Tire size for 2006 YZ450 for motocross


6 replies to this topic
  • Eric908

Posted March 24, 2009 - 06:07 AM

#1

There is a difference in tire sizes for my 2006 YZ450 compared to the 2008 YZ450. I'm just wondering if I should move up to the 2008's tire sizes. I race motocross and am wondering if there is an advantage to changing from my original 80/90-21 front and 110/90-19 rear to the newer bike's size of 80/100-21 and 120/80-19. Also, will the newer ones fit?

  • spark250

Posted March 24, 2009 - 06:18 AM

#2

I tend to like the skinnier rear tire which is the 110/90. I have trouble in rutted turns and jumps with the wider tire. I guess it depends on the terrain you ride in.
Also the 120/80 will change your gearing. The second number refers to the sidewall height.

  • grayracer513

Posted March 24, 2009 - 06:35 AM

#3

Also the 120/80 will change your gearing. The second number refers to the sidewall height.

Not true. The 120/80 and the 110/90 are functionally the same height.

The third number in a tire size is the rim diameter. Everyone pretty much understands that.

The first number is the nominal width in millimeters of the tire body (not the tread) when mounted on the specified rim size. The tricky part here is that there doesn't seem to really be any standard practice as to whether the width is measured inside or outside, but no matter...

The second number is the aspect ratio. This indicates the nominal height of the tire body, measured from the bead seat to the top (somewhere), as a percentage of the width.

So, a 110/90 is 110mm wide, and 99mm tall, while a 120/80 is 120mm wide and 96mm tall. Virtually identical (less than 1% different in overall diameter)

I like the "standard" 80/100x21 and 110/90x19, but some tires come in 120/80 for certain kinds of soils, and these can be treated as interchangeable with a 110/90 in almost every case. I don't like the bigger, heavier 120/90's much at all.

  • WILLIAMS37

Posted March 24, 2009 - 07:04 AM

#4

Thanks for the info Grayracer. I have a 110/90 laying around that I didn't think I could use. I didn't understand the difference between the sizes.

  • spark250

Posted March 24, 2009 - 11:02 AM

#5

Not true. The 120/80 and the 110/90 are functionally the same height.

The third number in a tire size is the rim diameter. Everyone pretty much understands that.

The first number is the nominal width in millimeters of the tire body (not the tread) when mounted on the specified rim size. The tricky part here is that there doesn't seem to really be any standard practice as to whether the width is measured inside or outside, but no matter...

The second number is the aspect ratio. This indicates the nominal height of the tire body, measured from the bead seat to the top (somewhere), as a percentage of the width.



owned! :thumbsup:

  • writebrian

Posted March 24, 2009 - 01:19 PM

#6

Quick... What is stock gearing on 2006 YZ450F?

  • grayracer513

Posted March 24, 2009 - 01:22 PM

#7

13/49

Why?





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