Alternative Wheel and Tire Sizes

Here's the new shoes I put on for most recent 1700 mile road trip... Gen 3 wheels designed for 195/65R15 tires with some Ecopia 422 Plus Energy Saver 185/60R15 tires.

Now mostly home from a long drive of harsh winter mountain climbing on highways and backroads between Seattle and San Francisco for the pre-holiday season. (40psi rear & 42psi front).


Note: as always https://projectlithium.com/?ref=9qLPw battery pack not dropping below 4 bars on mountain passes that would drop even a new OEM pack down to one or two bars.

True to Prius ways was saving money on #blackfriday (measly $10 dollar discount) on these tires. However, because they were 60% and not OEM 65% nobody buys them and excess inventory means the cost of 4 of them came close to $200 less that normal 65% tire size.

And the 60% aspect ratio (aka: tire height vs width) means less rubber leverage above the tread so better handling in corners (low profile). As in instead of feeling like you're driving a couch, you're driving the vague sense of a sports car that's designed to hug the curves on steep curvy roads. I had no idea my old clunky Prius could do that!

The drawback of course is that this also means tire circumference is near 2% smaller so speedometer is off sometimes as close to 2mph faster than reality at peak freeway speeds. And the car's computer predicts a way more overly optimistic MPG than normal and then you fill your gas tank and calculate how much way worse your MPG is by a 3-4 miles per gallon less than normal... A major tragedy for a Prius nerd to think about too often while driving 1700 miles.

What's best about this configuration is that although the Gen3 wheel is heavier than Gen2, the smaller tire is lighter than usual Gen2 tire weight so they balance each other out a bit and the tire is also stretched to a 195 width, which likely lowers the aspect ration more than 60%.

As in twisty mountain smaller roads in California it was the first time in my 278K miles on all original unmaintained drivetrain (experiment) that I felt like I could go faster instead of braking early for fear of traction on the sharpest curves when being chronically tailgated by locals who I'd like to think know I don't know the roads.

Anyways, looking forward to your thoughts on all of it...

(And remember what ya mom says about what to do if you don't have anything good to say!)

 

Nope... Costco will refuse to install tires that aren't exact same tire size and wheel size the vehicle requires. As in Costco is for boring people who don't like to experiment with wheels and tires. Mine were mail order for $399 including sales tax & shipping and then there's a family owned tire shop of spanish speaking folks who put the tires on the wheels for a $100 bill under the table. Only thing that went wrong is they said they don't do maintenance/new battery for TPMS sensor and wasn't an issue, but then 100 miles into the road trip the battery failed on one of them. So that's gonna be a hassle.

 

Nope... Maybe you're forgetting the pricing difference between Canada and the US? On black Friday cheapest price for the 185/65/15 Ecopias online was $600US installed. But had I shown up to that seller with 195 Gen3 Wheels they would of refused to do it and that'd be nightmare to get a in person refund for a black Friday online purchase.

What's more, these tires aren't for my car, but for a project Prius that I'm customizing for good looks and high performance for re-sale so I have money to build an even better project Prius in 2023. If you'd like to follow the thread it's here: Requesting Suggestions For Mods and Upgrades For A 2005 | PriusChat

All of this is for learning what's possible to give a Prius the very best performance package possible and what I learned on the road trip is 185/65/15 may get great gas mileage but they're total garbage on the twisty back roads, much like driving a couch. You'd be amazed at how well a Prius handles with a slightly lower profile tire. I've got 277K miles on the shocks and brakes on my daily driver and handling has been awful because of it. But with a slightly lower profile tire, it felt like a sports car despite the worn out suspension.

Also TPMS was working fine after tire install... It wasn't till after 100 miles till one went bad. Once I find out which tire it is that's a $15 part and a $10 charge to get my Spanish family who I think live in a motorhome at their tire shop and they're far more deserving of being paid than a corporation with an overpaid CEO.

 

I would of had to buy a Cosco membership to do that. And I used to have a Cosco membership specifically for these tires. And as a single person living in a studio apartment with a tiny refrigerator, there's no other products at Cosco that I ever bought. If I had a huge family and a big house with a full size fridge Cosco would be a good way to save money, but paying for a membership just so I can buy tires every 60K miles is a waste of money, especially because they would of refused to install the 185/65/15 tires on Gen3 195 wheels. What's more, sales tax in Washington state is just under 10% so that would raise the price even higher.

 

Well... I still need to buy tires for my daily driver so if you could help that'd be great.

 

This thread was just moved to a different forum... Not sure why? But I just want to say again, that the Prius handles so much better with a slightly lower profile. Oncoming headlights are worse for my eyes because of it too.