How about a real thread about TIRES?

I put on comfortrends on my 05 at 2000 miles and when i traded for the 06 i had 13,000 miles on the
05.I had the dealer put my comfortrends on the 06.I feel i would rather have the comfortrends with 11,000
miles than the orig crap tire.
I run with 35 front and 33 back.I have put on 4,000 miles since i swiched to nitrogen and the tire preasure
has not changed.I couldnt ask for a better ride and it handles just fine for me.the first trip i took with nitrogen
i stoped at 250 miles and felt the tires and they were cold.........

 

<div class='quotetop'>QUOTE(duanerw @ Jun 25 2006, 10:04 AM) [snapback]276447[/snapback]</div>

Nitrogen is the best thing you can use in a tire. The problem is if for some reason there is a slight leak, you end up topping it off with air, then have go go deal with the nitrogen refill again. But yes... nitrogen is great because the tires remain the same pressure hot or cold.

 

<div class='quotetop'>QUOTE(tnthub @ Jun 25 2006, 12:14 PM) [snapback]276509[/snapback]</div>

When they mount a tire and then inflate the tire with nitrogen, do they evacuate the air in the tire first? It seems to me that the air that was in between the rim and the tire probably stays there. Since 1 ATM = 14.7 psi, it seems that about 20% to 30% of the gas in a tire that is freshly installed and inflated with pure nitrogen, would be the air that filled the void between the mounted tire and rim.

If air is about 78% nitrogen, then I guess a tire inflated with pure nitrogen would be only about 93 to 96% nitrogen. The horror.

I thought that nitrogen nearly follows the ideal gas law that I learned in high school, PV=nRT. Is the issue that the water vapor in humid air can condense and evaporate with changes in temperature under pressure in a tire, changing the amount of gas and making tire pressure more sensitive to temperature?

Actually, since my short trips are often on pot-holed bumpy roads and long trips are often at high speeds on smooth highways, I like my tire pressure to rise some with tire temperatures. Before hitting a highway, I get a smoother ride going over potholed side streets on cold tires at low pressure. On the smooth freeway, I get higher pressure and lower rolling resistance. (I also believe tha german manufacturers often recommend inflating tires to higher pressures when driving at high autobahn speeds.)


Does anyone inflate with pure helium to get the benefits of nitrogen and to reduce unsprung weight by a few grams?

 

Here is a very good link in regards to tires and how heat and cold, radial/bias ply, and use affect them. I have quoted the paragraph below in regards to nitrogen. This is a fairly easy to understand article and although it is based on automobile racing, that is where many of the efficiency ideas come from for consumer cars. http://www.longacreracing.com/articles/art.asp?ARTID=33


"Many top teams know the tire pressures increase with temperature. Straight air contains moisture which expands more rapidly than oxygen. To combat the problem, nitrogen is commonly used to pressurize race tires. Commercial grade nitrogen is very pure, nearly moisture free, inexpensive, and is readily available.

While nitrogen does not add to the moisture content, there is moisture filled air and water already in your tire. Air is present due to atmospheric pressure and water is often spilled in during the mounting process. Tire beads are commonly "soaped" with soap and water to reduce the friction thus protecting the bead during the mounting process. Tires also have moisture trapped in the rubber which releases as the tire gets hot.

If you could put the tire into a vacuum condition, you could removed at least some of the moisture and removed the moisture filled atmospheric air that is inside. Practicality dictates that vacuuming the tire interior proves to be difficult and expensive. A more practical solution is to simply purge the tire. With proper purging you will see one to three pound reduction in your hot pressures due to the effects of thermal expansion."

 

I went to the local dealer for an oil change and got new tires (before I found this site). They are Yokohama AS430. The size numbers are correct but I've lost at least 7 mpg. How do I tell what the revs per mile are on these new tires? Did I get sold the wrong tires?

 

I just got my 06 and put Comfort Treads on 2 miles from the dealer.
Very quiet, SLIGHTLY better handling then Integrities.
Here's my ratings for handling quality on highway:
Integrities 0
Comfort Treads 4
RE950 10
The CT are no wheer close to the Bridgestone RE950- I would now rate the RE950 as a performance tire for the Prius- with only a 2mpg hit, but harsh ride.

Does anyone else pay attention to WEAR RATINGS. I see the CT are 700 and my RE950 are 400. This may be the best indicator of effect on mpg, since lower wear ratings are usually stickier tires.

