I have the predecessor Quatrac 3 (which has a different profile pattern than the Q5) on the nicer of my two classic 900. This car is not intended to be driven on salty roads, but I wanted something like "emergency snow capabilities", as I had planned to drive the car up the norwegian coast (has not happened yet) and through the Alps (done). You cannot outrule the occasional patch of ice at altitude, nor sudden changes of weather, with temperatures dropping 10-20° and snow fall, even if there is spring or even summer in the valley...
Every review I found prior to purchase described the Q3 as a more summer-oriented all-season, with so-so winter capabilities, but rather decent dry handling. Having driven 15.000km on the Q3 by now, I can concur. Steering response is crips, and the tyre behaves very civilised when pushed to the limit while cornering, both wet and dry. There is no understeer or sudden oversteer, just a very neutral veer to the outside of the curve, slowly sliding over all four corners. This is indicated early and, through any and all stages, very controllable. So while the Q3 has flawless manners at the limit, one must also say that this limit is not hung too high. A decent summer tyre will effortlessly outclass the Q3 in cornering speeds.
Wet and dry braking also leave to be desired. No, the tyre is NOT outright dangerous, such as some cheap chinese [censored] (Wanly and Nankang are the first to come to my mind...), whose breaking distance go to infinity and beyond when the road is only slightly damp, but I have driven many summer tyres which are way better in this regard. There are also some, which are worse. For example, the Falken Z-something on my w126 had no wet grip whatsoever, and the Kleber Dynaxer HP and HP2 which I had on my first two Saabs were also worse. (But then, Kleber has a very pronounced and well-earned reputation for not being good in the wet at all.) Aquaplaning resistance of the Q3, on the other hand, is good.
I had a chance of testing the Q3's winter capabilities a bit when I was surprised by a weather change last easter. Weather went from sunny 15°C to snow and back within 45 minutes; the road was covered in wet, thick snow, that quickly turned to slush. The Q3 had no diffiiculties finding sufficient traction, both when accelerating, as well when braking ( I did some strong braking maneuvres on an empty road to get an impression of the tyres capabilities). I cannot say much about lateral grip or handling at the limit on snow, as I did not push the car; but at least there were no unpleasant surprises. I have the Impression that my Michelin A4 on the other 900 would probably have been noticeably better, but then, these are dedicated winter tyres. No chances I could have gotten through this on summer tyres, so the Q3 did excatly what I bought them for.
To sum it up: you give up some dry and wet performance compared to a summer tyre, and the Q3 is no match for a true winter tyre, but it will get you home in a sudden weather change, which a summer tyre will not. And even with the reduced performance, the Q3 will spare you the squishiness of a true winter tyre and give a much more responsive and controllable feel at higher temperatures.
There is one drawback, though: The tyre seems to have very stiff sidewalls. It rides considerably rougher than my Michelins and I had to lower tyre pressures considerably (which makes the tyres run measurably hotter and probably wears them out faster). I run the Vredestein at 2.0 bar and the Michelins at 2.6, yet the Michelins still ride smoother. I guess this is exaggerated by the chassis layout of the 900, whch is known for not damping minor road irregularities at all...
Would I buy the tyres again? It depends. On a double-whishbone Saab (99/900/90), probably not. On cars with a more conventional chassis, if I faced a similar usage profile, why not?
For those of you who understand german (or can cope with what google translate makes of german texts, which can be hilarious), here is my blog post written directly under the impression of my first and only snow drive with the Q3:
https://turboseize.wordpress.com/2015/04...sbetrachtungen/
