Pros: Smooth when new, quiet, lasts long, asymmetrical design, excellent traction, mileage warranty
Cons: Not very responsive, slightly harsh ride developed when worn and aged
My 2004 Infiniti G35 came with mediocre Bridgestone Turanza EL42 tires. You can see in my review of the EL42 how mediocre they were. Even before they wore out, I headed to America's Tire to get some Falkens. But they were out of Falkens and suggested that I get the Yokohama YK520 and offered to reduce the price to $104 per tire.
Since I saw nothing but good reviews for the Yokohama tires that featured similar characteristics and/or tread patterns (e.g. Yokohama TRZ, etc.), I decided to try them. After all, at $104 per tire for the 225/55VR17 size (close to $600 installed) with 60,000 mile warranty and the premise of good ride, handling and free tire rotation/balancing for the life of the tire, this seemed to be a good deal.
Note: I bought the Yokohama YK520 in 2006 and after almost 6 years and 44,000 miles replaced them with the newer Yokohama YK580.
The Yokohama YK520 are wearing very well. I recently performed the sixth rotation at 41,000 miles. The tires look pretty good still with 44,000 miles and 5.5 years on them, nowhere near wear bars (still 4.5/32" of tread left of the initial 11/32", which means they could last over 55K overall).
The Yokohama YK520, at least in my size offers 60K warranty. Since the mileage warranty is only valid for 3 years (as far as I understand the fine print on the back of the invoice) or 5 years (according to Yokohama's web site), I will be unable to take advantage of it if the tire wears out in under 60K miles. I simply don't drive much. Still, being able to get close to 60K from these tires would be an impressive achievement and I should be able to achieve this easily. I don't drive on sandpaper-covered roads, but I do use throttle to improve the turn-in with a bit of power oversteer sometimes.
The Yokohama YK520 is an asymmetrical non-directional tire, which can be rotated to any position. The outer, meddle and inner parts serve different purposes for dry, wet and light snow duty (the tire is an all-season one).
At first, the ride became much smoother and quieter comparing the Turanza EL42. The so-called progressive sidewall of the Yokohama tire might be helping in this respect. And certainly new tires ride better than the ones that have some part of their tread worn-off. As the Yokohama YK520 wore, the ride was getting worse, but this is not the worst part (see below).
The traction in dry and wet weather is excellent (when new and when worn) and much better than the EL42. The tire is speed-rated V and can go as fast as I can legally (and illegally) drive. I took it to 130 and the car was very stable, but it is no big deal since I took a small Volkswagen Polo turbo-Diesel to that speed in Germany on some other tires and it behaved well too. Tires are speed rated to ensure the construction is robust enough to withstand the force that tries to rip it apart the faster the tire spins. So V is good enough for my driving.
Despite the fact that the traction in turns, acceleration and braking is very good, the tires are not very suitable for spirited driving. They are not very responsive: it seems that the initial split second you turn/accelerate/brake nothing happens. Is it the fault of the progressive sidewall that gives you cushy/quiet ride? Maybe.
I do run recommended by Infiniti 30 psi and tried 35 psi with no noticeable responsiveness improvement. And in LA, when someone cuts in front of you (I have seen some of the worst drivers in the world right here in LA, and cutting in front of someone with no use of turn signals is what they do all the time), you want maximum deceleration or turning immediately.
As mentioned above, the traction is excellent. It doesn't rain here much so most of my driving is done in dry conditions. The speed I can sustain in turns is much higher than what I could do with Turanzas (equating to high g-loads), same with ultimate acceleration and braking acceleration (or deceleration). And as most tires, these grip even better when worn.
Behavior When Worn
After 45K miles, having 4.5/32 of an inch of the tread left (slightly less than 1/3 of usable tread left), the tires grip extremely well in dry weather, but the ride is a little harsh now. Also, as was expected with such shallow tread, the handling in the wet weather requires careful planning. Fortunately it doesn't rain here often, otherwise I would replace any tires before they reach 4/32" of tread depth.
In the past I thought that the tires somehow developed what appeared to be permanent flat-spotting. The symptom was a constant thump-thump-thump noise that happened at every turn of the tire and becomes a constant drone at freeway speeds. But once I replaced the tires, the noise didn't go away and was later diagnozed as a damaged wheel bearing.
My tires are worn very evenly and were rotated and balanced religiously. The inflation pressure was maintained at a factory-recommended 30 psi. I never let the car sit for more than 3 weeks at a time and it never gets below freezing in Southern California.
Due to deteriorated ride and noise, I replaced these tires with the Yokohama YK580. Since that didn't help, I then made a switch to the Michelin Primacy MXV4. and only then the bad wheel bearing was discovered as the culprit. Had I not had the bearing issue, I would have kept the YK580 until 2/32" of remaining tread, which would let me go to about 65K miles on them.
Another Yokohama Tire
I have another Yokohama tire on a Honda Accord; check it out: Yokohama TRZ.
The Yokohama YK520 was a quiet, smooth tire when new. It is a long-lasting tire with excellent traction in dry and wet weather (we have no snow here). It is an excellent choice overall, provided you want exactly that: smooth, quiet tire with good traction that will last long. A great replacement for any OEM all-season non-sport tire and possibly even for sporty tires.
It is not for you if you want responsiveness and/or the best traction possible.