Tire Upgrade

<div class='quotetop'>QUOTE(stevejm @ Oct 24 2006, 08:32 AM) [snapback]337343[/snapback]</div>

I'm a bit confused how folks have determined that the 205/60-15's have a larger diameter than the Integrity's 185/65-15.

According to the respective web sites, Integrity's diameter is 24.5" as is the Exalto A/S.

As for rotations per mile, the Exalto is 850, and unfortunately, I don't know what the Integrity is. Perhaps that's where folks are getting this 2% difference?

Or is it because the Exalto's specs are based on a 6" rim width while the Integrity is a 5.5" width, thus somehow changing the outside diameter of the tire???

I just installed a set of 205/60-15 Exalto's based on general comments here. While it's only been 15 miles so far, at the "standard" 34 psi (that Costco pulled from the specs off my driver door even though these are different tires altogether from OEM) it did appear to significantly drop my mpg while feeling like a drag while coasting. I went back to Costco and had them inflated to 41/39 psi and it immediately felt better, although a bit bumpier. I'll drop them down a bit tomorrow in hopes of compromising mpg with comfort.

I'll provide an update after a few hundred miles, but overall they look nice, track better, and feel tighter than my old 30k mile Integritys ever did.

/mark

 

<div class='quotetop'>QUOTE(stevejm @ Oct 24 2006, 10:32 AM) [snapback]337343[/snapback]</div>

<div class='quotetop'>QUOTE(mmccking @ Nov 6 2006, 12:27 AM) [snapback]344368[/snapback]</div>

As tire tread wears down from 10/32" to 2/32" deep, the diameter falls to 24, and the rolling circumference falls by about 2%. When comparing the diameter or revolutions per mile of different tires, remember that these measurements are for new tires. Worn tires can differ by about 2% or 1 MPG measurement error.

Most new 205/60R15 tires have a larger diameter and rolling circumference than most new 185/65R15 tires, but there's variance between different tire models in the same nominal size. There's even greater variance within the same exact tire during its tread life.

 

Hi Group,

I don't post much but thought the "tire club" would be interested in my experience with the 205 Hydroedge. In short, I took them back to Discount Tire for adjustment to 185 Comfortred (got about $100 back). There's something to be said about their "Free Ride" program. If you don't like the tire, they'll do whatever to make it right. The problems I had:

• 8 MPG mileage hit.
• 1-2 MPH speedometer error.
• Hardpan ride.

On the good side, there was no question about the road grip.

I went to the standard size Comfortreds and have found all but 1 MPG of the mileage returned and the speedometer is back to matching the Garmin navigation system. The Comfortred addressed my gripes about the stock Integreties particularly in the traction area.

With the Hydroedge, downhill sections I'd hold speed on previously netted the opposite. I also noted needing to put the pedal down more to accelerate from a stop. Another engineer mentioned the notion of "unsprung weight" which in my recollection deals with the energy needed to get mass in motion or in this case, rotational motion. I note the OEM tire weight was 17 pounds, the Hydroedge 22, and the Comfortred 18.

Thanks for the earlier reads.... Warm Regards, CAPT Seabee

 

Update on my switch to Exalto 205/60-15 a couple months back:

7-8 MPG drop
Slightly smoother ride
Slightly less road noise
Much better grip
Heavier feel (I'll explain below)

As you can see the hit in gas milage was more significant than I thought. In fact, my worse tank before the switch as 42 MPG, while during the Christmas holiday while my in-laws were driving my car with the new tires, I got it back at 33 MPG on a empty tank. I was shocked to say the least.

The car also feels heavier, I need more throttle and break pressure to get it going, maintain speed, and come to a stop.

I'm wondering if my MPG hit has something to do with the nitrogen gas that Costco uses to fill up the tires? Since air expands and contracts as it gets hot or cold, it would ultimately produce a higher operating pressure. But doesn't nitrogen maintain a more constant pressure hot or cold, resulting in a lower operating pressure than air?

 

<div class='quotetop'>QUOTE(mmccking @ Jan 11 2007, 03:45 PM) [snapback]374429[/snapback]</div>

I don't think there'd be much difference between nitrogen and air. After all air is about 80% nitrogen. OTOH, it's not even close to an ideal gas at 40+ psi gauge pressure.

Dave M.

