I have a 2020 Polaris sportsman 450HO with 24x10-12 and I bought some tires and rims off of a 2015 Polaris sportsman 1000xp that are 26x11r14. The rims do not seem to fit. Is there a right way to make it work?

 

25x10x12
the first number is the od of the tire, the second number us the width of the tire, the last number is the rim diameter. In your case you had 12" rims and bought 14" rims

 

I understand that part. I bought tires and wheels already mounted and doesn’t seem to fit my hubs. Thinking I might need a spacer or adapter?

 

Have you tried all 4? The Sportsman 1000 should be 4/156 bolt pattern like your 450 HO. Are you sure that's what they came off of? Are you sure the 1000 didn't also have adapters? It's possible the 1000 they came off had wheel adapters to change the bolt pattern to match the wheels.