I'm looking for new wheels, but I was thinking that 15" wheels were always best to compensate both LOOKS and fuel economy quality. And for tires... I know most of that stuff from my physics class back then. haha

Does anybody here know what size wheels would support/answer my question?

 

If you're not finicky about looks, 14s are definitely the way to go. I managed 66 MPG on my GD1 on my stock 14s (you don't get these in the US). I've never been able to repeat that or come anywhere close to that since I upsized to 16s.

As for tires I had 175/65R14 Michelin Vivacy rubber. Not the best-handling tires for sure, but certainly pretty good for economy runs.

 

^^Yeah 14s would be best. I barely noticed that today when I was thinking about my post and a bunch of HYBRIDS pass by me with the smallest wheels ever haha. But I think i'll stay with 15s cuz I'm trying to compensate between looks and mpg.

 

In that case lightweight 15s are right up your alley. There should be a fair number of those...I'm looking/saving up for a set myself And to be honest my stock 14s looked really pathetic (check the photo thread on my signature for photos). Hahahaha!

Downside is, lightweight wheels are pricier than their heavier counterparts, depending on what construction method you opt for. Forged wheels fetch a pretty penny, but there are lightweight cast wheels too.

 

Type 100 is right... the lighter your wheels the better milaege you will get, but if you compare 14 with 15 inches that have the exact same weight, the 15" will be less fuel efficient since it's weight is farther from the center of rotation and your tire will probably be wider (therefore heavier) and Michelin uses compounds that are less resistive=better milaege and less noise... in fact, i have Michelin X-ice and they get better milaege than my khumo in the same size...

 

The big heavy wheel and tire combinations are about the most counterproductive styling fad that people have ever bought into... The flywheel effect of large heavy wheels can be a good thing for maintaining speed while coasting in effort to drive economically in a straight line on relatively flat roads or down a hill but they hamper mileage terribly during acceleration.... Another fuel wasting concession to style is spoked wheels that create some major aerodynamic drag at higher speeds..... At some time in the future the benefits of inboard mounted brakes, disk wheel covers longer travel suspensions and smaller diameter and cross section wheels and tires will be realized and again implemented in automotive design and engineering..... As for wheels and tires , the combined weight of all 4 of mine weigh 102 lbs. and the tire cross section is 7.6" hight 23.4" and it wouldn't hurt anything if they were smaller.

 

The Dunlop SP31 OE tire for the Insight, 175/65R15 LRR, is available from Tirerack for a lot less money than any Michelin. Ride quality? I dont know. Since the aspect ratio is 65 vs 55 it might not be too bad.

 

I used 165-70-13s on 6" alloy wheels on a VW pickup in the 80s and loved it... Ihad gone as big as 195-70s but they screwed up everything.... It is surprising that a tire can be too wide and cause a loss of traction on a relatively light car..... Wide performance tires are terribly overrated.

 

Lol... freaking SP31... i really hate these... had them 3 years on my car and they wore horribly bad... they were good on milaege, but the car felt sloppy in corners and the tires always jumped while cornering a little fast... I'm far more happier with my khumo 722... they have a stiffer sidewall so i don't feel like driving a humongous four-door sedan anymore... XD

 

No such thing as the best . . . . especially when it comes to ride quality, since everyone has a different definition. The easy answer to your question is that for the "best" ride quality & mpg, you want the smallest possible wheel with the most sidewall. And the lighter the overall package is, the better your ride quality is going to be since your sprung/unsprung weight ratio improves. But obviously there's a practical limit - 1 inch wheels aren't an option, since whatever you choose has to physically fit over the brakes. Not only that, but you need to be able to find a tire size that keeps you in the ballpark of the original rolling diameter. So even if you downsized your brakes to some ridiculous degree and got some custom 10" wheels, you're going to have a very hard time sourcing a 175/95-10" tire . . .

But like I mentioned, ride quality is subjective. My winter tires are on 14" rims. So not only is there an extra half inch of sidewall, but it's a lighter overall wheel/tire setup than my stock wheels & Eagle GT's . . . that said, but I much prefer the ride quality of my summer tires. The primary job I want my tires to do is stick to the road, not absorb bumps - that's what my suspension is for.

 

I don't see these ever coming back on commercial cars. The automobile's primary purpose is to transport things, and inboard brakes just take up way too much real estate that's in demand for cabin space.

Not to mention they're a pain in the ass to service, and unless you've got F1 style bodywork, keeping them cool is no picnic.

 

I took a cross country trip in a Lancia Flaminia in 1967 that had inboard drums on the front and disk mounted on the rear axles at the trans axle. The ride and handling was great for that period and even while flying low through the Rockies the braking was great and never showed signs of fading... On a light car with small light wheels the metallurgy, friction material and hydraulic advances not to mention light weight alternative multi disk designs not unlike that used in clutches, it is possible to create smaller brakes that are less affected by heat.... Hydraulic disk have been applied to automotive use for over 50 years and sure to be superseded in design and function at sometime in the not to far off future.... Big wheels and tires are hogs for interior space as well.

 

I believe Dunlop SP31's 19/55/15 are used as OE for the GD3's.