I was just watching some show on the Speed channel. The guys on the show were modding a Honda. I will skip the small details, but through trial and error they figured out that bigger/liter brakes and larger/lighter wheels/rubber actually ended up costing them five horse power at the wheels on the dyno. They did end up with slightly better times on the track due to better dynamics, braking, etc.

I just found it very interesting.

Discuss amongst yourselves.

 

I think it was an Acura.

 

Think of those 4 big wheels & tires as flywheels. You have to turn then which takes power. The bigger & heavier the more power loss. Your engine still makes the same power, but it's lost in the wheel/tires. One other thing, your braking will be affected to. Got to stop those big flywheels = longer stopping distances. All in all big wheels suck....IMO.

Chuck

 

the larger diameter has a longer lever arm, and the torque out the drive shafts (a constant) results in lower forces at the contact patch. So, if you have 100 ft-lbs of torque out the shaft, and a 1 foot radius, you "push" on the road with 100 lbs of force. If that's a two foot radius, you get 50 lbs of force pushing on the road, and half the acceleration (F=Ma).

Matt

ps, this is a well known effect, and why autocrossers don't run 18" wheels. Going to a shorter tire and wheel is "poor mans gear change".

 

Makes you think why one doesn't see 14, or even 13 inch rims for the mini.

 

Don't know for sure, but I'd bet they wouldn't clear the brakes.

Chuck

 

On the road. If a little is good, a lot may not be better.

Matt

 

all you 18" haters.....