Dear Tom and Ray:
I drive Lincoln Navigators. I like as good a ride as possible for this size vehicle. If I remember correctly, the one I bought in 2008 had 16-inch wheels. I think my 2010 also had 16-inch wheels, but you could get optional 18s. By 2012 year, they still offered 18-inch wheels, but no one had them, so I had to get 20-inch wheels. Lincoln Navigators have not changed much over the years, but there is supposed to be a major change in 2015, so I thought I would wait. The big change: 22-inch wheels. When the wheel size goes up and the sidewall of the tire gets smaller, doesn't the ride get worse? My thinking is that the smaller wheel with more sidewall will get a better ride — right or wrong? Thanks. — Arlon
Ray: Right. Generally speaking, you are correct. With more sidewall to absorb bumps, the ride will feel softer.
Tom: But the handling will be sloppier. That's what they're trying to combat with larger wheels and shorter sidewalls.
Ray: Usually, the total diameter of the wheel/tire combination stays the same, regardless of which wheel size you choose. The larger the wheel, the shorter the sidewall. This is so that they all fit in the same wheel well. They wouldn't want to redesign the wheel well, because that costs what? Money.
Tom: But the shorter the sidewall, the less "flex" there is in the tire when you change direction. So shortening up the sidewall is a cheap way of improving the handling without modifying the truck's suspension — which costs what? Money.
Ray: And if Lincoln believes that most potential buyers would prefer crisper handing to that living-room-sofa feel, that's an easy way to accomplish it.
Tom: On a vehicle like a Lincoln Navigator, where the ride already is designed to be Barcalounger-esque, you often can "afford" the ride penalty of larger wheels and lower-profile tires. But on a car that is already tuned for handling rather than a cushy ride, like a BMW 3-series, for instance, we encourage people to avoid the larger wheels, because they may turn what had been an acceptable ride into an unacceptably harsh one.
Ray: But lots of people are going for the larger wheels these days anyway, for styling reasons. Wheel aesthetics have changed in the past 10 years, as your history of Navigator wheel sizes illustrates. These days, if you see 16-inch wheels on a Navigator, they'll probably look tiny and out of scale.
Tom: But if you prioritize a pillowy ride over crisp handling, then you're right to opt for the smallest wheels that the manufacturer makes available — if you can find 'em, because even the dealers rarely order them. Good luck, Arlon.
(Car Talk is a nationally syndicated column by automotive experts (and brothers) Tom and Ray Magliozzi. Write to them at the Car Talk website.)