Rolling resistance video

[tjts1]

Some of you might enjoy this. The RR parts starts at 24:40 if youtube doesn't take you there automatically. Enjoy.
http://www.youtube.com/watch?feature...FQ_414#t=1484s

[kah]

At 35.05 min. they talk about tirepressure, might be very interesting for all those ecomodders running overinflated tyres!

[niky]

That's pretty standard knowledge. Overinflated tires incur a penalty in terms of longitudinal traction, but they're often better in terms of wet grip and cornering. If you want the best braking, underinflate your tires.

Also note: ABS. A rigid tire will "bounce" and trigger the ABS system more. If you adjust the suspension to make up for the bounce, you can shorten that braking distance.

Too bad they didn't specify what pressures were used in that test. Hmmm... sounds like something we can test on track next month.

Love the drifting truck sequence afterwards...

[MetroMPG]

Bugs me when they say things like "rolling restistance is the friction of the tires against the road."

Good find, though. Thanks for posting.

[doclees]

Originally Posted by niky

That's pretty standard knowledge. Overinflated tires incur a penalty in terms of longitudinal traction, but they're often better in terms of wet grip and cornering. If you want the best braking, underinflate your tires.

Where did you find the information on over inflated tires are better in wet grip and cornering?

[niky]

The narrower a tire's footprint, the better it resists hydroplaning, though I suppose that not all tires will lift off the road in the same way, and it depends on what your door sticker pressures are. Lots of new cars require higher pressures than before, but there are still benefits. Of course, when I say overinflation, I mean inflating to the maximum sidewall pressure, which is usually higher than door sticker.

As for cornering, maybe I should retract that. Higher inflation doesn't increase grip, but it improves response. Definitely a must for taller tires on the track, as they roll over dangerously onto the sidewalls at stock inflation pressures and change direction sluggishly through switchbacks. Many performance tires are perfectly fine at regular pressures, though. stiffer sidewalls.

[arcosine]

https://www.youtube.com/watch?v=igrJ_QI9eBg

[F8L]

Not much on rolling resistance but a great video nonetheless! Thanks for posting it!