ASK THE MXPERTS: THE LONG & SHORT OF KTM’S LARGER AXLE SLOTS
Since the 2018-1/2 KTM 450SXF Factory Edition has longer axle slots, what would the benefit be of sliding the rear axle all the way back?
All 2019 KTM big bikes models are fitted with a reworked cast aluminum swingarms featuring a longer slot for the rear axle. This allows the adjustment of the rear wheel in a position up to 5 mm further back. It is a good thing that you said you wanted to slide the axle all the way back, because the the 2019 KTM axle slots don’t go any farther forward than they did in 2018. There will be three effects of sliding your rear axle all the way back.
(1) When the rear axle is moved rearward, it increases the leverage ratio on the rear shock, thus it will make your rear shock feel softer—and you may have to stiffen up the compression to deal with this.
(2) By making the wheelbase longer, you will effectively move the engine forward in relationship to the wheels. This will put more weight on the front tire, thus it could make your bike turn better or worse (depending on track design terrain, tire choice and body position).
(3) Conversely, moving the rear axle rearward increases the bike’s wheelbase, thus the handling in corners could slow down. Conversely, high-speed stability should improve. You will have to judge whether the effects of the longer chain make your bike feel better or worse.