Screw embedded in tire tread Only *three days* into new ownership, I headed down into town for a meeting.  In the process of pulling aside somewhere in Charlestown to check where I was going to park, a small but pointy screw managed to find its way business-end-first into a tire and tightly embed itself.  I realized it was there no more than ten minutes later, by a most fortunate circumstance of this trip -- while tooling silently around in an enclosed parking deck, I could hear a distinct tick, tick, tick as the wheel went around.  The fact that 1> I almost always have windows on either side open, even in cold weather, and 2> went through almost the exact same experience early in my Prius ownership, meant that I immediately knew what that sound meant.  A metal screw head does sound subtly different from a stone stuck in the tread, and doesn't fling out by itself with continued driving.
I got out, felt around for where it was and turned the wheel out to see the situation better.  On the first check I couldn't hear any hissing, and figured that the screw had for the most part sealed itself into the tread and might even be okay for the run home.  But I needed to get to the meeting, so I parked and figured on doing whatever was needed to get out of town afterward.  When I came back a couple of hours later the tire still looked fine, and was only down a few PSI.  I was suddenly thankful for the TPMS display, knowing that I could monitor the pressure there and stop to either air it back up or swap the donut on if needed.  I made it home without needing to do anything else, parked with the screw easily visible, and put a jack under that corner of the car so that if the tire did leak down overnight, it wouldn't totally flatten.  Further attention would wait until morning.

Screw puncture repair, wheel off The tire was lower in the morning, and I got a screwdriver and carefully backed the screw out a little bit.  It started hissing, confirming that it had reached the interior.  I put a little gasket-sealer around under the head and ran it back in, figuring I could get to wherever it would be fixed that way instead of having to try out my nice new donut after all.  The screw was in an outer tread-block, and I wasn't sure if that was too close to the sidewall to safely patch.  Long story short about reviewing options, consulting with dealers, and determining that road hazards were *not* covered under tire warranty, I then drove all of two miles to the local-boys tire place and presented the problem.
The fix was far easier than I expected: the guy assured me that it was far enough away from the sidewall, and confidently plugged the hole right in place with a generic string kit, without dismounting or even deflating the tire.  Said I was "good to go" right on the spot -- nothing short of amazing to me that a gooped-up plug could cure to a reliable seal that quickly.

The clipped-off string did leave a little lump on the outside which quickly wore down, as the real magic of sealing happens on the inside where the plug spreads out and vulcanizes in place.  Videos I found later on the subject implied that having a bit of pressure left inside the tire actually helps the plug seat and seal against the interior surface. One thing the tire-guy pointed out was reliable plugging this way requires the installer to carefully "follow the injury" and not cause any more damage while leading the plug thread in.  This seems inconsistent with what passes for wisdom on youtube, where people demoing such fixes are sawing enthusiastically in and out with the reamer tool that comes with plug kits.  He did go slowly with the point and felt that the screw had actually gone in at a bit of an angle before it flattened itself against the tread, presumably stretching the hole a little but not actively ripping it farther open as I'd driven home.

I decided I was going to get me one of those plug-string kits anyway, as it might provide a better quick-fix on the road than trying to run on a sketchy donut with the wrong hub offset for some indeterminate number of miles.  Having an air pump always with me and being able to monitor pressures is all key to being self-reliant in any tire-puncture situation.

Plastic wheel spoke inserts As long as I was pulling random wheels off for a looksee at the structures underneath, I took out one of the silly plastic rim-slot inserts.  Removing these wouldn't be productive at all, really, as each one is held in place by four thru-screws from behind and without them the rim would look awfully odd.  Unfortunately, the complexity of the inserts would probably constitute quite the crap-catcher, especially for winter slush and muck.  These wheels would probably need a good hose-out every spring.

They are also substantially heavier than the wheels on the Prius, but I suppose that's generally true for a "SUV/crossover" type vehicle.

  One downside of the car is the "electronic" rear parking-brake, arguably a poor design choice.  It has a *switch* to apply and release, using servomotor-driven calipers that rapidly go from open to squeezed.  The description in the manual is rather sketchy, but hints that Hyundai did make some mild operational concessions on the system.  I was very hesitant to experiment at any speed on dry pavement, but after a couple of cautious tests in loose gravel I was able to report back on the basics.  It can be used on the fly for emergency braking, where pulling the switch at any appreciable speed sets off a lot of insistent warning beeping and the rear brakes rapidly engage, fairly hard but from what I can determine, not quite enough to simply lock up the rear wheels on tarmac.  It's still an abrupt enough event to make your groceries tumble off the seats.  At least letting go of the switch immediately releases everything, so to a very limited extent it can be modulated sort of on-off while rolling.  It could thus still give that quick pulse of the e-brake we want to, say, break the back end loose to start spinning donuts in a snowy parking lot.

As this was written before the onset of slippery weather in New England, I figured I'd wait for appropriate conditions outside before experimenting further with this in any serious way.  I didn't need to let myself in for *more* tire damage by messing with it on dry pavement.

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