What tires did your Prime come with?

I just set 'em all to the same pressure, seems ok.

 

Toyota says 36/35, so 1 psi delta, on my Gen3 there was a 2 psi delta

 

To allow for engine weight in the front. Vehicles have always done this, except for VW Beetles.

 

Beware that the wheel covers help with aerodynamics/fuel economy.

 

Doing my own rotations was my motivation in part, for setting them all to the same pressure. The car doesn't seem to behave any different. I've been driving front wheel drive Honda's since '81; they always spec'd same pressure all around.

 

My car had the Toyos. I told the dealer to switch them with another car's Bridgestones on the lot. He said he didn't blame me, since he also had bad experiences with Toyos. This photo is exactly what mine look like now, with no frisbees and with the center caps. I'm happy too, and looking forward to the Michelins in the not too distant future.

 

Toyo NanoEnergy A29 195/65R15 89S on Prime Plus bought in MA last week.
I don't like that they're 44psi max, nor that they're 89S load/speed.
The same-size snows on my 2005 are 95T.

Was going to sell the tires and install new Michelin X-Ice3 right away, but after now seeing that everyone calls the Toyos "Nanocrappers" and that they're cheap tires, maybe I'll run them until winter and sell them used then, or just put them on my 2005 to have a nice new set on it when I sell it. That will give me more time to decide whether, and how much, to go to oversize diameter for increased ground clearance on the Prime. Every time I look at those huge wheel wells, the farther I decide I might be willing to raise the car via tire diameter!

Removed the wheel covers to sell on ebay. Turns out they're more valuable than the tires!!!

Installed $1.07ea Home Depot 1-1/2 inch electrical-box knockout plugs as center caps per the ingenious post by theloop82 on 4/14/10.
On the Prime, they don't sit flush on the wheel surface, they instead insert perfectly inside the bore, and depth-wise sit against the odd smaller-diameter shoulder in there. So, don't expect to get them out without removing the wheel, which is the only time I'd want them out anyway. Think of it as theft-proof $1 center caps!

Will post a photo if the site lets me upload (I just recently signed up, not sure I've posted enough to post links or photos)

 

Couldn't find a way to add a photo into post #67 after the fact, so here it is.

Photo doesn't quite show how innocuous/natural the $1 center cap looks.....flash reflections make it look like there's an ice cream cone logo or something in the center, and bright spots on its rim. It actually looks fine in person. I may try various $1 sticker/cap designs over it. Already ordered some with a Transformers/Autobots theme to match my username. One adult daughter is an anime fan who will get a good laugh out of that, too.

 

My eyes! Those rims are quite off putting. I like the covers much more.

 

They aren't the ugliest wheels I've ever seen, but they're up there.

 

It’s because they’re designed to have plastic covers over them. So, they bulge out and the spokes don’t go all the way out to the edges of the rim.

 

Advanced, "optional" Alloy wheel's came with Toyo Nanoenergy A29's threads started at 10/32nd

 

Nanocrappers? I actually asked my dealer to switch them out for Ecopias. He said that he could not due to the dealership's contract, as they are required to keep whatever tires were on there at the point of sale. I guess I don't care too much either way since the nanos are supposed to be low rolling resistance and I have my 175/65/R15 winter tires leftover from my c anyway.

 

I get a chuckle now that others have adopted my "Nanocrapper" name for those jinxed Toyo tires that I'm glad to have replaced with "Micheleens" as my Louisiana-born neighbor called them!
And by the way, different strokes for different folks, but I much favor the underlying factory alloys to those pizza plate covers, fuel saving or no.

.

 

Although I personally have no objection to using non-stock widths/speeds/diameters of tires in many cases, I'd strongly advise checking the load rating number on your Prius c tires before putting them on the Prime. If the load rating isn't up to the spec on the door jamb, simply don't use them. And realize that the 175/65 lowers the car 13mm (over half an inch) versus 195/65. And that 175 might not even be in the safe range of width for the stock wheels.

The lowering alone would make me never, ever put those tires on my precious and already too low Prime, though if I lived in Anaheim's climate/conditions I might feel differently. Which begs the question, why use winter tires in Anaheim? And if it's because you ski at Tahoe or something, then why make the car lower to the ground in winter conditions than summer. That seems backwards to me. Personally, I want to raise the car rather than lower it, both for winter conditions and to help prevent approach-angle and parking-curb scrapes.

I'm already trying to act as if the car has zero ground clearance front and rear when parking, never overhanging any sort of curb or tire stop. I'm also replacing the stock 89 load rating tires with at least 95. Having extra safety margin on load vs speed vs inflation pressure, helps protect against many causes of tire failure, including defects, slow leaks, fast leaks, car overloading, potholes, etc. Remember, we don't have a spare tire in this car! I'm not quite paranoid enough to switch over to run-flat tires, but an ounce of prevention is a good idea. Putting undersized Prius c tires on the Prime just plain sounds like a bad idea to me, though if they're load rated 89 or higher like the stock tires it's at least not a clear and immediate danger.

