- Car Care & Maintenance
Low Rolling Resistance Tires For Better Fuel Economy
What Is A Low Rolling Resistance Tire?
One simple way to improve the fuel economy of your vehicle is to purchase tires that are rated as having a lower rolling resistance compared to conventional after-market tires. They improve the fuel economy of your vehicle by reducing the amount of energy lost due to flexing of the tire. It is estimated that 5-15% of the energy consumed by the average vehicle is used to overcome rolling resistance. This is due to the fact that as a tire rotates, the portion that meets contact with the ground is being squeezed flat against the road and as it the tire rotates, the portion of the tire bulges back out into its original shape. All of this flexing converts a lot of the forward momentum into heat.
Low rolling resistance or LRR tires reduce the amount of flexing and therefore the amount of energy wasted as they roll. This improves fuel economy if they're replacing tires that have a relatively higher rolling resistance. LRR tires may sound expensive and as if they have a small niche market, but auto manufacturers install them on most vehicles in order to improve their fuel economy and in some cases, just to meet the CAFE minimum standards. They're also very important for hybrid and electric vehicles as they can greatly improve fuel economy and range respectively. Owners of hybrid vehicles who have mistakenly had standard tires, with a higher rolling resistance as compared to the original ones from the manufacturer, have noticed a significant drop in their average fuel economy.
Where Can I Buy Low Rolling Resistance Tires?
Where can you find LRR tires? Give your local tire center a call, they may be able to help you find the model and size tire that will fit your vehicle. Although, be prepared to do a bit of research on your own. Most manufacturers don't list the rolling resistance coefficient of their tires. Some manufacturers do market some product lines that promise to improve your fuel economy, but they might have another product that is cheaper and just as good in terms of efficiency.
One great place to check and compare different brands/models of tires is Tirerack.com. Their site has recently made it easier to find low rolling resistance tires and also browse reviews from other customer's who've bought the tires and provided feedback on them as well that can help you make a better decision and find a tire will best suit your driving needs.
The easiest way to find out what brand/model of tire will work well for you and give you the best fuel economy, especially when you own a hybrid or plug-in electric vehicle, is to search forums focused mainly on improving fuel efficiency (e.g., Ecomodder) or focused mainly on hybrids like the Toyota Prius, Honda Insight or the Nissan Leaf (e.g., PriusChat.com, InsightCentral.net, MyNissanLeaf.com). Often, someone else has already done the footwork and tried out a particular tire, and most importantly, they often review these tires on these online forums, detailing how they handle, their tread life and how the tire performs in general and how much of an improvement in their fuel economy they experienced.
Tire Pressure Also Makes A Difference!
One thing to keep in mind with low rolling resistance tires is that their performance (i.e., how they can impact your fuel economy) is greatly influenced by the pressure of the air within them. In general, you never want to have a tire inflated at a pressure that is less than the vehicle manufacturer's specifications (found inside the door jamb on the driver's side of the vehicle). However, did you know that if you over-inflate your tires, and this goes for standard tires as well, you can actually boost your fuel economy just by doing that alone? Its true! Keep in mind that as you increase the pressure in the tires, your contact patch where the tire meets the road will decrease in size. Most tires manufactured as of late have a max PSI rating from their manufacturer, typically the LOWEST that this would be for the majority of passenger tires is 44 PSI and some can be taken higher than that.
How much of an increase could one see with this? Well, I'm glad you asked! The Mythbusters have already done this on a previous episode. I will link to the procedure and test method (Mini-Myth #2) they used and will display a table and chart of their results.
Tire Pressure Gauge
Table of Findings From Mythbuster Test
Change In Fuel Economy
35 (Control/Manufacturer Recommended)
Chart of Results From Mythbusters Test On Tire Pressure's Effect on Fuel Economy
So, we all know now that a low rolling resistance tire can boost your fuel economy, but also so can bumping up the pressure. As you see by the chart, improvement slows down the higher you raise the pressure but a few pounds over the manufacturer specification won't harm you or your tires. At most the ride itself will feel stiffer, and some may prefer this. Just remember that if you do raise your pressure above the recommended level, if the manufacturer calls for pressure bias between the front and rear tires (e.g., 35 PSI Front/33 PSI Rear or vice versa), be sure to maintain that amount of difference between front and back tires the same. As an example, with a 2004-2009 Toyota Prius, you could set the front tire pressure at 44 PSI and the rear tires at 42 PSI. Just be sure to find the best tire for your climate and expectations (Snow/Summer/All Season) and your budget.