Six wheeled vehicles Possible?

Hi Im trying to get a 6 wheeled APC working based on the advanced vehicle template.
I have everything set up and working But only using 4 of the wheels on the apc and just faking the other 2,s rotation by copying the bone rotations of 2 of the rear wheels I have set up,. BUT NO SUSPENSION :(. Because every time I try to add the 2 other wheels in the Advanced vehicle BP all the wheels stop working.
Is there some kind of issue with adding more than 4 wheels to vehicles in UE4.