Supercross BMX | SX250 - 33 Year Radaversary BMX Chassis

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Back in 1989, when we started Supercross BMX, the original frame was our 6-bar design. We used the 6-bar for over a decade on our Cro-mo and Aluminum BMX race Frames.

During the SX250's design process, the Steel Mills were limited on tube sizes. So to solve the issue of frame flex, we added additional triangulation. By lowering the first set of seat stays and adding the second set of stays, we increased rear-end rigidity. This produced a stiffer, faster-accelerating frame, that still rode smoother than other options on the market.

Since we discontinued the 6-bar rear end, we always get asked about doing a re-issue. In 2019, for our 30-year anniversary, we did a limited run of 6-Bar SX250's . But this was no old-school wall hanger. Rather an actual modern race frame with a retro aesthetic. We brought TANGE back on board to build a few more Prestige® Tubesets for the ultimate Retro Race bike. There were only 30 pcs of each size!

Since then, we've had a ton of people ask us to do it again. But this time, they wanted the 29" frame set. So for our 33-year Radaversary, we are bringing you something similar.

Introducing the SX250 6 Bar Chassis Kit - A Reynolds Cro-mo version of our original 6 Bar frame in a 26" Pro! We're also bringing back the popular 24" Pro XL Cruiser.

You'll be getting all the goodies:

- Triple Butted Reynolds Tubing

- Flared Seatmast

- Heat Treated Cro-mo Dropouts (CNC'd with the Supercross Logo and also weight on the back side.)  

The Serial Numbers on these are 25033 "6" for 26," and then 1-50 for the 50 Limited Edition Frames in the 26" Size.

"4" for the 24" and 1-50 for the 50 Limited Edition Frames in the 24" Size.

26" Frame Specs

 Top Tube 22.75" (577.8mm)
Head Tube Angle 73°
Seat Tube Angle 71°
Chainstay Length 15.75" (400mm) at center
Bottom Bracket Height  11.625"


24" Frame Specs

 Top Tube 22 (558.8mm)
Head Tube Angle 73.5°
Seat Tube Angle 71°
Chainstay Length 15.35" (390mm) at center
Bottom Bracket Height  11.625"

The Chassis Kit is the Supercross BMX SX 250 Reynolds® Butted Cold Drawn Cro-moly Steel. A Heat Treated 4130 Seamless Cro-mo Supercross Pro Fork with Welded in Star Nut, and a Speedline Sealed bearing Campy Style Integrated Headset.

Please post pics of your builds and share your serial # on the Supercross BMX Riders Group on Facebook. We love seeing our frames out in the wild!