Hi. I am looking for some recommendation for a shop, which could make good customs training wheels. We just upgraded my sons bike and it is a lot bigger, than what he used to be and is now not confident to ride. The training wheels you can buy online are not suitable for the size he is now riding and getting it from overseas is quite expensive.

Probably wait and let him grow into it.

Training wheels are a personal thing: My Son's both learnt without training wheels, balance bikes first.

A recent trend is Balance Bikes and then straight to pedaling w/o training wheels. 

 

Perhaps you can take off the cranks with pedals and use his existing bike like a Balance Bike.

 

Not sure of your sons age or skill level etc but if it's not his first bike you might be surprised how with a little help he might be able to ride a bike w/o training wheels with a little practice. A slight decline is often of assistance when starting off for the little ones.