So I found a 60/60 14" dirt bike tire to fit the MSX. I was looking for something more dual-sport but I settled on this one made by CST (easy to find, available from multiple sellers). I have seen on this forum and on the facebook group that someone had fitted a 2.75" tire but had to trim it. I was reluctant to do this since I was not sure if I could do this evenly enough to not effect handling.
When fitted with this tire, the MSX is a true 18" wheel since the sidewalls are shorter. The tire is a bit narrower, of course, but is well accommodated in the shell. The tire is very stiff.
I've had it on for a few, limited sessions. With the tire pumped to its max 30 PSI it felt way too squirrelly. I lowered it to 20 PSI and it felt much better, though still very different. Part of this can be attributed to the narrower width but most is probably due to the tire geometry. The tread wraps more aggressively and remains deep as it rounds to the sidewall. Theoretically this should provide superior cornering grip. Riding it some very muddy grass it proved to be vastly more sure-footed than the stock tire.
On pavement, though, it has been an adjustment as the feel is totally different. Low-speed turning is almost no existent at this point and turning generally is difficult. With more time I found that turning was easier when under acceleration. More broadly it makes the MSX more active and, in a way, more nimble. Shock - absorption is great. Definitely a drag on speed. Certainly brings back early learning days...
Going to give it some time before I make a decision. Only have one wheel so this tire has to serve on and off-road. Going to take it out on the MTB trails after it rains...
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