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Do Low Rolling Resistance Tires Hurt Hybrid Braking Performance and Safety?

By April 10, 2009

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Mark Chung (c) and racers Alex Job and Paul Ritchie pose with the ADVAN ENV-R1 racing tire--predecessor of the dB Super E-spec passenger tire.
A few days ago we wrote about Yokohama's new eco-friendly citrus oil tire. We stated that it was not only more environmentally friendly in its composition (that would be the citrus oil component), but that it was designated as a more fuel-efficient low rolling resistance design for hybrids.

An observant reader questioned whether that more fuel-efficient design at all impacted braking performance. We answered that in general it does, but that we'd forward the question to Yokohama engineers for their official answer regarding the Super Nano Power Rubber dB Super E-spec tire in particular.

Following is what Yokohama's Mark Chung had to say:

"Your readerís astute speculation about the compromise between lower rolling resistance coefficient (RRC) and overall tire grip makes perfect sense if we assume using conventional tire compounding and building methods. The unique feature about the dB Super E-spec is that its compound addresses the mentioned compromise by utilizing the interaction between natural rubber and orange oil. Specifically, this compound, which we call the dual-mode compound, maintains its low RRC mode when in straight-line, non-cornering, non-braking situations. But when the tire is placed under load, whether braking or cornering, it quickly generates heat and the compoundís characteristics change to deliver the grip necessary to negate any compromise I mentioned earlier. When the tire returns to straight-line mode, its characteristics change back to the low RRC mode. It is like having a switch to turn on/off the tireís behavior, except that the tire takes care of the switching itself! This dual-mode behavior is activated by orange oil. Orange you glad your reader asked this question?"

Guess that answers that, and if we must say so, it's a very clever manipulation of chemistry and physics on the part of Yokohama's engineers.
Comments
April 15, 2009 at 11:42 am
(1) Dotun says:

The dual nature of the compound does make sense and one presumes that the switch over has been tested to see that the compound reacts within a useful period of time and that both the reation time and level of grip are adequate in the various road conditions your average tire buyer is going to encounter.

Clever tire Hey :)

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