new aerodynamic frontiers for tyres.

[fabrio.]

I find in internet some very interesting articles about tyre aerodynamic

yokohama tyres with dimples



SIM-CEL

description



THE YOKOHAMA RUBBER CO.,LTD?Activity Report in the Fiscal Year of 2011

http://www.yrc-pressroom.jp/english/...21915tr001.pdf

Hankook introduces a prototype tyre with aerodynamic winglets



Hankook introduces a prototype tyre with aerodynamic winglets | MyAutoBlog

relative patent

Patent US20130014877 - Vehicle tire having a sidewall section with a plurality of curved protrusions - Google Patents

[nemo]

It would seem that any reduction in drag would be vehicle and wheel well dependent. The news release from December 2012 indicates that they will begin testing an actual vehicles. It could come down to needing to design a tire for each vehicle and wheel combination. Wonder if it would be more efficient to design the effect in to the rim?

[gone-ot]

Has anybody found any Yokohama test information/data about their "sidewall dimples" vs. air turbulence?

[botsapper]

...side dimpling on the fastest carbon disc wheel. "Aerodynamics...trump weight"

http://www.youtube.com/watch?v=yFUcIinqkCo

[Xist]

How often do we have aerdynamics versus weight discussions? To me it seems more like cD versus frontal area.

[NeilBlanchard]

Aerodynamic drag definitely trumps weight, and Cd trumps frontal area. The Allert Jacobs streamliner 125cc motorcycle gained ~80 pounds in weight (a 1/3 increase!), and yet it more than doubled in FE. And if the fairing was left off it, it would have less frontal area - but it would lose a LOT of FE.

214 mpg with DIY aerodynamic fairings on a Honda 125cc motorbike

[KamperBob]

Everything's relative. Motorcycles have notoriously poor Cd compared to cars and trucks. My 225cc has no fairings. The only ecomod is tires. It averages 90 mpg. I attribute that respectable baseline to frontal area, weight, gearing, and driving habits. (While 200+ sounds good on paper, being cooped up inside a fairing would undermine why I ride; so I respectfully applaud from a distance the envelope pushers out there.)

Bask on topic, I think FE gains have to be case by case dependent.

[Blue Angel]

Originally Posted by nemo

It would seem that any reduction in drag would be vehicle and wheel well dependent... ...It could come down to needing to design a tire for each vehicle and wheel combination.

You may be right, but I tend to think gains would be available on just about any car. The SIZE of the gains it what would likely be be the variable. Overall I can't see a great deal of benefit coming from this, but I CAN see a huge new opportunity for tire manufacturers to market these "innovations". The Hankook tire looks like something people would like based on asthetics, even though the added material thickness would add weight to the tire and reduce city fuel economy.

Originally Posted by nemo

Wonder if it would be more efficient to design the effect in to the rim?

Look at the wheels on the Koenigsegg Agera R. The spokes are like fan blades and are unique to both sides of the car so the "fan" effect would push air out. I bet this has something to do with aero as they are not particularly attractive wheels to look at. I wondered the same thing about the Tesla Model S, but on further inspection it seems they went with the same wheel left and right… likely a cost cutting measure. Aero wheels do have merit.

EDIT: Here's an article that supports some of what's been sait in this thread:

http://www.atzonline.com/index.php;d...loc=3/id=15997