How much do smaller rear tires take away from the top end speed of an LT80? I'm looking into buying a set of 16x6.5-8 or 18x6.5-8. I plan on staying with the stock size up front.

 

Its the same thing as making a gearing change. Your just doing it at the tires instead of the sprocket. No different...

 

I understand going with a smaller tire will give me more low end. I just want to see how drastic the difference is from the 16" to the 18" tire from someone running these, but thanks for the reply.

 

don't know about on the lt80, but on my 250x 2 sizes smaller was quite noticable.

 

There is a big difference IMO.
We ran the 16's for MX. Usually a tooth bigger on the front sprocket for the 16's.

 

Jack, do you run a 13T or a 14T with the 16's.

 

Yes....LOL
As you stated, the 16's are going to give more grunt and less speed.
Depending on your riding condidtions:: big hills and I'd have the stock 12 tooth (428) front. To bring the speed back, a 13 front. If your a flatlander, a 14 front but your not going to rocket out of the hole. Usually for a stock motor, gearing up is what most do. the 14 or even a 15 isn't out of the realm with some roller weight adjustment.
I run a 13/26 with 16's with my motor but the rpm's are increased thus the smaller sprocket is used.