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Old 01-30-2010, 05:05 PM   #1 (permalink)
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Bridgestone Tires and LRR

This is the response I got from Bridgestone concerning LRR tires:

"Thank you for your inquiry, LRR means low rolling resistance generally associated with tires. Most consumers associate LRR in reference to fuel economy. Rolling Resistance information is not available as measuring would need your exact vehicle along with exact road you are driving on. Rolling resistance is measured by road service ambient temperatures, tire pressure, tire foot print, weight of vehicle on tires, the suspension, and so much more. There can be two different rolling resistance numbers depending on what road you are driving on. Every vehicle in combination with tires and the road driven on will vary in rolling resistance. This means that in order to calculate your rolling resistance we would need to test your vehicle with whatever tires you have on it, and on the exact road you drive on.

I want to clarify if you are actually looking for rolling resistance information as a means to better your fuel economy. If this is the case, MPG and rolling resistance are two completely different things. Rolling resistance is such a small factor of the overall fuel economy. A decrease of 10% in rolling resistance only gives you 1-2% increase in fuel economy. This is extremely minuscule.

There are 3 things that make up fuel economy. 1) Tires 2) Aero Dynamics 3) Engine torch. So tires make up only 1/3 of the overall fuel economy with only 10-15% of that 1/3 being rolling resistance. The best ways to increase MPG/Fuel economy is not worrying about rolling resistance; it is focusing on the information below.

The weight of the tire will have some affect on gas mileage. What is more of a factor, though, is the tire "footprint". This term refers to the actual area where the "rubber meets the road". The same size tires may have different contact areas and therefore different gas mileage implications. More rubber coming in contact with the road can create increased rolling resistance. Generally, narrower, taller tires are better for fuel economy, if you retain your current wheels. Increasing the tire aspect ratio, for instance from 70 to 75, will provide additional load carrying capacity.

But what makes a difference is to monitor your tire inflation pressure frequently. Checking once a month will assure you are running that pressure recommended by your vehicle manufacturer and provide the best fuel economy. Tires will naturally lose air pressure, like a balloon, and the loss of just 7 psi can lose you 2 mpg.

Thank you.

Rod Manibo
Merchandising & Inventory Management
Bridgestone Retail Operations, LLC"

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