Michelin demonstrates how low rolling resistance tires work

Tires get overlooked in the headlines about fuel economy and CAFE standards, which is a little odd. After all, a car's tires are the only contact it has with the road, so more efficient rubber means more efficient use of fuel, and even tiny gains spread over the huge number of road-going vehicles can translate into remarkable overall gains.

Michelin has made a spot that demonstrates the difference its Energy Saver A/S tire can make by staging a downhill drag race. There's a twist, though, and it makes the point beautifully.


http://www.autoblog.com/2012/09/16/m...ce-tires-work/

 

the video doesnt correlate to the title of the article...

what exactly make these tires low rolling resistance?

 

It doesn't mean anything. It's a nonsense term that was made up by laymen as a marketing gimmick.

It's analogous to a <Brand X> facial cleaner claiming that it has "micro-pore technology" or <Brand Y> shampoo claiming it provides "ultra hydration technology."

 

Michelin tires having "Low Rolling Resistance" plainly marked on the sidewall of the tire have lower rolling resistance than standard tires which directly translate to increased fuel economy. That's what it means.

 

You're wrong about this.

Tires are designed with the knowledge that the sidewall will flex when the car is rolling down the road. This sidewall flexing is beneficial for things like helping chemical compounds that prevent the rubber from drying and cracking to permeate through the tire and continually condition the rubber, but it does have an energy cost associated with it. This is pretty traditional tire technology.

Low rolling resistance is absolutely not a marketing term. It's an entirely different way to design a tire, and by making the tire sidewall stiffer and less prone to flexing, it reduces the amount of energy needed to make the tire rotate. This has the side effect of increasing braking distances because the tire is no longer dissipating as much energy - the point of this advert seems to show that Michelin has developed a low rolling resistance tire that also doesn't take as much of a hit in braking distance.

It doesn't seem to match the thread title very much, though.

 

if the sidewalls are flexing less, sounds like the ride quality will be worse

 

yea that video didnt really say much of anything

 

You are definitely right that low rolling resistance tires are not a gimmick, but, it doesn't necessarily mean the sidewall is stiffer. For instance Bridgestone does it by using a whole bunch of proprietary technology, but, some of the simple explanations include a lighter weight carcass, then what Bridgestone refers to as Nano-pro-tech, which is a way of distributing the molecules in the tire more evenly, allowing mixtures of materials that weren't possible before. The Bridgestone Ecopia has already proven itself to a large number of people I personally know, with measurable fuel economy increases. They also stop, even in the wet, just as good as their non-LRR counterparts... Nice thing about Bridgestone is that the LRR tires are priced right - meaning they are similar or even less expensive than most other tires, with 65k warranties as well...

Here is a test of Bridgestone non-LRR vs LRR

 

LRR tires come at the expense of tire grip. The more fuel efficient the tires are, the less grip they have. It's a trade off, you can have your cake but you cannot eat it.

 

Yeah I spent some time looking up "low rolling resistance" tires and it seems like F1Driver is correct.

It looks like Michelin was trying to make the point that despite the fact that these tires boast a lower coefficient of static friction, this doesn't affect braking performance. The coefficient of static friction is still sufficiently high enough that it can stop shorter without slipping compared to some arbitrary non-Michelin tire.

I think the main downside of having a low coefficient of static friction more readily manifests itself during hard accelerations (particularly from 0). Like F1Driver said, the bottom line is grip. If you really care about having the ability to coast as long as possible at the expense of grip during hard accelerations or cornering, then low rolling resistance tires are a good buy.

It'd be much more useful if they did some tests to actually quantify how much one can expect to save on gas $ by purchasing LRR tires. I'm skeptical that it's anything significant, even if most of your driving is highway driving where you have plenty of opportunity to coast from time to time.

 

All of this info is out there guys. Search Bridgestone Ecopia calculator... you can put in your vehicle information and it will give you an idea of what to expect. Average is $450 at current fuel prices, over the life of the tires. Traction is also very similar. 1st Gen LRR tires were terrible, and I can't speak for Michelin, but Bridgestone has got them so good, most people can't tell the difference in traction terms...

 

PS, LRR tires are not high performance tires. You can't compare them versus one
Instead, compare against a touring tire, and you will find similar acceleration, road holding and braking performance.