Improvements in modern LRR Tires

[hispanicpanic]

So there's lots of information available as of 4 years ago on some of the best LRR tires out there..... but each list and comparison i come across doesn't seem to be conclusive. I hear a lot of people preferring to use snow tires, yet all the tire rack tests and such only pick tires from the touring categories... Not only that, most of the tires in these tests are no longer made! Or at least there's been a modification of the compounds.

So.... anyone have any idea what the end all be all is of a LRR tire available today? I'm currently shopping for new rims for my CRX HF and i need to know if i need to stick to 13's, 14's, or 15's too, so the tire size availability will probably determine that.

[rmay635703]

Until the us government requires an lrr metric and rating you only have a best guess.

13" are poor lrr but usually light,

14" the only choice is the re92, the others are designed for heavy cars and not as efficient

15" is Ecopia but their discontinued in that size

[freebeard]

You can debate and compare tread patterns and rubber compounds all you want, but the real action is in the gross geometry. The advantage goes to tall and narrow:

http://ecomodder.com/forum/showthrea...-25208-13.html

TL;DR

If you have a 5x112 or 5x120 BCP and 27+ inch diameter it's a fairly straightforward fitting. These are as new as the BMW i3. You can get Moon disks in that diameter, too.

[brucepick]

Originally Posted by rmay635703

Until the us government requires an lrr metric and rating you only have a best guess.

Yes.
The European market requires rolling resistance testing and their ads post a letter indicating relative LRR performance. Unfortunately for us North American drivers, most of the tire model names sold over there are different from what's sold here. AND, if you ARE lucky enough to find a make/model/size sold in EU with good LRR performance, that same model sold here in the US could have different characteristics. Makers are under no obligation to provide the same tire here as over there, even if the name is the same.

To find overseas market tires, I've google searched using "tyre". The UK spelling. That way I get results in English. And yes, shipping tires or tyres from overseas is costly and sometimes cumbersome. I investigated briefly. You need a "Freight Forwarder".

[brucepick]

That said, I'm partial to Michelin for LRR. They've been offering LRR tires longer than most (all??) makers, and seem to at least have some idea of how to get results while simultaneously still building a great tire in other regards.

[Ecky]

I can't speak for tires at large. I'd like to, and I've looked for data, don't get me wrong.

My personal experience: In the 14" size, Michelin Defenders, which are relatively new, perform no better than the 16 year old RE92's. Most Insight owners agree they're worse, but it's marginal at best. They do last 2-3x as long, at the expense of being (subjectively) a bit more noisy.

My winter tires, Nokian Nordmans, are not rated for low rolling resistance, but I've seen 100mpg @ 50mph during the winter with the car fully warmed up, which is basically what I get with RE92's in the summer.

[Joggernot]

I just bought a set of 15" Michelin Defenders (green) and am very happy with them. The coasting distance is much greater than the previous tires. So much so that I've had to adjust the start points for coasting to all the stop signs on my route. Where I use to start coasting left me still going 30 mph at the stop sign.

PS: just noticed you're in San Antonio. I'm in Rockport, so we should have similar results.

[CapriRacer]

First, there is a technology triangle involving treadwear, traction, and rolling resistance. To get better properties in one area, one or both of the others have to be sacrificed. That's why OE (Original Equipment) tires - the tires that come on new cars - have such a poor reputation. They were designed for good rolling resistance, and the treadwear and/or traction were sacrificed to get it.

Further "LRR" is a relative term. It means better rolling resistance compared to other tires with similar wear and traction properties. It does NOT mean absolutely low rolling resistance. In fact, many LRR labeled tires will have fairly high RR values - some higher than non-designated tires.

So why hasn't the US government required labels for RR (fuel economy)? Because the tire size plays a large role in what the value is and the regulators (NHTSA) want to use RRF (Rolling Resistance Force) which makes smaller tires look better (which also means overloaded tires), where the tire industry wants to use RRC (Coefficient of Rolling Resistance), which makes larger tires look better. The courts have ruled that NHTSA's proposal is unacceptable, but NHTSA has not yet issued a revise regulation.

[iveyjh]

14" insight wheels and re92's

[rmay635703]

Originally Posted by CapriRacer

So why hasn't the US government required labels for RR (fuel economy)? Because the tire size plays a large role in what the value is and the regulators (NHTSA) want to use RRF (Rolling Resistance Force) which makes smaller tires look better (which also means overloaded tires), where the tire industry wants to use RRC (Coefficient of Rolling Resistance), which makes larger tires look better. The courts have ruled that NHTSA's proposal is unacceptable, but NHTSA has not yet issued a revise regulation.

So what you are saying is that nobody wants to rate the tire so you can tell what affect on fe it will have?

I would think you would load the tire to 75% of its rating and measure the drag it creates and test the amount of wind drag at a simulated 65mph fender less drive.

Then weight the two measures appropriately to create a drag metric.

One could then subjectively compare a real metric as opposed to one that is likely meaningless.