GM 2500HD 37” Nitto Tires on just a leveling kit!?? 

The ideal combo for this is the factory 20” wheel and 37x11.50r20s

also does the 37x11.5 rub at all

Stock wheels we run no wider than 11.50's works out perfect!

Unfortunately we have never tried to clear 37's with out at least a leveling kit. All our clientele prefer to have a leveled stance.

not without rubbing, really depends on how wide they are. i have 33x13.50 on mine and it rubbed a little trimmed it a little and it clears now stock height

@cjcallen5974 the tires in the video are 11.5 wide. Thats what im asking. If 37x11.5 fit on oem wheels no leveling

That is a great question. We are a shop that does the installs for different clients unfortunately we do not drive them everyday so we cannot comment on how it effects the fuel mileage.

Short answer Yes/No. Ride quality is subjective. One person may hate the way the truck rides stock but love it when it's leveled and vice versa. Here is the biggest difference in the Cognito kit vs others. Cognito allows for the proper amount of droop travel which in turn has the best overall ride. Some of the other kits don't address the droop travel and the upper arm slams into the droop stop making a banging noise and causing the truck to ride terrible. If you follow the Cognito guidelines in our opinion this is the best riding "Leveled" set up out there. We have a lot of positive feedback on this set up. We have never had to take on off because the customer was unhappy with the ride. We have taken other brands and other set ups off in favor of the Cognito set up.