Where Best To Get 34T cassette & 38T to 42T For Giant Folding Bike

[johanhorak]

We have two Gaint Expressway 1 folding bikes.

 

I want to change the gearing to better meeting touring needs:

 

Currently, the cassette is specified at 11x30 and want to replace it with a 34T cassette (R330 olympiccycles.co.za).

 

I want to replace the 52T chainring with a 38T to 42T (5 bolt - 130 BCD).

 

Replacing the cassette seems to be easy via olympiccycles.co.za in Claremont but they seem to have a problem with getting a 38T to 42T (5 bolt - 130 BCD). (It does not have to be Gaint originals).

 

Not sure why.

 

Do you know of any Cape Town southern suburbs bike shop that can assist? 

 

I was able to find a 39T at $18 from Aliexpress. 

 

I hope you can assist.

 

BTW: I only learned yesterday what BCD meant