Replaced the tires

I posted a review of Bridgestone Potenza RE-950's in 195/60HR-15 on stock rims. Search will give the details. Briefly, they were phenomenal, better in every way than OEM, especially for wet grip, tracking, ride comfort and quietness. The downside was a manually calculated fuel economy hit of around 20% even when using the best techniques from here.

I pick up my first of two '05's on Friday. I'm still deciding between the HydroEdge and Assurance TripleTred. Whichever I get will be on the car by early next week. I have so little confidence in the OEM Integrity's that the sooner I can upgrade the better. What is a safer, more stable Prius worth? I suggest not waiting to find out. Plus, my tire dealer gives a generous trade-in allowance when the Integrity's are new. The upgrade will cost between $180 (TT) and $240 (HE) including lifetime replacement road hazard warranty, balance and rotations with the trade-ins.

Good luck with whatever you choose. You'll wish you had swapped out the tires even sooner! It's the single best, most cost effective upgrade to any vehicle IMHO.

 

Thanks to all for the tire information, thoughts, etc.

Now I have another question. But maybe this cannot really be answered until people actually have experience on snow:

How are the HydroEdge tires likely to perform in winter compared to a winter (snow and ice) tire? My '04 Prius did pretty darn well on ice last winter. (I seldom drive in much snow, as I wait for the snowplow.) Safety is my primary concern. Cost doesn't matter much.

My choices now would be to just switch to the HydroEdge, or to use the HydroEdge in summer and a snow & ice tire in winter. Again, handling on ice is my principal concern in winter. And I don't anticipate any long highway trips in winter.

 

Daniel,
I don't have experience, but the Michelin site gives the Hydroedge an 8 rating for winter traction, compared to a 10 (max) for the 2 snow/ice tires they make.

 

The tirerack site also rates the Goodyear Assurance TripleTred an 8.8 for snow traction. The downside is that in 195/60-15 size it's a very heavy tire at 23.0 lbs. The HydroEdge is 20.0 lbs., the OEM Integrity 17.0 lbs. I prefer a lighter tire for theoretically improved economy, acceleration, braking, and less suspension stress, so the HydroEdge is looking good.

The tirerack rep warned me that either the TT or HE will have nowhere near the dry and especially wet grip of my previous Potenza RE-950's. I'd miss that because I place higher value on a grippier tire. He also commented that their ratings are relative to other tires within each performance category, not absolute. Hmm, those Potenzas have amazing wet grip and with their stiff sidewall improved turn-in, eliminated tracking and cross-wind problems, yet rode more softly and quietly. I'm still considering whether 43 mpg is an acceptable trade off for turning Prius into a sports sedan.

 

Where can I find the weight of a tire? I've been trying to figure out why the tire would make such a difference in MPG, and I guess the weight plays a pretty important factor. I tried TireRack and Goodyear, but I didn't find it in the specs. Specifically, I'm still interested in the Assurance ComforTred, since I'm looking for tires that would reduce road noise (particularly bad on some of the highways in LA =/).

Also, is the maximum load weight of the Prius, simply a function of the 4x the weight rating of the tires minus the weight of the car? The ~865 lb. max weight seemed low, and kind of worries me for lugging 4 people around with overnight bags and ski/snowboarding gear. I may want to take maximum load weight of the tire into account if that's how the max load weight of the car is determined. Thanks in advance.

 

Thanks again to all those above for the further tire information.

To ryogajyc, I've always assumed that rolling resistance is the major factor that the tire contributes to mileage. The weight of the tire seems insignificant compared to the overall weight of the car. As for maximum load weight, someone else will have to answer that one.

 

Hm, I misunderstood what rolling resistance was. I assumed that greater tire weight => more inertia => greater rolling resistance, but doesn't quite seem right now that I think about it a bit more.

In any case, where can I find the rolling resistance of a tire then?

 

The weight of the tire, if greater and all things equal, ie location of the weight relative to the center of the tire, will increase inertia as well. And this will in turn affect the amount of energy it takes to get the tires rolling. So you'll likely see a larger difference accelerating to speed. And so the around town mileage might suffer more.

