ugh.. no this is not intentional and it's only temporary..

so I'm ready to put on my 525 sprocket. My entire setup right now is 525 everything.. I go to put and realize it's not the right product (wrong model holes don't match up). So I'm mad.. and I look over and see next year's 520 aluminum sprocket in the corner of the garage.. So I throw it on.

Anyways.. Am I good for probably half a week or so. As soon as I get the proper 525 sprocket in I'm swapping back.. but in the mean time the 520 aluminum rear is on a 525 chain. At most I'd probably put 100 miles on it before the new one comes in.

 

Don't give it a second thought. Yes there is more room for the chain to move laterally, but if the wheel is aligned properly, it's not an issue. I rode with a 530 chain on 525 sprockets for thousands of miles before replacing it. It's what the PO had put on and not having something to compare it to, I didn't know it was wrong.

 

Chain pitch is different, each link has slight different length.. spaces between each tooth on the sprocket is different between 520 and 525 pitch. Iit might look like it works, but it would just wear out the chain and/or sprocket much sooner.

You gotta have chain and all sprockets the same pitch... all 520 or all 525, can't mix-n-match.