Finally had a chance to roll some Rollerbones Turbo 85a while at Sk8mare in Oil City and these are not Your Mom's soft sticky 85a marshmallows.
To start off, these wheels are poured by Rollerbones themselves in Santa Barbara, USA and they use their own proprietary compounds. This lends to them not feeling like most other wheels on the market. The polyurethane in the Rollerbones Turbo is rubbery instead of like a plastic. Given this, if you pick up the RBT 85a and push on the edge of the wheel you will see it's really flexible and I believe this makes it grab far better.
Next, their wheel design is different. The extruded aluminum hub with the distinctive turbo blade design is larger than most other hubs but at 62mm diameter they are the same size around as most other wheels. This means the tire, or layer of polyurethane, is much thinner. The hub also has a slight extension on the inside which allows you to use them without frog washers if you need extra clearance for your hangers or trucks.
A bit of a lesson on polyurethane wheels. Given a specific and likely extreme weight, a typical 85a durometer (or hardness) polyurethane should compress about 5% maximum and for the same weight a 95a should compress about 1%. So if there's a 10mm thick layer of polyurethane a 95a will compress about 0.1mm whereas an 85a will compress about 0.5mm (source http://www.sdplastics.com). Not really much difference but, it's the energy you exert from your legs along with your weight which compresses that tire instead of propelling you forward.
For comparison, a common car tire is about a 70a durometer and the old school phenolic wheels (the rock hard ones which wouldn't compress at all) are about a 145r which would be really slippery on almost any floor. A 145r would be about equivalent to about a 170a durometer on the A scale or maybe even higher, if there was such a thing. The Shore A scale only goes to 100a technically (source http://en.wikipedia.org/wiki/Shore_durometer).
Now, with a thinner layer of polyurethane and the stiff Aluminum hub you get a sticky but really fast wheel which on some of the floors we skate on in Alberta is pretty awesome! The softer tire can grab even the smaller scratches in a slick skate surface giving you more traction and because the layer of polyurethane is slightly thinner than most wheels it compresses overall less (not less percentage wise) making it roll faster. On some slick floors, like the one at the Grind House, this is really awesome. So awesome in fact that I firmly (pardon the pun) believe that this is what let me pass my 10 lap WFTDA administered skate test there.
Now the question on everyone's mind, are they worth the money? After all, they are one of the more expensive wheels out there (not the most though). Yes, I totally believe they are. I'd say if you skate on hard to grip surfaces then they are definitely something you would want to try. They are a bit narrower and come in 62mm diameter and 37mm width only for now. Word is, they are also going to start producing some colours soon so stay tuned for that.
Rollerbones turbos come in hardness from 80a to 101a and we have them all in stock. Remember too, if you buy the wheels and a set of bearings we'll press the bearings for you!