I am considering buying one or the other. I have tried to the Polaris website and searching the forum but I still am not sure about all the differences. Here is what I know:

- Bore Size
- Different tires
- reseivior front shocks on 450

Also what is the HP for each model and how would they compete against each other in stock form for drag race on dirt/gravel road and on the trails?

 

the only diffrence i can find is:
450mxr
front 20x6-10
rear 18x10-9
weight claimed dry 365lbs
shocks fox podium x on front and rear
tires maxxis razr mx
525s
front 21x7-10
rear 20x11-9
weight claimed dry 375lbs
shocks front fox podium rear fox podium x
tires maxxis razr
the 525s will beat the 450 in a drag and better on the trails due to the bigger tires.if you get the 525 get a jet kit for it if you've looked at the other posts on the site you know it's on the lean side from the factory. dirt wheels did a shoot out between the 525s and the 525irs. they liked the irs better than the sra.

 

Thanks sjbr549 !!!!!

 

Here a good read up on both at once. with Videos also

The 450 is KTMs 450 MX moto while the 525 is KTMs largest MX engine. So naturally it will out power its smaller brother.