Riding a bicycle is prohibited on some roads according to Dubai traffic Police. While on some roads you can ride a bicycle by only following these rules;
The speed must be 60 km per hour
While the accessories that you need while riding a bike are;
Helmet.
Bike Bag.
Patch Kit.
Spare Tube.
Minimum Tools.
Pump.
Tire Pressure Gauge.
Water Bottle and Cage.
Here are some stores in Dubai that offers bike accessories;
Bike Shop Dubai
Revolution Cycles Dubai
Dubai Sky Motorbike Trading LLC
Satwa Bike Shop
Sameer Hassan Bicycle Trading LLC
Wolfis Bicycle Shop

https://www.amazon.ae/Cycling-Accessories/b?ie=UTF8&node=12264335031