Fly Sierra 3 BMX Frame Review

4.0 rating

The Fly Sierra frame is one of Fly’s most popular frames. It has some bigger geometry like the chain stay and top tube, but this frame has a shorter stand over. This will provide a good balance between flowy and technical riding. Sierra parts have been Sergio Layos’ signature line for years, and they kill it each year.


✅ – 13.6″ chain stay
✅ – 5 lbs
✅ – drilled for gyro tabs
✅ – Full Chromoly
✅ – Built-in chain tensioner

Price & Weight are comparative to how good the deal is.

Good deal = 5 Star

Bad Deal = 1 Star

Sergio Layos Signature


After another amazing year for Sergio Layos, Fly has only made a few small changes to make his signature frame even better. Sergio has decided to make the move back to a 75° head tube angle, The frame features internal and external gussets, multi-butted and tapered tubing, an Investment Cast seat post clamp with the Horizontal Cut System, removable EBS style brake mounts, and Investment Cast Dropouts with integrated chain tensioners!

From Source


Price: $369.95



  • 20.6″
  • 20.8″
  • 21″

Learn about frame sizes here


Frame Specs
MATERIAL: 4130 Chromoly
BB HEIGHT: 11.5″
HEADSET TYPE: Integrated
GYRO TABS: Drilled
WEIGHT: 2.300 kg / 5 lb (21″)

Frame Geometry

This image has an empty alt attribute; its file name is geometry.png

A: Top Tube Length: 20.6″, 20.8″, 21″ – Learn what size is right for you here.

Good options for medium to tall riders. Make sure you know what size you need.

Check out the BMX Size guide to figure out the right size for you.

B: Chain Stay Length: 13.6″ – Learn About Chain Stays Here

This is a long chain stay. A long chain stay will give riders more control and stability.

But it will make spins harder.

C: Head Tube Angle: 75.º – Learn About Head Tube Angles Here

Steep head tube angles make the bike “snappy” meaning more responsive to fast turns.

A less steep head tube gives you more control.

D: Seat Tube Angle: 71°

E: Bottom Bracket Height: 11.7″

F: Stand over height: 8.75″

This is a medium standover. A medium standover balances responsiveness and control.


Sergio Layos has always killed it and he really deserves this line. The Sierra frame is strong, light, and simple. Designed best for a rider that wants to flow park. Since the specs are aimed at the “flow” aspect of riding, technical tricks will be harder to do.

Buying a frame?

Don’t forget a bottom bracket here

Don’t forget to get a headset here

Douglas Laird

Douglas is a 23-year-old BMX rider who got his first true BMX bike for his 13th birthday and has been riding nonstop for over 10 years. “Bmx has taken me too well over a hundred skateparks across multiple states and countries.” was born to help people understand the sport that has changed my life for the better. My goal is to help you with everything BMX related. With over 200 BMX posts and counting, is quickly growing to be one of the best bmx related websites.

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