Wood wheels [also known as woodies] are typically made of maple wood. The main purpose is to try to provide a sliding experience to the skater.
The most interesting thing I can say about wood wheels is that they don't provide a consistent experience on all surfaces. I've skated several rinks, carrying my wood wheels with me and testing them across several levels of coating, no coating, and material. It is difficult to predict how they will act on surfaces.
Wood wheels will change the way you skate because they are fickle. No stomping, no jumping, no tight corners, no aggressive pivots down the straight. When I skate my wood wheels I feel like I skate a little faster but pick up my feet less frequently. I cannot tell when I've touched back down on the surface as well as I can on other wheels; that lack of feedback causes me to be more cautious when I'm rolling.
Here is my best estimation of slip:grip [and definition].
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* - The good - *
+ Excellent for cheating out moves and keeping control on coated surfaces
These wheels are not particularly great at sliding all the time but break free from most surfaces on pivoting moves. In dance, you pivot a ton so these are fantastic for those applications. My most common cheat is sliding to reposition. I cheat out crazy legs, spins, grapevines, and more; wood wheels are reliable accessories to those crimes since they lock back in quickly when you slow down the sliding motion. For comparison, urethane wheels are gross, sticky, and don't let you cheat; what's up with that!?
+ Lock into the floor when rolling straight
In my experience, rolling straight locks the skater in the straight line which is desired by most skaters (I don't see the appeal myself, I prefer controlling every aspect of skating and sliding in all directions when I want to but to each their own).
+ Are exceptional on perfectly coated maple floors
You would hope they were lol. At the same time, FoMac (FM) are more satisfying and lock harder on perfect floors...
+ Don't cut into any surface ever
I don't know if it's good or bad, but maple wheels are hard as the maple floor, they can't deform the skate surface at all.
That said, they can get deformed themselves because they are not treated and are more porous. I have some indentations on my wood wheels from rolling over sand or broken spots on wood floors. They didn't impact the immediate skating experience but they will reduce the structural integrity of the wheel.
* - The bad - *
– Do not sound satisfying
If you like the clink of two wooden blocks smacking eachother... you're weird. Wood wheels have a soft feel (compared with FoMac and Fiberglass; they have a dull clinking impact sound and feel as if they sink into the skating surface a little bit on each step (They don't actually deform but they feel significantly softer than other hard wheels). I think this comes from the previously alive, fibrous material and the fact that there are literal air pockets in the dried wood that absorb impact and dull sounds. FM and FIberglass are solid (fiberglass is the best).
– Not precision precision
Bearings slip out when I pack them away all the time. This is [obviously] not a problem when they're on the skate but it's annoying when they keep coming apart when I'm packing them up and taking them out.
The lack of precision also makes spacers more necessary [in a similar way to how spacers are needed for loose ball bearing skate wheels.
– Hard to clean
The surface of wood wheels are not perfectly smooth and as such, get floor gunk (sweat caked with dead skin/dust, and carpet) all up in there. It's a pain to clean all wheels but wood needs special attention to you don't shorten the life [even] faster. Wood will absorb moisture so the standard approach for cleaning water, soap, and an abrasive surface will shave life off the wheel. Wood fibers can catch the abrasive surface you're using (old cloth/sponge). Suffice to say, it's a pain.
* - The ugly - *
– You cannot use stepping or jumping styles
Stepping styles live for the *clack* sound from smashing your skate wheels on the surface be it [lifeless] sport court, sexy wood, or cold concrete. Point impact will eventually break wood wheels. I spoke with a few rink owners in Detroit where kids just love wood wheels because they are able to slide pretty well in them (kids are light so maple wheels slide pretty easily under them). The owners told me that they didn't like kids on 'em because they break the wheels all the time and the plates end up punching little divets out of their floors.
– Don't slide well on the flat
Pushing slides (think of doing a plow stop... but not stopping, sliding the whole way through. Now think of doing that on a gross, sticky,85a wheel; it's a horrible feeling [not to mention dangerous]. Wood wheels don't take well to sliding forwards at medium and low speed on lightly/mid coated wood floors or finished/sealed concrete. They only slide on the flat of the wheel consistently on painted concrete, sport court, and uncoated wood. Dragging slides (e.g., powerslide) are passable if you can stay on the flat... Good luck with that if your boots are hightops.
– Don't slide well on the edge
Edge slides are some of my forte and I cannot do them at all on wood wheels. The pressure that is generated flats them no matter the surface I skate on and will chip away sometimes because the wheel does not slide on the edge, it stutters. No soul, cross acid, star, magic slides should be done on wood wheels. Trash! Okay, so you can do them but at the risk of your wheels' geometrical integrity. On a well-coated wood floor you can slide on edges but friction will crush the corners some.
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TL;DR
[In my not-at-all-humble opinion,] A wheel that has bad sliding properties is a trash wheel.
[Not a matter of opinion, but straight facts ->] Wood wheels are a tease unless you're on an uncoated maple floor. It's also a matter of when they break, not if. Wood has been outclassed by material science for decades.
Skip wood and go to fiber [if you want to slide].
Go vanathane if you want to dance.
Go FoMac if you want to jump.