Michelin’s tagline of “feel more secure – whatever the conditions” is derived from claims of increased stability across a huge variety of machines, and unparalleled grip in both the wet and dry.In addition, Michelin also claims that the tires will maintain performance across a broad 90 degree F (50 degree C) range of temperature starting from minus 5 degrees C up to 45 degrees C. Think about that – it’s an amazing claim. The tires will work in ambient temperatures well below freezing up to sweltering hot! It doesn’t quite resolve the “cold tire syndrome,” but the fact that Michelin has addressed this issue is encouraging.Since sport-touring motorcycles arrive in an enormous variety of weight and power output, Michelin has created three variations of the Pilot Road 4: the Standard, the GT, and the Trail. The Standard is designed for usual sport-touring platforms such as the Triumph ST, the GT for heavier and more powerful machines (now standard equipment nearly half of the new BMW R1200 RT production), and the Trail for the growing segment of ADV owners who only ride asphalt.Although considered radial tires, the GT model is partially constructed using Michelin’s patented 2AT (Dual Angle Technology) with some bias belting to increase the strength of the carcass for heavier machines. Such is Michelin’s development of this mix of belting architecture that the Pilot Road 4 GT rear tire is actually 15-percent stiffer than the Michelin Pilot Road 3 ‘’B’’ – and it does it with one ply less.Some motorcycles will fall into a bit of a gray area and you may be unsure which tire to fit to your particular ride. However Michelin assures us that dealers (and its website) will be able to identify the correct tire for your machine. Michelin personnel admitted that if you did fit the wrong tire, it wouldn’t be a disaster and certainly not dangerous; however it would affect stability and of course that won’t feel good. So make sure you buy the right one!We mounted the tires to my personal Triumph Sprint ST, and although the bike is getting a little long in the tooth, it is nevertheless a strong performer that falls quite a bit more towards the sporting side of the category.I admit the Triumph takes a certain amount of effort to turn, yet the handling has always been nice and predictable. Happily, the Michelin PR4s actually helped quicken the turning slightly; the steering was a little lighter and yet it retained the nice neutrality that makes the ST so stable.The test took us on a 300-mile round trip through the mountains of Southern California, and although the distance wasn’t huge, the road conditions were extremely challenging. The ride featured super twisty sections with mixed asphalt, fast and slow corners , and high wind conditions that left the roads strewn with rocks and dust.The temperatures varied from pretty hot (about 92 degrees F in town) to close to freezing up in the mountains where snow was still very much in evidence on the roadside. As we were running late and wanted to beat the fading light, the pace was cranked up too. With all these factors in mind, I’d say the tires ended up being pushed beyond normal riding limits.The Michelin Pilot Road 4 worked impeccably. At no point did the tires give a hint of letting go. They stuck firmly to the oftentimes poor surface, and my confidence in the tires grew exponentially as the day continued.Michelin tells us that the grip comes from a new all-silica compound that uses a “Functional Polymer SBR Technology (SBR = Styrene Butadiene Rubber)”. I won’t pretend to know what that means, but you read it here first anyway. What I can tell you is that Michelin’s 2CT (Dual Compound Technology) is on both the front and rear tires. The rear has a hard compound center line for good wear, and medium compound shoulders for grip when leaned over. The front tire is also (and unusually) a dual compound tire with one step softer compound rubber; in other words a medium compound center line with soft compound shoulders.Although our testing wasn’t able to include wet conditions, nevertheless the XST+ Technology is a further development of its namesake that first appeared on Michelin products some years ago. The patented sipes and integrated chamfers of Michelin’s XST X-Sipe technology clear water quicker and deliver better grip under braking and acceleration than ever before. The chamfers on the leading edges of the sipes ensure that the blocks of rubber don’t wear too quickly, so the performance of the Pilot Road 4 is maintained throughout its life. Michelin enlisted the quality assurance testing company DEKRA to thoroughly test the PR4s and over 2 Million Kilometers were covered in European testing. In addition, DEKRA tested the wet weather performance using a Yamaha FZ1 ABS at the Michelin Test Track in Ladoux, France. Over a variety of surfaces (Painted lines, and polished concrete), the Michelin PR4s outperformed their competition in wet braking distance by an average of 14 meters – or to put it another way, the length of three Audi A3s together. To reduce wet stopping distance by three car lengths could be the difference between a heart in the mouth moment or a trip to the Emergency Room. Although this is just an initial riding impression that only covered a few hundred miles, nevertheless the variable temperature through the day, the often highly questionable road surfaces, and the hurried pace of the ride proved that the Power Pilot 4 is a very worthy motorcycle tire.The Triumph retained its happy stability and neutral handling, however the bonus was that turn-in slightly improved. Grip was truly excellent, and even in some quite sketchy road conditions the Pilot Road 4s held their ground perfectly and gave me enormous confidence in their ability to grip, no matter what we encountered. Interestingly, I also found the PR4s to be “comfortable”; they absorbed bumps well and the overall ride of the Triumph ST’s chassis was definitely improved by the tires.Michelin’s final claim is that the Pilot Road 4 will last some 20-percent longer than the 3 Series tire it replaces. If that claim proves to be correct, Michelin is close to achieving the Holy Grail of sport-touring tires: stability of handling, superb grip in almost all conditions imaginable, and several thousand miles of hard use before you have to shell out for another set. Sign me up!