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One Year 15,000 Mile Test of Bridgestone Potenza Pole Position RE970 AS Super Premium Tires.

PHOTO (select to view enlarged photo)
Potenza RE970AS v2

By Thom Cannell
Senior Editor
Michigan Bureau
The Auto Channel

Just a year ago we began a long term test of one super premium all season tire, a tire we reviewed in 2012 and thought highly of. That review was based on a single day’s testing, not thousands of miles. Our question to ourselves and the tire company was, would we continue to think it was worth your money? In short, yes.

The tire we liked and tested was the then-new Bridgestone Potenza RE 970 AS. This all season tire replaced an already popular tire, incorporating better wet weather traction, better high performance traction, and some of Bridgestone’s Ecopia technologies that promised better fuel economy. That’s a lot to deliver on.

The test bed was a company owned Audi allroad Quattro, already a mean all wheel drive machine. Although standard tires are 225/55/R17 we fitted 235/50/R17. They are slightly wider and have a slightly less tall profile. However their overall diameter was nearly identical. If you’re thinking of substituting different tires for your vehicle, keeping the diameter in line with stock means your drive train, the speedometer in particular, thinks everything is normal.

Our first user note said “Potenza RE970 All Season. Right after getting them mounted and balanced, they felt softer than the aged tire they replaced. These are newer, have full tread depth, and are inflated two PSI less at each tire. That said, they feel considerably softer and we feel a better grip of the road, particularly attack of the road on our bumpy pavement. We also notice they are far quieter, and that is in only four miles of pleasant weather driving.”

Dissecting that, although the outgoing tire was inflated harder and had less tread—which normally equals better grip, the newer tire with full tread depth gave the driver more assurance. Note that they were quieter as well, which isn’t normal. Tires with full tread often sound noisier than old tires as the tread blocks are free to move about and, like a tuning fork, create sound. The RE970 Pole Position AS incorporates what the company calls “3D stealth tread elements” to make the tread blocks stiffer for better handling, better grip, and they are asymmetric for less noise. The center of this tire is continuous for responsive turning, more like a racing slick than regular tires (many companies use this approach) and it does make quick turns feel crisp.

The second note reminded us that “the rest of the proof will come as miles and seasons accumulate.”

As you consider moving up in tire performance many think “bigger is better” and try to buy 19”, 20”, or even larger wheel sizes. Oops! You have to ask if the new wheel and tire will rub the wheelwell at extremes, cutting or wearing the tire and making the turning circle larger than New York. Any really significant difference in tire width could give you problems rubbing on suspension parts. It can also be very dangerous if the wheel width (measured bead seat to bead set, not side-side) isn’t wide enough for the tire section width. That is something you absolutely must discuss with the tire salesclerk and not with a seller on Craigslist, particularly when fitting super low profile tires. Our test tires are only a bit different from the 26.8” diameter of Original Equipment, slightly smaller at 26.3” and well below the suggest 3% maximum variance.

Another benefit of new tires is a potential cure for annoying slow leaks due to freshly cleaned rim sealing surfaces, all new tire valves (which you should normally do when dismounting a tire) and less permeable new rubber. Please remember that your new tires are fresh from a tire forming mold and have some slippery mold release compound on them (they’d still be in the mold if not) and take about 500 miles to wear in according the mega-merchant Tire Rack.

During the test period we noticed that the new tire, after sitting for two days in 20°F weather, didn’t deliver the “thump-thump-thump” of tire plies settling and assuming a flattened shape. They always round out when warm, but are noticeable until then. Test drivers did not miss the thumping every winter morning.

Here’s the less than stellar news, despite an “All Season” rating they didn’t have as much claw in snow and ice as we’d hoped to have. That’s not really a surprise. Remember, All Season means more compromises than would be in a pure summer and pure winter tire. Most of us have been sold on the idea that a single tire can do everything. It likely cannot depending on where you live. Snow belt drivers really should consider using all season or summer tires until winter, then switching to snow tires. Studs and chains are a very good option for folks living where deep snow is regular, or in the mountains.

For the rest, all season tires may be the best set of compromises if you get frequent rains. They’re designed with big extraction channels and can actually rip deep water off the pavement to prevent hydroplaning. Simply put, hydroplaning means your car becomes a boat riding on water when the tires cannot push enough water out of the way. And because our test car lives in Michigan where there are four distinct seasons, including occasional 2+inch rainstorms, great water handling and superior dry handling were our biggest concerns. Those are one of the claims Bridgestone makes for the tire.

PHOTO (select to view enlarged photo)

Three months later winter struck. We’d hoped that snow and ice traction would equal their renowned Blizzak snow tire. Ah, hopes. We’d hoped for better traction, steering, and grip on icy, snow covered slippery roads. On the good side, the Potenza RE970 AS has amazing grip in snow and ice off the line, but under braking its non-Blizzakness reminded us that Assured Clear Braking Distance Ahead as Drivers Ed teaches, is a necessity. Again, superb all season tires will never equal superb snow tires once the temperature dips below freezing.

The final fact about the tire, one you won’t see on any advertisement, is that the technologies used in this tire borrow from their Ecopia low rolling resistance green tire. One reason they don’t mention it is that any new tire typically delivers less fuel economy than the one it replaces. Why? All those squirming tread blocks softly gripping the pavement so you can drive safely. It’s the difference between a bowling ball and a Nerf ball. So we were hoping to improve mileage over the worn tires, but not expecting to really gain. What we did discover was either no loss of fuel economy, or a very slight gain. And that was new, with full tread depth. As the tires wear in we expect to improve fuel economy by half a mile per gallon, perhaps a bit more.

For the technically inclined, the Potenza RE970AS Pole Position is an ultra high performance all weather tire that wears better than the RE960AS it replaced. Optimizing was set for wet and dry weather handling. The tread compound (the rubber) contains generous amounts of silica, which creates micro-gripping edges on the surface. It also has big blocks of rubber at the shoulders for cornering stability. In the center, a continuous rib yields steering responsiveness. In between, the tread blocks are asymmetric for noise reduction and are heavily siped (cut) for better traction and braking.

Before initiating our test we compared the RE970 against a very highly rated Michelin tire, the Potenza RE970AS Pole Position had more wet traction in every way. Mounted on identical BMW 328s and driven on a wet skid pad, the Potenza RE970AS Pole Position turned in better, offered more grip, and provided better steering feel. For most drivers of high performance vehicles who want to experience high cornering ability while preserving wet weather traction and good snow traction, this tire provides an excellent compromise.