Is it true that if you put bigger wheels, and wider tires (lower profile as well), that it wear-out your suspension FASTER? A mechanic of mine told me this. He said the thicker profile tires will take away MORE of the bumps from the suspension, than lower profile tires. Thus, making it last longer. Is there any truth to this?
Wear out suspension?
Weight, harder on joints and bearings.
WAY outta spec offsets, as it makes the suspension work in ways it wasn't designed to move. So, bearings and bushings aren't working the same way as designed.
That is correct, the higher aspect ratio tires have more air between the rubber face and wheel metal, allowing more air to "move" and absorb shocks so the suspension doesn't have to. Also, lower profile tires have stronger, thicker sidewalls than higher ratio ones, as the smaller ratio ones can't flex as much before the rim lip hits something. That is shown in the tire weights. If you get a chance, look at manufacturer's tire specs. An interesting thing you will notice is lower profile tires are actually heavier than taller profile ones with the same outer/rolling diameter.
Now, as long as one stays close to the original overall weight (rim and rubber weight together) of the stock steelie/tire combo (around 40 pounds, per) and keep the offsets within reason (45-30-ish, depending on wheel width), you won't have any problem.
The tire profile in regards to "ride" is really dependent upon road surface and driver preference/toleration. On a smooth road, one can get into the 15s and be fine. On a rougher road, 15 beats things up, esp. as they tend to be on heavy rims too (weight). Many high-end sports cars have stock tires in the 25-ratio range, with more around 35.
As for me, the rubber's qualities are more important than ratio. The difference between 45 and 55 ratio rubber in the same tire isn't all that much in regards to grip. However, a massive change is noticeable in changing from "all weather" to "ultra performance" rubber, even in the same ratio.
So, I run performance tires (no worries about snow, just rain) in either 205/55/16 (stock size on steelies) or 225/50/16 (whenever I get 16x7 alloys).
Note the green on: http://newscionxb.com/wheels_tires/eddnogs_xb_20_wheel_tire_chart-t23.0.html
Those are close rolling diameter to stock.
I am only interested in alloys significantly lighter than stock. Often, width works in pairs of diameters (13/14, 15/16, 17/18, 19/20). Accordingly, the pairs of the same width rims have only a small jump, say, between 15 and 16 inch diameter, but a larger one before 17 inch.
Therefore, I plan to keep 16 inch diameter wheels unless manufacturers stop making ultra performance tires in 225/50/16 or 205/55/16 sizes.
The alloys I am interested in most are 16x7, 40 offset, and only weigh 13 pounds each, so that is 7-9 pound/PER less than the steelies with the same rubber. So, the rolling wight should drop drop from the 40-pound ballpark to low 30s. Also, the That way, there is less unsprung weight to work the suspension components, the centerline is about right for the slight increase in width, and so forth.
Another dimension of weight on wheels . . .
Heavier wheels take more effort to get rolling and to stop them from rolling. It is an inertia thing, that law of motion part of physics thing. That is why "donks" take a LONG time to accelerate and also smoke the brakes trying to stop. On our xBs and in the ballpark most folks talk about with their rims, it isn't enough to really worry about, unless you are a performance/handling nut like me (and a few others on here).
Keep the weight close to stock, the offsets/widths within reason, and you shouldn't need to worry about it. I wouldn't, and I plan to drive my box 300,000 miles or more.