 

My Hakkapeliitta R2s say "175/65/R15 88R Extra Load" - so given a load index if me and the car and gas and light storage weigh a total of 3600 pounds, and each tire is weighted for a load of over 1235 pounds (vehicle total of 4940), that's still 37% more than the maximum load that my Hakkapeliitta R2s tires can take. So, do you still think that I'm putting myself at risk?

How do you figure? The 175 vs. 195 difference is from sidewall to sidewall, not radially from the center of the tire out.

I checked with the local dealer to be triple sure, about putting those winter tires from my Prius c (which they've serviced) on my new Prime (which they've seen), and they said, it's not a problem.

Given my question above, I don't see how my car would be lowered.

I would appreciate your advice on these.

 

So 89 tires have a load rating of 1289 lbs and 95 tires can carry up to 1521 lbs.
The curb weight of a prime is 3375 lbs and another thread mentioned the carrying capacity is 670lbs but let's even assume we put a little over 1000 lbs of people and stuff like some claimed they may do and you could get to something like 4400 lbs for the fully loaded car.

If it was 100% equal distribution, that would be 1100 lbs per tire but we certainly don't always equally distribute.
What math makes you think that the 189 lbs of extra capacity are not enough and that the added 232 lbs the 95 tires offer are now enough?

 

The issue is that when you drop the width (195->175) it gets multiplied by the aspect ratio (65 in your case) and the resulting sidewall height is now smaller in addition to the width being narrower...
With a narrower sidewall, you have a smaller diameter so you are lower to the ground.
Other unfortunate things like speedometer values are now wrong as well.

Here's some data
diameter...........25" -> 24" = -4%
width................7.7" -> 6.9" = -10.4%
sidewall.............5" -> 4.5" = -10%
circumference..78.4" -> 75.2" = -4%
revolutions/mile 832 -> 868 = +36

If you really like 175 width, a 70 aspect ratio would be closer to what the car expects.

 

What @ct89 said.

Who were you talking to? That's not very responsible.

 

It's lowered 13mm. Here is why:

Tire diameter is equal to the wheel diameter, plus 2 times the tire sidewall height.
Sidewall height is equal to tire width multiplied by aspect ratio (number on sidewall over 100).

Any difference in sidewall height directly lowers or raises the car by exactly that amount.

Here the profile height changes by 0.65 x the difference in tire width.
0.65 x 20mm = 13mm

(195mm x0.65) - (175x0.65) = 13mm

Similarly, the overall tire diameter is 26mm (just over an inch) smaller than the 195/65R15
So it would take a 175/65R16 to approximately match the diameter of the 195/65R15


As for load rating, the placard on the car specifies 195/65R15 but surprisingly doesn't specify a load range.
All tires I can find for that size are mostly load range 91, but vary from 89 to (XL load range tires with up to) 95.

Luckily, your 175s are XL so are 88. But technically, they still have a lower load rating than ANY 195/65R15 I can find.

Sure, the car doesn't exceed the sum of the load ratings of the tires. But you're eating into the engineered safety margin. ALso note that the max load specified on the sidewall is also only true at the max pressure on the sidewall. So you're pushing yourself into the "coffin corner" of the load vs pressure chart. I run my tires at max pressure all the time, but if they lose even 15psi, I'm still covering my actual load with safety margin left to spare. Start pushing real loads toward max load, then you lose the luxury of being safe when the outdoor temp drops and causes a "deflategate" pressure drop.

I guess you could subtract 4 times the difference in load rating between 88s and 89s, from the already low 670 pound load capacity of the car on the placard, and make sure you never exceed the lower weight limit. That would keep you physically as safe as using the placard tires at the placard weight limit, but it still puts you legally at risk.

One chart shows the max-load difference as 44 pounds per tire. Do you really want your awesome car's already marginal 670 pound passenger+cargo capacity (on my 2005 Prius it is 825 pounds) reduced by 4x44=176 pounds to give you a total passenger + cargo limit of 484 pounds? Just to reuse tires as hand-me-downs from your Prius c? Plus risk a ticket for not meeting the safety requirements on the tire placard? Plus risk failing inspection? Plus risk getting sued over it after an accident you didn't even cause, because they can point to this as an unlawful act on your part which may have contributed? Plus, you'd need to check if 175mm may be outside the design range of widths for the stock 6.5 inch width wheel (someone said 185mm-215mm is OK, I haven't verified it).

I hate how big-box stores won't install 118mph tires on a 110mph car if the manufacturer originally delivered it with 130mph tires, and how they make other asinine decisions based on fears of lawsuits. Yet when BMW specifies some low inflation pressure good only up to 85mph or with an empty back seat, they'll insist on inflating to that dangerous pressure. So I love that there's always a tire guy somewhere willing to do whatever I decide to do. BUT......I do try to figure out that I'm maintaining at least the designed-in safety margins.

I can't wait to get the 89S (1279 pound, 112mph) tires off my car and put on 95T (1521 pound, 118mph) tires for added safety margin. Not that I'm planning to load the car up to 6084 pounds while going 118mph. But it's nice to have that extra safety margin when you do something like smash into a pothole or have to jump a curb to avoid a head-on accident.