is 16" the best compromise?

This is all about appearances, technicalities

Looking around at various rim / tyre combinations, Im feeling the pain of reluctance for 17" options, and might be tempted instead to feel out lightweight 16" sizes. The chances of getting 16" touring wheels are next to zip here but there are a few options fielded primarily for Subaru performance cars.

I had been favouring Yokohama db tyres, mostly because I can get them locally and I've been a little persuaded by their tech speak marketing, but Im not sure if theres a 845rpm tyre for 16" diameters.

Does anyone have any data on these tyre possibilities as they seem rather less on 16" ?

My strategy is to source lightweight rims, with tyres that work well, in the hope of competing in weight with the stock 15" fitment and Michelen X that I have now, and yet access a little more grip that I will surely need on these country roads here. This isnt a place where it snows, it last snowed here in 1996, but roads can get pretty greasy in infrequent summer rains.

In the end I will lower the car possibly as much as 2" (perhaps a fraction less), and fill out the wheel wells using spacers on the rims (that most Sub's carry). That will improve appearances a little and give the car a wider footprint. Im assuming it will carry higher but safer corner speeds and reduce the amount of throttle up after cornering, and hence improve fuel mileage.

 

thanks for the list

I fell over this a bit earlier
Car MPG Efficiency Modifications Main - EcoModder

 

interesting
I have seen these tyres marketed but know nothing about them, so I guess I have some research in front of me.

I might have to be a little flexible in tyre/rim widths so that may prove very important, .........thanks

 

I dont do much dirt trecking, usually at the end of journeys. I suppose it might be around half a percent and I always take it easy.

This area is a mixture of straight flat gunbarrel highways in the valleys and slow 40 mph winding sealed narrow roads either side. Bitumen is usually pretty coarse

this is the top of a mountain my V6 couldnt get up at 100kmph [edit: I should have said not on cruise], but the Prius could. Fatal accident marker at right, I did a bit of a series of photos on that subject, young 17 yo girl died on a Christmas Eve. The site is always attended by flowers


and a bit of a look across one of the valleys 30 min north of here

 

quiet would be nice
my Michelins arent really all that quiet, and sometimes finding myself with no engine noise in an aluminium car it seems to resonate road noise

 

20 mins east of here annual rainfall falls off a cliff
ok now this tyre thing is getting confusing !

are the db's run in yet ?

 

expansion joints is a bit sophisticated for out here
they do seem to be very promising to me

 

hmmm, it gets more and more difficult doesnt it
money isnt really an object
Ive been working this out on efficiency as a system, so thats a highly important feature unless I can compensate somewhere else. Other discussions have highlighted weights too, so it might become more important unless I can get a favourable wheel deal.

Something like Enkie or Volk wheels will take the weight off that side of the equation, and I think I might need to resolve that side of it first. I came to the point of view some time ago that weight and LRR are balancing factors, I might be lucky to cover both but it seems less likely

 

now this is timely, Im off to look at some Enkies and Volk wheels today. .... and thanks for the reminder about sway bars

I used to get a bit enthusiastic about driving, actually I drove the wheels off of every car Ive had. But the Prius is different, you cant just power on out of corners or throttle steer like other front wheel drive cars, so the best I can attempt is 'brisk' to be safe.

I had a look at this site the other day, Fuel Economy, Hypermiling, EcoModding News and Forum - EcoModder.com which quantified some aero features Im interested in. Now I would never have thought this was true but theyre saying that wheel covers have made a 4.6% improvement at 65mph !

65+ Vehicle modifications for better fuel economy - EcoModder.com

the 'trims' on the stock wheels contribute to this same phenomena, and actually I dont mind the look of them, they just show more sidewall than is modern to do so right now. And they have the advantage of letting cooling air through to the brakes, this is a similar arrangement to current practise in some race cars. Of issue is how theyre securely attached.

Indeed you have to spend a fistful of money to do better than the stock arrangement, and by the time you pressure up to 40-50 psi all its about is the esoterics of the amount of visible sidewall, contact patch and loss of ride quality.

Potentially deeper trims overcomes both sets of objections, and frankly the easiest way to attach them would be to the stock trims. Then fill out the guards better by dropping the car (mine is a full 8" off the deck at the sill!) and push the wheels outward with spacers to adjust, which Im convinced will lower the Cdo by reducing/redirecting the transit of turbulent air beneath the car in a more controlled fashion, while not interfering with the quite good job Toyota have done with the body considering it is an aluminium pressing (which doesnt adapt to curves easily).

But that doesnt give me more contact patch on the road at an acceptable rpm which is one thing I hoped to achieve. For that I think I have to go to 16" 's.

not silly at all, the esoterics are important, its how to balance them thats the problem

 

agreed, in your case expensive but agreed !
I was thinking on Enkei RP F1 in 16x7, I can import them new for around $230 ea and theyre acceptably light. Just occasionally though I see sets of lightweight Ray's and the like for $1,500

I live on the fringe of the bush really, so we have to get most stuff ordered in. Sometimes it feels so remote the postie will start airdropping mail in from the back of a Herc. But I wondered which way I would go if faced between the conundrum of LRR tyres and those that just bite better in the wet and carry corner speeds better so Im accelerating out a bit less. Im operating on the theory that LRR might count for less than wheel weight, which is the reverse of where I started.

You see that MPG isnt bad at all, Im hovering 4.1-4.2/100 on my Michelin X's, but while I glide a bit etc, I drive pretty fast from time to time. I got in the wake of a fast SS Commodore going up Mt Crawford a few days back and went up the mountain at over 130kmph, the guy in the SS looked a little surprised to say the least.

I've no doubt your light wheel weight contributes to your MPG performance. Poorer choices would see some ground lost there, to me thats avoidable.

I was thinking of coilovers as they would be adjustable, but all I could find in au was KSport who Im told suck, so that part of it is on hold, or I go to springs like you and F8L have done.

there are some quality setups around, theyre used on 4x4's and the Subaru rally crews use them. They fit a bit differently in that they screw onto the hub and carry a new set of studs for the wheels. You can even convert from 5x100 to 5x114, check this out

KICS PCD Changer - Pro Speed Racing

but I have to admit 'illegal' might be tricky, not only the law but the insurers, in which case I would look at the wheel offsets again