wheel size pros and cons??

[torreto]

Was just wondering what the pros and cons of having 15's on are as opposed to 16 or 17's? heard about better acceleration on smaller alloys etc but are there any other impacts?

 

[Chris205]

Better acceleration, braking and handling. Also cheaper tyres

 

[torreto]

what about lowering the car? I guess there are like restrictions with bigger alloys...

 

[Chris205]

Would need less modification's needed to the bodywork/arches if you fit smaller wheels yeah. Fitting things like 17's then coilovers and putting it down very low will require modifications to the front arches, never had a clio on 17's for the rear end so you'd need to check that out.

 

[ben lee]

if smaller wheels are better why do rally cars touring cars ect all use 17"+ alloys???

can fit 17s on a clio and lower it without having to modify anything without any problems if you run the correct offset wheels.

15 and 17 tyres prices are nearly the same in common sizes.

 

[DanFreemanPhoto]

But 17s on a Clio look s**t.

15s for go, 16s for show. (and no 17s at all!)

 

[Sam@NP]

if smaller wheels are better why do rally cars touring cars ect all use 17"+ alloys???

can fit 17s on a clio and lower it without having to modify anything without any problems if you run the correct offset wheels.

15 and 17 tyres prices are nearly the same in common sizes.

BTCC cars run 17 inch due to regulations.

 

[105e]

I do not see why 15 inch rims give better acceleration, as the wheel dia gets bigger , the tyres normally have a lower aspect ratio, so overall dia is very similiar .

 

[deer_dodger]

Generally smaller wheels weigh less, therefore less rotational mass and less torque required to accelerate them to any given speed. The mass is also closer to the central axis (hub). Cast your mind back to playing on roundabouts, when you lent out it slowed, when you moved into the centre its rotation accelerated and all with no external forces (mum / dad pushing) acting upon you.

i.e 17" have most of their mass further out than 15" wheels. 2" give or take depending on the rim construction.

Or something similar if I remember my A level Physics and Rotational Dynamics right :-|

 

[Fletcher]

I would never go back to 16" wheels on my 172. 15" wheels are so much cheaper!

 

[105e]

Generally smaller wheels weigh less, therefore less rotational mass and less torque required to accelerate them to any given speed. The mass is also closer to the central axis (hub). Cast your mind back to playing on roundabouts, when you lent out it slowed, when you moved into the centre its rotation accelerated and all with no external forces (mum / dad pushing) acting upon you.

i.e 17" have most of their mass further out than 15" wheels. 2" give or take depending on the rim construction.

Or something similar if I remember my A level Physics and Rotational Dynamics right :-|

I would imagine that trying to pull a ton of car along takes more effort from the engine than trying to rotate a pair of wheels

 

[DanFreemanPhoto]

Isn't every kilo lighter a wheel is equivalent to something like 4kgs when it's rotating?
Something like that anyway.

 

[deer_dodger]

Isn't every kilo lighter a wheel is equivalent to something like 4kgs when it's rotating?
Something like that anyway.

It is, 1kg lost of unsprung weight is approximately equal to 4kg lost of sprung weight. Sprung weight being anything held up by the suspension, unsprung the remaining, some suspension components, brakes, wheels and tyres.

Reducing unsprung weight greatly increases driving dynamics, increasing it makes the car feel heavy and unresponsive.

 

[deer_dodger]

I would imagine that trying to pull a ton of car along takes more effort from the engine than trying to rotate a pair of wheels

Absolutely, but the engine will have to work harder to accelerate the car if you increase the rotational mass of the wheels and the brakes will have to work harder to stop the car if the rotational mass is increased.

http://www.ux1.eiu.edu/~cfadd/1150/09Rot/RotDyn.html

 

[deer_dodger]

Tyres can vary in weight considerably too.

I remember ready an article on an MX5 website I think which weighed a number of 15" tyres. They varied by over 2kg I seem to recall from the heaviest to the lightest.

 

[105e]

Absolutely, but the engine will have to work harder to accelerate the car if you increase the rotational mass of the wheels and the brakes will have to work harder to stop the car if the rotational mass is increased.

http://www.ux1.eiu.edu/~cfadd/1150/09Rot/RotDyn.html

Yeah and going from a 5 inch dia rim to a 30 inch for example would make a difference, but going from a 15 inch to a 16 or 17 is not going to be noticed, and as you say in your other post , what about the tyres,i would guess a 195/50 x 15 could weigh more than a 195/45 x 16 because of the bigger sidewall, and this is weight at the on the edge where its more noticeable. So no i dont see a 15 inch rim helping a car to accelerate quicker than a 16 or 17 inch rim.

 

[JonC219]

if smaller wheels are better why do rally cars touring cars ect all use 17"+ alloys???

You're forgetting that rally cars have brakes the size of the moon in some cases... Bigger wheels to accommodate!

 

[MartinR]

Flol another one of these threads...

 

[105e]

Another one of those irrelevant comments

 

[MartinR]

Another one of those irrelevant comments

No problem

 

[deer_dodger]

So no i dont see a 15 inch rim helping a car to accelerate quicker than a 16 or 17 inch rim.

You're absolutely right, Isaac Newton was wrong and it's taken from 1687 and a genius like you to disprove it, we'll done!

 

[Chapster5]

Just DO NOT get 18's as I found out.

Ahh them where the days.

 

[105e]

You're absolutely right, Isaac Newton was wrong and it's taken from 1687 and a genius like you to disprove it, we'll done!

Mr newtons theories do not take into account gearing and 150 bhp plus

 

[Dan519]

Mr newtons theories do not take into account gearing and 150 bhp plus

wheel size changes the gearing though. You get better acceleration and worse economy with 15s compared to larger wheels

 

[105e]

No you wouldnt, because as wheels get bigger, tyre aspect ratios get lower, a 195/50x 15 is as near dammit the same as a 195/45x16, thats my point the overall dia dosnt change, obviously 20 inch rims may be taller and do as you say but thats not in this discussion.

 

[magos84]

I agree 100% with 105e...try to weight a 195/50R15 or a 195/45R16...considering same tyre maker, the 45/16 is more or less 0.8 lighter than the 50/15....so what you save for the rims you will lost for the tyre weight.
I agree that the handling is completely different, 16" are funnier then 17"....but don't think to accelerate more or brake better...the overal diameter is exactly the same....