LRR tires for almost 100% city driving?

[camaroman101]

i know lrr tires are most beneficial for highway driving but what about city driving? is it worth the extra $$

[HypermilerAX]

Not only is it worth, I'd say i's even more important than on the highway.

[euromodder]

At slow and unsteady city speeds, most of the drag will be coming from mechanical drag - rolling resistance being the one component of this drag that's most easily improved.

[CapriRacer]

A couple of thoughts:

Most fuel consumption in city driving is due to accelerating the mass of the vehicle, where highway driving, it's the drag on the vehicle. So I would think that reducing the weight of the vehicle would be the most important thing to improve fuel economy when dealing with city driving..

The fuel economy of tires is strictly a distance sort of thing. So tires with low RR work better in highway situations. The benefits are there for city driving, but it doesn't come out as strongly.

City driving also means lots of turns - and since turns is what wears tires - and tires with low RR do not wear well - this seems a bad combination from a dollars perspective.

And lastly, the term "LRR" is not an absolute term. It does NOT mean the tires have low RR. It means the tires have low RR compared to comparable tires (same treadwear and traction characteristics.) Tires with truly low RR suffer from treadwear and traction shortcomings - and in a city driving situation, neither of those sounds like a good thing to have.

[NoD~]

When I went from regular tires (2 new, 2 worn) to LRR tires, the difference in city was AMAZING! I didn't expect to be able to ...roll... as well as I did! I went from having to let off 35MPH to get down to ~15 at the end of the road and the new tires would get me ~10MPH more by the end of the same stretch! This also included a wheel swap to wheels that were slightly lighter, but shouldn't have made that much difference in coasting like that (especially since the new wheels are much less aerodynamic).

According to some of my notes at the time of the swap, I gained 2-3MPG going to the LRR. I can only assume that's city, simply because the majority of my driving is city.

[MetroMPG]

Originally Posted by CapriRacer

The fuel economy of tires is strictly a distance sort of thing. So tires with low RR work better in highway situations. The benefits are there for city driving, but it doesn't come out as strongly.

This is undoubtedly true for the average driver.

But eco-drivers / hypermilers who maximize neutral coasting up to turns/stops (ie. minimize brake pedal use) will definitely see a marked improvement in sub/urban fuel economy with reduced rolling resistance, IF they're able to take advantage of the longer coasting opportunities. (Not everyone is - depends a lot on driving environment.)

I saw a significant efficiency improvement in my 100% suburban usage when I put LRR tires on my electric car... because they allowed me to coast significantly further. (See: http://ecomodder.com/forum/showthrea...eet-19126.html )

[CapriRacer]

Originally Posted by MetroMPG

This is undoubtedly true for the average driver.

But eco-drivers / hypermilers who maximize neutral coasting up to turns/stops (ie. minimize brake pedal use) will definitely see a marked improvement in sub/urban fuel economy with reduced rolling resistance, IF they're able to take advantage of the longer coasting opportunities. (Not everyone is - depends a lot on driving environment.)

I saw a significant efficiency improvement in my 100% suburban usage when I put LRR tires on my electric car... because they allowed me to coast significantly further. (See: http://ecomodder.com/forum/showthrea...eet-19126.html )

Just to be clear, the fuel economy improvement with tires with low RR would be there regardless of whether the driver coasts or not. Put a different way, the fuel savings is always there: 2 ounces less per mile is still 2 ounces per mile (which would translate into mpg). How that translates into a percent improvement is what is affected by how the car is driven.

Certainly a guy driving around the city isn't going to go as far on a tank of gas, so his ability to discern these differences is reduced.

But where this becomes a problem is in tire wear. Changing tires more often just to achieve fuel economy improvement may not work out in the final cost analysis.

[mikeyjd]

Originally Posted by NoD~

When I went from regular tires (2 new, 2 worn) to LRR tires, the difference in city was AMAZING! I didn't expect to be able to ...roll... as well as I did! I went from having to let off 35MPH to get down to ~15 at the end of the road and the new tires would get me ~10MPH more by the end of the same stretch! This also included a wheel swap to wheels that were slightly lighter, but shouldn't have made that much difference in coasting like that (especially since the new wheels are much less aerodynamic).

According to some of my notes at the time of the swap, I gained 2-3MPG going to the LRR. I can only assume that's city, simply because the majority of my driving is city.

Impressive. What time of the year was it when you switched tires?

[NoD~]

It was July of last year. How I know this is because we planned to take a road trip then and did the tires a week before. The ~600 mile trip (each way) through the desert... in a record breaking July... without AC... yup. Easy to remember (or, hard to forget!)

[nackerton]

Yes, you really notice the RR difference in low speed rolling. With summer tyres (Michelin Energy saver), I can roll easily in neutral gear the last 400 metres to the parking slope of my house, with studded winter tyres (Michelin XI2 North) that's not possible.