liquid_helix136

This was a thought that popped into my head JUST now after reading that one dudes thread that wants to get bigger rear brakes, and he asked whats the ideal wheel size for tracking

anyways..
heres the concept

Bigger the wheel, bigger the diameter, the farther the wheel travels in one rotation correct?

So if we were to have a 16" wheel that weighs, say 15 lbs...

If we could get an 18" wheel to rotate just as easily as the 16" wheel (take just as much amount of force)

would the 18" wheels make the car "faster"?

My whole thought process is if the displacement of the 16" wheels say 5 feet per rotation and the 18" wheels displacement is 6 feet per rotation, with 18" wheels would the car move a longer distance with the same amount of force?

and yes i am very aware of how ridiculous this may sound

ahrmike

Not quite.

The reasoning is on the right track, but there are some engineering problems. First off, you have to know the sidewall heights.

Im assuming youre talking about not rim size, but tire diameter. A smaller tire diameter will actually allow faster acceleration 'quicker' since it acts as a gear reduction - The torque to the HUB will be the same, but torque = r*F, and with a smaller diamter wheel, the radius will be smaller which means more force can be put to the ground, and according to F = m*a, since your mass remains the same, you will accelerate faster.

NOW, if youre talking top speed - our cars are not GEAR limited. If our cars had more power, then it could possibly overcome the air drag and require a higher gear ratio - which would make a bigger tire make you go 'faster'.

Drag limit = due to the amount of power you make. Since we are drag limited, no matter how big/small the wheels are (up to a certain point, we also have to take into account the gear ratios, what power you're making at a given RPM, etc- but assuming youre making peak power when you finally become drag limited) your top speed will not change.

If you were to have a gear limited car, where youre making so much power that you are able to hit redline while flooring it, then yes, bigger tires/rear end gears will allow you to go 'faster'.

BTW, apparently our cars have 'lift' not 'downforce' at the back end so I suggest not going too fast

liquid_helix136

ah i see, yes physics wins again...

that makes sense..

so much for my thought of ingenuity

JohnnyP912

^^

Small wheel diameter = Better Acceleration
Big wheel diameter = Top Speed

16'' wheel can be compared to someone with 4.77 gears
18" wheel can be compared to someone with 4.10 gears

The gear sizes are not actually correlated to the wheel diameter, but an example

Tracking = Smaller wheel diameter
even better mod is the driver

Euroflavor

why u can buy tires with different sidewall.

K1LL3R 1NS1D3

wow really

ruexp67

Uh... NO.

The wheel size is not really the key here. As the second poster mentioned, the size of the TIRE is critical. When you have 16" wheels, or 17" wheels or 18" wheels on an S2000, you get tires that are the same diameter (with progressively smaller sidewalls.)

Euroflavor

hahah well hes asking about bigger wheels. so i can say something dumb also.

Suzuka_Joe

Can a helicopter take off from a Lazy Susan? think about that

jeffbrig

Depends on how fast the lazy susan is spinning.

And a plane can also take off from a conveyor belt - I saw it on Mythbusters once.