Is it ok to have say 27" tires on back adn 26" on front of a fulltime 4x4? please help if you know

 

If factory original quads of the make and model in question have different diameter tires front and rear, no problem; front and rear drive ratios are different, accommodating the different tire sizes.

If new quads have the SAME size tires front and rear, you'll get ground-scrape if you mis-match tire sizes.

Diogenes

 

Your front and rear tire diamater should always be the same. Unless your quad came from the factory that way with the correct R&P set up to allow for the different tire size.

Rick