With the Midwest-spec 410 cubic inch engine being the preferred package — and in 2021 the only option — for Pro 2 in the Lucas Oil Off Road Racing Series this season, there are a lot of new, or newly rebuilt, trucks in the class. And they’re winning.
Both Jerett Brooks (pictured above) and Doug Mittag had new trucks make their debut in the second weekend of LOORRS 2020 competition at Lucas Oil Speedway in Wheatland, Mo., in August. Both drivers started the season at Glen Helen in older machinery — defending Pro 2 champ Brooks in the truck he raced last year and Pro 4 refugee Mittag in a Pro 2 he borrowed from Brandon Arthur. And both drivers won in their new trucks at Wheatland. But the trucks came from two rather different directions, although the approach for both was similar.
Brooks and Tanner Stephens started building his new truck, dubbed “El Diablo,” after winning the championship last season, and it was built from the ground up. Mittag, on the other hand, has been competing in Pro 4, and his decision to race Pro 2 after the Pro 4 class was eliminated in LOORRS due to lack of entries was late. So he, his father Chad and the rest of the crew at Chad Mittag’s Custom Offroad Design took an old truck owned by sponsor Pinnacle Nutrition Group, which they had intended to sell, and sliced and diced it to the current way of thinking in Pro 2 design.
“The truck was really old,” explains Mittag. “Austin Kimbrell had it way back in the day; it was built by Keith Stanford and it needed to be redone. We knew that, we build trucks — half the trucks in the field have our front spindles and A-arms on them — so we needed to do some stuff. We finished Round 1 and 2 and finished pretty good in a truck I barely knew. We got home, took one day off, and we got out the chop saws and started going after it.
“We cut off the whole back half, basically left the frame rails and the mid-rail tubes, and some of the front structure. New front shock tops, new upper A-arms, spindles, upper top cab … we lowered it and lightened the truck. We did our back half on it; we get the radiators real low, fuel cell real low, the coolers real low, looking for a lower center of gravity compared to the old style, top-heavy trucks — that’s how they made traction back then; now there are so many ways to get traction we don’t need to do that.”
The thinking with Pro 2 design was a lot of weight transfer to load the tires for grip in the dirt, so getting a lower center of gravity was not a priority like it is with most race cars. But with advancements in shocks and suspension design, fabricators have found better ways to get grip than having the truck roll a lot in the corners and squat back on the rear tires to get forward traction.
“Everybody evolves,” Mittag notes. “Look at F1; look at anything. People figure stuff out and you go with that and you start having a different theory. Our theory is making the truck a super low center of gravity so you can enter the corner that much faster, where the old style was maybe a little slower in the entrance, but middle and exit is better because the thing is so top heavy it’s rolling on the back tires. We got our Bilstein shocks and put ’em on the rear-end housing and move our swaybar. There’s a lot of stuff we do at Custom Offroad Design that helps with traction, all the way up to front spindles. It all makes big difference.”
Stephens took a similar approach with Brooks’ new ride. Stephens was working with Jeremy McGrath’s team and Brian Deegan’s before that, and has built a few trucks along the way, learning with each one.
“The biggest philosophy that I had building this truck is a low-CG-style of truck,” Stephens says. “A lot of people think they won’t work, due to the thinking that in Pro 2 you need the body roll to kind of load the tires a little bit more. I studied a lot of Formula 1, IndyCar, and stuff like that … I don’t really look at the realm of truck racing. I don’t study Trophy Trucks; I don’t look at stuff like that. I come from more of a dirt bike background, so I kind of relate a lot of that, that’s where I get my dirt experience from. Then I take the F1 technology and stuff like that. That’s my theory — low cg, then I can work with ride height to control body roll or anything else I want to achieve.”
There are differences that come with the new style of thinking, but also with the differences between running the old Unlimited engines and the lower-horsepower, but theoretically more economical, 410 package. Even though the minimum weight is 4200lbs., weight always matters, but even more so with less power. That factors into the design.
“Once I knew we were switching to the 410 package, I narrowed the truck up just a little bit, knowing it had to be a bit of a hybrid truck – a little bit Pro 4 style, a little bit old style Pro 2,” he explains. “I think we nailed it pretty good. Everybody says it’s so low, it doesn’t transfer weight; but then when you watch it on the track, it definitely does exactly what I envisioned it to do. It was a clean slate, and really, to be honest, this was my first opportunity to build a race car from scratch.”
Pro 2s, including Brooks’ old truck, typically had 18-inch bypass shocks in the rear and 12- to 14-inch bypasses in the front. Stephens was able to get down to 12-inch bypasses all around. And it worked from the beginning — since the first laps of testing, the team has only made external shock adjustments and a spring change in the front. Mittag, though, still has some things he’d like to do to the truck, especially in the front end, but time has been at a premium.
Either way, what both teams are doing is working. Brooks has put his new K&N Filters/Bilstein truck into victory lane three times, once at Lucas Oil Speedway and twice in the Wild Horse Pass Motorsports Park tripleheader. Mittag won a day after Brooks in Wheatland and hasn’t finished lower than second in six rounds. Whether truck design philosophy continues in the same direction or takes a different turn will be seen, but the low center of gravity thinking is certainly working for these two drivers.