If the new rims have the same offset as you have now, you won't hurt wheel bearings or brakes. However, that's a big change in rolling diameter and hence a big change in wheel speed. You'll be affecting overall gear ratios and speedometer calibration. Is there a reason you wouldn't go to a "plus 1 configuration" where you go up an inch in wheel diameter but drop down in aspect ratio so rolling diameter remains the same?
Looking to go from a 240/70/15 to a 265/75/16.
Tire calculator says a 12.1% difference.
What is the risk here (wear down on bearings, brakes, etc)? I do a lot of highway traveling and don't want to F my shiz up.
Thanks.
More mass to turn
Tires will cost more
Increased stopping distance
Less MPG...ETC
It's only an inch so I wouldn't even worry especially if you are staying around or close to stock parameters.
240/70/15 isn't a tire size, you must have meant 235 or 245, and neither of those is the stock tire size for a 3rd gen 4runner anyways.
You will feel the extra weight of the tires with acceleration and braking, and in your mpg (although this will be offset a bit by taller gearing on the highway).
Metric tire sizes go up in increments of 10mm, always ending in 5's, so 205, 215, 225...standard sizing may not translate exactly to metric. I've never purchased tires based on standard sizing, but it looks like the size tire currently on your truck isn't the proper sizing anyways.
Stock 15" sizing is a 225/?/15, and stock 16" sizing is 265/70/16, although many run 265/75/16 when they replace the tires, which requires no lift for the most part.
Can you elaborate on the "for the most part"
From everything i've seen, 265/75/16 will fit on a 99' SR5 2WD with no rub.. (no tow load, etc.)
When I put my 265/75/16 Duratracs on, they rubbed a bit in the front if you hit a bump when turning, or that kind of thing. Very minor, but annoying. Swapping to '99 tall springs fixed that.
Mine came with the same wheels, I believe they were 225/75 r-15. which came out to about 29.5 inch diameter. Not sure what will fit, but going up to a 30 or a 31 wont cause much of an issue. I went up to 33 inch and the speedometer is off by about 18% and I could tell there was some performance loss but not to the point of making it un-drivable. I was in the same place you were, but now looking back i kind of wish i had kept the stock Enkei wheels and just painted them black.
FYI...
Most tires that are made for 15" wheels are generally sized in inches (i.e. 31x10.5R15), but not always. Tires made for 16" wheels are generally sized with the metric system.
There were 2 different sizes that came stock on 3rd gens and they are both metric..
225/75R15 (which is about a 29" tire) and
265/70R16 (which is about a 30.5" tire).
Your current 30x9.5R15s aren't stock size tires, but are very close in diameter to 265/70R16s. Going up to 265/75R16s aren't going to make a big difference in power or mpgs.