i second Johnyx, i went -1/+2 and it does exactly what he says, i did it for stunting tho... and my speedo is off about 6-9 mph off... the only reason i switched to 520 was because the guys at my honda shop told me 1) the sprockets are cheaper and 2) there are mnay more sprocket combonations for 520 rather than 525. everybody i stunt with runs 520...

 

Many stunters choose a massive rear sprocket for wheelies, +5 being the most common. +8 is somewhat common as well but it's like an "instant" 12 if you WOT. You may have heard them called "pizza sprockets" due to their size.

The speedo will be off by a percentage, not a specific MPH; that's why it varies. I don't have the math, but it depends on the bike and where the speed is measured on it.


All of this is absolutely true. 530 also has a wide range of sprocket options. 525 is an oddball pitch, so it gets overlooked. It should also be noted that depending on exactly what sort of "stunts" you're doing, the faster shifting of the 520 may be beneficial.

 

It should also be noted that your speedo is off by about 5% from the factory. Of more important concern: Adjusting your gear ratio affects your odometer by the same percentage as the speedo, making it look like you put more miles on your bike than you actually did.