if so, which size spacers would I need for stock rims?

 

It depends on the width of the 35's you get.



The spacers move the tire outboard, to prevent inboard rub, (Brakes, wheel well, etc)....they can ALSO cause OUTboard rub (Fender), if TOO far out.

A wider stance is more stable, and most people feel it looks better.

If you are getting the classic 12.5" section width 35" diamter tire, most people find 1.5" of spacing, or new rims with 4.5-4.75" of back spacing to be perfect. (People with 3.5" of BS for example have tires that protrude outboard of the fenders, which in most states, is not allowed by law....and, can hit the fenders on the way up, etc. (Plenty of people do "out rigger" stances anyway....but, you should know at least that these are potential issues, etc)

The stock rims have 6.25" of BS....-1.5" = 4.75"

The stock tire size of 255 mm section width is like a 10" section width, 2.5" narrower than the 12.5" section width 35's.

(305 - 315 mm section widths work out to about a 12.5" section width equivalent TREAD width...mathmatically, the 315 is closer, but many 305's have the same tread width despite a narrower section width in that size range)

As HALF of the extra 2.5" width protrudes inboard (~ 1.25") a 1.25" spacer is the minimum....but, as the 35" diameter makes it swing in a wider arc too, on turns for the front tires....the extra 0.25" of spacer thickness helps to prevent turn related rub too, etc.

Hope that helps!