Question: what size bmx pegs do i need?
Answer: Most being between 4" and 4.75" in length. The only other thing to look out for is what Axle Size pegs you'll need. BMX axles come in 10mm (3/8") and 14mm so likewise pegs can come in these sizes too. However most Pegs today are supplied in 14mm with 10mm adapters, to save manufacturing two different sizes.