Big Wheels, what's the point?

[Peter103]

Are there any advantages in having 19inch wheels over 18's, or is it purely aesthetic? Seems to me they give a harder ride, tend to transmit more road noise, and are more expensive to replace, I've got 19's on my coupe but still don't get it, who knows?

 

[Bobby Dazzler]

In real life conditions, with average drivers, it's only aesthetics.

Even in racing, bigger doesn't always mean better when it comes to wheels and tyres.

 

[Giantvanman]

It's a bling ting, blud, innit.

All the effort and research by done owners for selecting the best tyres that suit the car, the perfect wax for the colour, the best fuel for performance etc etc yet when it comes to wheels, the only criteria is how big and if will they fit. It makes no sense to me either.

 

[flango]

All race designers will tell you when it comes to wheels there is no performance or handling benefits to be gained by going past 15" diameter

So why go past 15"? Because as cars go faster you have to make them stop quicker so you have to increase the size of the discs and calipers which then means in turn you have to increase wheel diameter to accommodate them.

So most mainstream car designers these days spec the brake configuration and then size the wheels to fit

Sent from my iPhone using MBClub UK

 

[zoros]

Mostly aesthetic methinks! On some cars and ironically on the SL55 I have, the 19" fit the wheel wells better than the 18". But you are right, the smaller the tyre shoulder (which happens when you go bigger), the less rubber and thus the harsher the ride.
Horses for courses perhaps?
As a slight aside - have you noticed that if you go one size 'wider' with your tyre tread and start to drift away from the main stream tyre width for that particular car - the price plummets? IE: Normal rear on mine is 285. Buy a 295 and the price drops by between 40 and 60%? (For more rubber).

 

[rifiki]

Go faster? There is a 70 MPH max speed limit in this country.

 

[Bellow]

Mostly aesthetic methinks!

That is it.
As cars have bloated in size, to retain the balance of wheel to bodywork proportions, the trend has been toward ever larger wheels. This trend has now reached caricature proportions by some. None of them are capable of exploiting the supposed extra grip and handling imbued by their efforts to outdo the paid-a-salary professional designer who styled the car, all slowing to a granny pace at the first sign of the road deviating from arrow straight.
A fashion that has had its day. I cannot wait for designers to have the balls to start enclosing wheels and we can be shot of this nonsense and engineer cars for purpose not some notion of style as percieved by those with wardrobes that the high point of sartorial elegance within will be a baseball cap.

 

[GLK]

Go faster? There is a 70 MPH max speed limit in this country.

 

[mornin clatter]

Bling

Soooo happy with my gangsta 16" elegance alloys(with light scuffs) ).

 

[kam05]

It's a bling ting, blud, innit.

This, plus dem wheels look cool innit bruv

 

[mersum1es]

sure

http://www.stancenation.com/wp-content/uploads/2012/12/1314.jpg (not merc)

https://www.youtube.com/watch?v=G_vxzD6Cd6w

 

[E270 Owner]

https://www.youtube.com/watch?v=ija7oDgCNLI

Lol

@ 1:20

And @ 5:20 wtf lol

 

[automaniaman]

The point is, there doesn't need to be one.

 

[Ndubber1970]

I try to look at the way the wheel looks against the car itself....a dished alloy always looks smaller for example... I want my car to drive well and slapping massive rims on rarely improves that, especially if the tyres, ride height, and suspension setup is wrong. I find that sometimes a little wider and a little lower has a better impact.

 

[E55BOF]

https://www.youtube.com/watch?v=ija7oDgCNLI

Lol

@ 1:20

And @ 5:20 wtf lol

Dem is k***s, innit...

I suppose it's a sort of twisted Bauhaus approach - "form follows function" - for them, the function is to look cool; nothing else matters much.

 

[markjay]

It's a bit like a big wing spoiler.

It is easy to demonstrate how spoilers help improve race cars' behaviour - but the reality is that people fit them for the aesthetic effect, rather than for any real-life benefit when driving at Motorway legal speed...

And no, a 'GTI Turbo' decal won't make your car go any faster either

 

[markjay]

Or fake air intake and vents....:

 

[ChrisA]

Are there any advantages in having 19inch wheels over 18's, or is it purely aesthetic? Seems to me they give a harder ride, tend to transmit more road noise, and are more expensive to replace, I've got 19's on my coupe but still don't get it, who knows?

It's similar to the question or "Myth" that bigger tyres/wheels means higher velocity due to further rotational distance covered by the larger wheel/tyre

Mathematically, the question is easily answered, with the equation: length=radius*angle, where we take the derivative to get velocity=radius*angular velocity.

If we held angular velocity constant, and increased the radius, we obviously get a larger straight velocity. But in a scenario with a car where one is deciding on which size tyre to buy, this isn't enough information.

You could, maybe, model this such that you have a single tyre that you just give enough rolling energy such that it rolls exactly 60 miles in 1 hour.

That is, if you have a moment of inertia (cylinder, rotating about the z-axis where the circle of cylinder is drawn in the xy plane) 1/2mr^2, then you need an energy (from the equation Rot.KE=1/2Iw^2 and v=rw) 1/4mv^2 where v = 60mph. m is the mass of our smaller tyre.

Then you "enlarge" the tyre, m becomes the mass of the bigger tyre, and v is now the new rotational velocity.

