Hi,

I have a flat rear tire on a City bike (Africa Kona bike).
I know how to repair a flat, but there's a few unfamiliar things to me.



a- theres quite a range as to where the axel locks in
b- there;s this extra thing here.
c- the gear box is covering the other axel.

d- yellow thing in the first pic

My concern is in removing the wheel and also in putting it back properly, specifically that the chain is tight.

any advice is very welcome
cheers,
Xav