Tire Discussion - what kind to get

If you are interested in the sttel wheel/tire combos the wheel is the same as 03 Carolla 185/65/15. I got the new Nokian WRA,s and a have been pleased so far with dry, wet, icy and a little snow. Am waiting for significant snow for final opinion, but so far I think I have solved the 8 tires and 8 wheels problem and can leave them on all year. Peace, Ammiel

 

Prius winter tires

I've ordered Nokian winter tires from www.etires.com before and got very good service. Their car selector is out of date but you can select by size. Here a list of tires they have for the Prius's size:

57285 P185/65R15 88H Michelin Energy MXV4+ $119.99
44798 185/65R15 88S Michelin MX4 Grx (Honda) $97.99
40771 P185/65R15 86S Michelin Symmetry $90.99
65134 185/65R15 86S Michelin Harmony $108.99 Black
T451265 185/65R15 88H Nokian Hakkapeliitta NRW
72387 P185/65R15 86H Uniroyal Tiger Paw Touring HR $77.99
51166 P185/65R15 86H BF Goodrich Touring T/A HR4 $66.99
66607 P185/65R15 Primera $57.99
63863 P185/65R15 Cavalier Accolade Plus $51.99
187620 185/65R15 88H Toyo Proxes TPT $81.99
235060 P185/65R15 86T Toyo 800 Ultra $67.99
54702 185/65R15 86Q Michelin Arctic Alpin $85.99
55780 P185/65R15 86S BF Goodrich Winter Slalom $77.99
T442616 185/65R15 88Q Nokian Hakkapeliitta Q
T443434 185/65R15 88H Nokian WR
T442964 185/65R15 88T Nokian Hakkapeliitta 2
T443432 185/65R15 88T Nokian WR
T442564 185/65R15 88T Nokian Hakkapeliitta NRW
T442860 185/65R15 88H Nokian NRH2
30911 P185/65R15 86H Yokohama Avid H4 $57.99
30471 P185/65R15 86T Yokohama Avid T4 $57.99
013852 P185/65R15 86H Dunlop SP Sport A2 $65.99
109401 P185/65R15 86H Bridgestone Turanza LS-H $80.99
100013 185/65HR15 86H Bridgestone Potenza RE950 $73.99
109010 P185/65R15 86T Bridgestone Turanza LS-T w/UNI-T AQII
021091 185/65R15 87H Bridgestone Potenza RE92 $60.99
061786 P185/65R15 86T Bridgestone Potenza RE910 $59.99
055182 P185/65R15 86H Bridgestone Eager $55.99
060909 185/65R15 88S Bridgestone BT70S With Uni-T $52.99
035335 P185/65R15 86T Firestone Affinity Touring (Saturn Sl2,Sw2) $58.99

Peter
Miami, FL

 

That is the problem. XL stands for extra load and it is a rarely used designation of tire load capacity. This is why when you do a tire rack search of Prius compatable tires, nothing comes up. I am curious, all you actual owners, what does the tire load rating on the sidewall of your tires say? It should be designated in ft lbs (i.e.- 1285) or coded (i.e. 86, 87 or 88 followed by a letter)
The problem is that for the size of the car (due to batteries and two engines) the Prius is very heavy. This causes the need for XL rated tires (they also allow higher tire pressure). Someone on this board put Bridgestone RE950 replacement tires on their car. While I do not believe these have the XL load rating, they do allow for extremely high (I believe 44 ft. lbs.) cold tire pressure rating. This could make them a good fitment for the Prius (if the load rating is sufficient), in addtion to the fact that they are excelllent handling tires in both dry and wet conditions.
Could some owners actually check the tires on their cars and report back.

 

I just went out ito the bitter cold to look at the tires.Wear 420 tractionA tempA
max load 1235# maxpressure 51# (I think). They are product code
T443432 rated 88H. 'nokiantyres.com' (note sp) to get your local dealer.
I paid $398 before tax out the door. I have tried them in downpours, dry, and ice. They are truly outstanding and quiet. I have not had enough snow to comment. Once I found 8 inches of slush on wet ice and drove onto that uphill and stopped. That was so slick the front tires just turned slowly without engaging the traction control. I had to rock D-R and turn the steering to get out, but get out I did saving me the embarassment of getting stuck in an alley beside the local beer distributor. I think I have solved the 8 wheel 8 tire problem. Will be selling the OEM tire with 1700 gentle 'break in" miles after the next snow.

 

PS am running them 40F 38R

 

Reviewing this thread, a bit of confusion is noted.

First, the Prius is not much different in weight than other cars. For instance, it reportedly has wheelbase (i.e., footprint) of the Avalon, but weighs 500+ pounds less. It also is regarded as "Camry" midsize, though it weighs about 250 pounds less. The thing that requires the tires to have a higher load rating is their relative width (185/65 15 on 6 inch rims). A four cylinder Camry automatic comes with 205/65 15 on 6.5 inch rims. Oddly, the base Avalon has the same size mounted on 6.0 inch rims.

Second, tire sidewall markings for maximum cold pressure is just that. It has nothing to do with the car it is mounted on. You must consult the manual or door jam (?) to see what the engineer's advise. Clearly, the Prius' fuel efficient design utilizes higher pressure to reduce rolling resistance.

Any search for a replacement tire must take the following into consideration:

• appropriate load rating
  stock size, or a carefully chosen alternative size with equivalent rolling circumference and applicability to the 6 inch rim width
  ability to function properly (braking, handling, comfort and noise) at higher inflation pressures
  • 
    
    A discussion of Owner recommendations, such as this, will be invaluable to my own selection of replacement tires. However, at this stage I'm still waiting to experience the stock tires...

