+18 might be a little much with a 9" wide wheel. Are the stock 17s 9" wide? I know the 20s are 8 or 8.5" with just over +18. Does that wheel come in a 0 offset? If it does, I'd buy those instead, since you know 0 offset will fit without issues.

 

2100 is sufficient, average after-market wheel capacity for a 1/2 ton pickup would probably be in the 2400-2500 range so that's not terribly low.

a 9" wide wheel with a +18 is gonna be close IMO. Might just fit but I'm not sure. I don't have ANY experience with wheel specs anywhere close to what you are looking for. All truck owners in my circles are usually going the other way, pushing the tires out as much as they can. I would imagine an 8.5" with a +18 would probably clear ok.

Obviously if you need spacers, you are defeating your purpose as they will push the tire out from under the truck.

 

If you go with an 8" wheel, anything less than 4.75" BS'ing will push the wheel out over stock.. If you go with a 9" wide wheel, anything less than 5.75" will push the wheel out over stock.

If the stock 20's are 9" wide and have a +19mm offset. Then +18mm is not as quite as into the fender so what will the problem be? Aslong as your not sticking a larger tire than 265 on there with a total diameter of 34" you'll be fine.
Stock 20's are prett much flush with the fenders. If you want a slightly sticking out tire on a 9" rim, get 5.25" backspacing and some wider than stock tires such as 295 series. As long as you stay under 34" with that backspacing, you should be fine at full lock.

BTW, 0-offset on a 9" wide wheel is 4.5" backspacing pushing the tire out 1.25" over stock. Stock 17's are not 9' wide(only 8 I believe) and you must add the extra 1" over the top of the stock 17x8 stock BS'ing of 4.75".

 

And now I'm starting to see why another guy warned me that this would be "fun". I haven't put aftermarket rims on a vehicle in over 20 years. I don't know if I was just lucky then or if there just weren't as many options, but I don't remember having to consider these things.

No, stock 17's are not 9", but my stock 20's are, so that's why I was doing a lot of presumptive math. But I guess that's comparing apples to oranges when the wheel diameter is different and so is the tire size.

I want to go with bigger tires but they don't need to be monsters. And I don't mind them sticking out if the need to but I don't want them sticking out any more than they need to, if that makes sense. If I'm confident that I can find rims I like in about any sizing combo, is my best bet to pick out the tire size I want first and then figure out the proper rim specs to properly fit the tires?

 

I didn't realize the daisy 20s were 9" wide. My 20s are only 8 or 8.5" and are offset a little under +20. With the exception of a few steel wheels, all of the stock 17s appear to be 8" wide. As dirtydog pointed out, if you at least match the offset of your current 9" wide wheels, you should be able to fit a 34" tall tire. You'll want less offset if you want to mount a wider tire though, and with a lift or level, 35x12.5 seems to be pretty popular.

 

Don't get so worked up about the numbers. a 9" wheel is a 9" wheel as long as you have the correct backspacing/offset and is 17" or larger to clear the calipers.
285/70/17--32.7" tall 295/70/17--33.3" tall 305/65/17--32.5" tall 305/70/17--34"tall
Early daiseys are 8.5" wide and have a slightly diff offset than 9" wheels. But it's irrelevant when comparing to a 9" wheel as you stated.

As I already stated stock 17's are Not 9" wide, but the offset corrects their alignment if you will. If you use the link provided in my sticky you can compare side-side the offset/backspacing need for an 8" wheel as compared to a 9" wheel. But all you need to look for is a 17x9" wheel that has a backspacing of 5"-5.75". Period! To find the offset, which is a direct result of backspacing, use the link in my sticky.

So far, there isn't anything discussed yet that isn't covered in my sticky, so not too sure what the problem is? I know it can be confusing, but your earlier posts it seemed you had a grasp on what was correct and have been confusing yourself as posts/time has gone on. Just sayin.

 

For tires, I'd probably be looking at Goodyear Duratracs. That's what my tire guy sells and pushes these days and I know several guys that have them and like them. I like the Nittos as well and my guy can get them for me if I really prefer them. But, for the sake of researching, I'm looking at the Duratracs in a LT315/70R17. If I'm reading the size chart correctly, the outside diameter is 34.4" and the width is 12.7". Good for rim widths of 8.5 - 10.

 

Dog, not saying you haven't covered it. For sure, it's not you, it's me. Just a noob with this stuff but I'm slowly getting it. So, if I'm reading you right, so far I'm on the right track with a 17 x 9 rim, and a 5.7 backspace is in the ballpark? So, I just need to get the right offset so as not to get too far inside so that something is touching or rubbing but not too far out such that I just won't like the look? If I'm getting there so far, do you have any thoughts on an offset for the tires I'm looking at?

By the way, I'm going by my build sheet when I say I have 9" rims. I haven't measured anything myself.

 

As far as width of tires go, you'll need to be on the closer side of 5" if not 4.75". I stated 5-5.75 because you said you weren't going towards "monsters"
315 is monster tire as far as width goes. It puts you 2" wider than stock. That means you'll be 1" wider on the inside and outside compared to stock. 1" on the inside means a .75"-1" reduced backspacing over stock.(4.75-5") It also means that you'll not only be sticking out 1" past your current tires, but 1" plus the difference in backspacing of .75-1". So 315's with a 4.75" backspacing will push those tires out 1.75-2" further out than what you are right now.
NOW, the heighth issue when going that wide... You need 4.5" backspaced wheels because the wider you go when going taller than stock, the closer things get when turning the wheel. All-in-all, 315's on a 9" wide 4.5" backspaced rim, will yeiled you 2.25" stick out of what you are currently running.
I wouldn't get 4.75"-5" for fear of being too close for clearance. Your only other option is to go with a narrower tire as I have already listed above.

 

Thanks for sticking with me on this. I'm going off of available sizes on a website. Sounds like they are probably bigger than I want then. And looking back at the size chart, it doesn't look like I can get the Duratracs in the size I want unless I go with an OWL tire, which I don't want. So, switching gears to a Nitto Terra Grappler tire. A lot more options for me in a 17. I can go 295/70R17 with a height of 33.19 and width of 12.13 or 305/70R17 with a height of 33.98 and width of 12.36. Are those still fairly wide? Would I be more comfortable in a 285/70R17 with a height of 32.76 and width of 11.5? For all of those, a 9" rim is in range but all but the 305's put an 8.5" rim as the "sweet spot". The 305's designate the 9" as the sweet spot.