Original equipment stock tires for the 2002 Kawasaki Super Sherpa (KL250) were Bridgestone Trail Wings (TW301 and TW302). The Trail Wings are categorized as 50/50 dual sport tires (generally averaging 50% trail and 50% highway). Factory specification for tire sizes associated with the model are:
- Front: 2.75-21 (Loosely converted, On-Road 90/90-21; Off-Road 90/80-21)
- Rear: 4.10-18 (Loosely converted, On-Road 120/80-18; Off-Road 100/100-18 or 120/80-18)
Of course, 50/50 tires aren't suitable for the southeast rally circuit, nor were they at least as to the rear for the prior owner. When I took delivery the little trailblazer, it had a 90-dirt/10-highway Dunlop D606 120/90-18 stuffed in the rear. The original OEM Trail Wing, now over 18 years old and showing its age, was still holding air up front.
The category of tire that I need for the kind of riding I have planned (sand, mud, clay, gravel) is in the 90/10 category. While the D606 is in that category and had a good deal of life left, it was way too big for the little Sherpa. In fact, the left knobs had worn the strangely shaped swingarm and the mudguard that sits at the top of the swing arm was smashed to smithereens!
I considered a number of options, but the tires that I landed on were Kenda's K760 Trakmaster II in the sizes of 80/100-21 and 100/100-18. The price tag at RMATV was $45.88 for the front and $46.88 for the rear.
The bad thing about motorcycle tires is that the published sizes often don't equate to the tape readout when measured. That can be a problem from a "width perspective" when you measure the width in the swing arm to accommodate a size only to find that the actual width is more! The "height perspective" can equally be an issue when a tire that's too tall doesn't fit under a fender or offer enough room for trail media to channel through. These issues are both present in the Super Sherpa. This is well know and require that I get the ruler and the caliper out.
As it relates to the Trakmasters, the actual width measurement at the widest points of knob at full "in-use" inflation front and rear are 90mm and 116mm, respective, where the published widths were 80mm and 100mm. I faced this very same issue (albeit worse) when spooning Michelin AC10s on the old KLX250 where a published 110mm tire measured out to a whopping 130mm installed!
I got the Sherpa home, pulled the rear wheel out and put my ruler to work because I was much more concerned with the rear than front clearances. The first thing I noticed was that the swing arm was not symmetric such that it made width decisions very difficult because the distance from the center line to the swingarm was a different number on each side.
Note that the left side of the swingarm is straighter than the right. Also note the size and shape of the corners.
The good news is that the 100/100-18 Trakmaster (116mm wide) fits in there just fine, although with very little cushion, particularly on the left.
Unfortunately, my obsession with the rear tire fitment caused me to miss the problem up front ... fender obstruction. Yeah, the 80/100-21 Trackmaster fits fine between the two forks, but doesn't allow use of the low fender. It will will bolt on, but provides almost no space for channeling trail materials like dirt and sand. That's actually dangerous.
Now, this is by no means the end of the world. First and foremost, these are aggressive knobby tires that, as you well know, have ridiculously short lifespans. Between now and the inevitable, I have two options. One is a simple square set of brackets that raises the fender; easy fabrication. Another is a plan I was already working on which is installing a high fender.
As a former Sherpa owner, in addition to being a current Sherpa owner, I already knew that the stock fender location wasn't going to cut it for dual sport rally conditions in the southeast. While I want to have the option of lowering the fender for some riding activities, I need a high fender for the rally work.
I had a raised fender on my old 2009 Sherpa as shown in the photo below. It's a UFO SuperMotard fender that costs under $25 and is easy to install. I have another on the way and will figure out what to do with the low fender between rallies this year.
In summary, the Super Sherpa is a bugger to source more aggressive DOT knobbies for. That's due to the strangely designed swingarm and the low fender. Essentially, fitment calls for saying at or below the true "in-use" tire widths below.
- Front Max Width 90mm
- Rear Max Width 116mm
The maximum section heights are:
- Front Max 72mm
- Rear Max 100mm
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Note:
It should be noted that some tire manufacturers post actual widths on their websites. There are two different measurements. One is Static Width, which is the width of the unmounted carcass. The other is In-Use Width, which is the width of a mounted, inflated and warm tire. It's likely that the in-use width is going to be (at least) closer to the true width.
For example, I'd previously mentioned working with Michelin's AC10s on a KLX. The published rear tire width was 110mm. The actual measurement was 130mm. Michelin's website showed the in-use width of that tire as 120mm. Some help; not much, though.
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