2020 Freightliner vs 3500 GMC Dually at the Ike

They praise the performance of the engine brake on the Freightliner over the performance of the exhaust brake on the GMC, however, if more weight had been loaded into the trailer the Duramax would have held 50 mph yet the Freightliner would have required additional brake applications. Comparing two trucks on one hill with only one weight in tow doesn't really offer an honest comparison. I'm having trouble understanding why the GM slowed down as much as it did going up the hill ..... something doesn't add up. Even back in 2015 (with 396 HP and 765 lb ft) the Duramax towed 19000 lbs up the Ike in just under 10 minutes. link

bguy wrote:
What percentage of each vehicles towing capacity is the trailer at that weight?

And how close is each to the rear axle weight rating ? This is a perfect example that "payload" is primarily a registration class derived number. This Freightliner is likely capable of being registered up to class six.

What percentage of each vehicles towing capacity is the trailer at that weight?

Measuring the time required to tow a trailer up a hill is an accurate method of measuring rear wheel hp. It surprises me that the GM didnt smoke the Freightliner.