Wheels that create downforce!
thats a lot of assumptions.
heres a good example:
at 185 mph and with 18inch rims with 255x45 tires, your tire diameter is 27inches, thus your circumference is about 7 feet. at 185mph, that is 2371rpm the wheel is spinning at.
your common household 20" box fan spins at about 1000rpm, and is barely enough air to keep me cool in the texas heat. double the speed and it might keep me cool, but its still not going to increase the downforce of a car going 185mph. even if you have what is equivalent to 8, 18in box fans (two per wheel).
think about it... its like using a box fan in a catagory 5 hurricane.
heres a good example:
at 185 mph and with 18inch rims with 255x45 tires, your tire diameter is 27inches, thus your circumference is about 7 feet. at 185mph, that is 2371rpm the wheel is spinning at.
your common household 20" box fan spins at about 1000rpm, and is barely enough air to keep me cool in the texas heat. double the speed and it might keep me cool, but its still not going to increase the downforce of a car going 185mph. even if you have what is equivalent to 8, 18in box fans (two per wheel).
think about it... its like using a box fan in a catagory 5 hurricane.
Here is a quote from the R&T article:
"Again, Steve is right. Our data show that at 1 mile, the SLR is traveling at 181.2 mph. Over the next mile — in a performance much like the Lambo's — the car gains only 18.6 mph. What's more, Steve complains that "at around 185 mph, the SLR starts to wander a wee bit. It gets your attention. It feels like it's packing air under its nose."
He may be on to something. The Mercedes folks had fitted this SLR with 18-in. winter wheels thought to create less drag than the stock 19-in. ones, which have special blade-shape spokes that work as fans to extract air from under the car for added downforce. The 18s, they presumed, would have less drag because the car wouldn't be getting sucked closer to the ground. However, this means the nose of the car on 18s is likely higher, creating that feeling Steve noticed of air getting stuffed under the nose of the car."
"Again, Steve is right. Our data show that at 1 mile, the SLR is traveling at 181.2 mph. Over the next mile — in a performance much like the Lambo's — the car gains only 18.6 mph. What's more, Steve complains that "at around 185 mph, the SLR starts to wander a wee bit. It gets your attention. It feels like it's packing air under its nose."
He may be on to something. The Mercedes folks had fitted this SLR with 18-in. winter wheels thought to create less drag than the stock 19-in. ones, which have special blade-shape spokes that work as fans to extract air from under the car for added downforce. The 18s, they presumed, would have less drag because the car wouldn't be getting sucked closer to the ground. However, this means the nose of the car on 18s is likely higher, creating that feeling Steve noticed of air getting stuffed under the nose of the car."
"Hey guys … what do you say we do the top speed run on the winter wheel setup? The engineers at McLaren don't have a clue. We need less drag and less control because we here at R&T live on the edge! While we're at it … call Ford. Tell them I have a new tagline to sell their crossover SUV."
Rednecks & Trailers!! Ha, Ha!! That was good!
"Hey y'all, lets put duct tape over the entire front of the car to create less drag just those NASCAR folks do."
Later.....
"We noticed that our Mercedes was overheating after several high speed runs. Apparently changing the airflow in the front of the car affects cooling."
"Hey y'all, lets put duct tape over the entire front of the car to create less drag just those NASCAR folks do."
Later.....
"We noticed that our Mercedes was overheating after several high speed runs. Apparently changing the airflow in the front of the car affects cooling."
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drewblueeye
Evo Tires / Wheels / Brakes / Suspension
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Jul 28, 2007 07:47 PM




