A couple of years back, Finnish ski wax brand Rex jumped into cycling with a two-part race day-only chain lubrication system developed to get you free watts. Now they are back with a new nanotech-powered Black Diamond chain lube that is easier to use, longer lasting, and has been independently-tested to be even faster!

Update: Rex has since updated us with pricing. See below…

Rex Black Diamond wax-based, “fastest ever” chain lube

Rex Black Diamond lube, paraffin wax-based nanotech fastest ever bicycle chain lube

While Rex is still a big name in ski wax, they continue to shave watts in cycling as well. The result is a new ultra-low friction chain lube called Black Diamond that uses nanotech particles specially mixed into a liquid wax formula to make an easy-to-use lube, which just so happens to be the fastest ever tested by Wheel Energy.

Rex Black Diamond lube, paraffin wax-based nanotech fastest ever bicycle chain lube

Wheel Energy laboratories, who remains one of the few truly independent lube efficiency testing facilities in the world, helped Rex in development by testing several iterations of their latest chain lube. Ultimately in the independent 300km test on the dyno (at 175W load), this new Black yielded the lowest resistance of any of the tested premium lubes. Rex even claims that the new lube was ridden to a stage win at the Tour de France this summer. Although they don’t say which rider it was likely due to sponsorship agreements, it looks likely to have been French rider Thibaut Pinot.

Tech details

Rex Black Diamond lube, paraffin wax-based nanotech fastest ever bicycle chain lube

The new lube is said to use “Black Diamond particles that are mixed into the lube in a time-consuming ultrasonication process” that Rex does in-house at their Racing Service laboratory. Those particles are embedded in the same high-fluorocarbon, paraffin-based N-kinetic nanowax carrier that Rex uses for their XC ski wax due to its low friction & excellent penetration. The new combination reduces overall friction, decreases wear, and also possesses improved rain resistance.

The new lube is simple to apply. First, degrease the chain, then just a single drop to each chain roller before you ride. Black Diamond does not use an evaporative solvent carrier, so you can ride immediately after lubing up.


Rex Black Diamond lube, paraffin wax-based nanotech fastest ever bicycle chain lube

The new Black Diamond lube is produced in-house in Finland by Rex. The first production batch Black Diamond just rolled off the line at the start of October, so it hasn’t made it out to shops just yet. And we are waiting to hear back on final retail pricing.

Update: Rex tells us that the new Black Diamond sells for 40€ for this 30g bottle. That compares to 18€ for their standard Domestique chain lube.

We have however gotten a small 30g/1oz bottle to try out ourselves, and have already put it to a few days of tough gravel testing. So far it’s been mostly dry drivetrain abuse, but with enough water crossings to accumulate a fair bit of dust & dirt. So far it is running smooth & quiet on the first application, but we’ll clean everything up and re-lube, then see about testing out the “rainproof” & “all-weather” claims. Stay tuned.



  1. Tom on

    be curious to see how long this stuff lasts. I’ll take a few extra watts if I can lube on a weekly basis, rather every ride/every other ride.

    • Collin S on

      Nano= 10^-9 or .000000001 meters in size or 1 billionth of a meter
      Micro= 10^-6 or .000001 meters in size or 1 millionth of a meter. That means that a nanoparticle is 1000 times smaller (technically it could be 100 times smaller as particles that are 10’s of nanometers long are still considered nano particles)

      • Dolan Halbrook on

        Yes, that’s exactly what scares me in terms of environmental impact. The smaller it is, the easier it disperses and becomes part of our soil and water.

  2. Bob on

    So this independent lab helped this company develop this lube? Kinda hard to stay independent if you are assisting in the development of something.

    • Tom on

      it definitely open up conflict issues if other mfgs are trying to do the same kind of things with the testers help. I’d bet Chinese walls don’t exist in this company, as it i likely tiny (1,2 guy max). On the other hand, if the testing co is transparent and honest, they are in a position to help guide development of good product.

    • MIkey on

      I’d say Wheel Energy is as independent as it gets. They also do lots of tests for many of the biggest tire manufacturers and some Pro Tour teams. Their tests help companies develop better products and being independent is a key selling point in their business (results don’t leak).

      I’ve been using Rex Domestique as a race day chain lube and I’m really impressed with the longevity, especially on long muddy XCM races. But it’s quite expensive and I assume this new Black Diamond stuff is a lot more expensive than the Domestique.

      • El Pablo on

        One has to doubt the validity of Wheel Energy’s testing as they show the Muc Off lubricant getting down to 0 watts of drag. How do you trust any of their other results if they didn’t take the time to sort out why one test resulted in impossible numbers.

        • Seppo on

          @El Pablo, you have misreadt the table. zero is the lowest point on the test, it’s not zero watts used. Everything is actually compared to clean, new dura-ace chain. Rex Black Diamond saves 19W compared to that D-A, with no lubrication.

  3. paul barrett on

    So the vertical axis is Watts, whats the horizontal axis? Looks like Muc Off performs better between 9 1/2 and 19 1/2? Did I miss something?

    • Viinapiru on

      On the horizontal axis there are 20 measurement points, spread evenly on 300km distance at 175W, 40km/h, 90 cadence. High and low peak values removed. It all reads in the whitepaper on their website.


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