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Discussion Starter #1
Looking at some Pirelli Sport Demons for my Bonnie. I know what all the 130/80H 17 means.

But then the tire states "TT", as in 130/80H-17 TT. I'm betting that means "tube type" versus the other tires that state "TL", which I'm guessing means "tubeless".

Confirmations on my theory???

276 Posts
Tire Sizing: Inch System
Ex: 3.00 - 21
3 is cross section
21 is rim diameter

Ex: 4.10 - 19
4 is cross section
.10 is cross section height is 10% less than cross sectional width
19 is rim diameter

Alphanumeric System
Ex: MH90-21
M = motorcycle tyre
H = cross sectional height
90 = aspect ration (90%) - if "H" is 2.5" from manufacturer's chart then the cross-sectional width is 2.5" Therefore, the cross-sectional height is 90% of 2.5"
12 = rim diameter

Metric System:
Ex: 120/70-17
120 is cross-sectional width in millimeters
70 is 70% of the width
17 is rim diameter in inches

There will also be a date on the tires
Ex: DOT MAL9MHL 3301

3301 = 33 week of 2001

Tires 1970-1999 used 3 digits

your H is the speed rating which is 130mph

I am used to seeing Tubed or Tubeless but I think it is safe to assume that TT is tube tire and TL is tubeless.

Sorry for explaining what you said you know, but figured it might be useful to others.

10,212 Posts
FYI, the Pirelli Sport Demon 130/90 is a good fit for the rear too, makes it slightly taller, 13mm as I calculate it. I wound up with it because that's what the mechanic got for me when I asked him to replace the tire.

It also makes the bike really easy to get up on the center stand, and I assume it makes the gearing slightly taller too.
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