My Continental Contact-Pro Tires

[2win2rbo]

Originally Posted by cfg83

Old Tele man -



Yeah, at first glance the RS-A's look similar to mine and a Prius OEM :

Your Eagle RS-A's :


My ContiProContacts :


Toyota Prius Goodyear Integrities :


And, I think my friends' Prius also has road wiggle. Your OEM tire is usually picked for upping MPG to increase the EPA MPG score. Maybe that's a clue that we have a tread pattern that is conducive to LRR.

Hrmmmmm, this makes me wonder. If it fits, should I try Prius OEM tires next time?

CarloSW2

Those tires look very eco but also with less grip probably. They're really fun attack the corners with though. I am to change tires soon I maybe looking at using these LRRs.

[AeroModder]

Word of warning- The Integrities have lousy wet traction.

Here's a video from Tire Rack comparing various LRR tires: When Round and Black Becomes Lean and Green


Here's the ones I'm getting this week (Yokohama Avid Touring-S):

[cfg83]

AeroModder -

Yup, that's what I look for in a tread pattern, smooth + wide gaps. It's not scientifically proven on my part, but the LRR tires all seem to share a uniform style of tread pattern.

CarloSW2

[Frank Lee]

Think of treads (ignore slicks because we can't run 'em legally) as a continuum: knobby and blocky = bad, ribby and non-blocky = good; the closer to solid ribs the better. The pro-contact has so many sipes I would think that makes for a squishy tread. I'd think the nearly solid center ribs on the Integritys and Avid Tourings are a good indicator of likely low r.r.. Of course there is an element of armchair aero in this; but in the absence of good data what else is there?

About 3 days after I bought new tires I found Integrities on close out for dirt cheap! Oh well, the Falkens I bought have the right visual indicators for low r.r. AND are rated to 51 psi so they should be good too.

[cfg83]

Hello -

I just did another GPS correction test :

              Car Odometer    GPS       GPS/ODO    % Correction
2007/06/19    19.00           19.6      1.0310     +3.1% (after purchased)
2007/06/19    36.15           37.2      1.0290     +2.9%
2007/12/01    30.40           31.2      1.0263     +2.6% (6 months later)
2007/12/05    31.40           32.3      1.0286     +2.9%
2008/10/08    34.1            35.1      1.0293     +2.9% (16 months later)
2008/10/09    35.6            36.5      1.0253     +2.5%
2009/06/01    29.2            30.0      1.0273     +2.7% (24 months later)
2009/06/01    44.0            45.2      1.0272     +2.7% 
2010/05/07    28.9            29.7      1.0277     +2.7% (35 months later)

I am getting the same results. However, you can see in the above that I am working with 1/10 mile resolution. I watched the GPS click over to 29.7 miles. If the odometer was also about to click over, the result is different :

              Car Odometer    GPS       GPS/ODO    % Correction
2010/05/07    29.0            29.7      1.0241     +2.4% (35 months later)

This implies to me that the tread depth isn't as important as I thought.

QUESTION: Would it be fair to say that "young/deep tread depth" just compresses? It is a form of (synthetic) "rubber", after all.

In any case, me still happy, .

CarloSW2

[CapriRacer]

Originally Posted by cfg83

..........
I am getting the same results...........

If you look carefully, you've got a very slight downward trend.

Originally Posted by cfg83

..........

This implies to me that the tread depth isn't as important as I thought.

QUESTION: Would it be fair to say that "young/deep tread depth" just compresses? It is a form of (synthetic) "rubber", after all.

In any case, me still happy, .

CarloSW2

Perhaps this will help:

If you go to Tire Rack, you'll notice that in their tire specs,there is both a column for Overall Diameter and one for Revoultions per Mile (RPM). This seems to be redundant, but if you do that math, you'll find that the 2 values are off by 3%. In other words, RPM value is related to 97% of the diameter, not the full diameter. This varies somewhat from tire to tire, but the rolling diameter is not equal to the measured diameter.

Why?

The best explanation I have heard is that the true rolling diameter occurs at the diameter of the steel belts - and that the steel belts act much like a tank track, in that it hardly matters how much rubber is on top of the belt, the length of the belt (or the length of the tank track) determines how far the vehicle moves in one revolution.

So you shouldn't be surprised that the speedometer doesn't vary much over the life of the tire.

[cfg83]

CapriRacer -

Ok. I love tirerack because of all the specs they publish, but I don't always know how to interpret them. It never occurred to me to cross-reference the stats. In the back of my mind I was wondering if the steel belt had something to do with it, but I wouldn't have been able to describe the mechanism.

CarloSW2