Having a quick debate with a buddy regarding 4.10 and 4.88 gears with heavy 315/70r17 Nitto Ridge Grapplers on a 5th gen 4runner.

Taking into account the increased weight and rolling resistance of the tire versus stock sizing, would 4.10 or 4.88 be better? I've read that people with 34s do well with 4.56 and some even wished they went with 4.88. It doesn't make sense to me that 4.10 would work better than 4.88 with such a large and heavy tire.

By how much do the tires referenced change the stock gearing? Choose the appropriate ratio to compensate, may be 4.10, 4.56, 4.88, it depends.

There are no 4:10's available for a 5th gen so 4:56 or 4:88 would be your choices.

I think it would also depend on how heavy your rig is.

Let's say they did make 4.10 and the truck has rack, full skids, and camping gear. I don't see how 4.10 would be more beneficial than 4.88. If anything, 4.56 might give better mpg but definitely not 4.10 with big 34s.

According to the gearing charts 4:56 is the way to go.
However, you don't drive a gearing chart. I'd hesitate to make a recommendation because I have no idea what your situation is. Saying you have rack skids etc doesn't mean much to me cause I can't quantify what your saying.

What I will say is 4:56 works great for me. My rig is definitely far heavier than your rig however my tires are lighter and smaller, although not much.

Maybe find someone who is set up close to what you want and see if they'll take you for a spin

This ^ No 4.10 option. Choices currently produced are 3.73, 3.93, 4.56, and 4.88.

Personally - I think 4.10 would be the correct stock gearing for stock tire size. I have had both 3.73 and now have 4.56 gears. I have some 33" tires and some 34" tires. I have not had enough miles to give a full review. I don't know how the gear change will effect highway speed MPG yet. I suspect it will go down when empty. I'm hoping it may actually go up when towing my small camper. I thought the 3.73 were just fine off road. I felt the biggest issue was highway cruising and maintaining 5th and sometimes 4th gear at speed. Otherwise I would have been happy with 3.73 gears most of the time.

IMO the ideal ratio for my use would be 4.30. They are not available or I would have chosen that ratio. I would not probably have gone to 4.10 over 4.56 with 34" tires. For a 35" tire - I'd still go with 4.56 myself unless I were doing a lot of towing, racing, or was very heavy.

When I was running Toyo MT's in 285/75's (34.1"), the 4.56's were great. That was with full armor and everything. Since stepping up to 315/70's (General X3's and heavy), I find the 4Runner shifting more versus before and would really like to go to 4.88's now, just do not see that happening any time soon with the current investment. If making the investment, I would opt for the 4.88's and be happy.

That's only a .3" measured height difference I believe. Do you feel that is just due to the heavier rotating mass?

I have 33" Duratracs and I just put in 4.88's and they are great. After driving awhile with the 4.88 I dont see any purpose in spending the money for just 4.56. Not a big enough difference.

On the highway now Im about 500 rpm higher than I was before at 70mph and everything under 70 just feels the way the vehicle is supposed to feel.

So in my opinion 4.56 gears nobody should bother with. either go 4.88 or nothing.

I do plan on going with 35" tires when these wear out, then Ill be back to the slow sluggish 4runner feel again probably

I'm running 4.88's with 35" Falken Wildpeak MT's. These are some heavy tires. It holds 5th a lot better on highway speeds. I'm glad I went with 4.88's cause the truck is just so heavy. I also wanted to be able to crawl offroad...4.56 would be fine with 33's, but if you want to go bigger in the future go with 4.88's.

i'm running 4.56 with 34" tires and the magnusson supercharger.
It's perfect, I would not want 4.88

Does Magnuson have any guidance on which gearing to use with their superchargers? Or does anyone know whether or not you want higher or lower gears with superchargers in general? E.g. 285/75r17 with weight, people typically go 4.56; are you advised to stay stock gearing with the same setup, but with a supercharger? Or is it advisable to regear with a supercharger as well?

Where do you get 3.93 gears? I've only been able to find 4.56 and 4.88.

There's no real right or wrong. It depends what your goals are and what you think the ideal balance of acceleration/pulling power and MPG/cruising RPM is. Lower gears(numerically higher) will have better acceleration, better towing ability and will be better for crawling slowly off road, but the highway cruising RPM will be higher and highway fuel economy suffer. It comes down to personal preference.

3.93 is an OEM ratio that comes in the gx460 and prado 150 models. It was also used in the MT version of the fjcruiser. They're cheap, but only about 1%different, so im not sure swapping would be worth the effort.

Depends what you're going for. It's actually 5.4% lower which when combined with 285/70 still ends up a little lower geared than 3.73 on 265/70, and exactly the same overall gearing as stock when on 295/70. It's not a bad option for mall crawlers and dailies near stock weight that are okay with stock acceleration and want to keep the highway fuel economy impact of 285/70 or 295/70 tires to a minimum.