Reynolds 631 - cold drawn
UTS: 52 - 58 Tsi, 115 - 130 Ksi,
800 - 900 MPa
 
Following on from the success of 853, Reynolds have added 631 to the range of AIR HARDENING STEEL tube sets. This seamless cold drawn steel tube will allow the benefits of this new steel to be used in the manufacture of a wide range of frames and is now considered a worthy successor to our legendary 531 tubing. Like 853 it is suitable for TIG welding and brazing and in the heat affected joint areas will gain strength, to ultimate tensile strengths in excess of heat treated chrome molybdenum. The strength to weight ratio of 631 is equal to that of many aluminium frames, and it has an excellent fatigue life whilst providing a supple ride quality suitable for long distance events.

On road and touring frames we suggest 631 or 525 forks be used in conjunction with 631 frames. As 631 is only available in main frame tube sizes, we recommend the use of either heat treated CrMo (725) or cold drawn CrMo (525) seatstays and chainstays to complete the frame.