Here’s a summary of what I remember over the years.
- Steel wheels are cheaper and usually stronger than alloys, although that may not be true any more given today’s metallurgy.
- Alloys are generally more expensive to replace (and they may need replacing more often), and so are the replacement tires.
- Optional alloys are generally sold for three reasons: style, style, and a higher profit margin. They can be a bit lighter than steel wheels but this is a negligible consideration regardless of what the salesperson says about “unsprung weight.” A large-diameter alloy wheel/tire combination can even weigh more than a smaller diameter steel wheel/tire set, and the unsprung weight nonsense can also be negated by 5c. below.
- Steel wheels are pretty generic, whereas manufacturers frequently change the style of their alloy wheels. If you damage a steel wheel, or lose a wheel cover, it’s less problematic than damaging an expensive and unique alloy wheel a few years down the road and wondering where you will find a replacement style for just one wheel.
5.Alloys often have a greater diameter than steel wheels for style reasons, which means they will need what’s called a “low profile” tire to give roughly the same diameter as their standard steel cousins (profile is given by the second number after the tire width, so a 165/60 series tire is a lower profile than a 165/70 series tire).
Low profile tires have several relevant characteristics:
–a. Low profile tires are wider than high-profile tires of the same diameter, so they can handle better in dry conditions but will generally hydroplane more and will handle much worse in the snow (depending on tread design and tire quality). This might mean buying winter tires, or a set of wheels with higher-profile winter tires, for winter use. Because they have less tread-to-wheel distance, they also feel more responsive up to a point. That same lower tread-to-wheel distance means they will “flex” less, which means they can be more “squirrely,” feel less stable, and have a harder ride.
–b. Low profile tires are usually more expensive, may be harder to find, and are generally more unique in their handling characteristics (meaning you will have a hard time duplicating the handling of the original tire if you switch to another brand for some reason, or if they stop making the tire or tread style, which manufacturers often do. If/when this happens, you may be very unhappy with the characteristics of the replacement tires. It also means you are likely to be talked into four new tires if just one of yours is damaged. The house always wins.).
–c. Because low profile tires have less distance from the tread to the wheel, they will not have as much cushioning when you hit a severe bump at high speed. This is very uncomfortable and generally has a much higher risk of damaging your expensive wheels and suspension, not to mention your irreplaceable spine. If you live in an area with lots of bad roads, test drive the car with low profile tires on a bad road at high speed and see how they do before you shell out $1700 for a set of wheels. IF you live in an area where you get lots of bumps or potholes, you should NOT consider a tire with a profile lower than about a 55 series. This helps explain why heavy duty vehicles usually don’t use low profile tires.
–d. Low profile tires protrude more from the car because of the width. This means you will run the risk of scraping your expensive tires/wheels against the curb (see “2” and “4” above).
–e. Because of the more confined air space in the tire, low profile tires usually run hotter and wear more so they don’t last as long as higher profile tires.
–f. One car magazine tested a car with different wheel and tire sizes and found there was a “sweet spot” for tire/wheel size where the handling felt better, where it actually was better, and the tire/wheel weight was lowest, but finding this “sweet spot” for your particular car is probably a matter of luck. You’d like to think the manufacturer has already made this decision when they designed the car.
BTW wheels have been getting larger mainly because of style, and even a cheapskate wants to look at something nice sometimes even if it is far more expensive, higher maintenance, and less reliable. You can also use larger brakes with larger wheels (although my old BMW 2002 with 13" wheels had great brakes, and if you buy larger wheels as an option, chances are you will get the same brakes as the standard car), and a larger wheel can let you use low profile tires which can make the car handle more responsively in dry weather.
This is mainly general information and actual performance depends on many factors. TIre rack also has good information. Good luck with your choice.