If you are talking about bycycles then decathlon will be a food option but if you want to buy for motor bike karol bagh will be the best option
Karol bagh bike market naiwalan.
Gaffar Market or Lajpat Nagar .
Karol Bagh is the best option for your bike. There are many whole sale shops.
Cycle Market in Karol Bagh is the place to be!
Karol bagh and Gaffar market
One Stop - Karol Bagh, there are various shops on the same road.