Where can I find it a variety of strong Velcro tapes? Preferably self adhesive.

To stop my leg from slipping off the pedal?

And other uses?

Lazada has just about anything you could ask for. I recently ordered several different widths, all self-adhesive, and they have the shipping down now to a science. Sometimes I receive overnight shipping!

I'm a regular customer of Lazada but for some reason I didn't think of Velcro, thanks

 Do I miss something? I'm looking for ready  to use Velcro with buckle or clasp of different lengths and width and strengths.

Where to find ?

Be cautious when buying velcro...

There is velcro and then there is 'Velcro™.  I've received too many orders of the bad stuff. All stiff plastic and wears out quickly. Look for the registered brand product.

OT group out on Chotana across from the golf course, but not sure if they’re still there. Other option is to try home pro, thaiwatsadu or maybe decathlon. If you get it online, be sure it’s 3m or Velcro tm as mentioned above.  

I would think the shops behind Worrorot market would have plenty of selection.