120/80 vs. 120/90 How do they ride?

We're probably not good enough to notice a difference but I ran a 120-90 and didn't even know it. I think it was an in store closeout at Chaparral. Made no difference to me. 

Almost 40 yeara ago, the 120/90-19 D695 was the OEM tire for the KX500 and all the other tires to fit the KX500 were also 120/90.. Wasn't until the four strokes came around that stuff started coming out in a 120/80.

With the massive variance between the actual tire sizing from brand to brand even when they have identical numbers on the side it isn't an apples to apples comparison unless it is within the same tire brand, and even then could be a casing difference (MX vs an XC type tire).

In the world of the mx34. The 120/90 is significantly lighter than the 120/80. Toss them on a scale.

The ride exactly the same for 99% of riders….

It's tall, so gearing is changed. Your triangle stand will be suddenly too short. Can run less air in it due to taller sidewall,  rear is softer, more traction, more wallow(feels kinda like half a flat) but the traction is nice at lower psi so. Great for rocky off road conditions 

Did that on my 250f, just felt like I had to shift more often…

120/90 better straight line stability, grip, and a more comfortable impact going through like desert whoops, but also can affect handling. Also somehow lighter than the 120/80.

120/80 more responsive in corners.

If youre doing a lot of choppy straight line stuff, on hard pack youll notice a different in the 120/90 vs the 80. If not you probably wont see or feel much difference.

A or B both are good tire sizes and it comes down to personal preference or whats easily available. Typically you have to order 120/90s online from what I've seen around my local shops. If you're the type to just wanna run in and grab a tire on a whim. 120/80s will be the go to.

I’m a fan of 120/90/18s..

I've always run 100/90's even on my 250 2 strokes/250 4t, guess i'm crazy...

Another 120/90-19 fan here, on both my KX450 and KX500.

It should be the opposite, the taller tire will make the gears pull longer. 

Maybe it’s in my head hahaha

Like I said...for 99% of riders they ride exactly the same.

120/90 more cushion for absorbing chop (like SX whoops) and slightly less likely to pinch flat.
120/80 slightly more grip surface area leaning on hard packed corners, shorter height allows slightly tighter turn radius.

*measurements, tread pattern, and sidewall rigidity all vary across tire models, even within brands.