The tire sizes are in the old format, ie 4.00x18, but what does that translate into the metric sizes? I suspect the rear is a 100/100-18 and the front is an 80/100-21 but I am not sure. Can anyone confirm?

 

That sounds about right. There are 25.4mm to 1 inch, so 25.4x4= 101.6mm Sounds like the 100-18 might either 1.6mm narrower (whoopie!) or maybe they are just rounding things off, since 1mm won't matter for squat when it comes to tire width.

 

According to the Dunlop "fitment guide" the metric sizes are 90/90-21 and 120/90-18.

http://www.dunlopmotorcycle.com/fitmentguide.asp

 

Thanks, I found that, but good luck finding many off road tires in those sizes. I read here or on Advrider that a 100/100x18 will fit in the back, so I ordered that and ordered a 100/80x21 for the front in the Dunlop 756s. From what I can gather, these should fit, also, assuming the rims on the KLX250 are the same size as the KLX300, all should be fine.

What I do not understand is why off road bikes have the sizes in metric but dirt bikes have them in inches and why it is so damn hard to find true off road tires in the exact sizes. Must be my newness to off road riding I suppose.

 

Kawasaki lists them as 100/100-18 & 80/100-21

http://www.kawasaki.com/Products/Det...specifications