It was Eurobike 2015 when we last spoke to Spank and found out a little about their Vibrocore handlebars. In short: No, it’s not just expanding bulders foam, yes it does attenuate vibration, and the biggest surprise: it dramatically increases the fatigue life of the handlebars. Unlike this thing, Spank actually had lab testing and data to back up their claims of vibration reduction.
For 2017, they’ve returned with a new product bearing the Vibrocore moniker: rims. That’s right, foam filled rims. Just like with the bars, Spank have made similar assertions for Vibrocore rims: attenuated vibrations, and higher fatigue life. They also said an unexpected effect of the Vibrocore rim was a quieter ride: without a hollow rim to bounce off, apparently sound that would normally echo around inside the tyres is significantly deadened.
These also have a completely new rim profile – they haven’t just taken an existing rim and filled it with foam, but taken what they learned with handlebars and designed the rim extrusion to work with the filling. In a move that bucks current industry trends, they’re also saying their 35mm outer width rim profile is designed to allow riders to move back towards higher tyre pressures while maintaining traction. The foam adds 40g per rim, and they also said one of the hardest problems they had to solve during prototyping was how to inject a rim full of it cleanly and efficiently without it going everywhere. You can shove the foam in any hole, but there are 65 others for it to shoot back out of!
As you can see, the rim has a very low profile, at just 17mm vertically from the spoke holes to the top of the bead lips, compared to a 35mm outer width. The foam apparently reinforces it enough that this can greatly increase wheel compliance and comfort without compromising strength.
The rims have been ridden by the Spank Team, Commencal, and been put through their paces in the SGS test lab. At present, Spank are only planning 27.5″ and 29″ versions of the rim, no 26″ for now. Initially, the only wheelset it’ll be included with is their Spike DH wheelset, with a 150mm rear hub, but rims will be sold separately too. A non-Vibrocore version of the rim will be on their trail wheelsets and also available separately.
You can read Spank’s own pitch for Vibrocore and how it works here.