Very few components matter as much as tires on a performance vehicle. Acceleration, braking, handling; anything involving a force exerted on or by the car is completely at the whim of the traction provided by the tires. "Traction" is but one characteristic of the performance of a tire; others will be discussed later.
The SVT Focus uses Continental ContiSports as the OEM tire. For an OEM tire, the Contis were an aggressive choice as numerous "performance" cars ship with sub-standard all-season tires. The best example of this would be the Bridgestone Potenza RE92s included on the Subaru Impreza WRX as the handling capability and 227 HP of the WRX completely overwhelm the tire. Considering the WRX is touted for its all-wheel drive and thus ability to drive in all sorts of conditions, shipping with an all-season is a satisfactory compromise. The Contis are purely a summer performance tire and perform abysmally at cold temperatures, let alone in the snow! I was able to crawl home when a freak hailstorm hit Redmond, but thankfully all roads between work and home were fairly level. If I had to get back to where I live in Seattle now, I highly doubt I would have been able to get up half the hills I would need to take. All summer tires act this way, so that aspect is not surprising, but the dry performance for a stock tire was quite competent. Moving from all-seasons to a summer tire is a dramatic jump so I was definitely happy moving to the Contis on my 2004 Focus in comparison to the all-seasons on my 2003 Focus.
Roughly 12k miles into the life of my car and tires, I developed a slow leak in the passenger rear (don't you hate leaks from the rear of a passenger?). Instead of replacing that single tire like a normal person, I used this as an opportunity to upgrade the whole set. After careful research and deliberation, I decided upon
Kumho Ecsta MXs. This was a compromise of price, dry performance, wet performance and durability. The performance improvement was noticeable, but nowhere near the jump from all-seasons. Traction was improved in the dry, the tire was more predictable at the limit, though there was less feedback as it reached that limit (the Contis howled like a bitch in heat before they broke from the leash). I never did autocross the Contis but I'm assuming I wouldn't have been that much slower than on the MXs.
At least four months ago, I remember running over a HUGE pothole, expecting torn-off body work, a bent rim, a scraped tire and damaged suspension components. The car seemed to drive fine, so I figured there were no problems. At the last autocross of the 2006 season, I couldn't seem to hook up, especially in the slaloms (or as Shawn calls them, shaloms!). At the first few autocrosses this season, the issue worsened and was absolutely impossible to overcome as I increased tire pressure. Instead of pulling the tires off for an inspection, I could tell just by looking at the outer edge that the MXs were toast. They survived 18k miles and probably 10 autocrosses, so durability was impressive.
The replacement tire research was less oriented toward wet performance and durability. I wanted to maximize performance (autocross season is in full swing) and there is a good reason why I don't care about durability (Jan2008, Subaru something something). For $140/tire, shipped, installed and balanced, I picked up a set of Falken Azenis RT-615s! So far, the performance jump is closer to the all-seasons-to-summer jump than the Contis to MX jump. I have yet to find the adhesion limit of the tires; my traction control (which I keep forgetting to disable) jumps in before the tires even start to screech.
The reason why I was having such difficulty in the slaloms was made painfully apparent and is probably related to that huge pothole I hit. I'll upload pictures tonight, but the inside edges of my front tires are completely bald! The outer edge is probably closer to 40% viable so I some how picked up some negative camber AND toe (not sure if it's out or in). I have an alignment scheduled for Friday afternoon so if anything is damaged, I can hopefully pick up the parts before the autocross on Sunday. To say I have high expectations would be an understatement; if I don't place at least in the top 10% of novices, I'll be highly disappointed.
Third set of tires and I just hit 30k miles on the car; that is the sign of an enthusiast.
