The Kia Rio is fun to drive, with a willing engine, 6-speed transmissions, and capable if unsophisticated suspension. It conveys the willing, youthful energy most of its buyers will share.
A 1.6-liter four-cylinder engine is the only one offered. It employs direct fuel injection, first used on a street car more than 50 years ago and still reserved primarily for more expensive cars. This yields good power and fuel economy. The Rio's 138 horsepower is better than anything in the class except the Chevrolet Sonic with the same rating. Peak torque is 123 lb-ft at a fairly high 4850 rpm, but again this has most of the class covered, except for the Sonic's optional turbocharged 1.4 at 148 lb-ft.
The Rio needs to be revved for maximum power, but so do most gasoline engines. This one is smooth so it doesn't really matter if you want to push hard because it adds only a bit of busy noise, absent the vibration or harshness. And with the most power and among the lightest weight in the segment, the Rio accelerates comparably well.
Fuel economy is another good story for the Rio. EPA numbers are 30/40 mpg City/Highway, which are unmatched by the Fiat 500, Honda Fit, Toyota Yaris, Ford Fiesta, Nissan Versa, or Chevrolet Sonic. A couple of them can match the Rio automatic EPA Combined rating of 33 mpg, however. Even the fuel-economy specials that account for a small fraction of Fiesta sales (and Chevrolet's Cruze with the 1.4 turbo available in Sonic) don't rate 30 mpg City with an automatic. (Remember these are EPA estimates and driving style makes far greater differences.)
While Rio's direct injection helps fuel economy, so do 6-speed transmissions where competitors often use 4- or 5-speeds. More gears allows better acceleration, lower highway engine speed, or both, hence better performance and fuel economy in the same car.
Rio EX automatics offer an option no one in this class does: Idle Stop and Go (ISG). Much like a hybrid, this system automatically switches the engine off at stops and restarts it when time to go, saving gas in urban situations and adding one mpg to the city rating. ISG requires nothing of the driver: No switches to activate, no shifting into neutral, no special pedal techniques. As the car stops with the brake pedal depressed the car disengages transmission from engine and switches it off. As you lift your foot off the brake pedal the car restarts and drives off as normal.
We found the Idle Stop and Go system works just as it should, limited by circumstances including engine temperature, battery state, air conditioning demand, and so on, and it won't reset to activate again until the car has passed 5 kph. If you get stuck in a lot of stop and go traffic, as we did in Seoul, the system helps, and it can be switched off if you wish. My co-driver was so engrossed in the entertainment system he never noticed it shut off the first time it happened, but you should feel a slight change and hear the starter on restart. On a hot, humid day with AC on, we averaged near 35 mpg, not bad in light of the circumstances.
Both transmissions are easy to operate. The automatic has been programmed for economy so you have to be forceful with the gas pedal to effect a downshift when speed is needed, or you can shift manually; it will hold the gear selected even if you mat the accelerator in sixth gear. The manual offers light throws and clutch action, not as precise as a Fit perhaps but we never got the wrong gear. Throttle activation has been tamed relative most recent Kia models, so it doesn't jump forward with just a minor touch on the pedal. Rio now has hill start assist to keep it from rolling backward on uphill starts.
On the road, the Rio feels quite comfortable, though the road surface determines how much noise seeps in from the rear tires. The ride is taut without being firm, the feeling one of stability and not punishment. Wind noise is not an issue, at least up to Interstate speeds, and the 6-speeds allow relatively low engine speeds for most highways so there's no mechanical noise.
Economy cars aren't designed for top handling marks but frequently make plausibly entertaining drives because they weigh less. With just 2500 pounds to control, the Rio has low mass on its side; it changes direction with minimal effort and no drama. The electric-assist steering is vague on center (many are) but does offer up some feel at speed.
The Rio SX, top of the line in luxury and sportiness, adds bigger front brakes, slightly firmer suspension settings and 17-inch wheels for a minor improvement in responsiveness at a minor cost in ride quality. We imagine the majority of SX buyers go there for the features but some will find the ride/handling balance skewed more to their liking and pay the features-heavy price premium to get it.