Unbelievable... my Yaris showed up!

[Goose]

Well, 2 1/2 weeks after I placed my order, the dealer called and said that my Blazing Blue liftback has arrived! Thank goodness. Hopefully I can pick it up tomorrow.

I'll be sure to post pictures, although it won't be anything exciting yet. Spec is (as far as I know) the Convenience Package with 15" steelies. I'm probably going to drive it for a while before I start to do some basic OEM-type mods, such as the TRD suspension. I might even get raped for the tasty 18" TRD wheels -- they do look nice.

Can't get ahead of myself, though. Anybody care to speculate on what kind of impact wheels/tires like 18's would have on mileage? :confused:

[stuffy]

congrats goose!

as far as the big wheels effect on fuel economy, would i be right in thinking that they would require more power to get going? if so, would it be a noticeable difference in fuel consumption (and acceleration time?)

[ricko]

Congrats. The 18's will improve gas mileage somewhat, but I think the real benefits lie elsewhere.

[stuffy]

improve? i would have thought they would have the opposite effect

[ricko]

The 18's will require LESS power to get going, due to less weight.

[ricko]

Remember 18'' alloy wheels have less rubber, and the wheels themselves are significantly lighter than the steelies.

[stuffy]

ahh, i see, i was thinking by just being bigger that they would require more energy to get going, which would probably be the case if the weight were the same

but i'm no physicist, so i could be wrong on that one

[Idjiit]

The 18's will require LESS power to get going, due to less weight.

Ummm, no. The 18" rims will be significantly heavier than the stock rims. The difference in tire weight will not balance that out.

[Idjiit]

ahh, i see, i was thinking by just being bigger that they would require more energy to get going, which would probably be the case if the weight were the same

You are correct. Even if the wheels are the same weight, if the wheels is a larger diameter more weight is further away from the axel, which takes more energy for the car to move. Needless to say, the heavier the wheel, the bigger this problem becomes.

[Idjiit]

Here's some sample numbers -

Yaris 15" Steel Wheel/Tire Combo - 37lbs (17lb wheel, 20lb tire)
Toyo Proxes 4 Ultra-High Performance Tires with light Rota SubZero Wheels:
15x6.5 w/ 195/50R15 - 29lbs (12lb wheel, 17lb tire)
18x7.5 w/ 215/35R18 - 39lbs (19lb wheel, 20lb tire)

So, even with a lightweight 18" setup, you're both heavier than stock and a lot of that weight has been moved further away from the axel, so you'll definitely see a drop in performance.

[Ziv]

hum...... tell me if I am dumb. Is that mean bigger wheel is not as fuel consuming?

I know a few basic, the smaller the wheel obviously will have more power to go up the hill and stuff, the bigger the wheel will have better performance. Right?

I am getting confuse.

Oops, sorry where are my manners, Congrats, Goose!

[Idjiit]

hum...... tell me if I am dumb. Is that mean bigger wheel is not as fuel consuming?

Err... you mean, will you get worse mileage with a bigger wheel? You'll definitely get worse mileage with a larger wheel, all else being equal. The car has to work harder to turn the wheel, not sure why this is a difficult concept to grasp.


I know a few basic, the smaller the wheel obviously will have more power to go up the hill and stuff, the bigger the wheel will have better performance. Right?

It depends on what you're defining as "performance". The smaller wheel will have less rotantional mass, which will allow the car to move quicker (assuming the traction is there). But in terms of cornering, the small wheel with larger sidewalls may not have as much grip so having a larger wheel with shorter, stiffer sidewalls will be better.

The best option will be the wheel that gives the best balance between weight and cornering stability. That certainly isn't the 18" option - I would say if you're performance-minded a 16" wheel with a good performance tire would be the best compromise.

[ricko]

I had NO idea the 18's would be THAT heavy. I just know the 16" alloy on my Acura was significantly lighter than 15" winter wheel, and they were only Honda alloys. The extra weight must come from the added width of the tire???? In Canada the 15 inch wheels come with 185/60 tires. How does the rolling diameter compare to that of the 215/35/18's.

