Payback on low rolling resistance tires?

[Ryland]

Does anyone have any solid numbers for mileage increases from low rolling resistance tires? I've read about people seeing a 5-10% increase but how accurate is that?
Last I looked at low rolling resistance tires it didn't seem like they were much more expensive, $7-20 per tire more then the cheaper options.
So please correct me if I'm wrong, but if your average car on the road gets 25mpg and a set of low rolling resistance tires improves your mileage by just 5% then over the course of 50,000 miles on that set of tires with $3 per gallon gas you would save around $500, right?

[Daox]

I'm going to say it depends. Tire price is really all over the map. When I went to get new tires for the Prius, I looked at the Michelin energy saver which seems to be the best tire out there for FE. They were roughly $115/ea. I ended up going with the Bridgestone ecopia EP100s because they were pretty close to the energy savers but were only $80/ea. I didn't even look at normal tires to see how prices compare. I imagine most are close to the ecopia's price though.

[Ryland]

I realize it's going to vary alot by tire and size, I just looked at 175/70 R13 tires, a common size for Honda civics and the LRR tires are $52 each and the lowest priced tires are $45 each... that right there is a no brainer, now the question is, if you can easily convince the average person on the street to get LRR tires based off simple math of "you will save $xxx over the life, or $.XX per mile" my rough figures showed one cent per mile... penny per mile is not alot but average person drives 25 miles or so per day, $1.75 per week, it adds up!

[Patrick]

The problem with the original LRR tires as used on the Prius was their low treadwear. I believed they got about 2-3 mpg better than a normal tire, but they wore out quickly and the replacement cost outweighed the savings in fuel. Consumer Reports has some ratings for both rolling resistance and treadwear.

[Ryland]

Originally Posted by Patrick

The problem with the original LRR tires as used on the Prius was their low treadwear. I believed they got about 2-3 mpg better than a normal tire, but they wore out quickly and the replacement cost outweighed the savings in fuel. Consumer Reports has some ratings for both rolling resistance and treadwear.

So stock Prius tires are not worth getting but there are other options out there for LRR tires, I would assume that it's still worth getting LRR tires for the Prius over discount tire options.

[CapriRacer]

Ryland,

You've asked for an estimate in the improvement in fuel economy by changing to Low Rolling Resistance (LRR) tires. Probably the best way to describe the situation is with an analogy:

Imagine I put you in a car and have you drive very conservatively around a long loop of the city and measure the fuel consumed. Then I have you start at the same spot and instruct you to drive like a mad man over the same route. Would the fuel consumed go up? Of course it would! But the tires on both trips consumed the same amount of fuel. They only cared about the distance traveled - so the percent the tires contributed to the fuel consumed changed between the 2 trips, even though the amount didn't.

But tires vary widely for Rolling Resistance (RR) - as much as 60% - and what you change from and what you go to is going to have a HUGE effect on the amount of fuel consumed per mile.

- BUT -

RR is not without its penalty. Treadwear and traction are both adversely affected by the things done to improve RR. It is quite conceiveable that you would have to replace tires twice as often - and that, of course, is going to affect the cost calculation.

- PLUS -

There is no standard as to what "LRR" means.

Bottonline: There are just too many variables and too many unknowns to give you even an estimate. Clearly, LRR tires will improve fuel economy compaored to High Rolling Resiance tires, but trying to calculate the $$'s is next to impossible.

BTW, I cover a lot of the engineering aspects of RR here:

Barry's Tire Tech

[Ryland]

I agree that it's hard to judge what kind of improvements you will see in your mileage without a good way to measure the LRR of a tire, but I disagree that LRR have to give you a compromise in life and traction, I currently have Sumitomo HTR T4 tires on my civic, up near the top of the list of LRR tires when I was looking around they have a wear life of 560 and an A B traction and temp rating, they are near the top end of the middle as far as wear life and good as far as traction goes only place that they are lacking is heat dissipation and if you keep them inflated properly that is not much of an issue.
With my old tires I saw a 5mpg to 8mpg drop in mileage compared to these LRR tires, they also have a better wear life, 380 compared to 560.

[IsaacCarlson]

I got a few more miles per gallon with the old goodyear's than I do with the new kumho's...without driving/vehicle mods. I inflate to a higher pressure than I did before.
BUT: I now live at the end of a long driveway, have to stop twice to get into town, and have to drive through water/mud to get to the road. I used to live right on a highway and could start the car and be doing 55. Now I have to drive just to get to the road. There are too many variables to say there are savings.