Rear wheel swap ~~ important info

[oldnortonrider]

You'll get a FULL INCH difference (lower), if you go from the 17" wheel to the 16" wheel ~~ reason being, is because the wheel rim part is about 3/4 inch more narrow on the 17" wheel~~part that holds the bead of the tire; this squeezes the bead sides of the tire closer together~~makes the tire "taller" from the ground up to the wheel part that's holding the bead ; if you draw an imaginary line (motorcycle parked straight up and down) from axle down to ground, perfectly vertical; the line would touch the ground in the middle of the tire's "footprint"~~the tire patch part that's touching the ground~~measuring from ground to bead rim part of the wheel, you've got at least 1/2 inch gain in distance with the 17" wheel, cuz the much more narrow wheel part that holds the bead(s) of the tire is contorting the tire in a different fashion than the 16" wheel. I made this switch from 16" wheel to the 17" wheel about 2 years ago; planned for doing this swap for at least 5 years; all the time getting around to getting around to doing this~~not realizing that the wheels' width measurements) at the bead/rim part was different. When I had both wheels off the machine and was mounting the new, same tire onto the 17" wheel, I made this discovery, and knew that "this was not good" ; I went ahead and completed the tire mount and wheel change , anyhow, to see how it would make the motorcycle "act" different. I knew the gearing would be "taller", which was some of what I was after. Main gain that I thought that I would achieve~~what I was really after~~was a bigger footprint on the road; i.e. larger circumference would compute to more rubber on the road. Wrong; cuz the skinnier rim made the tire much more narrow. Sidewall is 3/16" further away from the driveshaft housing on that side of the tire. Multiply that times 2 to get approximate change in tire width I might mention here, that this change means you've got to use the stamped out steel brace that holds the part of the caliper; they're angled different; keep the brace that was with the brake setup on the 17" wheel ; keep with that wheel. And vise-versa, same with 16" inch swap, if one would do that swap, to put the 16" wheel onto a Standard. This is addressed in other explanations, in other threads; but I'll say it again, in my own words. The axle spacers on wheel hub side and the last one against swing arm side are different...................................The machine, when I made the swap from 16" wheel and tire~~to the !7" wheel and tire~~differences as follows; I did get taller gearing; but I'm not on roads that I'm motoring along, very often, above 60 mph~~the machine handled fine above 25-30 mph~~but one could tell, cuz it'd been raised up (in the rear) that it was not "balanced" as well at low speed(s) ~~these machines have a "top heavy" problem, bad enough, without raising the front and/or the rear to change center of gravity, or any other geometry that might make them more top heavy. Added to my own top heavy problem~~the 7 & 1/2 gallon Concours gas tank with the extra fuel, because of where it's located; adds to top heavy problem: where these problems are really noticeable is like under 5 mph; navigating tight areas, and Walmart parking lots, etc. The taller gearing in 1st gear, definitely made "tight navigating" more difficult. As I type this, I'm able to look across the room at "the old" 16" wheel next to a new 16" tire , ready to be mounted, and returned to being the rear wheel that I was the most happiest with. Anyhow, the "point" of my post, is = when this wheel swap is done; the change; up or down; is an inch; half inch from axle to bead, and another half inch (difference) distance from the bead to bottom of the tire (i.e. the ground).

[fredintoon]

Hi JC,
you sure about all that?
Clymer's sez Standard rear is 4.5"-17" and the Special rear is 130/90-16.
Also sez the Standard rim width is less than the Special rim width.
I would suppose that the narrower rim width matches the narrower tire so the "squeezed tire" thing likely ain't happening.
OTOH those old inch-defined tires were "square" at 100% height to width ratio
so they'd "stand taller" (if you can still get them).
Suppose you can get a metric equivalent 120/90-17 it's height would be 108mm while the Special's 130/90-16's height would be 117mm.
Working the tire heights into the rim diameters puts the Standard rear axle ~1/8" higher than the Special rear axle.
Tires wear more than that during their working life so I don't think your theory is true.
YES! they handle different but it's the tire width what's doing it, not the diameter.