Iñigo Roces / Iñigo Roces | August 16, 2011 14:46
The new Michelin Energy XM2 improves wet/dry handling, fuel economy and comfort
Laundry List Requirements
Wet handling, dry handling, fuel economy, ride comfort and quiet; these are all qualities that the new Michelin Energy XM2 tire claims to improve should you equip it on your car. It sounds like quite a lot to claim, particularly since this is just a tire, not an entire vehicle upgrade. Yet during a whole day event at the Utapao Airport in Pattaya Thailand, to test the tire first hand, I found myself ticking these boxes one by one.
It was all a part of the extensive ASEAN launch of the new tire. The successor to the original Energy XM1 tire, the XM2, like its predecessor, was designed with the average passenger car in mind which can range from a small city car, to a compact or executive sedan. Being an all-purpose tire, it has to meet all those needs too like returning good fuel mileage, longer life, and better grip in wet and dry conditions to ensure safety. Of course being comfortable and quiet would also help. Perhaps hardest of all is beating the high benchmark already set by the original Energy XM1.
The Technical Background
Before anything else though, a very technical briefing was in order. The new tire may make a lot of claims simply because it easily one of the most essential components of a car is the tire. Tires are the vehicle's only contact with the ground. Power, grip, braking, and ultimately, economy greatly depend on the state of your tires, which is why the choice of tire is such a critical one.
The vehicles themselves also have a great effect on the tire, compounded by the fact that the MICHELIN ENERGY™ XM2 is intended to equip a wide array of vehicles, from small models to the largest sedans, fitting tire sizes from 14", 15" to 16" tire segments. In creating such a multi-role tire, engineers constantly have to make tradeoffs when developing new technologies. To achieve this each tire feature was worked on separately to efficiently improve overall performance without sacrificing one particular area. Each department, after all, was working toward one simple goal: last longer with maximum safety.
The first of these new advancements implemented in the tire is called Alternating Bridging Technology and helps the tire give 20% more mileage than the last Energy XM. Alternating Bridging (the connection from one sipe to the other) reinforces the rigidity of tread blocks. With rigidity enhanced, the tread blocks move less freely, reducing the rate of tyre wear.
The second feature is aimed at improving fuel efficiency. Here, a full Silica compound is used compared to the usual partial mixtures. Adding more silica in the rubber compound reduces friction between the rubber particles generating less heat. With less heat generated, less energy is lost, thus reducing fuel consumption. The silica also increases the tire's flexibility, therefore improving road holding.
For the safety aspect, two new features are responsible. The first is the use of a Micro-Adaptive Compound. This allows the tread compound of the MICHELIN Energy XM2 to be more flexible. It better adapts itself to the irregularities of the road surface and therefore guarantees excellent grip. The tread suppleness of MICHELIN Energy XM2 is better than MICHELIN Energy XM1 by 3 points (measured in shore).
The second feature is the use of Optimum Void Grooves. The grooves of the MICHELIN Energy XM2 can evacuate up to 20% more water compared to the MICHELIN Energy XM1. A higher volume of water evacuated at a faster rate lowers the risk of hydroplaning.
With that explained, it was on to the launch event proper. Strewn across parts of the old military airstrip, with broad flat runways ripe for vehicle testing, were modules and exercises designed to showcase the tire's performance in each of the aspects mentioned. The first would demonstrate its lower rolling resistance, followed by its fuel saving ability. Next up would be a showcase of its safety. The event would be rounded up with a scenic drive through real roads to better establish the tire's performance in the real world.
Of course, in a bid to tease us even more, participants were first shown an AVP. In it was a short feature of the extensive tire test the XM2 underwent before launch. Five identical vehicles (Toyota Vios 1.5 J) were brought in for a test. Before accumulating any more miles, the oil was changed, suspension replaced and tires fitted. Each car was fitted with tires from different leading brands competing in the same tire segment. The last two were fitted with sets of Energy XM1 and Energy XM2. The vehicles travelled some 50,000 kilometers around Thailand's roads with the tests results witnessed and reported by TUV Rhineland Thailand. The energy XM2 showed 20% more longevity than the previous XM1, which, on its own, outlasts the other brands in terms of wear. As impressive as the results were, the presenters were met with a few yawns from the jaded audience. That was clearly the cue to start the first hand tests scheduled for the day.
To benefit fuel efficiency, the tire is designed with as little rolling resistance as possible. This simplest way to demonstrate this was with gravity. The first setup involved two exactly identical vehicles, right down to the trim level and options; one with Energy XM1's and another with Energy XM2 tires. Both cars were positioned on a ramp and left to roll in neutral with the engine off. Once left to roll, the vehicles were head to head. When both had rolled to a stop, it was clear the car with Energy XM2 tires had rolled a car length more.
