I think JBarca has it calculated fairly well for forces and the comparison there.
Tires do make a world of difference. Take my wagon for instance. From 2008-2013, it was my tow vehicle. 26' 5,600 lb trailer.
Car has aftermarket Hotchkis sway bars, front and rear.
I've never towed with my winter tires, but they are the original 225/75R15 sized tires. Handles pretty bad with them.
Summer tires for the first several years were 245/60R17 Michelin Energy LX4 tires, an OEM style all season tire. They were an extra load tire with more load capacity. Handled pretty good with those tires. Towed fairly well with those as well but still had stability issues on really windy days. Ran those from 2007-2010 during the warmer months.
2011 I bought some 235/65VR17 high performance summer tires for it. Bridgestone Dueler H/P Sport XL tires made for high performance SUV's. Made a huge difference in towing performance. Much more stable, could pretty much run 65 mph in nearly all conditions with good stability.
116" wheelbase, same as a Tahoe.
219" overall length. (Tahoe 197", Suburban 219")
The rear overhang is HUGE.
Only switching from a single friction to a Reese Dual Cam sway control made more difference in the stability. Tires had a huge impact.