 

<div class='quotetop'>QUOTE(Three60guy @ Jun 28 2006, 11:19 AM) [snapback]278138[/snapback]</div>

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Could you repost the spreadsheet?

Thanks

Cy

 

I got a screw in my OEM tire (on the car that I bought 4 days ago) and since I bought used and the tires had 27400 miles on them, I opted to use the opportunity to get a full new set.

I took Myprius' advice and went with the 195/60's and I also got the TripleTreds because the Yokohama TRZ's that I wanted would have been special order from NTB. (Costco would not install anything other than the stock size either) Keep in mind that I am still a big fan of Costco.

I have had the TripleTreds on my (now my fiance's) Dodge Intrepid and loved them. You can't beat them for all around driving and they are next best to studded tires on the snow.

I saw some others who are purchasing ComforTreds. Just a HUGE word of warning. In my experience, they reach 50% tread wear and then it is like driving on racing slicks. I don't know why it is but I have found that on two vehicles myself and if you search google groups, most people will tell you the same.

P.S. I love this site!! I have learned so much over the last 4 days.

 

Wow, I found this site/topic at the right time.

I am seriously considering putting the standard Scion TC wheels which are 215/45-17 on my 2004 Prius. I saw a pic of this same application on ebay and I really like the look.

Any words of wisdom? I have seen where some have tried 205's but I didn't see anyone mention 215's. I'll try to post a link to the pic when I get home as the "computer communists" block me from getting to ebay at work.

Regards

 

Are there any 195/60 tire options with runflat technology?

 

<div class='quotetop'>QUOTE(YodaddyAlex @ Apr 1 2007, 06:43 PM) [snapback]416123[/snapback]</div>

I don't know of any run-flat tires in any size that will fit a 2004-7 Prius with 15" rims. Using 16" rims, there are many options, most notably in size 195/55-16.

I would guess that fuel efficiency will drop. The greater rolling resistance will probably outweigh the mass savings from foregoing a spare and a jack, after subtracting the added mass of the runflat tires and larger wheels. Of course you might value the convenience or the additional freed up space where the spare once was. I would also expect higher tire costs and a harsher ride or reverting to lower psi for a similar ride.

 

Hello,

I've been reading this thread and as many others as I could about the subject as I now need to make this important decisions. I ended up getting 47K+ miles out of my Integrities, which is pretty good from what I've gathered. I have it narrowed down to the Michelen Hydroedges and Goodyear Assurance TripleTreds. I believe these will both be a good choice for my needs. A couple of questions for you guys (and girls!):

1) For those that live where you encounter lots of snow... do these seem to be good in that. Now, I went through this past winter with just the aging Integerities and I think it was a mistake. I'm still thinking maybe the Hydroedges and then the X-Ice for the winter.

2) Much discussion on 185 / 65 or 195 / 60... I like the idea of the 195's... I think? If I go with the Michelins, would you get the "stock" 185 size, or would you choose to go with the 195's. Obviouisly with the Goodyear TripleTreds the 195 / 60 is the only option.

3) Hmm... I guess I'm having a hard time deciding any other thoughts would be appreciated.

 

<div class='quotetop'>QUOTE(kjbetz @ Apr 26 2007, 11:47 AM) [snapback]430586[/snapback]</div>

I had the Goodyear Tripletreads on my Honda Odyssey and thought they were very noisy. Once they started to wear, I changed them to the Goodyear Comfort Treads and have had those on every car since then. I think these are great tires and can't wait to replace the Integrity tires with Comfort treads.

 

ya never know.
i got 47K on my integrities (integritys?) and after trying 3 different sets of tires thanks to discount tires, i settled on tripletreds by goodyear. i now have 87K, 40K later, and i love them. no sign of wear, virtually. no more wandering, and i don't find them noisy at all.
go figure.
i guess that's why there's lots of choices out there.

 

Wowzer! Thanks for all the tire information. This goes right along with what an auto-writer friend of mine in Chicago is telling folks about the Prius: go with 195 tires, instead of 185.

So - 195/60 R15 will be the next thing I research. I'm assuming that these tires will fit on the Prius rims with no problem, and no safety issues?

what about steering weight, and road "feel?"

I hope to get my new Prius next week - and I want to get new tires on the car NOW.

This thread gives me new hope.