Tire size

[Matt-04-883]

Ok guys and gals I finally bought a 19" rim to replace my 21" on my 04 custom. I still need to buy rubber for it and I know there are a few threads floating around about which tire people prefer. I just don't understand what the first few numbers mean, for eg. 100/90-19 or 90/90-19. What do the first two numbers refer to;tire width? If so can I expect that a 19" tire will be the same width as the tire currently on my 21" rim. thanks for the help
Matt

[Shamdog]

100/90-19 is:

100 = tire width
90 = aspact ratio ie, height to width ratio
19 = rim diameter

[DLM32]

The first number is the overall tire width(100=100mm) , second is tire aspect ratio(90-90mm etc.), and of course third is rim size (in inches). Rim sizes are measured inside bead to bead (2.15, 2.50, etc. in inches) and overall diameter 19", 21",etc.)

The 100/90-19" should be about 10mm wider than the a 90/90-21" on a 2.15" rim.

What width 19" rim did you get?

Later,

[Matt-04-883]

Thanks for the responses guys that makes sense. To be perfectly honest I don't know what the width of the rim is. I bough tthe rim off ebay and haven't received it yet I guesss I really should of asked what the rim width was before purchase but live nad learn. So let me ask you this. Can a 100/90 and a 90/90 tire fit on the same rim. I want the widest tire I can get. thanks
Matt

[DLM32]

You are probably getting a 2.15"x19" rim. That is the same size as the 19" cast wheel on the 1200 roadster. A 100/90-19 tire fits that rim. :D

Later,