The spacer that you should run is the width spacer that comes with the Mi3 kit. However, you will need to ream the centre a little to fit over the step that is now on the axle sticking out past the hex.
This will make the width of the car wider. If you really want it narrow, then you will need to modify the wheel a little. You can put a small chamfer on the inside of the wheel with a hobby knife.
It is a little hard to explain (or be sure people understand). If you get the steel driveshafts and fit them, i'm sure it will make sense.
I don't use the steel's personally, but i know what needs to be done to fit. I run the TiR "Worlds Edition" Alloy ones.
Originally Posted by jopor
i´m going to put the steel ones (U2151) but a guy told that i have to put a spacer.
anyone of you are using the steel drive shafts and how you tighten the hex´s against the Hub ball bearing, cause i want to wear that ones but i don´t know what kind of spacer do i have to use.
please help me in this issue