polaris bogie wheels question

[sean34590577]

I have a 2005 xc/sp. I'm missing the middle bogie wheels on the outside?? I think I need these SUBSTITUTED BY 2873928-244 Is this correct. What size are these. They are smaller than the 2 on the outside back. I think I measured right at 5 1/2

 

[jimfsr]

All the smaller idler wheels are the same size. the rear ones are larger.