39-53t chainring on full suspension bike I have a Giant Reign x1 bike which has 2X factory installed 22-36t 4 bolt Sram Truvativ chainring. The question is, is it possible to find 39-53t 4 bolt chainring that can be fitted to this bike  or if it's not possible what tooth ratios are possible?????

The reason I want to increase tooth ratio is my bike doesn't go fast enough on downhills no matter how fast I keep pedaling but in the same trail with my hardtail 3X chainring bike I can gain speed much better.

The highest speed record on trail, downhill, with full suspension bike: 61km/h (it's not possible to go faster unless the hill is steep slope) and with my hardtail one: 74km/h (It was possible to go faster)
The Giant Reign is a long travel 'enduro' bike that is designed to be ridden down steep technical trails, not pedalled down road/fire trail.

It's most likely that changing to a 39-53 will not work as the inner chainring will catch the chain stays, and even if it did work, it would compromise the bike in technical terrain, increasing the chances of 'grounding' the big ring on rocks etc.  You would also probably run into problems with the front derailleur as mtb derailleurs are not designed to work with such large rings, and the frame itself may not allow the derailleur to be mounted high enough to clear the 53t ring.

In addition, it would basically turn the bike into an 'uplift' only bike, as a 39t chainring would be much too large a gear for climbing off-road terrain.