a bicycle fails on a hill is because the added resistance eats up kinetic energy. There is not enough energy to carry your pedal forward to an effective ratio.  Crownring keeps your speed up thus maintaining energy.

It is true that there are hills to challenge Crownring, but just as your pedaling nature skips the dead zones of your stroke so will you skip the radius that is too high for your strength, but by then you've already increased speed so while Crownring might not tackle every hill, it has a much less stall rate than normal bikes operating at the same T value.


Will I still need gears with Crownring?

Yes and no. If you are used to gear clusters then you can continue to use them. Crownrings can be set up the same as a 21 speed, three rings upfront. This creates a very powerful bicycle.

On the other side Crownring makes a more effective single speed. It provides a dynamic gearing system without the need of additional gears. Your highs and lows are built into each stroke. The ratio that is effective will be used while the other relies on kinetic energy. When pitting a 48T Crownring against a 48T round chainring not only will the Crownring be much easier to power, but it is faster as well.

What ever you are used to, Crownring will improve it.


Does Crownring take getting used to?

No. In fact you won't notice the change at all. For the casual rider Crownring requires no change in technique. Hop on and go. For specialized riding; racing, tricks—Crownring can still benefit but not as seamless as when cruising. Specialized riders will need to take into account the changes in pedaling dynamics. But they'll get the hang of it in a minute or two.


What about compatibility?

Crown ring can replace any chainring on any bike. It has no special needs save for forward derailleur adjustment or replacement. The crown radius is higher than its counterpart and requires clearance. On the other hand, Crownring provides the same mechanical advantages as multiple chainrings. The best configuration is a single Crownring up front, and a wide gear spread on the wheel. This will give you more range than having multiple chainrings forward and be a lot easier to operate. It also avoids front derailleur complications.

A note on derailleurs: The front derailleur is a simple design that works but has never been entirely without issues. It can clack if you aren't adapt at adjustments, and it is easily knocked out of alignment. Some have difficulty holding themselves in place.

A Crownring derailleur can be made less complicated than the rear derailleurs and much more effective than current forward derailleurs. If you are set on multiple Crownrings forward then it can be done reliably with a derailleur specifically designed for Crownring.


Does one Crownring fit all?

Just as there are varied T-values for chainrings there are varied T-values for Crownrings. But Crownring goes a step further. You can chose the size of your crowns. In fact Crownrings with the same T-value but different crown sizes have entirely different performances. In addition to that, Crownring can be tuned by advancing or delaying its timing. There is not a more versatile bicycle drive component than Crownring.


Can I use it on an electric bike?

Yes! In cases where the motor is on a wheel and not on the crank axle, Crownring will let you use its greater efficiency to prolong your battery life. Keep in mind, Crownring replaces chainrings. Many electric bikes have a gearbox to replace the crank axle.  If you don't have a chainring then Crownring cannot be applied.

A common bicycle with a Crownring, and a front wheel motor conversion is a pretty good set up. You get the best of everything.


What about maintenance?

Crownring takes no more maintenance than a traditional chainring.


Can Crownring help me with my handicap?

If you struggle to ride a two wheeler or a three wheeler then yes, Cownring can reduce the effort you need to power your bike. In fact, Crownring was born from overcoming a handicap. Your special need will have to be addressed individually, but  Crownring is your best chance at getting riding again.


Will Crownring improve my fitness?

No, not in the way you might think. Crownring is easier and faster than a traditional chainring. It takes less effort to exceed common performance. In that, you get more from working less. That is the opposite of a workout. Then, if your goal is to increase stamina, Crownring can help with that.

However, you can increase your workout by using a larger T-value, and/or specific crown sizes. Crownring will challenge your entire leg regardless of posture. You will get more from a Crownring if you equip your bicycle for the workout. This takes more consideration than just using a bigger gear. Terrain and distance factor into your choices more than with a standard chainring. These dynamics will effect the choice for your Crownring profile. It is all here on this website. Just a little reading and you'll be able to equip your bike for any use you intend.


Crownring is more efficient, more versatile, easier, faster, and because it utilizes ergonomic bio-mechanics completely naturally, it has no downside. Crownring has the potential to benefit every human powered appliance in the world. It's not just bicycles and trikes, but camping generators, hybrid human powered vehicles, and anything with rotory pedals.

Crownring has the ability to increase bicycle acceptance and reduce the number of fuel burning vehicles thereby benefiting the environment. Crownring offers nothing but a host of advantages for the entire world. This isn't just hyperbolic fluff. Crownring will change the bicycle industry and it will do so quickly.

You can learn more about the many facets of Crownring by following the Crownring link on the left panel.