Tire Tread wear

200 Volts......the NASA Critical DYNAMIC Hyroplaning velocity formula is expressed in KNOTS not MPH......so your 54 is correct except that it is KNOTS and would equate to 62.1 MPH using 9X the square root of the PSI of tire pressure formula!

However, hydroplaning can occur at MUCH lower speeds as the formula for DYNAMIC hydroplaning is not the same as viscous and reverted
rubber hydroplaning.

True, "Dynamic" hydroplaning takes place when 1/10 of an inch or more of
standing water is on the roadway surface. When dynamic hydroplaning
occurs, (hydrodynamic) pressures build in front of the tires and lifts
them off the roadway. They are then supported on the surface of the
water.

"Viscous" hydroplaning happens when the roadway surface is wet or damp
and the tires roll up on the top of a film of water. It is possible for
this to occur at much lower speeds than dynamic hydroplaning, but it
requires a smooth or smooth acting surface.

"Reverted-rubber" hydroplaning occurs when there is a prolonged locked
wheel skid. The rubber of the tire is heated from steam
generated by the friction between the footprint of the tire and the wet
surface of the roadway. The tire tends to become sticky or tacky, as it
was in its original uncured state, and the steam tends to lift the tire
off the roadway.

There are two simple formulas for predicting the speed at which
hydroplaning will occur. The first formula involves the spin-down speed
of rotating tires. The formula is expressed as the hydroplaning speed
being equal to nine times the square root of the tire inflation
pressure.

The second formula relates to the spin-up speed of
non-rotating tires when roadway water depth is greater than the tire
groove depth. That formula is expressed as hydroplaning speed is equal
to 7.7 times the square root of the tire inflation pressure.

One should also note that the speed at which hydroplaning can occur
is lowered by 1 knot for approximately each 2 lbs. of tire
underinflation. This is of course a real PLUS for all Prius owners that are running 44 to 42 psi ....... they have RAISED their hydroplaning speeds!

 

I think I will just tag along on this topic instead of starting a new one.

I just measured my tread depth today and here is what I found.

Tires have 30,000 Miles on them and have been rotated every 10,000 miles. Tires pumped up to 44-50psi most of their life. Measurements are in millimeters.

	Column 1	Column 2	Column 3	Column 4
0	Tire	Outside	Middle	Inside
1	FL	4.1	3.9	4.1
2	RL	4.8	5.3	4.4
3	FR	3.5	4.2	3.8
4	RR	4.3	4.6	4.2

YAY! I figured out how to make a table!

So what do you all think? The tire wear not the table.

 

Yes it looks like there has already been much discussion on tire wear, but is there anyone out there who can explain why this "little 'ol" Gen 2 eats up tires? I'm at Discount Tire once again after having run my 60K warranted Yokohamas down to 2/32 in less than 29K. Any answers? (BTW, this has been the pattern since the car was new.) I use recommended pressure, rotate regularly, and drive easy. The tread wear is even.

Posted via the PriusChat mobile app.

 

All of mine eat through tires (Michelin X-ICE-III all-year long) because I run winters throughout the entire year and I drive it like I stole it. All our hybrid cars eat through them. Combination of torque and weight plus here there's granite on the roads eats through rubber.

 

At those pressures, I was expecting to see all your measurements to be more like the FL, i. e., with the "Middle" measurement less than the "Outside"/"Inside" – which is what to expect from over-inflated tires. However, the other tires show a typical under-inflation pattern. Not sure what to make of that.


* On the table, nice work. If you update to this (replacing the "*" for the "[" for each tag)

*B]Tire Tread Depth*/B]

*TABLE=HEAD]Tire|Outside|Middle|Inside
*B]FL*/B]|4.1|3.9|4.1
*B]RL*/B]|4.8|5.3|4.4
*B]FR*/B]|3.5|4.2|3.8
*B]RR*/B]|4.3|4.6|4.2*/TABLE]

it will come out as below loosing the column 1-4 row.

Tire Tread Depth

	Tire	Outside	Middle	Inside
1	FL	4.1	3.9	4.1
2	RL	4.8	5.3	4.4
3	FR	3.5	4.2	3.8
4	RR	4.3	4.6	4.2

 

Is wear really even in all positions? Or just averages to even when tires are rotated?

I don’t know why you answered a question asked in 2008. But as the tires have been rotated there could be a misalignment that causes some tire to wear on inside and some from outside and because of tire rotation it just seems like under-inflation. It would be better to measure the tires before they are rotated.

 

Whoops, mea culpa, I didn't notice that that post was old. But, nevertheless, at least the table info is useful to anyone.