Noise, and rolling resistance. Yes, and yes.
Noise? Keeping in mind that on the Nokian Mount and Ground W160's, the studs are arranged in two rows that are about a centimeter off from the centerline of the tire - compared to other studded tires models that have studs closer to center - things could be louder for sure. At the maximum sidewall pressure of 45 PSI, it is possible to ride along on the center section of the tire without having the studs "engaged" all that much - but there is still noise, because keeping the bike centered on the tires at all times while cornering and pedaling is impossible in practice. Some of this noise is created by the open and raised tread design creating air-pockets between the tire and the pavement, but some of it is stud chatter, for sure. The result is a satisfying buzz as you ride along. I've qualified this as "satisfying" as opposed to "annoying", because no matter the effect of the noise there is no getting around the fact that it's noise with a purpose. After last week's successful "rubber-side-down" icy trail commutes, I find it hard to put black marks on the tire's reputation simply because it makes a little more noise than another tire while riding on dry pavement. Part of it is indeed my own fault: while mounting and remounting tires is not a gigantic hassle, it does fall down low on the priority list when the garage is cold, and the body is weary from riding home in the cold. Spending any extra time in the garage after a winter commute tends to negate the maintenance time savings of using a single speed, after all - tire changes included. In this sense, a spare wheelset would be REALLY nice. It is also, partly, Kansas-weather's fault: as shadowed sections of trail thaw more slowly than sunlit sections, the studs necessity tends to extend several days after a snow event - and with each passing day more and more of the trail becomes bare again. Since the sections that are still covered over are generally long and still treacherous for normal tires, I have elected to keep the studded tires in service until complete clearing and melting occurs. Contrary to conditions in Finland where the tires are made, and most northern-tier states, midwestern winters are fickle with many freeze-thaw cycles. If I lived in a state where it snowed and then stayed below freezing for weeks at a time, this issue with noise probably wouldn't even be relevant. On ice and snow, they are muffled nicely - with only occasional audible hints that the studs are working.
Stud wear? Perhaps a week is too soon to tell, but carbide is very hard material indeed and holds a nice edge. So far, with probably 120 miles on studs, I can not detect any smoothing, shaping, dulling, shortening or other wear on the studs themselves. For those that haven't seen studded tires in person, or have not seen good pictures on the web, the studs themselves are not sharpened to a point - the tops are rounded off slightly, and the edges of the studs are sharp. Think of a tiny cylinder with a slightly domed top, and the edges where the sides of the cylinder meet the top "cap" is where the sharpness of the material can be felt. This gives traction by an "edge effect". Instead of forced traction by using the weight of the bike to drive a spike into the ice, this design allows a little slippage before engagement. Further, this edge ends up being much easier to keep when inevitably riding on bare pavement because only the domed area contacts the dry surface (unless cornering hard), and overall it provides more biting surface area against multiple directions of force. My assumption is that once the slightly domed top wears flat, the edge might begin to dull - but the nature of the material suggests this will take a lot more use to actually see. Multiple seasons, indeed a possibility. My only additional concern, something that pure trail-riders wouldn't need to worry about, is the harsh nature of chemical treatments our fair city applies to the roads primarily for the benefit of automobile traffic. My commute isn't all-trail, so I have several miles to ride through this white dust and salty-sandy residue - and I can see the chalky results clinging to the tires every day. Will this eventually affect the studs? Plausible - but, so far, I can't see any evidence of this. Something to keep an eye on.
Rolling resistance? While not really apparent until I remounted the "normal" tires for today's commute, suddenly reducing nearly 300 grams of rotating weight per tire and putting a smoother tread to the ground made it seem like I was flying - even though I was still riding the same, speed-limited, single-speed bike. Again, this is not something to hold against a studded tire - it's simply an observation. The benefits of sure-footedness on ice and snow far outweighs any negatives. Yes, the tires are heavy - yes, they can feel sluggish once the snow and ice is gone - but most of that is only because once the snow and ice is gone, I automatically want to start riding flat-out again - and you can definitely "feel" the tires fighting against you as you attempt to increase speed. Descents are slower, cornering is slower, and climbing is more of a push - but this all must be balanced against the notion that when these tires are used as intended, they are brilliant: and you won't be doing ANY of those things quickly anyways when the trail conditions warrant the use of the tires.
So, all-in-all, merely some observations - and motivation to either get that extra wheelset, or to go ahead and get those "normal" tires back on the rims no matter how cold it is in the garage. Silver-lining? It probably provides a slightly higher margin of "training" during the off-season. If the switch to "normal" tires this morning is any indication, I can imagine what riding my regular road-bike with 28c tires at 105 PSI will feel like come springtime.
Any changes to my initial conclusions? Not really: still worth every dime - no doubts - but in the guise of giving a properly well-rounded review these points do bear mentioning - even if they really shouldn't be a big surprise. After all, you can't put 160 hunks of metal into ANY tire and not expect some sort of outcome.
Thanks for reading! See you out there!