KLX 250 Tire Quandary

I didn't go into the Wild Bear Safari last weekend with high expectations from Kawasaki's OEM tire selection. The 2019 KLX 250 is equipped with a Dunlop model D605 50/50 dual sport tire. Honestly, I've never heard of this model and I can't even see where it's for sale in anywhere other than some very distant places...like Australia..say nothing of the lack of information on things.

Overall, it really isn't a bad 50/50 tire from a performance perspective. In fact, I might put it a slight notch over the Heidenau K60 Scouts in performance...a tire that I'm very familiar with and that has moving toward being the Gold Standard in middle duty dual sport and adventure rigs. Getting through the Wild Bear requires good sand skills and a good sand tire to back it up. I have lot's o' experience in the Florida Sandbox, so technically I was able to make them work. In my opinion, a true 50/50 may really find these tires a good match.

Unfortunately, I'm a 10/90 rider and I need to move onto a tread that I can spend all day on sandy or muddy forest roads. The amount of physical drain that sugar sand and the technical skills to get through it demands is one thing. Doing it all day, one needs some help.

My regular 10/90 tires that I used on my KLR650 and my DR650 were the above's big block brother, the D606. I know them well and they were in the selection process, but I wanted to really take a close look at some others, specifically the Pirelli MT21 RallyCross, Pirelli XC/MS Soft, Michelin AC10 and Michelin S12 XC. Michelin was a favored sand tire provider during my motocross days.

However, before I could even get into researching the individual tire choices, I actually found myself in a quandary trying to figure out what the actual size of the OE tires were and the clearances for other brands on the motorcycle!

Essentially, the quandary started with the fact that the D605s used the old numeric standard that excludes the aspect ratio. Here are the sizes of the tires. If you're as old as me, these numbers have some meaning, but we both have lost touch with what they really mean in today's metric measurements.

Front: 3.00 x 21

Rear: 4.60 x 18

So I initially thought that I could just do a conversion from inches to mm to get the first of the metric conversion. That would be:

Front = 3.00" = 76.2 mm; Rear = 4.6" = 116.8 mm

Rounds out to an 80 mm front and a 120 mm rear

Then I started to see indications that the rear width spec (which didn't seem available from Kawa) may be quite a bit smaller. The indications were found in a KLX250 discussion forum and even on Rocky Mountain ATVs site as follows:

So they're saying:

80/90-21 Front and 100/100-21 Rear

Well crikey, now they've done it. Heading out to the shop with my caliper to get the tire (and clearance) readings. Here they are:

So, here are the actual measurements:

Front: 87/91-21; Rear: 119/86-18

In popular sizes:

90/90-21 Front and 120/90-18 Rear

Total clearance between the two points closest to the widest point of the D605 tires (forks front, swingarm rear) was 132 mm front and 163 rear. While those are pretty good numbers to work with, I need to force myself to keep in mind that as I look at other tires, different tires with different widths and different aspect ratios could have difference total clearances. These numbers are just useful to work with.

This new information helped me with a short list of two tires that were available in the sizes that I decided would be best (both 10/90 DOT), and that was largely based on the fact (generally) thinner knobby tires are going to be better in the sand than wider knobby tires. The sizes I'm going with are...

80/90-21 Front and 110/100-18 Rear

...and the brand/models are:

Michelin AC10

Pirelli MT21 Rally Cross

I put my order in for my selected tire at Rocky Mountain ATV and will post some photos when I get them installed. Stay tuned...