Wheels and Steering and Shocks, Oh My!

Hello, I am not only new to posting in a chat room, but soon to be new to Prius Ownership, I hope. I have a 2010 on order (placed money down last Sept. so hope I get near first pick).
I have a number of questions, but want to focus on the decision to choose 15" or 17" wheels.
1) Given that I drive a 2005 Corolla, will I notice a huge difference between the two wheel sizes?
2) What kind of a difference will the basic dude notice between them?
3) Would anyone ever recommend adding them later... after-market?
4) A dealer in MN told me that it would cost a lot more to add them after-market... should I trust him?
5) I don't like that to get the 17" wheels I have to take all the other technology with Model V (leather, back up camera, navigation, etc.) I do not want navigation, leather, or most of other stuff... so what would you recommend I do, and where? (IF I want to try and get JUST the 17" wheels.)
I'll stop now. Please feel free to give me advice on posting as well.
thank you!

 

After reading this entry, plus the rest of the entries in this thread, I'm still a bit confused. As I understand this thread, the 2.75 lock-to-lock steering ratio will be initially available only on the Prius V (with the 17" wheels). The shocks will be the same on all of the Prius models. The EPS will be tuned differently on the Prius V at launch, but later this year the EPS tuning will be the same on all models with an upgrade available to the early adopters of the non-Prius V models. So far, so good.

Since I really like the 2.75 lock-to-lock steering ratio, will the EPS tuning adjustment scheduled for later this year include the ability to make a non-Prius V have the 2.75 steering ratio - even if it means a mandatory 17" wheel upgrade? Or, is 2.75 ratio only available on the Prius V even with the EPS tuning upgrade?

Thanks for any clarification!

 

Bumping to see what the story is with "upgrading" the EPS system on early cars.

Any word on how and if this can be done (under warranty?), and when the 2-4 trim cars will ship with factory 2.75 LTL steering ratio.

 

Well I would assume that if the steering is electronic, not just power that the software would indeed tell the gears how much to turn with a corresponding turn of the steering wheel. It's not a direct connection betweel a steering wheel shaft and the gear box.

 

""" From Prius Team"""
"Wheels and Steering
Prius Connection LA/SF attendees were right to notice that on the Prius V, due to the 17" wheels, there is a different steering ratio (~2.75 lock to lock, versus ~3.75 lock to lock for the 15" wheel). This is planned for the production car. Fun fact: the 17" wheel EPS has a brushless motor system that allows the tighter ratio."""

This is a quote from the first thread of this message... Therefore, I do not think it is only a software change...

 

I'm just saying the mechanical changes they made in the 17" package would not necessarily keep someone with the 15" wheels from upgrading. The wheel is an independent piece of equipment you can take off and put on. If the offset is similar, the bolt circles the same (they are) then all you usually have to be concerned with is the tire clearance. So unless the mechanical changes they made meant a physically larger brake was installed on the 15" package than the 17" package you wouldn't have a problem. I can't imagine Toyota making two sets of wheels that are not interchangable on the same model.

 

This is what I thought too, that the software could simply be adjusted to have the steering motor move the wheels more or less per unit of steering wheel turn.

What is it that prevents you from turning past lockout- the force feedback motor or is it an actual mechanical point you cannot turn past?

 

Steering is a direct mechanical connection from the steering wheel to the front wheels. Boost is provided electrically.

Test:... with the car off wiggle or turn the steering wheel. Notice the effect on the front wheels.

 

Certainly if the electronics simply replaces the hydraulics for boost it would be interesting to see how a software change affects the mechanical connection for the turn ratio. I'll be watching for that explaination.

 

If you read Doug's statement, he does not say that models I-IV will get the same lock to lock steering ratio as the V. He says "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 could mean a "tighter" feel, more "road feel" etc but not a change in actual ratio.

It is also possible that the 2.75 vs 3.75 ratios may not be a big as it seems because the 17" wheels can't be allowed to turn as far because they are wider and therefore the steering wheel doesen't have to be turned as far to go lock to lock. I'm not saying that this explains the entire difference in ratio but it could explain some.

What we really need is an update from the Prius team.

Roy

 

Bumping for update.

Does anyone have any actual information what the EPS tuning differences actually are, and if and how they will be upgradeable for early adopters.



I drove a 2010 with 15" wheels and the steering feels too motor aided, giving it that cheap 80s american car feel with no connection to the road. It would be great if this could be changed.

 

I was told it would be standard on all models.

 

Told what and by whom? I'm still totally confused.

People are reporting 2010s with 3.75 lock-to-lock steering...

I WISH someone could explain this, it's looking more and more like the summer batch of cars are not worth the added expense of being 'first'.

 

This is probably a dumb question. But with more resposive steering, would there be increased risk of losing control of the vehicle due to over-correction during an evasive manuever. Or will the enhanced EPS tuning and/or increased tire width negate that risk? I'm just wondering if there's an underlying safety consideration.

 

It's not a matter of 'more responsive.' You still have to turn the steering wheel the same distance to turn the wheels the same distance. You don't turn it all the way left, the wheels won't go all the way left.

The issue is by how much the power steering motor will help you do that. The current 15" wheel has very little force feedback to the wheels. You can turn it with a light touch because the motor helps you out a LOT. I'd like this turned down, so I can feel the tires on the road more. It should not feel like playing a video game where you can spin the wheel as fast as you want.

Also, the 3.75 lock to lock ratio is pretty high, you've got to spin the steering wheel pretty far to get close to what I'd call an 'evasive maneuver'. The further you have to turn the steering wheel, the longer it will take you.



Still waiting for an answer...

 

I still think that's a bit far- I wouldn't want to have to readjust my hands on the wheel or have them crossed over one another in the heat of the moment. Even a 1/2 (180 degree) turn requires some arm gymnastics. I want to be around the hazard and back straight without as much movement. I'd want to keep my grip steady and strong, as anytime you do something like that you're in danger of fishtailing and whatnot. I think you'd benefit from having more agile steering, not less when it really matters.

_______

So what is the story?!?!?!?

Will there be a 2.75 ratio available for 15" cars?
Will the tuning "upgrade" be available for the summer batch of 15" cars?
What exactly is the difference between tuning in the summer and fall 15" cars?

Bueller... Bueller...