considering upgrading to OEM 17" wheels

PC member Thai checked this out a couple of years ago, there are some differences. There are different part numbers for shocks and struts and some other components. The biggest difference (other than the wheels and tires themselves) is the steering. The 2010 Prius V (V as in 5), has a more powerful brushless steering motor and a different rack and pinion to provide a faster steering ratio.

But despite those differences the 17" wheels and 215/45 tires should work just fine on your Prius II. Many others have done the same thing and have had no problems as far as I know.

 

Very interesting if that were true that the trim level 5 has differenct shock and rack. I would think that if differences are intentional(upgrades) on the package 5, then they would advertise it. On my Persona, nothing I recall was noted about different shocks or steering. BMW offers packages like these and charge a serious premium.

 

That's the major argument against Thai's finding. Different part numbers do not necessarily mean upgraded. Brushless EPS and tighter steering ratio are the biggest concrete differences in the Five. Nevertheless, many members have upgraded to OEM 17" on the lower trims with no problems.

 

Actually larger turning radius for five.

From the 2013 eBrochure;

Turning radius, "34.2 (15-in. wheel); 36.0 (17-in. wheel)

For Steering and suspension, it only notes "standard" as in only 1 option.

 

Sorry, I meant tighter steering ratio. Will edit my post.

 

Right, I knew you were referring to steering ratio not turning radius but I would think that would be advertised/noted somewhere.

 

The general public is dumbed down compared to us and they're clearly not targeting us in terms of advertisement.

 

So this was never in any of the brochures? Just wondering if they ended the difference and made them all the same. I find my steering lock to lock to be pretty short for a Toyota.

 

I don't remember if it was included in an official Toyota document such as Prius Product Information. We got our information from the Prius Team, who used to be a regular here. They were planning to upgrade the EPS software in the lower trims to provide the tighter steering ratio but Toyota got embroiled in the stupid unintended acceleration fiasco so they cancelled that plan. You have the Persona which has the same 17" rims but in black chrome so I don't see why the Persona wouldn't have the same system as the Five?

 

I think this kinda explains it, "Ultimately, ALL production cars will have the same EPS tuning as the 17" wheel (even 15" cars), but that won't begin in production until late Summer. We understand early buyers of the 15" wheel cars could probably update their system at the dealer later on."

That was discussion was in 2009. Also kinda expains why I hear complaints of handling as earlier models didn't have Euro shocks?

 

Except the Prius Team later informed us in a different thread that Toyota ditched that plan for the time being. Whether it eventually happened later on I don't know.

 

Understood.. but based on the posts, this kinda makes sense now..

Handling wise, I was wondering why so many complained about handling? the change of shocks makes sense..

Then you mentioned steering ratio which can be done with combo of software.. which also makes sense from what I noticed. I need to test drive a 2010 to check non trim 5 to confirm.

 

You should test drive a non-Persona lower trim 2013 as well. It's possible that the Persona got the same system as the Five given the 17" wheels.

 

This is not a "steer by wire system" and I really can't imagine how the steering ratio could be changed with software.

My impression is that the steering wheel is connected directly to the pinion gear, through a couple of shafts. The pinion is meshed with the steering rack which moves left or right and causes the front wheels to steer through direct mechanical connections. No software involved. The EPS motor simply detects when you apply pressure to the steering wheel and in turn applies some torque to help out. The ratio is determined by the gear ratio of the rack and the pinion gears.

I think you could take the EPS motor completely out of the car and the steering would still work fine, just be harder to turn especially at low speed. At highway speed it might not even be very noticeable.

 

We didn't know what the Prius Team meant when they said "We understand early buyers of the 15" wheel cars could probably update their system at the dealer later on" so it's speculative.

 

What about mpgs, are they affected at all with going from 15" to 17" wheels??

 

2016 Prius Two MPG changed after switching 15" rims to factory 17" ones | PriusChat
If you have a Gen 3, the mpg hit will be even more. The Gen 4 has a higher mpg rating.