Acura’s SUV lineup is comprised of two models — the RDX and MDX. While the two share their badge and numerous styling elements, the 2018 Acura RDX and the 2018 Acura MDX are quite different, competing in entirely different classes. Below, we’ll highlight the differences between the two, and give some recommendations about which other vehicles buyers should cross-shop them with.
The RDX has been on sale in its current generation since the 2012 model year and received a facelift for 2016. It’s a stylish and sporty 5-seat crossover that offers sound driving dynamics, but not the high-performance trim levels offered by its German rivals.
The MDX was last fully redesigned in 2014 and received a facelift for the 2017 model year. The MDX is meant for families and seats seven, while also offering ample cargo volume. In addition to its standard powertrain, it offers a unique hybrid system that, paired with Acura’s Super Handling All-Wheel Drive, makes for a rather compelling package. Though, like its smaller sibling, it still doesn’t offer the level of performance of its German counterparts.
Nonetheless, each of these vehicles presents a unique value relative to the German alternatives, not to mention unrivaled Japanese quality and resale value.
The MDX is bigger than the RDX in every way. The MDX is 196.2 inches long, 77.2 inches wide, 67.4 inches tall and offers 7.3 inches of ground clearance. The MDX has a handsome exterior design with a rounded greenhouse that offers room for a third row of seats. Up front, it wears Acura’s signature shield grille bracketed by bejeweled LED headlights. The MDX has a well-balanced design with slab sides and handsome front and rear valences.
The 2018 Acura RDX is 184.4 inches long, 73.7 inches wide, 65.0 inches tall and offers 8.1 inches of ground clearance. Its design is slightly more taut than that of the MDX, indicative of its smaller overall size. The 2018 RDX is one of the last Acura vehicles to still employ Acura’s beak-shaped grille; a polarizing design element that will be left in the past with the introduction of the 2019 model. Beyond the grille though, there is little about the 2018 RDX that would offend anybody.
The RDX seats five, while the MDX has room for seven. The MDX offers 38.1 inches of front seat headroom and 41.4 inches of front seat legroom. Back seat passengers get 38.3 inches of headroom and 36.6 inches of legroom. In its third row, the MDX offers 35.6 inches of headroom and 28.1 inches of legroom.
Up front, the RDX offers 38.7 inches of headroom and 42.0 inches of legroom, while the back seat offers 38.1 inches of headroom and 38.3 inches of legroom.
The MDX offers 38 cu ft. of cargo room behind the second row, and 68 cu ft. with the second row folded, while the RDX offers 30 cu ft. behind the second row, and 61 cu ft. with the second row folded.
The 2018 RDX offers one powertrain option — a 3.5-liter V6 making 279 horsepower and 252 lb-ft of torque and mated to a 6-speed automatic putting power down to either the front wheels or all four. The AWD-equipped RDX doesn’t employ Acura’s Super Handling All-Wheel Drive system, but rather a less costly traditional setup. Equipped with front-wheel drive, the RDX earns 20 miles per gallon city, 28 mpg highway and 23 mpg combined. Opt for all-wheel drive, and each of those figures is reduced by one.
The 2018 MDX offers two different powertrains. The standard setup is a 3.5-liter V6 making 290 hp and 267 lb-ft of torque and mated to a 9-speed automatic transmission. This engine can be paired with either front-wheel drive or Acura’s Super Handling All-Wheel Drive setup. Things get more interesting when you step up to the Hybrid powertrain, which makes 321 hp and 289 lb-ft of torque. The Hybrid also employs a "Sport Hybrid" version of Super-Handling All Wheel Drive. With the regular powertrain and all-wheel drive, the MDX earns around 22 mpg combined. Opt for the optional hybrid trim level, and this figure jumps to a respectable 27 mpg combined.
The MDX is available with seating for up to seven via a second-row bench seat, or second-row captain’s chairs that reduce overall seating capacity to six. Among the features offered by the MDX are power folding sideview mirrors, rain sensing windshield wipers, heated and ventilated perforated leather seats, heated second row seats, a heated steering wheel, a rear seat entertainment package, a power liftgate, remote start and, with the top-tier advance package, high-end leather, second row sunshades, LED fog lights and a surround view camera.
As it’s a less expensive vehicle overall, the RDX offers a shorter list of available features. Highlights of the 2018 RDX include available fog lights, a power liftgate, rain sensing windshield wipers and heated and ventilated front seats.
Overall, the infotainment systems in both the MDX and RDX are said to be somewhat lacking. Both vehicles employ a 2-tier, dual LCD screen design. Acura has also been somewhat late to the game when it comes to adding Apple CarPlay and Android Auto capability. The 2018 MDX is the first model year to offer compatibility, while the 2018 RDX lacks it altogether.
The 2018 MDX and RDX both score exceptionally well in Insurance Institute for Highway Safety crash testing with both earning Top Safety Pick designations.
The MDX offers standard lane-departure warning, lane-keeping assist, automatic high beams, front automated emergency braking and adaptive cruise control as standard. Optional packages introduce blind spot monitoring, rear cross-traffic alert, forward-collision warning and front and rear parking sensors.
The RDX offers front automated emergency braking, adaptive cruise control, lane-keeping assist, blind spot monitoring with rear cross-traffic alert and front and rear parking sensors.
Both the RDX and MDX should offer above average quality. Acura’s parent company, Honda, is known for offering some of the best reliability and resale value in the industry, and this should apply to both of their volume-selling luxury crossovers. Both also offer a 4-year/50,000-mile basic warranty and a 6-year/70,000-mile powertrain warranty, on par with the offerings of other luxury automakers.
The differences between the RDX and MDX are pretty simple. The RDX is a compact luxury crossover on par with the BMW X3, the Lexus RX and the Infiniti QX50. Also worth noting is that an all-new much-improved RDX goes on sale for the 2019 model year. The MDX is larger and offers greater overall cargo space and room for up to seven passengers and should be cross-shopped with the likes of the Infiniti QX60, Volvo XC90 and Buick Enclave. In short, while both are excellent luxury crossovers, the RDX is more for the individual, while the MDX is best suited for families who need the extra space it provides.