Equating the two energies, and solving for the larger velocity,
one finds, (ms/ml)vs^2=vl^2
ms = mass of the small tyre,
ml = mass of the large tyre
vs = velocity of small tyre
vl = velocity of the large tyre.

What you find is that the velocity of the larger tyre is smaller because of the accumulated mass.

This is a friction free scenario.

This, of course, doesn't answer the question of "further" but, what we see is that to get it to cover the same distance in the same time it would require more energy then we are given, this would cost MORE fuel.

If we want to keep axel speed the same (rotational velocity), you will not have enough fuel to even cover the 60 miles unless you make the tyre and wheel much lighter, as well as it already being larger.


Note also that larger tyres require more torque to accelerate to the same velocity. Larger tyres on a vehicle usually crushes fuel mileage since higher accelerations are not as efficient on cars. This is maybe why the Prius doesn't have larger tyres, it just doesn't have the output.


Only a disadvantage if fuel economy is your worry but if it isn't then they sure look a lot more fun

:bannana:

 

[HB]

It's similar to the question or "Myth" that bigger tyres/wheels means higher velocity due to further rotational distance covered by the larger wheel/tyre

Mathematically, the question is easily answered, with the equation: length=radius*angle, where we take the derivative to get velocity=radius*angular velocity.

If we held angular velocity constant, and increased the radius, we obviously get a larger straight velocity. But in a scenario with a car where one is deciding on which size tyre to buy, this isn't enough information.

You could, maybe, model this such that you have a single tyre that you just give enough rolling energy such that it rolls exactly 60 miles in 1 hour.

That is, if you have a moment of inertia (cylinder, rotating about the z-axis where the circle of cylinder is drawn in the xy plane) 1/2mr^2, then you need an energy (from the equation Rot.KE=1/2Iw^2 and v=rw) 1/4mv^2 where v = 60mph. m is the mass of our smaller tyre.

Then you "enlarge" the tyre, m becomes the mass of the bigger tyre, and v is now the new rotational velocity.

Equating the two energies, and solving for the larger velocity,
one finds, (ms/ml)vs^2=vl^2
ms = mass of the small tyre,
ml = mass of the large tyre
vs = velocity of small tyre
vl = velocity of the large tyre.

What you find is that the velocity of the larger tyre is smaller because of the accumulated mass.

This is a friction free scenario.

This, of course, doesn't answer the question of "further" but, what we see is that to get it to cover the same distance in the same time it would require more energy then we are given, this would cost MORE fuel.

If we want to keep axel speed the same (rotational velocity), you will not have enough fuel to even cover the 60 miles unless you make the tyre and wheel much lighter, as well as it already being larger.


Note also that larger tyres require more torque to accelerate to the same velocity. Larger tyres on a vehicle usually crushes fuel mileage since higher accelerations are not as efficient on cars. This is maybe why the Prius doesn't have larger tyres, it just doesn't have the output.


Only a disadvantage if fuel economy is your worry but if it isn't then they sure look a lot more fun

:bannana:

Did you swallow a maths book tonight. Away and give us peace ! And a set of 20s. Lol.

 

[danch]

It's similar to the question or "Myth" that bigger tyres/wheels means higher velocity due to further rotational distance covered by the larger wheel/tyre

Mathematically, the question is easily answered, with the equation: length=radius*angle, where we take the derivative to get velocity=radius*angular velocity.

If we held angular velocity constant, and increased the radius, we obviously get a larger straight velocity. But in a scenario with a car where one is deciding on which size tyre to buy, this isn't enough information.

You could, maybe, model this such that you have a single tyre that you just give enough rolling energy such that it rolls exactly 60 miles in 1 hour.

That is, if you have a moment of inertia (cylinder, rotating about the z-axis where the circle of cylinder is drawn in the xy plane) 1/2mr^2, then you need an energy (from the equation Rot.KE=1/2Iw^2 and v=rw) 1/4mv^2 where v = 60mph. m is the mass of our smaller tyre.

Then you "enlarge" the tyre, m becomes the mass of the bigger tyre, and v is now the new rotational velocity.

Equating the two energies, and solving for the larger velocity,
one finds, (ms/ml)vs^2=vl^2
ms = mass of the small tyre,
ml = mass of the large tyre
vs = velocity of small tyre
vl = velocity of the large tyre.

What you find is that the velocity of the larger tyre is smaller because of the accumulated mass.

This is a friction free scenario.

This, of course, doesn't answer the question of "further" but, what we see is that to get it to cover the same distance in the same time it would require more energy then we are given, this would cost MORE fuel.

If we want to keep axel speed the same (rotational velocity), you will not have enough fuel to even cover the 60 miles unless you make the tyre and wheel much lighter, as well as it already being larger.


Note also that larger tyres require more torque to accelerate to the same velocity. Larger tyres on a vehicle usually crushes fuel mileage since higher accelerations are not as efficient on cars. This is maybe why the Prius doesn't have larger tyres, it just doesn't have the output.


Only a disadvantage if fuel economy is your worry but if it isn't then they sure look a lot more fun

:bannana:

A that sounds like a load of old tosh as when you upsize you change the tyres to give you the same rolling radius therefore keeping your speedo et al the same as before plus the mass is generally the same or even less in some instances as the pricier alloys are lighter therefore less rotational mass.

I have gone from 18's on most of my cars to 19's due to aesthetics as they fill the arches, have suffered no ill effects on handling and/or mpg.

Basically it's personal choice on alloys...