It is not the thickness of the alloy wheel that stops a 15 inch from clearing the brakes....It is the size of the calipers and rotors that will not allow a 15" wheel to fit.I'm about to buy a dedicated set of off-road tires and wheels for my '05 CR-V and really haven't found any aggressive off-road tires for 16" rims that will keep my overall diameter within 5% or so (The 5AT is already geared too low for off-road work as it is). If I can get 15" wheels to fit I find that there's all sorts of tires that would work. I know that the OEM 15" cast aluminum wheels will not fit the 2005 but since steel is so much more dense than aluminum I'm hoping there's a chance that the barrel of the steel rim is larger than the cast aluminum. By the way, I'm looking at Tire Rack's steel rims (and have e-mailed them with my dilemma). Anybody know if it will work?
I don't think the answer is as simple as that. What I'm saying is that while the critical dimensions (width/bead profile/outside diameter/ lug hole and hub hole placement/ hub face/ offset, etc.) of the OEM cast aluminum wheel is identical to the steel wheel, I know for a fact that the steel used is ~3X more dense than cast aluminum and since the steel wheels don't weight 3X as much as the cast aluminum, there must be some secondary dimensions that are different between the two. Also, each is constructed differently with steel wheels usually comprising of two pieces of mild sheet steel stamped and welded together while our cast wheels are basically just a simple gravity cast. The result is that the dish of the rim portion of the wheel might be substantially different (I've also heard it referred to as the "barrel") and could provide some additional clearance for the caliper. I measured .480" of clearance between the caliper and my rim on my 2005 EX's cast front rims and if the 15" wheels are just a "mini" version of the 16" rims than there would be ~.020" of interference between the 15" cast wheels and my calipers on my 2005 CR-V. Because it's so close it warrants some investigation on my part because there are so many advantages of going to 15" rims for true off-road tires.