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Monday, September 28, 2020

Doug's Domain

Doug Vetter, ATP/CFI

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Saturday, November 17, 2012

Pirelli Winter Carving Edge Installed

I finally managed to get my Style 30 wheels to my technician for mounting the set of Pirelli Winter Carving Edge on Tuesday. I told him there was no rush so he finished them yesterday and I picked them up with my brother's pickup today. While I'm happy to have access to my brother's fleet of vehicles and heavy equipment for basically gas money, when the pickup almost refused to start leaving the dealer today I couldn't help but ponder the wisdom in having my own (*gasp*) truck. For giggles I priced a GMC 2500 HD 4x4 diesel and became violently ill. Would you believe they get $46K retail for that? I realize the discount levels are higher for domestic vehicles so I'd probably pay somewhat less but I'm still forced to ask -- in what fucking universe is a pickup truck worth $46K? Apparently GMC didn't get the memo -- they're not BMW. I now understand why the heartland of America is broke -- everyone is spending BMW money on trucks.

Back at the garage I made quick work of the tire swap. Exclusive of the time to gather tools the swap took an hour using jack stands. Given that 215/55 is a slightly larger diameter tire, while the front end was up in the air I turned the wheels lock to lock and spun each tire to check for rubbing. The right tire exhibited no clearance issues but the left tire did very slightly rub the inside edge of the wheel well at full left lock. The rubbing appears to be caused by the relatively high shoulder of the tread and is so slight I expect it to stop once the tread wears a bit. Incidentally, this confirms something I was fully aware of -- the steering rack is not perfectly centered -- but the offset was required to compensate for the fact that I reassembled the steering shaft one spline off during the front suspension overhaul earlier this year. That sounds bad but it's a far cry better from the setup prior to the overhaul. We're talking a couple millimeters of offset now vs. a couple centimeters. I'm not sweating it.

While cleaning up the PS2s before putting them to bed for the winter I took a good look at the tread. As expected the rears have slightly less tread remaining (perhaps by 1 or 2 mm) than the front, but they are still a couple mm above the wear bars. The tread wear is consistent from side to side on all tires, meaning that the alignment is damn near perfect front and rear. Due to the fact that the car was removed from service for 3-4 months over the last two seasons and the fact that I'll likely take it out of service yet again next year to paint it, wrap up the interior overhaul and *finally* rework the stereo I think there's a pretty good chance I'll be able to stretch those tires through a third season. They'll be at or beyond the wear bars at that point, but who cares -- they'll perform as well if not better as slicks. Just pray it doesn't rain. :)

A close look at the newly installed Winter Carving Edge tread revealed deep sipes in all the tread blocks. As I pushed against them with my thumb I could feel each portion of the block move easily in response. While I expected the tread to be soft today as temperatures hovered in the upper 50's I was surprised to see so much movement. I immediately assumed that this would translate into vague handling and the test drive home confirmed it. It's not so much that the initial "bite" of turn-in is sacrificed but rather that there is a slight delay felt mostly during recovery of a steering input. This is most easily demonstrated when the wheel is moved back and forth in a periodic motion at speed. I can feel the same delayed reaction of the rear tires causing the rear end to lag the steering inputs. The Winter Sport M3 did not have this problem but it was classified as a "Performance Winter" tire.

The Pirellis are naturally louder at speed than the PS2s and very slightly louder than the Winter Sport M3 (at least when they were new...all tires get louder as they wear) but this again is to be expected of a winter tire and I sincerely doubt you'll find me complaining about any of these traits when I'm forced to drive in a few inches of the white stuff. In fact, I can see how the sipes and flexibility of the smaller portions of the tread blocks could contribute to better traction in all conditions so I think it's safe for me to say what all software developers do: it's not a bug, it's a feature.

As usual, my technician wrote the road force numbers on the wheels: 8, 15, 15, 18. This is what I consider slightly below average tire quality -- nothing special and yet not the worst I've seen. It's on a par with Dunlop and near the top of the highest road force number (18 lbs) recommended by BMW. Fortunately the ride was smooth and I noticed no vibration or shimmying but I haven't exceeded 50 MPH yet. The commute on Monday should be enlightening. Something tells me I'm going to truly miss the PS2's razor sharp steering and handling the next four months.

Lock Cylinder and Housing Videos

I saved the lock cylinder and housing I removed during the front suspension overhaul earlier this year so I could do a couple videos on them but never found the time. I managed a first take while I was twiddling my thumbs during the recent power outage but the lighting sucked (a lack of electrical power will do that) and I rambled on for over 15 minutes. Since I don't have the time to edit I vowed to reshoot the video as two smaller videos and accomplished that today. If you're about to replace your lock cylinder or housing you may find these helpful.

Mileage: 227732, Labor: $200