Winter Tire Choice
Well if anyone's paying close attention I think I may have mentioned at some point in this bloated thread that about six months ago I picked up 3 Civic HX rims for $100 (no tires). Well just recently I broke down and bought a 4th HX rim on ebay for $100. That's right, $100 for just one, used, 10-year-old rim. That's ridiculous. But total for all four puts me at $200 and that's not bad.
Currently on the car are 15 inch Rota Slipstreams that I've had for about 5 years left over from my previous hatch. I couldn't retain the stock 13 inch VX rims because they would not clear my front Integra calipers. So some lucky bastard (actually he was a nice kid) unwittingly got my auto DX with VX rims. Note that I will have to grind some material from my front Integra calipers for the HX rims to clear. Rear calipers as you know are much smaller than the fronts so they clear the rims quite easily.
In any case, living in San Diego at the time of course I had some ultra high performance summer tires (Kumho Ecsta SPT). I didn't know that I would be moving to Utah. I'm pretty spontaneous like that. Summer tires are very specialized and do great in warm temperatures but they absolutely suck in freezing temperatures. I got some firsthand experience one morning driving to work in the snowy slush. I was doing 35mph at one point and hit the brakes, hydroplaned and stalled the car. If I hadn't been maintaining a big following distance I would have wrecked. Needless to say I drove the rest of the way to work at 25mph. So those are the circumstances that led me to pay an inflated price for an HX rim and complete the set.
The HX rims will get some winter tires and the Rotas will be stored away for brighter days. I've never owned 14 inch rims so I didn't even know what tire size to look for. Tirerack.com lists the stock tire size for the Civic HX as 185/65/14. But for some reason I didn't quite trust those numbers so I googled "tire aspect ratio calculator" and found a site that let me plug in some numbers. Here are the results:
96-00 Civic HX
stock tire size 185/65/14
tire diameter 23.47 in
sidewall height 120.25 mm
Actual speed when VX speedo reads 35 mph: 33.77 mph
Actual speed when VX speedo reads 70 mph: 67.55 mph
92-95 Civic (except Si)
stock tire size 175/70/13
tire diameter 22.65 in
sidewall height 122.5 mm
15 inch Rotas
tire size 195/50/15
tire diameter 22.68 in
sidewall height 97.5 mm
Actual speed when VX speedo reads 35 mph: 34.95 mph
Actual speed when VX speedo reads 70 mph: 69.9 mph
My Choice for HX's on a EG
tire size 185/
60/14
tire diameter 22.74 in
sidewall height 111 mm
Actual speed when VX speedo reads 35 mph: 34.85 mph
Actual speed when VX speedo reads 70 mph: 69.71 mph
Significance
The Tire diameter is the critical factor. It affects your final drive ratio at the wheels. The larger the tire diameter, the longer your gearing* and the heavier and more expensive the tire. It determines whether your speedo is correct. If your speedo is incorrect, not only will you not be driving the speed you think you are, but mile-per-gallon calculations will be incorrect. Your odometer will be incorrect.
*Longer gearing results in a higher theoretical top speed, slower theoretical acceleration (I say theoretical because there are other variables in effect such as aerodynamics and engine power), and possibly better fuel economy on the highway while worse fuel economy on the street.
Sidewall Height
Many armchair racers believe that with sidewall heights; lower is better. This is not true. Like many things in racing, you have your stock spec, your ideal spec, and then anything beyond that just causes performance to suffer. A small decrease in sidewall height from stock usually results in increased performance at the expense of ride quality and increased rotational mass. Going smaller from that point results in poorer traction in real world conditions such as imperfect roads as well as wet or slippery conditions. It also results in unpredictability in that the tires don't give you much notice before they lose grip. Road harshness increases quite a bit. Rotational mass increases even when the rims are lighter than stock because you are in essence replacing rubber sidewall with metal which is much more dense. It is commonly accepted that 195/50/15 is ideal for a street Civic.
Conclusion
My conclusion from the above calculations is that when using HX rims on a 5th generation Civic, 185/
60/14 is the ideal tire size. Do not ask for 96-00 Civic HX tires. Do not enter "96 Civic HX" into the text field at tirerack.com. If you do, you'll end up with 185/65/14 tires. This will throw off your speedometer, your odometer, it will increase your effective gear ratio, your tires will be heavier than they need to be, and you'll pay more for tires that are too big.
The tires I decided to go with are the Michelin X-ice Xi2. I considered all season tires since I really just need something that will work better in cold temperatures than my summer tires. I liked the Michelin Pilot Exalto A/S based on customer reviews and test results at tirerack.com, but they didn't offer them in the size I need. The clincher is that they are discontinuing the Xi2's in my size so they are on clearance for $43.
Slipstream vs HX
The Rota Slipstreams are 15 x 6.5 inches and weigh 11.9 lbs. The Kumho Ecsta SPT 195/50/15's weigh 18.3 lbs. Total comes out to 30.2 lbs.
The HX's are 14 x 5.5 inches and 11.75 lbs. The Michelin Xice Xi2 185/60/14's weigh ???. Total comes out to ???. The smaller diameter, thinner HX's have less rotational mass.
For reference, the DX steelies are 13 x 5 inches and 16 lbs.
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