Phoenix 101: Rules package, Goodyear selection, more for race weekend

The Monster Energy NASCAR Cup Series heads to ISM Raceway this weekend for Sunday’s TicketGuardian 500 (3:30 p.m. ET, FOX, MRN, SiriusXM NASCAR Radio).

Teams will have to adjust from their first two races with the 2019 rules package in Atlanta and Las Vegas to this weekend’s stint in Phoenix, where a different-sized tapered spacer — and no aero ducts — are on display for the first time this year.

ISM Raceway has an idiosyncratic layout where it’s nice to have a fast car — but a fast car that handles well is even better.

We explain that, plus much more, below to get you ready for racing in the desert.

RELATED: Full weekend schedule

Keeping up-to-date with the rules

In October, NASCAR officials unveiled a new rules package that would be incorporated into the Monster Energy NASCAR Cup Series, featuring a car with higher downforce and lower horsepower to develop closer racing.

The different packages are tailored to the specific tracks on the Monster Energy Series circuit. On the larger tracks, including superspeedways, cars will use a .922-inch tapered spacer to reduce horsepower and a larger spoiler to add roughly 50 percent more downforce.

Graphic for 2019 rules packages

At tracks shorter than 1.33 miles and at road courses, the Cup cars will use a 1.17-inch tapered spacer, with engines expected to generate roughly 750 horsepower.

This week’s configuration of  a 1.17-inch tapered spacer with no aero ducts will be used in 14 events this year — mostly on shorter tracks and road courses. Cars will feature traditional brake ducts, not aero ducts, at Phoenix and because tracks like this require heavier braking and additional cooling.

Tapered spacers, aero ducts and spoilers — oh my

Beyond the tapered spacers and ducts, the baseline aero elements of the 2019 rules package are a taller 8-inch by 61-inch rear spoiler, a larger front splitter with a 2-inch overhang, and a wider radiator pan that measures 37 inches wide in the front tapering to 31 inches at the rear. Those base changes will be in place at every race season with the intent of adding downforce to stabilize handling, a break from a trend of downforce reduction from 2015-18.

“For us, it’s really a focus on getting back to a true focus on the drivers and what NASCAR is all about — close side-by-side racing and trying to deliver more of that,” NASCAR Executive Vice President and Chief Racing Development Officer Steve O’Donnell said when the rules were announced last year.

Good(year) times

Monster Energy and Xfinity Series teams are going from a 1.5-mile track to a 1-mile desert oval and they will be under a lot of (air) pressure with the new rules package at ISM Raceway. This will be the first race with the 1.17-inch tapered spacer that produces more horsepower. Phoenix is a smoother surface, but is one of the more unique and challenging tracks on the circuit. It differs from other shorter tracks in that aerodynamics will play a more vital role.

ISM Raceway has three distinct corners with a lack of banking, so aerodynamics are more relevant. With this rules package being high-downforce, high-horsepower, the combination should result in higher speeds and increased tire loading, making the level of air pressure a very important factor.

“Teams will be under a new rules package this week at Phoenix, with all the new aerodynamic elements, but with more horsepower than they’ve had over the past couple weeks,” said Greg Stucker, Goodyear’s Director of Racing. “When we tested on this package at Phoenix last fall, teams were considerably faster than we’ve seen in recent years.

“With the extra downforce versus the 2018 rules package, much of that speed comes through the corners, which generates higher loading on the tires. Teams will need to be mindful of our recommended air pressures as they develop their set-ups to optimize grip. Running below our minimums can cause the sidewall of the tire to flex more and over-deflect, generating more heat, higher wear and fall-off, and even damaging the tire to the point of air loss. Finding that balance will be key.”

There will be a brand-new tire compound debuting at Phoenix. Teams in both series will run the same tire compound at ISM Raceway this weekend. This is the first time either of the two Goodyear tire codes will be run. The left-side tire features a construction update that Goodyear will begin displaying at many more tracks this season, while the right-side tire features a compound change designed to introduce more tire wear and run cooler. Phoenix is the only track where either of these two tires codes are scheduled to run.

There was a tire test in Phoenix last year (Oct. 2-3) with this tire combination. Drivers Denny Hamlin, Matt Kenseth, Kyle Larson and Paul Menard were among those at the test. Similar to other NASCAR ovals that are one mile or less in length, they will not run liners in their tires at Phoenix this weekend.