CH125 TIRES

In fact, it's a little surprising that outfits like Michelin and Bridgestone (which includes about 30 other brand names) bother with scooter tires at all - - and when you talk about "inch" size tires like our 3.5 x 10s - - those fall almost completely off the edge of the world!

Below is a chart from the fine folks at Motorcycle Superstore, Inc. If you want to thank them, you might buy a tire or two from them.

You will note that our 3.5 x 10 inch tires aren't even listed - - the MM90, 100/90 metric is as close as you are going to get!

The tires I selected for my CH125 are Michelin's S83 3.50 X 10 51 J TL/TT

- - but wait; Michelin also lists a S83 3.50 X 10 59 J TL/TT Reinf.

I hadn't yet found this handy chart, so I called Michelin's customer service line to find out what those codes mean. That "Reinf." obviously means "reinforced" but the Michelin service rep. could not tell me exactly how that was accomplished. The Load Index increase of more than 20% tells the story.

Now the only remaining confusion centers around the conversion of three and a half inches to 100 millimeters. My calculation makes 3.5" = 88.9mm; that seems pretty far from the 100mm given in the chart!

One of the Internet "Tire Size" calculators shows that a 100/90-254 metric tire has an outside diameter of 434mm (17 inches) giving a circumference of 1363mm (53.66 inches.) Rotating 733 times / km, the wheel will turn 1,180 times per mile traveled. This also tells you that at 60 mph the tire is rotating at 1,180 RPM.

There's the Michelin "type" designation.

The tire is also marked 3.5 - 10.