Can a car doing 45 mph with 12 inch wheels travel faster than a car doing 45 mph with 18 inch wheels?
45 mph is the same as 45 mph. How can one of the two be faster?
The only real reason I can think of is that they cost less. In theory the 17 ones have a smaller part of the surface to hit ground. This could mean that they throttle water a little bit better than 18 inch ones. 17 inch also mean that you use slightly more fuel per mile, but you have more torque/power transferred to the wheels from the engine. 18 inch makes you able to drive slightly…
They might be. You will have to try them to see. Check to see if the '97 has the 16 inch wheels for the oversize calipers. If so, the '87 most likely has the 15 inch wheels. They would only fit in this case with wheel spacers, 1.25 inch, and then you will have to grind down the top of the caliper say 1/32 of an inch to fit the wheel. If both wheels are…
The most obvious difference is that the 20" bike has 20" wheels and the 26" bike has 26" wheels. After that it's details like how the bikes are intended to be used. A 20" bike is likely to be a BMX, good for tricks, stunts and short courses, but not so sutiable for longer rides. A 26" bike isn't as nimble for tricks, but better at going faster and longer.
Not sure what you're asking here. You can't put 16 inch tires on 15 inch wheels (or vice versa), hence the different sizes. You can, however, put 16 inch wheels on a vehicle that normally has 15 inch wheels. You just need to ensure that the bolt pattern and center holes are exactly the same measurements and you may need to use a lower profile tire to achieve the proper tire-to-wheelwell clearances.
Not sure on other years, but the XR80 and XR100 1985/86/87 used the same frame. The XR100 had the same diameter forks, but 50mm longer than the 80, and the swingarm was 50mm longer also, but the wheels were interchangable, IE: the XR80 wheels would bolt straight onto the XR100. The XR80 had 14 inch rear and 16 inch front wheels, the XR100 had 16 inch rear and 18 inch front. HTH