Video: Stock vs Tuned Ford F-250 Super Duty – I Tow 10,000 LBS Up The World’s Toughest Towing Test Twice!

2020 2021 ford f-250 super duty 7.3L gas v8 ike gauntlet max towing test
Ford F-250 Super Tremor is ready to tow heavy!

What happens when you push a lifted off-road overland truck to the maximum gross combined weight on the Ike Gauntlet™ – the world’s toughest towing test? Let’s find out by running the mountain in stock and 5 Star Tuning configurations!

The truck is our 2020 Ford F-250 Super Duty crew cab 4×4. It started out as an off-road FX4 package. Now, it’s a modified FX5 truck with a 3-inch suspension lift by Carli Suspension that rides on 37-inch wheels/tires.

For this fully-loaded Super Ike Gauntlet, we had to find out exactly how much the truck, the camper, and the trailer all weigh. The truck (with all of its mods), and the Four Wheel Camper Hawk in the bed weigh in at 9,100 lbs. The old F-350 Diesel weighs about 9,200 lbs with the trailer. When you add, myself, and some gear – the entire rig is approaching 19,000 lbs.

The Ike Gauntlet is an 8-mile stretch of I-70 in the Colorado Rocky Mountains. It’s a 7% grade with the top elevation of 11,153 feet above sea level. Any truck with a naturally-aspirated engine loses about 1/3 of its power near the top of this run. This is why it’s the world’s toughest towing test.

The 7.3-liter gas V8 in the truck is rated at 430 hp and 475 lb-ft of torque from the factory. The engine is mated to a 10-speed HD automatic transmission. The rear axle ratio is a 3.55. The 5 Star Heavy Tow tune assumes the truck is using 87-octane, and pushes the power up by about 47 lb-ft of torque at the wheels. Take a look at the dyno chart below.


We are using 87-octane and the Heavy Tow tune during this test. The tune also adjusts the transmission shift algorithm. It is supposed to be more aggressive during the downhill grade shifting – thus do more to help and slow down the heavy truck and trailer.

The extra power should help go up the mountain faster and/or help to maintain the 60 MPH speed limit during this fully-loaded climb. Check out the video for all the fun and all the results.