 

I hate do disagree, but I must. You are comparing wheelbase and interior measurments which have nothing to do with the total actual size and relative weight of a car. This car has a smaller total footprint (total length and width, merely using wheelbase is misleading and cannot be related to the total weight of a car) ) than a Toyota Corolla. Reletive to that compaison and other cars of similar size the Prius is very heavy. Your are right that it absolutely has to do with the size of the tire though. Generally, larger tires support larger weights. Additionally Toyota opted for a fairly small and narrow tire (although larger than Gen 1 Prius) with low rolling resistance.
Still ultimately you must check what load capacity the OEM tires possessed and you must get replacements of at least that (or higher) load rating. As most previous Prius owners note it is more gas efficient (and seems to help with useful life) to run the tires closer to their 44 Ft. Lb. max. cold rating than what Toyota recommends on the door frame.

 

However, despite my finding some Michelin HydroEdge tires that have a load-rating sufficient to do the job, per posts in the Yahoo groups Toyota isn't authorizing any other tire than the ones they ship the cars with. The Michelins seem ideal for the second set.

This one-kind-only thing annoys me, since I don't want a we-told-you-so down the road when I'm looking for them to fix something wheel-related and they point at the word 'Michelin'...

 

Unless specifically stated in the warranty that came with your car, I can't see use of another tire (with sufficient load rating and proper sizing) voiding any warranty. They very well may recommend OE replacement, but this may be due more to the government mileage rating than anything else.
P.S. - In some instances they would have to allow for snow tire fitment as opposed to OE tires, so just another argument against voiding warranty.

 

Now, I must disagree with you. :?

When you speak of tires you are concerned with their individual footprint size (determined by measured width, rolling circumference, and to a certain degree, inflation pressure). The mass of the vehicle (sprung and unsprung weight) is the same as the amount of load on each tire times four (assuming a relatively even weight distribution). The length of the car is not its footprint, though it does have an effect on its center of gravity. In fact, for the 2004 Prius the amount of overhang is minimal, making this a relatively mute point.

The size of a tire's footprint is an important factor in determining the amount of "gription" available. For instance, whenever you purchase snow tires you should downsize your tires so there is more weight per square inch applied to the surface. (Note: deflating tires for snow actually does not help traction, since it only increases the contact area, thereby reducing the weight ratio) Want to turn your Prius into a slot car? Well, at a certain point, increased tire width combined with even the stickiest compound rubber will fail to provide sufficient gription (Re: not enough weight applied).

The notion of inflating to the maximum cold pressure level can be potentially dangerous. Depending on the tire / rim width combination, you can be close to centerlining the tire (Re: riding the center). This decreases traction, particularly while braking and in the rain. Heck, give me an air pump and I can improve ANY car's mileage 2 or 3 MPG. Just apt to kill a few people on the way. Please remember the Prius's design, as well as our usage, should be predicated on achieving a balance between safety, fuel economy and comfort.

PS: My kids love my "word" gription. :lol:

 

You're the one who mentioned "footprint" regarding wheelbase size. Of course when you're talking tire contact patch (footprint) you are right.

But, what we were talking about is the fact that for it's relative size (external dimensions), the Prius is heavy. This is an immutable fact and is a result of it having two engines and batteries. All the weight saving Toyota achieved in other areas cannot negate this fact. As a result Toyota specifies XL rated tires.
It is not necessairily dangerous to inflate tires near their maximum cold pressure rating and many Gen 1 owners do this to improve both the life of the tire and MPG (decreased rolling resistance and increased MPG). Remember this is Max. "recommended" inflation, not over inflation.
The recommendations and usage I have seen posted here and elsewhere are approx. 40-42 Lbs. of pressure, this leaves at least 2-4 lb's leaway under thje Max. rated pressure of 44 lbs.
Your statement "The mass of the vehicle (sprung and unsprung weight) is the same as the amount of load on each tire times four (assuming a relatively even weight distribution)", is only partially true. The load the tires must bear must also include the maximum passenger and cargo for which the vehicle is rated (not included in specs, but usually around 1000lbs.) and an additional safety margin usually set by the manufacturer.
Laslty, where the heck did you make up the word "gription"? :lol:

 

Ah, terminology, the means to greater understanding, and so much confusion. No wonder I married a Master degreed linguist.

To me, wheelbase = footprint of the entire car. To you, footprint = an individual tire's contact with the road. A simple misunderstanding. I too will refer to an individual tire's footprint = contact area, though I would have specified this first.

The weight is the weight (machine, man and luggage). The suspension determines how the weight is "hung" on the individual tires. Toyota had to go with the higher load rating due to the relatively narrow width selected.

My comment on maximum cold inflation stands, but allow me to clarify. A large number of road going Americans seem to presume this is the level they should inflate their tires. This is often 5 to 10 pounds above their vehicle's recommended pressure, thus significantly degrading braking / handling, and contributing to centerlining. Whenever I rent a car (typically with the family), I always check the pressures and often find it at, or near this level.

Back to the Prius, its suspension was designed to accomodate the higher inflation pressures, and of course, the tires were selected to match. However, if you go beyond the tire's pressure range (not saying you would) you also would be delving into this unsafe range (based on exceeding the design of the tire). That said, if you are within 2 pounds or so already, it becomes important that Prius owners mind their tire pressures whenever ambient temperatures change from place to place, or season to season. A general rule of thumb is that every 10 degrees produces a one pound difference in tire pressure.

Gription- I view my creation of words such as this one as contributing to my children's future. Of course, they've learned to not take their father too seriously.