 

<div class='quotetop'>QUOTE(cindyjh @ Jun 27 2006, 04:07 PM) [snapback]277506[/snapback]</div>

According to Yokohama's website (http://www.yokohamatire.com/pdf/007333.YOK_AS430 Bulletin.pdf) the revs per mile on the oem size is 848. These tires seem good from the specifications. The tireshop tried to steer me into buying these. I didn't only because I didn't find any tests or reviews on them.

I am not at all surprised that you are getting lower measured (revolutions per gallon) and even real (miles per gallon) mileage than on worn oem tires with harder tread, thinner sidewalls, and less mass. I am surprised that you report losing at least 7 mpg. The environtmental proponents of LRR (low rolling resistance tires) claim that LRR tires can reduce rolling resistance as much as 20% and fuel consumtion as much as 5%. On a Prius that's around 2-3 mpg.

I'd check the pressure on your new tires. I'd also check the oil level to see that it's not overfilled. Some _tire_ dealers will let you switch to another tire within a 30 day trial period if you don't like them. If you're really unhappy with your tires, it's worth asking your Toyota dealer for a change.

 

<div class='quotetop'>QUOTE(Jennjay @ Jun 22 2006, 02:01 PM) [snapback]275349[/snapback]</div>

JennJay -

Do you know if the Michelin X at Costco is the same as the Michelin MXV4+ that appears to come highly recommended here?

 

quote:

How about a real thread about TIRES?

I didn't know the other hundred or so threads were not real?

Here's my 2 cents...

I took the OEMs off at 2000 miles in favor of Comfortreds. They were a little smoother and quieter. JUST A LITTLE nothing earth shattering. The grip was better too as I hit a bend in the road everyday that would kick the VSC on when raining went away so I thought I was golden.

Down side was the MPGs.....And I mean Geez...54.3 to 46..? Wth The problem was a serious struggle to keep the car in EV mode. I usually take the car to 35-40 mph come off the gas and back on ever so slightly to obtain stealth mode. I've got two long streaches on my commute that give me some lenghty EV mode. With the Comfortreds there was a stuggle to EV the ICE kept trying to come on. I picked the tire pressures up from 35 to 40 lbs. and it got a wee bit better (46 to 48 Mpgs) :blink:

Now the car rode as hard and noisy as the OEM tires so I decided to put them back on and the MPGs are back over 50 once again. We all have our reasons for doing things but I didn't buy this car for 40 MPGs. I could have saved ten grand and bought a Corolla for 40...that plus there improvement was so slight it was barely noticable. Some food for thought...............
BZ

 

<div class='quotetop'>QUOTE(stevejm @ Oct 14 2006, 01:31 AM) [snapback]332638[/snapback]</div>

No

The Michelin X Radial at Costco is likely closer to the private version of the Harmony

You can also get the MXV4+ atc Costco

 

There are a number (?) of versions of the MXV4+. They are defined by speed ratings (V, H, etc.).
The higher the speed rating the thicker the sidewall and high load capacity of the tire. There is a BIG difference in handling within this same model of tire. I 've bought 4 sets of these on two cars (not my Prius, yet..)

 

interesting. costco's website only has 2 michelin models. no hydroedge or mxv4+. do u think i can get it specially ordered from store?

 

<div class='quotetop'>QUOTE(Clar @ Oct 29 2006, 08:06 AM) [snapback]340230[/snapback]</div>

I bought my MVX4+ tires at BJ's Discount Warehouse (an east coast chain). They had to get them in from their warehouse (took about a week), but they were on sale at that time (~$450 - full set of 4 installed).

JeffD

 

<div class='quotetop'>QUOTE(Clar @ Oct 29 2006, 07:06 AM) [snapback]340230[/snapback]</div>

I've found that some Costco locations refuse to order anything not on the website, while others will gladly do so. (The customer service at different Costcos varies wildly.) It requires them to make a phone call, more than the typical mouseclicks and keystrokes. This might require you to call a couple Costco warehouses. I believe Costco can only order or install Michelin brands like Michelin and BF Goodrich (Uniroyal?), since Michelin bought out Costco's tire stock and part of the operations last year.

Their $60 off 4 sale ends November 5 online, earlier in the stores. For superb traction and safety, the Pilot Exalto AS 195/65HR15 (Corolla LE or Corolla S OEM size) or the X-Ice 185/65R15 are great deals at $316 plus tax for 4 installed including road hazard and lifetime balancing. These two tires are available on the Costco website.