BUTTERWAGONTECH

HOW YOUR FORK FIGHTS FRICTION

If you drop the lowers on your new BoXXer Ultimate, you might see something you didn’t expect—a matrix of divots machined into your upper tubes. No, you can’t see them above the wiper seals, and that’s on purpose, because they’re there to help lubricate your bushings.
  

TO BEGIN: WHAT'S A BUTTER WAGON?

Good question. At RockShox, we call our trail and gravity fork team the Butter Wagon team. They came up with these little divots (and ButterCups!), so we leaned into that, and voilà: ButterWagonTech.

The idea is quite simple. Divots machined into the upper tubes collect oil from the bottom of the lower legs, then as the fork moves through travel, those divots deliver oil up to the bushings to reduce friction.

Adding ButterWagonTech to the upper tubes reduced static friction (friction between two resting surfaces) by 3%, a solid improvement on its own. But we found that they also reduced dynamic friction (the forces that resist the movement of the surfaces once they’re in motion) by 9%, which impressively impacted ride feel.

But our engineers weren’t done there.

Suspension, and really any parts that are designed to slide, are in a constant battle with friction—causing heat and stiction that can eventually bring things to a halt. It’s an invisible force that designers are always trying to find ways to improve upon. This is why ButterWagonTech was developed, but also why we decided to revisit our lower leg lube (and seal grease) to find the perfect trio to combat friction.

Lubrication is a player with many talents. Not only does it provide a fluid barrier between the bushings and the upper tubes in your fork, but it also keeps those moving parts running smoothly, reducing wear over time. We wanted to tweak that particular variable within friction, so we started looking for how to up our game. The science behind interactive surfaces in relative motion, Tribology, is complex, but our goal is to make sure your ride is not. Our engineers considered several factors while creating the optimal recipe:

• Lube that's too thin means the oil doesn't linger on the surfaces it's intended to benefit, and it can lead to greater degradation over time.
• Lube that's too thick can cause drag and can even act as another damper within the system.

The just-right concoction we've landed on improves friction durability for longer and lingers on sliding surfaces longer. And while it does add a modicum of extra damping, we addressed that in the damper itself, making it a tunable part of the fork’s feel instead of something you’re fighting against.