Saturday, March 12, 2011

Summer Tires! New Wheels, Too

Betting there won't be any more snow storms this year, we took off the Continental all-seasons and the OEM BMW wheels they were sitting on, and we bolted up a set of Hankook Ventus Evo V12 tires, with some VMR V701 wheels.  The wheels are 19x8.5" in the front, 19x9.5" in the back.  The tires are 235/35R19 front, 275/30R19 rear.

The visual difference is striking.  The large wheel diameter combined with the spoke profile of the wheels gives a nice sense of depth, and the 20mm wider rear tire fills out the wheel wells.  The V701 style seems like a good visual match for the car.

As you might expect, ride comfort is reduced.  The thinner and stiffer sidewalls transmit more harshness into the car, and sharp expansion-joint style bumps make themselves known more than the softer 18" Continentals.  I thought I might sense an increase in steering feel, but it doesn't feel that different.  The car does tend to tramline a little more, following troughs or grooves in the pavement more than before.

Weight-wise, the new setup is actually lighter than the old, despite being both wider and larger in diameter.  The stock wheels with 225/40R18 Contis on the front were 50.5 pounds for the package.  The new fronts are 49.5.  The stock rears with 255/35R18 Contis were 55 pounds even, while the new ones weigh in at only 51.5.  I didn't get a chance to weigh all this hardware separated from each other, so I'm not sure how much of the difference is wheel and how much is tire.  Still, it's nice to know the new rollers are actually saving weight.

On the ECU front, we're continuing to test new maps from Cobb tuning.  I should have some updates on that in the near future.

A desperately-needed limited-slip differential from Wavetrac is on the way, and should be installed in the car in the next couple of weeks.  Stay tuned.