The rolling resistance is just another aspect of the tire and of course this will affect you whenever the tire is rolling. This is affected by the structure of the tire such as plys, geometry, tread design, and materials used. Some of the newer materials have really lowered the rolling resistance dramatically for Michelin and others.

I have not really seen any kind of dramatic difference with the Hydroedge tires. At least nothing that affected my overall mileage is a perceivable way. In fact I've seen a very slight upward trend since putting on the new tires. Prior to the new tires, I saw my overally mileage sort of flatten and peak at about 48.25. Now it's at about 48.75 for 9500 miles. But that could be due to other affects as well. But I definitely didn't see any kind of dramatic drop. I'm running 40/38 psig now and pretty happy with the Michelin Hydroedge.

 

Hi Folks,

Just my 2 cents from Reno. Last week we had 2 - 8 inches of snow depending on you location. I have a stock car (PK# 9) with OEM tires and average 50.5 - 52.0 MPG day in and day out. The Prius went through the snow surprisingly well and had no problems on the ice and slush the next couple of days.

I initially complained about the light handling when I first purchase the Prius. 8K miles later everything works just find for me for my driving style (I'm in no hurry to get there....).

The snow is gone for the time being. All things considered, I’m going to stay with this setup until I wear out the OEM tires. This is not meant to be a criticism of those changing tires early, just my experience in my environment.

 

TOYO TIRES

Ok, after speaking with my local tire dealer and Fred (thanks again Fred) have decided to change to Toyo Spectrums. Have used Toyos in the past on various Honda products and they perform just great; handling, snow, various nails, etc. Had one Toyo tire which consistantly lost some air pressure and finally had it inspected only to find it had 5 nails in the tire, but it still held enough air pressure for highway driving. With the snow, sleet and slush coming here in Chicago and the OEM tires slipping in the rain already after 9000 miles, its time to upgrade. $360 for the set. Also, will be changing size to 195/60R15s; I drive the Prius like its a go cart so why not.

 

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Hmmm. And John was apparently willing to use the OEMs a second MN winter had he not lost one. Wondering if I should give the OEMs a go this winter. Given the low rating Goodyear puts on them for snow, I was expecting they would be close to worthless.

 

Went to NTB today to see those hydroedge tires, they want $525 for a set of 4; $505 for a set at the 195 size. Since the Toyos are only $360 (195 size), you guys really should consider the Toyos. They beat michelin in various dept of trans tests. Just an idea.

 

Personally, I have always gotten the best deals on tires at Costco. Here are their Prius tire matches.

 

I apologize for picking nits here, but using the term "larger" to describe a 195/60-15 tire compared to the 185/65-15 might be a bit misleading. The 195 is technically larger volume-wise, but I don't think that's how most people think of tire size when saying "larger". The 195 is a wider tire, but the diameter is smaller. I think it is the diameter that most people would connote with the use of the word "larger".

 

I went in on Monday and had the OEM (Goodyear Integrity?) tires replaced with HE. I think I paid $125 per tire, minus $20 each for the trade-in on the OEM tires (at about 6,000 miles) plus tax. Included was mounting, balancing, filling with nitrogen (not sure that makes any difference, but it was free) lifetime road hazzard coverage, rotating, and they'll check the pressure and fill as needed (with nitrogen) for free. That last item matters to me because I don't have a heated garage, and it hurts to mess with the tires at 20 below zero.

I don't expect to be able to offer any useful, objective data. With cold weather coming on I cannot make useful mileage comparisons. I expect the only real difference to be under extreme conditions. Kind of like a bicycle helmet. A good investment, even though you hope you'll never have occasion to know it's there. It's good to know I've got better (by all accounts) rubber in contact with the road.

 

I'm still waiting for the corning test on fresh snow. I recall last winter's driving with the OEM tires. They worked fine. I also recall the difference between the OEM on both wet & dry compared to the HE. That's what really impressed me. The improvement was quite pleasing. And corning is what I am concerned most about in winter driving. It's like ABS, they delivered increased control. So that is what I am expecting from the HE too. We'll see... eventually... white Christmas anyone?

 

<div class='quotetop'>QUOTE(john1701a\";p=\"52793)</div>

Thanks for the offer, John, but if I have a choice I'd like to skip the white altogether this winter.

 

To coin a phrase; "Snow's a great place to visit, but I wouln't want to live there"