If you want to increase the wideness of the car, you can use those.
Check ->Absima 2560020
This Adapters enlarge the wideness maybe 3mm per side. I made my similar to them but I designed a other kind of washer to make a better fit from the rim to the adapter.
I use them on my 1:10 Patron SC to mount buggy wheels with 17mm hex.
The round part of the adapter fits into the hole of the rim and the small "tube" part of my "washers" fits into the
hole of the adapter.....