new dually

yes i mean 3.73 and 4.10
I do not plan on towing anything
and yes It will be a drama

I'm quite certain the OP meant 3.73. It's called a typo.
OP, are you getting the diesel? If so the 3.73 is your only option, you can't have the 4.10. It's been this way with GM since 2001.
If your getting a gas rig I would get the 4:10. I have a 2015 Chevy 3500 work truck with the 6.0 and 4.10. It weighs about 9,000 pounds most of the time. I wouldn't want a higher gear ration. If anything it needs lower.

I would go with 4.10 gearing since trucks are so expensive if you need more towing ability later you'll be prepared for it.

3.73 with a TC. No doubt. You would have to be pulling one big hog to want 4.10 with a duramax.

What are you towing besides the camper?
Presume you're getting a diesel. If diesel and towing less than say 7k plus loaded camper then 3.73s are more than adequate. Don't think GM offers higher years than that like the other 2 mfgs.
If you're towing heavier along with hauling the camper then think about 4.10s.

I had 2000 F250 with 3.xx differential and 250HP Powerstroke pulled 18,000 lb trailer on overdrive just fine.
I am shopping around for dually and looking for lowest differential possible.
The only issue is that with low differential and 2WD your low gear might be too high, but with 4WD you will have transfer case changing gearing.

I'm sure the OP meant 4.30. In any case, if you are getting a gasoline engine truck, I'd probably go with 4.10 if you also plan to tow or go over the mountains a lot. If not, I'd go into the 3s with 3.73 or similar.

With higher gears, you shift less going over the mountains or when towing. Lower gears you'll get better mpg on flat ground.

Hi i am thinking about ordering a new Denali dually with either a bigfoot camper or northern -lite Question is it better to get a I think a 7.30 or a 4.10 gears for the truck
rear end, what is the difference
thanks

Wow, a 7.30 ratio would be way out of the ball field. For a truck camper you can easily tow with a 3.73 axle if you are not towing anything heavy behind. If you are getting a diesel then you definately will not need the 4.10 or 7.30(?) ratios. I have never seen a pickup truck with a 7.30 ratio, bet it could climb a telephone pole.

Back in the 70's when engines where much less powerful, they needed to run a higher RPM at freeway speeds to tow the load. There is a maximum amount of HP you can get from a engine at any given RPM before the truck decides you want to go faster, and will downshift and increase the RPM and thus HP.

But running higher RPM's means less MPG. So back in the day - I am talking 70's and 80's, having a pickup with 3.73:1 rear axle ratio could tow less than one with 4.10:1 rear axle ratio, and many tow packages came with the 4.10:1 rear axle. With the 4.10:1 running in drive (remember 3 speed transmissions in the 70's and 80's) you would be doing about 3,000 RPM at 65 MPH on the freeway, and the engine was under somewhat light throttle, and able to make more power at that RPM. With a 3.73:1 you could make just at much power, but would run 2,400 RPM and get better mileage.

Nowdays the engine are running much slower, and get better mileage. I would go with whatever rear axle ratio is offered, and let the 6 speed transmission worry about downshifting to 5th gear when you need a little more power. Especially with a slower turning higher torque diesel engine, lower axle ratio is better.

Fred.