Harley-Davidson Tri-Glide Ultra — 93 hpSomewhat appropriately, Harley-Davidson has three trikes in its lineup. The 90-hp Freewheeler is the cheapest, the also-90-hp Road Glide 3 sits in the middle, and the Tri-Glide Ultra sits at the top of this pyramid of bikes. And not only is it the priciest and most tricked-out, it's also the most powerful — by 3 hp. Yep, this is definitely splitting hairs.The Tri-Glide Ultra has the same 1,696cc Milwaukee-Eight 114, but Harley says that the Tri-Glide Ultra's engine makes 93 hp and 120 lb-ft of torque — you probably won't feel a difference, though. Given the bike makes this 93 hp at 5,020 rpm, compared to the 4,750 rpm at which the Freewheeler and Road Glide 3 generate their 90 hp, it's hard not to see this as a marketing ploy to ensure the priciest trike has the best specs on paper.Tech-wise, the Tri-Glide Ultra is a notable upgrade over the Freewheeler, however. Riders get a 6.5-inch touchscreen, four 25W speakers, Bluetooth and USB connectivity, plus all the rider aids you'd expect from a modern Harley-Davidson (including electric reverse). The mid-range Road Glide 3 has all that stuff too, but the Tri-Glide Ultra sets itself apart by being a fully dressed bike with all the fairings and extra luggage compartments you'd expect. This makes for a healthy 6 cubic feet of luggage space, and a 1,237-pound wet weight — almost exactly 100 pounds more than the Freewheeler. Maybe that's what the extra horsepower was for!Vanderhall Venice GTS — 194 hpNow it's time to get stuck into the really high-powered three-wheelers. The following trikes have horsepower numbers that'd be impressive on a mainstream car, let alone anything classified as a motorcycle. First up is the Vanderhall Venice GTS, a three-wheeler from the same company that builds the Brawley EV off-roader.The Venice GTS is one of three trike models available in the Vanderhall lineup, alongside the Santarosa and Carmel. Suitably, it's also one of three versions of the Venice that the company offers — the others being the basic Venice and the mid-tier Venice GT. As the affix might suggest, the GTS is the fanciest of the three, although all have the same turbocharged 1.5-liter inline-four engine making 194 hp and 203 lb-ft of torque. Vanderhall pairs that capable powerplant with a six-speed automatic, which has adaptive shift features like automatic grade braking — handy for keeping speed under control when going down hills.However, the GTS differs from its more affordable siblings in the details. The GTS has 19-inch wheels, fancy diamond-stitched leather, and Brembo brakes fitted as standard. The first two are exclusive to the GTS, while the latter is an optional extra on the more affordable tiers. Vanderhall also offers five colors for GTS buyers (matched to either Tan or Cranberry Red leather), compared to the two colors available on the standard Venice and Venice GT.