My Continental Contact-Pro Tires
Hello -
I just got these Continental Contact-Pro tires around June 3rd, 2007 : http://ecomodder.com/forum/member-cf...taltirepu7.jpg http://ecomodder.com/forum/member-cf...altreadkf4.jpg New tire size : 195/65 R15 Stock tire size : 185/65 R15 Here are some specs on the tire : ContiProContact http://www.tirerack.com/tires/Spec.j...irePageLocQty= Code:
Size = 195/65HR15 I used this site to figure out my difference in speedometer readings : Miata.net Tire Size Calculator http://www.miata.net/garage/tirecalc.html It told me that the speed will read 2.1% too slow. I don't use my ScanGauge for my mile/distance readings, I use my car odometer with a GPS correction. Here are the two GPS correction tests I have done using my wife's eTrex GPS : Code:
Car Odometer GPS GPS/ODO % Correction The only problem is that on freeways that are grooved in the direction I am traveling, the car "wiggles", aka the tread tracks into the grooves like a phonograph needle and the car has a noticeable wiggle. I had a feeling this might happen, but no proof until after I bought the tires. Thank goodness my main commute only has this for maybe a mile or two. My wife's new GoodYear Eagle GT's do the same thing to a lesser extent. Back in the day it was MUCH worse on my motorcycle, CarloSW2 |
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I used to have the Eagle GT's on a '90 Beretta. Brand new, they hyroplaned like crazy (stuck to the road pretty well, though). With the higher pressures on my Michelins, the biggest difference is cross-wind stability. It takes a bit more steering feedback to keep it straight. Yeah, Kansas City has a higher wind speed average than Chicago (the "Windy City"). RH77 |
RH77 -
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LOW ROLLING RESISTANCE TIRES - March 2003 - Page 5 http://www.greenseal.org/resources/r...resistance.pdf Code:
BRAND = Continental ContiTouring Contact http://ecomodder.com/forum/member-cf...ch95-ci2-l.jpg My tires are not an exact match, but they have the same "pedigree" (fingers crossed :o ). I didn't get the tires from the GreenSeal document because I could not get the size I wanted that was also rated at 51 PSI, :( . CarloSW2 |
That's a good value vs. RR. I think you'll find the treads a fine addtion to the Sat. Plus, the 51 psi certified max PSI is an added assurance.
As for the circumference, an adjustment to the SG may be necessary -- not a big deal. I usually have mine set to the most pessimistic settings so I try harder. The displayed FE prompts additional effort if it's perceived as low. The trick is to disregard the setting and shoot for that higher goal. Hopefully, I'll have 2 record tanks through this and lower cruise speed. Let us know how the new tires work out! :thumbup: RH77 |
RH77 -
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I will be doing a GPS adjustment in the next few weeks, so I will add the results to the thread. CarloSW2 |
Hello -
I just did another GPS correction test : Code:
Car Odometer GPS GPS/ODO % Correction In the 2008/10/09 test, I was much more careful. I *like* that the % is going down over time. This is consistent with tread wear. As stated before, I am sticking with a 2% error correction on my gaslog because I don't want to accidentally inflate (ha ha) my MPG numbers. Also, tire wear will eventually bring this correction down over time (i.e. always losing tread => always reducing tire circumference => always reducing odometer error over time). Me happy, :) . CarloSW2 |
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So the Odometer quits when the key is out? Weird -- I didn't know that some cars did this. It makes sense if the intention is to tow the car behind a motorhome as many Saturns are designed to do. RH77 |
Hello -
I just did another GPS correction test : Code:
Car Odometer GPS GPS/ODO % Correction I just got the tires rotated and they didn't say there were any wear problems. When I get the rotation I drop the PSI to 42 to avoid lectures, and fill 'em back up to 50 PSI afterwards. Me still happy, :) . CarloSW2 |
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Old Tele man -
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Your Eagle RS-A's : http://www.tirerack.com/images/tires...a_bw_ci1_l.jpg My ContiProContacts : http://www.tirerack.com/images/tires...tact_ci1_l.jpg Toyota Prius Goodyear Integrities : http://www.tirerack.com/images/tires...rity_ci1_l.jpg 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 |
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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): http://www.tirerack.com/images/tires...ings_ci1_l.jpg |
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 |
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! :mad: 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. |
Hello -
I just did another GPS correction test : Code:
Car Odometer GPS GPS/ODO % Correction Code:
Car Odometer GPS GPS/ODO % Correction 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 |
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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. |
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 |
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