[Idjiit]

Winter tires are generally heavier than all-seasons, and depending on the design of the wheels the 15" could actually be heavier than your 16". That's why my comparison uses the same wheel design in different sizes and the same tire in different sizes.

[Goose]

Actually, my first reaction to larger wheels/tires was the effect of the larger contact patch on rolling resistance. Most high-mileage cars are concerned with low rolling resistance, and therefore use skinny, harder compound tires to maximize this benefit. By going to an 18" wheel (with probably at least a 7" width) and similar tires, there's a lot more rubber in touch with the road; contrast this with a 6" or 6.5" wide steel wheel and 185/60 tires, and I assume the performace combo isn't gonna want to roll as easily by comparison.

I assume there's a rolling resistance calculator floating around the 'net somewhere. Just gotta find it.

[Idjiit]

Yes, rolling resistance comes into play as well. Not really sure if there's an easy way to figure that out - it's related to weight of the vehicle and designed of the tread as well.

[Goose]

A quick search found this site:

http://www.geocities.com/CapeCanaveral/Lab/8679/evcalc.html

Obviously, there is no provision for determining the rolling resistance of the wheel/tire, but it's pretty cool anyway. I'm going to keep looking, as I'm sure there's got to be a calculator out there...

EDIT: Rather than start another thread, I'll just tack this on: My dealer screwed up and ordered an AUTOMATIC liftback. Time to reset the waiting clock. It's probably going to be another couple of weeks for me...

[Idjiit]

Oh man, that sucks. Sorry to hear it. :(

[Ziv]

Damn, that is shitty. I felt sorry for you too bud.

Thanks Idjiit for answering our questions.

Tho, why is people so obsess with bigger wheels when it use more gas?

[ricko]

No Idjiit ...... I was comparing the 15" stock steel wheels to the 16" alloys, no tires. I did the same with my 18" Dymags (this was for my motorcycle) and the stock Honda wheels, but that is unfair as the Dymags really are magnesium. I would be VERY hesitant to use magnesium wheels on the street, even if cost was not a factor.
Rolling resistance is very difficult to determine. There are so many factors to be considered. For instance on bicycles a larger wheel has less resistance than a smaller wheel (700C vs 650C), but the smaller wheel accelerates better. If you want to be dazzled by techno-babble read some of the articles in the Triathlon mags on rolling resistance vs aerodynamic drag.

[ricko]

Perhaps the obsession is due to mis-information. I know I never thought that an 18" alloy wheel-tire combo would be heavier than the stock steelies + tires. You live ....... you learn.
Or maybe the 18" dudes are just going for that ................... look.

[Idjiit]

No Idjiit ...... I was comparing the 15" stock steel wheels to the 16" alloys, no tires.

K, I thought you were saying the 15" was also alloy. In that case, it's even less surprising. As I showed, the stock 15" steel Yaris wheel is 17lbs, the 18" alloy is 19lbs, only two lbs heavier - that's a pretty lightweight 18". The 16" version of that same wheel is 14.5lbs. But if you're going for an 18" that just looks cool, you will most likely end up with one that's much heavier - even tirerack considers any 18" wheel under 22lbs as "lightweight". And again, the point is that even if the wheels were identical in weight, a good portion of that weight is now 1 1/2 inches further away from the center, which means it will be harder to turn it.

[ricko]

Man ... that IS the pits. If there was more than one dealer in the area, I'd take my money and walk. Manual/automatic that is a pretty basic thing to mess up on. Next will it a be sedan-liftback mistake????? Sorry Goose, didn't mean to cause you more worry!

[Idjiit]

Or maybe the 18" dudes are just going for that ................... look.

Yes. Especially on a car the size of the Yaris. 18" wheels can provide a performance on some cars - but on a 2,200lb car with 106hp? Not so much.

[Goose]

The mileage issue isn't really a big deal to me - I just wouldn't want to trash the great mileage by making what is (for me) essentially a cosmetic change. Obviously 18's are much larger than the Toyota engineers originally spec'd for the car, so I'm sure it would change something in this regard.

Come to think of it, would there really be much of a difference in overall circumfrence between a low-profile (30-35 series) 18" wheel/tire combo and a 60-series 15" wheel/tire combo?

