Wheels & Tires

[Elio Amazed]

If the Elio is to achieve its fuel economy goals, tires will have to be < 85mm average section width, give-or-take...

My guesses:

15" diameters all around. Maybe 16" or larger for rear, probably not.
fronts: 85mm or 90mm section widths; recommended pressure range from 60-77psi depending on winter/summer.
rear: 90mm-105mm section width; recommended pressure range from 50-68 psi depending on winter/summer...

Also, I think the designers may have to compromise on aesthetics and fair all three tires all the way down to 1.5" off the ground. Otherwise that rear tire will add measurable form and friction drag, and car will struggle to achieve 84mpg at realistic freeway speeds, which is what drivers expect from claims, not to have to travel at 65mph top speed to get the 84mpg...

Well good luck getting anything NEAR 49/84 mpg with 140mm section width tires on this car.

Physics is a bitch--you can't wish your way around it.

So you believe the Elio doesn't have a chance of getting 49/84 mpg unless...
...it's front tires have a cross-section of 3 11/32" (approx. 3 1/3") to no wider than 3 35/64" (approx. 3 1/2")...
...and it has a rear tire with a cross-section 3 35/64" (approx. 3 1/2") to no wider than 4 9/64" (approx. 4 1/8").
...and has all three of those faired down to 1 1/2" from the ground.
...and you're talking cross section... sidewall to sidewall and not the actual width of the part that contacts the road.

I got my tape measure out and checked what those widths actually look like.
I urge all of us here to take a moment and do the same.
Interesting.

3 1/3" is almost exactly the width of the cross-section of the front tire on my little 250 Yamaha Virago.
The rear tire on the Virago is 1 1/2" to approx. 7/8" wider than your recommendation for the rear tire of the Elio.

I realize that the Virago tires (as do almost all MC tires) present a more rounded surface to the road and are made with softer compounds.
However I will also have to say that the average bike tire has a life of around 10,000 miles.
More for the front, less for the rear.
There are those riders that have gone "dark side" (car tire) and gotten 20,000+ miles, but we're usually talking 6 1/2" cross-sections or better.
There's almost always some kind of difference in handling reported.
Most riders quickly learn to compensate for it until it becomes second nature.
I'll also say that the Virago front tire tends to follow every crack and groove and they "squirrel out" on every tar snake out there.
Much more so than the wider 650 v-star's front.

Interesting. That's all I'm saying.

 

[outsydthebox]

I hope they develop 16 inch tyres then I could also use them on my Liege!

I think 15" tires with an aspect ratio of 75 or even 80 will fit EM's needs, and provide a wheel/tire combination that (compared to a larger wheel/ shorter sidewall tire combo) has less rotating mass & longer tire life & a smoother ride.

 

[outsydthebox]

Physics is a bitch--you can't wish your way around it.

In the last one hundred years :
"heavier that air" flight was deemed "physically impossible".
Sending "voice over wires" was deemed "physically impossible".
The human body withstanding the forces of traveling "over 60 mph" was deemed "physically impossible".
For a woman to run 100 yards without causing serious physical harm, was deemed "physically impossible".
To run a 4 minute mile...to break the sound barrier......should I continue?

These, and many more, were proven wrong by people who would not be confined by "the BOX of current understanding." The laws of Physics haven't changed. Our understanding has changed...and will continue to change.
If you "choose" to be boxed, chained & whipped, physics will be your "biatch." I refuse to "allow" YOU to make her mine!
Good day, sir

 

[wheaters]

Yes

I think 15" tires with an aspect ratio of 75 or even 80 will fit EM's needs, and provide a wheel/tire combination that (compared to a larger wheel/ shorter sidewall tire combo) has less rotating mass & longer tire life & a smoother ride.

Yes, I'm sure you're right. 16" is an uncommon size even for motorcycles. Hence the expense and present lack of choice.

Just read the above re 3.5" tread width on a car. All I can say is....I'd rather not. The 5.25" ones on my present car are narrow enough, even though it weighs 200lbs less and goes 20 mph slower than an Elio.

 

[Jambe]

I just hope that All Weather tires (M+S) will be standard or an option.
(Required 5 months of the year here to get over the pass.)

I'm not sure what effect aspect ratio has on mileage but the higher the better for a less harsh ride.

 

[wheaters]

One thing I noticed was how closely the front fenders hug the tyres. Might cause an issue with all the mud we get on some roads round here. I'd prefer open fenders and mudflaps.

 

[Snick]

Yes


Yes, I'm sure you're right. 16" is an uncommon size even for motorcycles. Hence the expense and present lack of choice.

Just read the above re 3.5" tread width on a car autocycle. All I can say is....I'd rather not. The 5.25" ones on my present car are narrow enough, even though it weighs 200lbs less and goes 20 mph slower than an Elio.

Reminder 1: the Elio is an autocycle with 3 wheels.
Reminder 2: Pressure = force/area; Force on tires = tire pressure * contact patch area; contact patch area = force on tires/tire pressure.
Reminder 3: Traction is force-dependent
Reminder 4: Fuel economy is strongly dependent on: a.) tire pressure, b.) rubber composition, and moderately dependent on aerodynamic drag of tires.
Reminder 5: Adverse weather and emergency maneuvering are strongly dependent on a.) tire loading/traction and b.) compound type (suspension design is set aside for purposes of this tire discussion.)
Reminder 6: Item 5b and 4b are in DIRECT opposition.

If you do the math, you will quickly see that the design choice of 3 wheels with 70/30 f/r weigh distribution and 49/84mpg DEMANDS that tire diameter, section width, and compound type fall within a very limited parameter range.

You can have your Elio economical and safe, or with "cool" wide tires and safe--pick one.

 

[Gas-Powered Awesome]

[155 or 165 section is] WAaaaaaay too wide for good fuel economy.

The smallest Prius (Prius c") uses 175/65-15 tires.

The current highest combined MPG car in the USA - the Honda CR-Z - uses 195/55-16 tires.

So I think we can safely say that statement is not true.

 

[wheaters]

Snick, you obviously missed why I said I wanted certain tyres. You are quoting basic physics without giving a meaningful answer (you missed out the significance of 9 x root P, btw).

I do understand how tyres work! I compete in on and off road trials (read all surfaces including wet grass and mud) on 145 section crossply tyres in that car, which weighs considerably less than the design weight of the Elio and has just 40 bhp. I also drive another road car that weighs five times as much and has six and a half times as much power and is fitted with very wide run flats (BMW M Sport saloon). I have also been riding motorcycles since 1967. So I do have a good understanding of tyre requirements, especially traction.

Again I ask of you, what size and type of tyres do you expect to be fitted by Elio?

Irrespective of the fact that the Elio is classed as an auto cycle it makes little sense to fit motorcycle tyres to any car. The vehicle doesn't roll into turns so during cornering the lateral forces on the tyre are far higher than on a bike.

Round profile motorcycle tyres wear out very quickly on a car, they run on the apex so another disadvantage is that the handling is skittish. You waste rubber because the middle of the tread reaches minimum thickness while almost full tread depth remains on the shoulders.

Been there, done that. The only way to improve the grip is to run low pressures, which causes tyre heating so you waste fuel and performance.

 

[goofyone]

Let's not lose sight of all the Elio Motors goals. EM is not trying to achieve the absolute best fuel economy possible but instead balance great fuel economy and a very inexpensive price. We have seen EM repeatedly make decisions which were not best for fuel economy however they were best for price. It is very possible that EM intends to use 175 size tires, or similar narrow but common sizes, and are calculating their fuel economy numbers with these standard types of tire sizes as this would be more cost effective even if it means more rolling resistance and reduced MPG.