rim gurus pls chime in

Negative, the wheel will be sticking out past the fender.

I'm running 18 X 8 rims with a 40mm offset and they are flush with the fender.

I would suggest a wheel with a 42mm offset or higher.

 

*EDIT* I just noticed this was for a 2010 and my experience is with the Gen II model

I agree with Dakine.

While attempting to make the rim more flush with the fender by going with less than stock offset, you will run the risk of rubbing on the rear tires. The front of the car has a ton of clearance but the rear will often ride just above the rear tire, especially when carrying a load.

The other problem with a lower offset is the general shape of the car. If you make the rim stick further out from the fender well you will increase the amount of debris that is thrown up onto the side of the car and this includes rocks.

To get a better idea of what this will look like simply take a yard stick and hold it flush with your fender (verticle) and look how much tire tread will be exposed near the bottom of the fender well where the body of the car curves in rather sharply.

 

Plus that would equate to one harsh ride with 18's. I've had several sports cars, including a Z4 Sport Edition & the Prius with 17x7's is almost as rough of a ride considering lesser suspension components.

 

Considering 98% of people who have experience between the Touring 17's and the regular setups, all saying the ride is Significantly harsher and Significantly louder, running 18's is just insane.
Its a Prius, not an M3. The "cooler" you try to make it look, the more laughs your likely to receive. Kinda like people pimping a Yugo.
Remember to most human beings, a Prius is already ugly, and considered a Dork Vehicle. Intentionally trying to make it look trick, is silly. It is what it is. An eco, gas miser that weighs a svelte but tin can 3,000lbs. No sound dampening to compensate for low pro's.
The 17's owners all say its pretty loud inside. You're getting into 2010 Honda aInsight territory-loud. 18's will ROAR.
Having M3's and other vehicles, I can tell you from experience that as low pro's get worn, they REALLY get loud and that's on a vehicle designed for them with 5 times the sound deadening material.
I think you're likely to get the same sound inside as being inside a tractor.

 

I'm not a guru, but 215/40R18 should fit on the wheels and car. 17" rims should be lighter with the same grip. so 18s will hurt performance but you can put them on for looks.

 

I know this thread is about Gen III wheels and tires. But I'd like to
make a gentle exception to this statement in a broader sense.

I am involved in STEM (Science, Technology, Engineering, and Math)
education mostly at the middle school level. However, we see students
from the 4th to 12th grades. At these ages the young people are at their
most impressionable. I've modded my '08 so that even as I drive
on and off the site, with luck students will notice the car. Later
statements like, "Yo, tight," or "Cool" can lead to authentic learning
moments about the hybrid with respect to ecology, energy use,
and about a million STEM related topics. These are the car buyers,
energy users, scientists, engineers, planners, maybe even visionaries
of the future.

Yeah, I bought the car for my own personal reasons, and I started
modding for personal reasons. But, an unintended consequence is that
in at least my specific case, a tastefully modded Prius is seem by
some as neither ugly, nor a dork vehicle. I think the answer to "Hey,
what is this?" also has educational value in a broader setting when I
am not at work too; The rear is debadged, but there are Prius decals
on both quarter windows. "What do ya' know, it's a Prius!"

(Be gentle now. Yes, I know you said "most human beings" above,
and my case involves only some of the all-minus-most remainder.)

Oh, and here's my car:

http://priuschat.com/forums/attachm...-plastic-covers-alloy-wheels-amapola-rims.jpg

Since this picture, I've substituted BMW side lights for the front fender
Hybrid SD badges. Rear wheel skirts are in the works. I just need to
find a suitable for me way to attach them securely.

Thanks for listening.

 

For my pics, look under this forum for "See bigger wheels on gen III Prius II." Post # 40.

You're probably looking for close ups of the tire/wheel correct? I'll try to post later on in the week.

As for running a 225/40-18 with a 45 offset you may end up where the tire is just flush with the fender. I think the main issue is the rim being 8" wide.

On the positive side, your tire (because it's wider) should be protecting the rim somewhat. On my car the wheel is wider than the tire = no rim protection!

 

This setup, IMHO sounds to be a safer setup to go with. Are you planning on lowering the car?

*Best thing to do if possible is to test fit the wheels on the car before mounting the tires to check tire/fender clearance.

 

I pimped my Yugo back when it was new...I was in college. What can I say.

 

does anyone have any difinitive info on the effects of increased wheel weight and mpg/acceleration?

the common gut-shot wisdom is that rotational mass does have a pretty big effect on both mpg and acceleration/deceleration...but that "hunch" or educated guess seems to be the only thing available on the internet.

the only legit "tests" are user's reported findings and those tend to conflict (tirerack tested different weighted rims on a bmw and found that the heavier rims got better milage, while some others report no change, and others report the expected loss of mpg).

I tend to believe the common belief, but I'd really like to know how INTENSE the effect really is for our 2010 prius. I'm moving from a 15" stock wheel (16 lbs) to an 18" wheel (25 lbs).

 

Here were some easy to understand tech blogs from HRE Wheels on the subject.

HRE Performance Wheels ? Blog – Unsprung mass: Why is this important?

HRE Performance Wheels ? Blog – Rotational Inertia?s Effect on Performance

I essence light weight wheels are always better for acceleraiton and deacceralation. That is the prevailing idea behind all racing venues. In my own experience a set of light weight wheels would improve my trap speeds vs. the same tires on a heavier wheel on the same car on the same race day with density altitude calculations included. I never did testing with wheels of similar weight but different diameter though (increased distance from axis).

Futhermore, you will be seeing an even larger negative hit on mileage due to tire choice for your 18" wheel. You are not going to have the same choices for a low rolling resistance tire and the effect of running a high traction oriented ultra high perfomance tire vs. a LRR all season or summer tire will be profound is all else is kept equal.

 

who wants to see me make it fit.. it will fit if you ask me. just will have to use a fender roller ... and stretch a 215 35 18 on.

my saying is "if it dont fit make it fit"

 

The effects are often exaggerated. A good rule of thumb is to multiply the difference in weight by 2 (someone correct this if there is a better number, its one I learned 10 years ago).

Someone said the weight of the oem 15s is 14lbs and tire rack said my stock Yokohamas are 18lbs. So 32lbs. If your rims are 25lbs and tires are 22lbs (the weight of the continental DWS I bought in your size) then you have 47lbs. The difference is 15x4wheelsx2(conversion factor) = 120lbs. Your combination should accelerate and brake like an extra 120lbs. As F8L's articles said handling is also affected. I think a little weight makes the overly rolly suspension feel better and better traction and a little weight helps the overly assisted steering. But I only added 5lbs per wheel (17" sp10 wheels 17lbs + 20lb tires). I'm guesstimating all of your extra weight will negatively affect the handling, but until you drive it we won't know.

As for gas mileage affected by the weight, I would think the difference would be less than having a passenger. If its mainly highway driving, I don't think the weight would hurt at all. As F8L said the big hit will be on the rolling resistance of the tires.

 

We are running a 18x7.5 ET45 with a 215/40R18 Yokohama Avid W4S on our Five Axis Edition Prius. The front is just about flush and does not rub on a slightly lowered suspension using JDM Tein Springs. The rear is about 10mm inboard, typical of all FWD cars.

On our Five Axis Prius Aerius Concept (shown at SEMA 09 and at the current LA Auto Show)we ran a 19x8 ET40 on the front and rear but had to actually shave off about 5mm form the FRONT wheel pad making it a 19x8 ET45. That was perfectly flush but could rub on big dip. On the rear we actually added a small 4mm (1/8") spacer to bring the 19x8 ET40 out to an ET36-ish and it was flush. We are all about the flush on our showcars!!! This is concept/showcar so we can't drive it on a regular basis so I can't vouch for the actual potential rubbing but I'd hazard to say it would rub on the inner wheel liner/bumper in both cases if the car is as low as ours. FYI, the suspension on the Aerius Concept is JDM Tein Superstreet coilover.

I would post images of both but can't because I'm new to this forum and I have to have 5 or more posts. Sorry, but hope this helps......

Troy
Five Axis