Need advice on wheels

I'm a noob owner as well, and looking at this too. What I've seen is in europe they offer 16" wheels (195's, I believe) and in Japan they offer 17" wheels (205/40/17). Gas mileage diff? Can't seem to find it, though I encourage you, a euro, or a jdm customer to respond whatever is found. I can tell you that you will need to watch wheel weights (keep them light), and I can see how 17" wheels would at least hurt city economy (the bead is the heaviest part of the tire, and you are moving it outward thus improving its leverage against acceleration.) Of course, this is all speculation and I do not offer this as factual.

Someone please speak up and prove me wrong, I'd like a certain set of BBS 17"

 

I am also researching custom wheels for my 2006 Prius. I'm leaning toward 16x7 lightweight forged wheels with 195/55-16 tires. 16x7 still leaves enough sidewall for a comfortable ride. I'm looking at all of the racing brands, such as Volk, Buddy Club, GramLights, Advan, Kosei, etc. I'm considering 17x7 as my secondary option. I want the same wheel+tire weight as the stock setup, or perhaps even a little lighter.

 

I think some people have use the 17" optional Scion TC wheels with 215/45-17 tires. In fact I think that size wheel and tire is what some people have called a port option (meaning that they can be installed at the POE by what ever Toyota Region). Check under performance modifications and I think you will find some good old posts on this subject. If you go to Les Schwab take a look at the Toyo Proxis TPT they might be a good tire for the Prius.

 

virtually everyone who has gone to 16's has said that they took a mileage hit. Some as high as 6 miles to the gallon. Most who went to bigger eventually went back to stock. V8CobraKid comes to mind, he hasn't posted much lately but the first thing that he did was changed tires and wheels, and mentioned the hit on mileage.

 

Take Bridgeston G009 for example,

size - weight - diameter
185x65/15 - 22lb - 24.5" (US stock)
195x60/15 - 22lb - 24.2" (size one up)

with 16" wheels
205x50/16 - 22lb - 24.1" (-0.4")
205x55/16 - 24lb - 24.9" (+0.4")
(extra weight on larger wheels, if same material)

Before you decide, make sure the tire will not rub against the inside wheel walls when turned to the max. Extra 1~2cm should be OK.

Cons: MPG hit: from heavier wheels/tires and wider contact friction. If you choose 205x50/16", I will entertain a guess at 5-8% hit on MPG.

Pros: Better roadholding, shorter stopping distance, better look.

 

I think the current wheel width is proper. Any wider than that, the wheels are not protected by tires. Therefore, you will be running at the risk of wheel scratching, especially curbside parking. Some tires come with "rim protector". Make sure you get those if you do go with wider wheels.

Other than the extra weight (due to wider), I see little impact on the MPG. (Assuming you only go 1/2" wider...)

 

You do. It can be quite significant.

 

No, sir. Adding 100lb to the Prius may be nothing to MPG, but adding 10lb to your wheels will have significant impact on MPG. Why? because your tires/wheels need to be spinned up while accelerating. The rotational momentum needs energy. Yes, your regenerative brake may recover some, but only a small portion of it.

Also, add weight to wheels worsens the "unsprung weight". In short, your car feels like less "glued to the ground" as you drive it on uneven surfaces.

 

There are some 16" wheels that are lighter than the stock 15" wheels. Most of them are forged and cost several hundred dollars per wheel. It is possible to end up with a new wheel+tire combination that is more sporty and lighter than the stock setup, thus preserving the light unsprung weight (good handling) and fuel efficiency. Wider tires = more rolling resistance, so don't buy a tire that is too much wider than stock. Wider wheels will certainly look better too. Good luck, and please report back on your experience.

 

Don't forget weird camber/caster issues you may have...

I've done this sort of thing on various v8's I've owned, and a lot of people ignore things like the effect upon camber/caster the wider your tires get. Put on tires that are too wide, and you'll upset the suspension geometry. I don't know what the threshold is on a Prius, but for example, if you put wide tires beyond a particular measure, you will get uneven tire wear, typically on the inside edges. In the performance vehicle regime, you buy these things called "camber/caster" plates, that allow alignment shops a greater range of alignment settings than can be done with stock.

Again, I don't know what the threshold is on the Prius, but it's been my experience that most cars can accept a range of how "big" or wide of a tire can be.

Another thing to consider, is what grade of rubber. Do you want a "hard", generally longer life tire at the expense of grip, or a "soft" performance tire that has a Devil's grip, but wears quicker...

 

Wider rims or tires? I'm assuming rims, and the only thing I've done is wider tires on the Civic while maintaining the same diameter. Went from 175 to 195 as a plus-zero resize for about 150K miles with no problems, unless you count the rear bushings breaking at 200K miles.

 

My favorite are those little Japanese cars, whose owners have mounted aftermarket wheels (typically fake wire) with massive negative offset (distance between center of wheel and mounting pad, negative means wheel center is to the outside of the mounting pad). The tires stick outside the wheel wells as though the owners were trying to make them into open-wheel race cars, except they're also equipped with the cheapest undersized whitewall tires and the aforementioned fake wire wheels. This causes a lot more wear on wheel bearings and stress on all the parts in the wheel carrier. I have to laugh when I see one of these cars broken down on the side of the road, with the wheel appearing to have broken off the end of the axle.