You are reading a single comment by @gbj_tester and its replies.
Click here to read the full conversation.
London Fixed Gear and Single-Speed is a community of predominantly fixed gear and single-speed cyclists in and around London, UK.
This site is supported almost exclusively by donations. Please consider donating a small amount regularly.
@gbj_tester
Who said anything about 'alloy'? To be precise, ljsfg said 'composite', although he was ambiguous about whether it was a steel+aluminium composite or steel+something else.
In the case of steel/aluminium composite, it seems perfectly plausible to explosively weld a very thin walled steel tube jacket over an aluminium core. This would exploit the stiffness of steel on the outside while the low density aluminium would provide support against buckling, which is a problem when the ratio of diameter to wall thickness exceeds about 60. By exploiting the different material properties where each is best suited, rather than compromising the design to get around the limitations of a homogeneous material, the steel/aluminium composite seat post ends up better than the standard Thomson part, and should therefore cost more in a rational market. The explosion welding patent was granted to Dupont; if the seat post were made by Thompson that would have to have been Dupond, which is clearly nonsensical
tl;dr: £45 for a Thomson is a steel