[Goose]

Obviously, Tire Rack is trying to sell folks larger, upgraded tires. Despite this fact, their information looks sound. Based on the linked article, going with a bigger wheel/tire isn't going to make a big dent in mileage. Food for thought.

Enjoy...

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=29

[Idjiit]

Come to think of it, would there really be much of a difference in overall circumfrence between a low-profile (30-35 series) 18" wheel/tire combo and a 60-series 15" wheel/tire combo?

If you get the right tires there shouldn't be any appreciable difference in circumference.

[Idjiit]

Obviously, Tire Rack is trying to sell folks larger, upgraded tires. Despite this fact, their information looks sound. Based on the linked article, going with a bigger wheel/tire isn't going to make a big dent in mileage. Food for thought.

Enjoy...

http://www.tirerack.com/tires/tiretech/techpage.jsp?techid=29

This article is only really making a point about rolling resistence, not wheel size. And clearly the factors weight differently according to whether you're driving city or highway.

[ricko]

But essentially you were right Idjiit ........ reducing weight, especially unsprung weight is certainly a factor. If the rolling circumference, and the frictional co-efficient are the same the lightest combination wins the gas mileage competition. The advantage might vary city/highway, but it will remain an advantage.

[Goose]

Thanks for all the info, guys. I'm still not sure if I would get the TRD wheels -- they're pretty expensive and I don't even have the car yet!

Also, thanks for the support with the dealer's screw up. Apart from having to wait a bit longer, there's been no harm done. I like my local dealer, and he's been a straight-shooter with me on past deals. Since my dealer has already gotten another car with the correct specs (he assures me) set up for shipment, I wasn't too disappointed.

I'm almost happy because I'm still getting a factory-fresh (no dealer trades for me) Yaris. I thought that this foul-up meant that I'd either have to take a color I didn't want or have to wait forever. Chalk up another interesting car-buying experience...

[AutoTech1]

congrats goose!

as far as the big wheels effect on fuel economy, would i be right in thinking that they would require more power to get going? if so, would it be a noticeable difference in fuel consumption (and acceleration time?)

Think of it like this. Remember that BMX bike you use to ride? Well remember how easy it was to get going fast? It required less energy to turn the wheel as well, because the wheel was smalll. Then you went to that mountain bike. The wheels were larger. It required a bit more energy to rotate that wheel... Getting wheels that are larger can throw off you readings for mph slightly as well as fuel economy... It shouldn't be too noticeable though.

[AutoTech1]

Damn, that is shitty. I felt sorry for you too bud.

Thanks Idjiit for answering our questions.

Tho, why is people so obsess with bigger wheels when it use more gas?

They don't use too much gas... It's not like you lose 10 miles to the gallon on a 18 inch compared to a 16. :-P Most people do it for looks. Not for performance. I think a car should have at most 17 inch wheels... Over that, you get a harsh ride, you can destroy your wheels on the streets and many other things...

[AutoTech1]

The 18's will require LESS power to get going, due to less weight.

They are more likely to wieght more... Even if they are light wieght wieght wheel... Just because they are bigger...

[AutoTech1]

Remember 18'' alloy wheels have less rubber, and the wheels themselves are significantly lighter than the steelies.

But the "steelies are smaller." The 18's are larger... The only gain I can see for getting 18 is the less rubber. You corner better... But you increase the chance or rolling the tire off the wheel under hard cornering...

[AutoTech1]

Here's some sample numbers -

Yaris 15" Steel Wheel/Tire Combo - 37lbs (17lb wheel, 20lb tire)
Toyo Proxes 4 Ultra-High Performance Tires with light Rota SubZero Wheels:
15x6.5 w/ 195/50R15 - 29lbs (12lb wheel, 17lb tire)
18x7.5 w/ 215/35R18 - 39lbs (19lb wheel, 20lb tire)

So, even with a lightweight 18" setup, you're both heavier than stock and a lot of that weight has been moved further away from the axel, so you'll definitely see a drop in performance.

Great point. I didn't see you wrote that, else, I wouldn't have posted what I posted before this. But you still explained better than me.:clap: