Downsizing from 205mm & 16" to 195 & 15" wheels/tires worth it?

[MPGee]

Hi all,

I'm getting close to needing new tires on my '07 Toyota Matrix. I'm running factory 16" steel wheels with factory size tires. I'm considering going to '07 Corolla 15" steel wheels. I believe my #s for the below are correct:

Existing stock Matrix wheel/tire:
205/55R16, 16x6.5" steel wheel, 5x100 bolt pattern, 39mm offset

Proposed stock Corolla wheel/tire:
195/65R15, 15x6" steel wheel, 5x100 bolt pattern ?? offset

See attached photos for calculator results from rimsntires.com's calculator (I can't post links, b/c I'm a n00b. )

How much gains do you think I can expect from getting a 10mm "thinner" tire and -1" on rim size? The calculator says that the 15" wheel+tire should be ~3 lbs lighter.

I drive, maybe, 40% city, 60% highway. I would be trying to get some Corolla steelies used or from the junkyard.

Thx in advance.

[Ecky]

Food for thought, I went to a local junkyard and picked up 2 nice sets of alloy rims. One set was ~$60, and the other was ~$100. There were tons of 15" and 16" alloys available, and the weight savings would be something like 5-7lbs per wheel in the same size. Considering how little more a set of junkyard alloys would cost, why not do that instead?

I couldn't guess how much savings moving to a narrower profile would give you, but all else being equal, there would be gains from going thinner.

[MPGee]

Originally Posted by Ecky

Food for thought, I went to a local junkyard and picked up 2 nice sets of alloy rims. One set was ~$60, and the other was ~$100. There were tons of 15" and 16" alloys available, and the weight savings would be something like 5-7lbs per wheel in the same size. Considering how little more a set of junkyard alloys would cost, why not do that instead?

I couldn't guess how much savings moving to a narrower profile would give you, but all else being equal, there would be gains from going thinner.

Thank you for not flogging me, Ecky. I was reading the chastising of another guy was getting for not searching first on another thread on this same subject at http://ecomodder.com/forum/showthrea...omy-25121.html... lol.

Seems like the lower weight should help, judging by that thread. And as you question, in theory the narrower-ness (if I may coin a term) should help, but 10mm really is nothing...

The concerns I have w/ alloys is that I lose aero benefits from having a (mostly) solid & flat wheelcover. Those things are all spokes, as you get to the lightweight racing wheels, as best as I could tell. I guess I could bring my bathroom scale along w/ me to the junk yard to weigh them. lol. From what I could tell by searching Tirerack.com, just because it's alloy doesn't mean that it's necessarily gonna be any lighter...

I appreciate your suggestion though. I will keep that in mind and not rule out non-steel automatically.

[MPGee]

Actually... reading up online, there are three other French benefits of "downsizing" wheel size that I did not anticipate:

1. Cheaper tires
I priced out how much Goodyear Fuel Assurance were on America's Tire, and it's $82 or so cheaper in the 15" size. That works out to about 16% less..

2. Less risk of damage to hub caps / wheels
This is due to the taller sidewalls, of course

3. Smoother ride
Again, this is also due to the taller sidewalls. I'm hoping it's also a little quieter (?).

I think I'm starting to like the sound of this "minus" sizing
..

[compdrag]

Take a look at konig heliums. If your stock rims were like mine which weighed in at 20lbs a piece. I dropped 10lbs a rim. Take a look at them.

[aardvarcus]

I did almost this exact swap on my old car, except I swapped to 15" Prius alloy wheels. Lightest weight factory option, plus a fairly flush clip on wheel cover with those. I used the black 10 spoke alloys which have the clip on 5 spoke silver wheel cover. I saw a MPG increase, but I also switched tires at the same time so your mileage may vary (literally). I had good luck with Michelin energy savers.

[oldtamiyaphile]

Originally Posted by Ecky

Food for thought, I went to a local junkyard and picked up 2 nice sets of alloy rims. One set was ~$60, and the other was ~$100. There were tons of 15" and 16" alloys available, and the weight savings would be something like 5-7lbs per wheel in the same size. Considering how little more a set of junkyard alloys would cost, why not do that instead?

OEM alloys on my Fiat are much heavier than steelies. With OEM tyres it's about 7lbs per corner. I think you'll find that's pretty typical. The fatigue properties of aluminium means OE wheels are much thicker so they end up weighing the same or more than steel.

Narrow steelies with smooth covers is the way to go, unless you can use some of the rare light weight OE wheels or don't mind spending on aftermarket forged.

Even then, the open faces of race type wheels may not pay dividends in economy terms.

[Ecky]

I believe most 14" steel rims are 18lbs. I have a total of 4 sets of alloy rims now which are 11lbs, 12lbs, 13lbs and 15lbs, the lightest of which are my Insight's OEM wheels and the heaviest of which are the Civic Hybrid's OEM wheels.

[MPGeo]

Originally Posted by Ecky

I believe most 14" steel rims are 18lbs. I have a total of 4 sets of alloy rims now which are 11lbs, 12lbs, 13lbs and 15lbs, the lightest of which are my Insight's OEM wheels and the heaviest of which are the Civic Hybrid's OEM wheels.

11lbs is a very good weight for factory 14" ... I'm pleasantly surprised.

[MPGee]

Originally Posted by aardvarcus

I did almost this exact swap on my old car, except I swapped to 15" Prius alloy wheels. Lightest weight factory option, plus a fairly flush clip on wheel cover with those. I used the black 10 spoke alloys which have the clip on 5 spoke silver wheel cover.

Cool! Aardvarcus, what was your last ride? And do you recall which year Prius those wheels came from, and maybe how much the weight was before/after?