Received this reply from Helwig 5/5/2021 . . .Know of any companies who make rear sway bars for a 2021 3500 srw with air suspension?
Thanks . . .
Thanks! I was wondering what the difference was between diesels and gas. The resonator makes sense now. So if Helwig makes a bar for Gen 5 Rams, the fuel used could make all the difference.You don't say what engine your truck has, and I don't know for sure if there have been exhaust routing (or other) changes since model year 2018, but back when I was looking for a RSB I dug into the weeds pretty deep. I don't have air suspension either, but I do have aftermarket rear air bags.
Hellwig makes some models that will fit the Cummins trucks, but the only company I could find who made one that fits the gas powered trucks (mine's a 6.4) was Roadmaster. The reason is the existence of an exhaust resonator on the gassers that doesn't exist on the diesels - it's in the way for the Hellwig and others.
I did a write up of the installation giving details of the fitment issues here.
Like I said, that's for the 2018 model. At the time I was looking, even Roadmaster didn't know for sure if their bar would fit because they hadn't had their hands on a 2018 model yet, so they could only guarantee fitment up to 2017.
But they were very helpful, and asked me to send photos of the underside of my truck, after which they said they were pretty sure it would fit, and if it didn't , a full refund would be no problem.
So I went with their product (model 1129-124) and have been entirely happy with it.
Don't know how much help this might be given the model year difference, but in terms of finding a company that's easy to work with and willing to spend some time trying to resolve issues, Roadmaster was hard to beat.