Hello guys,
there are several methods to reach your target, plz check these threads:
make-wheels-further-apart-when-folded-redux
maxxis-hookworm-16-x-1-95-53-305-tyre-request
16-custom-wheels-radial-36-spoked
strida-front-wheel-magnet-spacer
Preferably should the spacer be used at the front wheel, this keeps the magnet catch function 100% intact.
The required thickness can be calculated like so:
Wider tyre width minus initial tyre width = thickness spacer.
If you like such aluminium spacers as shown above in the second thread (plus longer bolts) you could drop me a pm.
Cheers,
Chris