Wednesday, September 9, 2015

Rookie Stripe: The Steep Price of Track Banking


It’s one of the most important elements of a NASCAR race, but track banking involves no financial transactions of any kind. So put the checkbook and banal jokes away, rookies.

Banking isn’t terribly complicated, but when I was learning about NASCAR it took me awhile to understand exactly how it changes the whole dynamic of a race. So let’s start with the basics.

Credit: Logan Stewart for Skirts and Scuffs
Banking 101
Each track on the NASCAR circuit is different, from length to width to surface material. Banking is basically how sloped the track’s surface is at any given point from the outside edge. It's measured in degrees, ranging from just a few degrees to as steep as 33 degrees. To put it in perspective, 90-degree banking would be a right angle, aligning the track perpendicular to the flat ground. That's clearly an impossible angle for driving, much less racing, but it can give you somewhat of a visual.

Sharp Curves Ahead
Pace and momentum in a race can mean payday, and track banking plays a large role in both. The steeper the degree of banking in a turn, the faster a car will go. Think of it as a tool drivers use to quickly gain speed and position. As a car barrels down the straightaway, something has to assist the driver around the corners of an oval, and that’s where banking comes in.

A race car going straight down the backstretch at 180 mph will keep straight going
down the backstretch at 180 mph — unless a net force makes it turn. 1

There’s a fascinating science and math component related to the force and velocity needed to turn at a track, which you can read more about here.

The looped ends of each oval, commonly referred to as “turns” or "corners," often have different banking than the straightaways of the track. In fact, sometimes the frontstretch, backstretch and different turns have varying levels of banking. These variables -- plus driver adeptness and agility handling the turns -- contribute to the often electrifying outcome of each race.
Credit: Logan Stewart for Skirts and Scuffs

Controlled Chaos
It's not surprising that many of NASCAR’s most colossal accidents happen in the corners. Banked turns stack cars side-by-side in close proximity on a sloped surface at high speeds and under massive force. The steeper the incline, the quicker and more risky the turn will be.

Some tracks feature progressive banking which gradually increase in degrees the closer the surface gets to the outer retaining wall. Progressive banking helps cars in the outer lanes sustain higher speeds in the corners, keeping the race more competitive and fair for drivers in those lanes with more distance to cover.

Talladega Superspeedway, at 33 degrees, currently holds the record for the steepest banked track in NASCAR. But short tracks like Bristol and Martinsville are perennial fan favorites because the combination of sharp banking and lightning fast speed can mean wild rides and constant danger.

It’s also worth noting that road courses do not have track banking.

Dangerous Dexterity
While the changing degrees of track banking add risk to a race, drivers and their crews are highly proficient in track strategy. Like other elements of a race, drivers have their personal preferences when it comes to banking, but are experienced at handling all levels. Adjustments such as changing the camber -- how the front wheels are positioned in relation to the car -- can provide more grip around corners. Camber functions like a wedge on the banking, giving drivers more contact with the track surface. Turns are also a golden ticket for passing. For example, if a driver takes a banked curve too quickly and loses control, another driver can seize the opportunity to get by and gain track position.

Credit: Logan Stewart for Skirts and Scuffs
Personally, I didn’t fully understand banking until I stood on the track in Turn One at Bristol, where the banking is 24 to 28 degrees. Imagine standing on a surface so steeply sloped you feel like you'll fall if you’re not careful with your footsteps. You can actually feel the gravitational pull downward.
 
For more information, this graphic at ESPN.com offers a helpful visual to better understand banking surfaces. This article on NASCAR.com has a list of current tracks and their degrees of banking.
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“Why Turning Fast is Hard.” BuildingSpeed.org. 13 April 2013. Web. Accessed 5 September 2015.

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