DESIGN OF LOW PROFILE FRAMES (Jim Cook MCEI)
Steel still the best material
A low alloy steel tube frame built correctly with lugs or fillet brazed is technically and aesthetically superior. The latest steel tube sets are equal in weight to their aluminium competitors.
They also have the advantage of having a longer fatigue life, and a superior ride quality.( micro vibration damping)
Thin wall tubular structures that are subject to continuous reversals of load require a material with a high fatigue life. Aluminium is not the material for that environment. According to recent reports the American market is moving back to Cr, Mo alloy steel for frames, I doubt that it is just a fashion statement.
TIG welded alloy steel frames should not be viewed as a technically advanced product. Yet again the cycling pundits express their opinion on the merits of TIG welded frames, what they should be
considering is why the manufacturer chose the process for frame fabrication. Taiwan factories can now produce complete aluminium frames in less than 3 man-hours.
TIG process advantages on main frame joints.
1. It can be automated, reduction of man-hours per unit. 2. Machine operators can be employed on production. 3. Skilled frame builders not required. 4. Reduction of high cost frame components. 5. Less finishing time on weld areas. 6. Ideal high volume production method. 7. Lower unit costs = more profit.
TIG welded steel frames should be purged internally with Argon at ambient pressure as a vital part of the welding procedure, without purge the weld quality is highly suspect due to internal
oxidation (burning) of the weld area.
Why have I written this about frame design and building.? I’d like to think that if you have got this far in my rants, like me you like bikes, and you would love to go faster or ride in comfort to your
maximum potential without backache and neck pains, neither of these contribute to your performance. . I hope this brief outline on design and construction will give you a guide to some of points you should discuss
with your frame designer/builder and the specification of the next frame you ride.
J Cook. . MCEI M.A.W.T.E NIMBUS DESIGN. FEB 2002
Hon Chairman. Cycle Engineers Institute (now retired)
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