My Frontier pickup truck has original 15" rims -- pretty small by today's standards, and actually a bit hard to replace.
With the advent of really large riims, the Q is: What is the "ideal" rim size for a given tire? Probably this varies with function, such as a pickup truck used for hauling, vs a truck used for snow plowing, vs. a hot rod.
Are there ideal "ratios" of tire size to rim size? I would imagine overall tire size is dictated by net-desired gear ratio. After that, some ratio of rim to tire would seem to be optimal.
For example, an '04 Frontier takes a 265/70-15. Would 16, 17, 18" rims offer a better performing ratio of rim to tire? Clearly the height of the sidewall (the 70 in this case) would have to decrease, and the Q is: how much of a decrease is helpful, if at all?
Varies. Northeast. Light to the occasional heavy haul from HD (10 mi) or a machine. Short commutes. Hilly area, use the 4 wd to get me, the wife to work in the winter, etc. Low miles. Sorta my "neighbor vehicle": My neighbors have to be much nicer to me, if they want to borrow it.
But the Q was more general, basically as to the wisdom of large rims, and if in general there is an optimal size, and how it would be generally determined. I read that low-profile tires are very uncomfortable, but mebbe are good for speed?
My tire guy also mentioned that selection was much more limited w/ 15", poss. 16's as well.
15's look a tad small on a crewcab 6' bed truck (even the "compacts"), and I'd move up (engineering notwithstanding), but a new rim set is a bit of a hit.
Existential Angst wrote: Varies. Northeast. Light to the occasional heavy haul from HD (10 mi) or a machine. Short commutes. Hilly area, use the 4 wd to get me, the wife to work in the winter, etc. Low miles. Sorta my "neighbor vehicle": My neighbors have to be much nicer to me, if they want to borrow it.
But the Q was more general, basically as to the wisdom of large rims, and if in general there is an optimal size, and how it would be generally determined. I read that low-profile tires are very uncomfortable, but mebbe are good for speed?
Tire shops around here can get me just about anything I want I usually run aggressive tires on my vehicle due to the way I use it and it runs 235 75/15 rubber stock. I have 31 10.50 /15s on it (31 inch tire) (Dick Cepek F-C)
Wifes Jeep Liberty runs 16" on it. About 40 different tires available. Hers currently has Uniroyal Liberators on it. The last owner put them on and they are still in good shape.
As for the rims. The larger sizes allow you to add larger brakes and run a stiffer sidewall. Great if you're doing something like auto-cross or racing. They also give you a VERY stiff ride due to the short stiff sidewalls. Many are not rated for heavy loads. Then you have the problem of pot holes and curbs. With a normal sidewall the tire absorbs the blow and usually that isn't a problem. With the low profile rims there isn't a sidewall to absorb the blow, it goes to the rim and usually the rim loses. I've seen a lot of the 18/20" rims with damage and even chunks missing.
On a truck it's likely that the optimal size is more in terms of aspect ratio then specific rim diameter. The shorter your sidewalls the worse the ride and the easier it is to damage the tire. For a vehicle that's used to haul stuff and to drive over rough ground you want something that is somewhat forgiving of a hard smack. So for a truck I'd stick with 70 or 75 series if it's really a work truck, perhaps as low as a 60 series if I was determined to give it an "attitude". But the 55 and 45 and lower are really easy to damage just going over a curb when turning into a parking lot. The other thing to keep in mind is that generally you want to stick with something similar in overall diameter as the factory put on it, perhaps stay within 10%. So as you go to bigger diameter rims you have to go to shorter sidewalls (lower aspect ratios and wider rims/tires). Wide tires are generally not as good in snow and mud as the "normal" tires.
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