How much speed will I lose on my Blaster's top end when i buy 20" Maxxis Razr's instead of the stock tires. I Know i can compensate for this speed loss with a 14 tooth countershaft sprocket, but how much low end power will i lose by doing this. I guess that was kinda confusing. Will i be better off leaving the 13 tooth sprocket on and buying 20" tires and sacrificing top speed, or should i get the 20" tires along witht the 14 tooth sprocket? I know this isnt an easy question to answer so just help me out if ya can. thanks

 

I wouldn't think there would be that much difference with the 20" tire. My brother put 18" tires on his Blaster and he lost a little on top end speed. He now has a 14 tooth sprocket on it so it doesn't rev so high. If you go with the 14 tooth sprocket and 20" tires, I believe that will overcompensate and it will be a little more sluggish on the low end. But it still would be fine because 1-3 gears are low enough and the Blaster revs quick enough to get you up in the power band. Someone who has used 20" tires and a 14 tooth sprocket may have a more accurate answer for you.

 

About one inch difference on about a twenty-inch tire is about five percent increase in RPM for the same speed. You might notice it, but it will not be much different.

I can’t calculate the change of the counter shaft sprocket without knowing the rear sprocket size but my guess is changing the counter shaft sprocket by one tooth will be closer to eight percent change. That is completely a guess…

 

stroke9, if this helps the rear sprocket size is 40 tooth.

 

21inch to 20 inch there it makes the atv sit a 1/2 inch closer to the ground and u will not notice much of the top speed being gone. i have the 20x11x8s on mine.

 

I calculated your ratio change from 13 to 14-tooth sprocket and came up with about 7% increase. So if you change the tires and sprocket you’ll be faster by 2%. It might even be faster than that because of less mass of the new tires. Engine might be able to rev higher even though you have changed your final drive ratio.