How long can I use the radian 3R, 3RX, or 3RXT for harnessed forward facing? June 07, 2021 11:02 Updated The Radian 3R series can be used up to 65 lbs. while forward facing. If you’d like to find out more about the Diono Radian 3RXT visit our store: https://store.diono.ca/radian-3rxt/ Related articles What is the maximum height and weight for the Radian 3RXT? How long can I use the radian 3R, 3RX, or 3RXT in booster mode? Will Diono remove flame retardants from their all-in-one convertible car seats? Radian 3RXT Comments 0 comments Article is closed for comments.