Introducing the Kolossos Pulsar, our fastest derailleur upgrade yet

When we threw our latest prototype oversize pulley system onto the test rig for friction testing, the standard setup gave us a reading of zero watts friction losses. Zero. Zilch.

Now, as much as we would love to claim that we broke the laws of physics and invented a perpetual motion machine that defies thermodynamics, we know better. Our regular sensors simply weren't sensitive enough to detect the friction losses coming off the bearings. We needed to procure a higher-precision, hyper-sensitive sensor just so we could get an actual numerical value on the board.

That prototype is now ready for prime time, and it's called the Kolossos Pulsar. It is our fastest Kolossos to date.

First, a Quick Detour Into Astrophysics

Before we get into what makes it tick, let's talk astrophysics for a second, because if you're going to give a bike component a space-age name, you better back it up with a fun astronomical tangent.

A pulsar is what happens when a massive star collapses at the end of its life. What's left behind is an insanely dense neutron star with a wild magnetic field, shooting giant jets of radiation out of its north and south poles. More importantly for this conversation, pulsars spin extraordinarily fast. We are talking about a star making hundreds of rotations per second. They are literally the fastest spinning physical objects in the known universe.

While we can't guarantee your legs will spin at seven hundred revolutions per second without causing severe biological distress, we wanted to build a pulley wheel system that lived up to the name.

What Full Ceramic Actually Means

The Pulsar runs on full ceramic bearings. Most ceramic bearings on the market, including our own standard hybrid ceramic setup, use high-grade silicon nitride ceramic balls rolling inside hardened steel races. Steel races are fantastic: they're tough, smooth, and durable.

Full ceramic bearings take things a step further by using ceramic for both the balls and the inner and outer races. With super round balls running on a glass like surface, there is very little friction to be lost. But the main benefit comes from the fact that full ceramic bearings do not need any lubrication. After all, there are no metal parts that can corrode.

That matters more than it sounds. In a standard bicycle bearing most of the drag comes from the lubricant and the seals. Even a light oil will slow down your bearings in a clean environment. This is why many other cages on the market are sold to you with dry bearings for showroom performance, and with a bottle of oil in the packaging to add your own friction for riding in the real world.

The 30 Second Free Spin

If you get your hands on a Pulsar and give the lower wheel a quick flick with your index finger while hanging your bike on the repair stand, you'll notice something right away: it just keeps going. And going. A 30-second free spin on that lower pulley wheel is standard.

Of course, free-spinning a pulley wheel on a workstand isn't the same as laying down maximum torque on a steep climb or sprinting for a town line sign. Free spin looks great in Instagram reels, but structural stiffness is what actually keeps your chain aligned when you're grinding up a climb or trying to win a town sign sprint. A flimsy pulley cage that flexes under load will ruin your shifting precision faster than a bent derailleur hanger, throwing away any wattage savings you gained in the bearings.

Built on Platforms That Already Work

That's why we didn't build the Pulsar on some fragile, ultra-light experiment of a cage. Instead, we built it directly on our proven, ultra-stiff Speed Kolossos and Aero Kolossos platforms.

If you're already familiar with our lineup, you know the Kolossos platform was designed from day one to keep derailleur cages rigid, precise, and dependable. The oversized wheels prevent the chain from excessive articulation to reduce friction, while the stiffest cage on the market guarantees crisp, snappy shifting every time you switch gears under load. The Aero version wraps that same stiff structure in a streamlined, wind-cheating profile for time trialists, triathletes, and anyone who thinks aerodynamic drag is a personal insult.

Good, Better, Best

With the Pulsar joining the family, our derailleur cage lineup settles into a clean Good, Better, Best hierarchy.

Last year we introduced the Kolossos ST, running on our stainless steel bearings for riders who want 90% of the performance with zero fuss. That's our "Good" benchmark, bulletproof reliability. Our standard Speed and Aero Kolossos sit squarely in the "Better" spot as the classic all-rounder for riders seeking a huge reduction in drag with everyday durability. And now, the Kolossos Pulsar takes the "Best" crown at the top of the pyramid for anyone chasing absolute peak efficiency and the lowest friction numbers humanly possible.

How to Spot a Pulsar

Visually, we kept the Pulsar clean and distinct. You can spot a Pulsar by looking at the lower chain guard, where we've etched an additional Pulsar icon into the metal alongside our standard branding. It's subtle enough to look stealthy, but distinct enough that fellow gearheads in the group ride will know what they're looking at.

Fits and Finishes

We are launching the Pulsar in fits for both Shimano road and SRAM AXS road systems, across both the Speed and Aero cage shapes. We do not recommend using Pulsar for off road use.

• Speed Kolossos Pulsar for Shimano Dura-Ace R9200 and Ultegra R8100
• Speed Kolossos Pulsar for SRAM Red and Force AXS
• Aero Kolossos Pulsar for Shimano Dura-Ace R9200 and Ultegra R8100
• Aero Kolossos Pulsar for SRAM Red and Force AXS

Color-wise, we're keeping things classic and offering a few head-turning custom finishes right out of the gate. You can get it in standard anodized black, a gloss white launch edition with a large Cerakoted logo, and if you want to match your frame or go down a personalized rabbit hole, custom Cerakote options are available on both the Speed and Aero platforms.

Whether you're looking to squeeze every last watt out of your race setup or you just really appreciate high-end engineering that spins almost effortlessly, the Pulsar is our answer.

Ride on!