Ok i am trying to get a new tire and all i see on the tire on it is 4.60-18, but when i go to search for a D606 I cant find that size am i doing something wrong?

 

120/80 -18 is probably the closest you'll find in the D606.

I'm running the slightly smaller/lighter 100/100 - 18 in a Michelin (AC-10)

 

That is the usual accepted tire to use, but is not quite right on some bikes, like the old 450 Honda twins. A 100/80 is about a 4.60. Per Avon the .60 means it is about an 80-94% aspect, the 60 is usually more like 80% per my experience, but try to find that in print...

The roughly 100mm width with about a 80mm height is near the roughly 4" width with about 3-1/4" height which are about (4 x 25.4 =) 101mm and (101 x .80 =) 80mm

Now you see why the inch measure not only is no longer used, but really sucks - it's just plain goofy and not a very accurate description. If you got all three tires, the 4.00, the 4.10, and the 4.60 together you'd find the 4.00 to look the biggest, the 4.10 next and the 4.60 to be much lower profile.

Is the Michelin AC10 sized by the new (can you say more confusion yet) knobby size? Seems they now size them by what appears to be the carcass size, which is smaller than the actual width... or something. Per Dunlop:

"For motocross tires, Dunlop changed to the industry tire standards in the same manner as street tires. However, because of the prior variations in actual dimensions, some adjustments in vehicle application have been necessary. An off-road machine that previously fitted a 4.50-18 or 130/80-18 under the non-standards markings, now fits a 110/100-18 under the new standards. These tire sizes share the same actual dimensions. A 130/80-18 is 110 mm wide in section width and, furthermore, the section height is also 110 mm or 100-percent aspect ratio. Hence, a 130/80-18 under the new standards markings is designated a 110/100-18.



Kind of more confusion!

At least the dual sport tires adhere to the old metric measure, so the tire to use would either be a 110/90 or a 120/80. Of course everyone wants a fat tire, so most run the 120/80. Maybe I'll be different and do a 110/90...

 

Damn dude you are full of knowledge! That's an awesome representation!

 

Wow thanks for the information, i still dont understand it but i do know what tire to buy

 

That was the problem with the 4.60-18 (and others like it, like MT90 or MU 80), totally loopy. And I spent over 20 years selling bikes/accessories/tires at a dealership full and part time. The metric system was the best thing to happen to tires - totally understandable, numbers up front. No black magic numbers or letters in the sizing.

Just don't go too big on your tire. Do your gearing for speed with the sprockets, not the tires. That is extra unsprung rotating weight and more cost. It also pinches up the tire making you run on less rubber when vertical. Smaller isn't always worse.

Mine has a 120 on it and honestly from a performance standpoint it looks too big in my opinion. I'd rather replace the tire a bit more frequently if it gives me enough performance value. When I go new I'll likely go 110/90-18 to see how it goes. Actually it should be a small amount taller than the 120/80 if you do the math.

 

What do you guys think i should go with for tire size i think i am going to go with the AC-10 I ride northern Nevada, almost no water. Mostly hard pack/gravel road, I tend to stay away from sand if i can should I go with the 100/100/18 or the 120/90-18? I have both in cart wait to push the button, let me know.

 

I vote for the 100/100-18.

 

just bought them went with the 100/100-18 got front and rear for 140 shipped 2 day

 

I agree, that is the equivalent of a 110 in width of tread. The 100 I think is the "new MX tire" sizing I spoke of.