This was originally posted back on March 28, but it was lost when the unexpected server change happened.
With the temperatures approaching 60 degrees, and the snow apparently gone for the season, I decided it was time to take the studded Hakka-4's off the 960 Sedan. I want to try and save as much of the studs as possible, and if there is snow, I still have the Vredestein SnowTrac 2 tires on another car.
In almost all ways, the studded Hakka-4 tires have impressed me. They have incredible grip on the ice and great snow stability. Their dry road performance is a bit lacking, but that's what you expect from a snow tire.
In the previous post about these tires, I mentioned that one or two studs had been lost. I was wrong. This is where I am finding that I am not quite happy with the Hakka-4s.
Before I go too much further, I should say something about the car the tires were on. It is a 1994 Volvo 960 Sedan. It has a 200 bhp motor putting power out through a limited slip rear end. It also has an independent rear suspension.
Tire wear was very interesting. The front tires still have plenty of tread, and 99.99% of the studs are intact. The tread depth is still over 8mm, and the tread is fairly uniform depth across the tire. There is some feathering of the tread blocks, particularly along the sipes, but it looks fairly normal. My experience is that the sipes in snow tires either open up or close down when driven. These chose to open up.
The Rear tires are another story. In the back, the tread depth is varied across the tire. The center is the lost, with only the 4mm mark still showing. The outer edges are much higher. I did not have a gauge with me, but I would put them at over 6mm. When viewed from the front, the tread looks concave. My first thought was that the tire pressures had been too high, but a quick check of the tire gauge showed 32 psi, which is normal for that car.
That was not the worst of what I saw. Over 25% of the studs had either lost their top or come out. Of the studs that were left, most were severely deformed. [I hope to put some pictures up in the next few days.] It really was not pretty site. While I believe that the front tires could go another season or two without much problem, I'm not sure I would want to use the rears again.
The interesting thing I did find was that the studs that were still intact were still incredibly sharp. When I work on the car, I put cardboard down to kneel on. Rolling the tires across the cardboard left a patterns of holes punched by the studs.
Knowing that the car is a RWD
car that has been driven hard in rallies, here is the explanation I put forth for the severe wear in the rear: The rear end was made to work much harder then the front. I would not be surprised if a fair amount of damage was done on rallies on somewhat dry roads. I expect the studs gripped the pavement to the point of deforming themselves to the point of failure.
The tread wear, I can in part also blame on the RWD
nature, but it still seams high. I expect the abnormally warm winter coupled with the high hp on the rear made the tread wear faster. I expect that the reason that it did not wear quite as much on the edges is because the studs actually worked to lift that tread away from the pavement. In the center, where there are no studs, the tread was left to be worn away.
So, bottom line, I love how these tires behave in the snow. Even though I don't like the wear on the rears. To me, I could almost justify getting 1 pair of rears every year and 1 pair of fronts every 2 to 3 years (I really think three is doable). Perhaps, I could even learn to be gentler on the throttle. The other answer would to do what Mike Kamm suggested in another post, only put the tires on when there is really snow coming.
The tires were driven on for approximately 3300 miles. Of that, 500 miles were in covered in 3 winter TSD road rallies.
BTW, look for an update on the Vredestein SnowTrac 2 tires to come out in the next couple of days.