For a more personal and real world experience, the media were invited to drive the cars around a track designed with long straights, slaloms and U-turns. Again, identical vehicles were equipped XM1 and XM2 sets, both with professional grade fuel flow monitors (Racelogic VBOX) that broadcast live fuel consumption figures to a monitor in the tent. Each driver would get to drive both cars around the track, their distance, times and fuel logged. In the final tally, and with almost all the drivers, the vehicles showed identical distances travelled but with better fuel economy results (2-3 km/L more) in favor of the car equipped with XM2's.
Wet and Dry Handling
During the safety workshop in another part of the airstrip, another pair of identical vehicles were fitted with a competitor brand and Energy XM2. Each car would go through a course that included a short straight, a fast U-turn, slalom, emergency lane change and wet handling course. Each participant would get a chance to take both cars through it to see the difference. Throughout the course, the competitor tire returned some fair performance in the dry portion and only minor road noise. In the wet section of curves, the competitor tire seemed to cope fine, with a few hairy moments in the tighter wet turns. The Energy XM2 on the other hand returned a noticeably quieter ride and slightly better grip in the dry. In the wet, the tire seemed to perform similarly in the first few seconds. Yet after those first few seconds, perhaps just a brief moment of hydroplaning, the tire seemed to disperse the water and recover quicker, beginning to grip harder, later in the turn. This made corrections easier and turns far tighter toward the end.
For an ice-breaker, another car was waiting nearby, its rear tires placed on rollers. This set-up is meant to simulate oversteer, particularly in cars with worn out rear tires. The rollers help achieve this effect at much lower and safer speeds (10 km/h). The object would be to drive (or drift) around the pylons in a figure eight. Just a little steering input would cause the tail to kick out in the opposite direction, making for drift-like maneuvers in a front-wheel drive car. This exercise also showed how a car's dynamics can radically change with worn tires, serving as a gentle reminder to regularly rotate and replace. It was also a great chance to drift on cars that never could under normal circumstances.
Real World and Comfort
Capping the day off was a scenic drive through Pattaya's local roads. For this, a fleet of vehicles, ranging from the diminutive Suzuki Swift to a Toyota Prius were equipped with Energy XM2 tires to test on real roads around the event venue. The convoy would travel through a route ranging from concrete, to asphalt to rough roads.
For the drive, I was fortunate enough to be assigned to the Prius with its extra quiet hybrid synergy drive system that would help me better monitor the road noise. Even over varying surfaces and the occasional drizzle, the tires seemed to maintain a consistently low noise level, good grip and comfortable ride.
Part of the trip was a stop at the nearby Sea Turtle Conservation Center operated by the Royal Thai Navy. Though in no way related to the event, seeing the numerous and adorable hawksbill, loggerhead and Olive Ridley turtle hatchlings up close certainly made for a worthwhile stop.
From there, it was an enjoyable drive back, this time in a Ford Fiesta, to the event venue tent where Energy XM2 tires in various sizes were on display for us to better appreciate after the drive.
The enjoyable and insightful exercises certainly helped the day whiz by. In each and every segment, it was clear Michelin had taken extra pains to make the tests as scientific, consistent and transparent as possible. No part of the tests were hidden and participants were even welcome to examine the cars and tires to make sure that they were indeed what the organizer said they were. Competitor brands of the same level were in fact equipped on the other cars and, while we were strongly discouraged from mentioning the said brands, clearly see that no switching or unusual wear, except for what occurred during the day was on those tires. Even the fuel consumption computer was revealed under the hoods of the cars, with setups and accessories easily attainable in any high end tuning shop.
All told, it was hard to argue against any of the tests' results. Michelin may have made a lot of claims, but they are indeed truly and certainly repeatable. Sure they may not be staggeringly large numbers, but it's easy to see how these incremental improvement can add up to bigger savings in the long run.
Technical specs aside, one regional executive seemed to summarize the whole event best.
"Tires are an angry purchase," he says. "It's an experience the consumer doesn't like. They go to the shop, sit and wait while the tires are changed. A set of tires is expensive and they hardly feel their money's worth. With Michelin's new Energy XM2, we hope to reduce the frequency of that experience and provide more tangible results with our high performance, fuel efficient, safe and longer life tires."
It's an end result anyone who's ever had to replace their tires can definitely agree with. And after the day's event, is also pretty reassuring.