The above URL was my report on 'indexed' headsets in the used bikes that I have purchased. All bikes with head tubes of 24" and larger were indexed, EXCEPT for the TREK 500 which had many, many miles and which had a CAST (heavy!) head tube, and a schwinn paramount (which might even have 9/6/9 tubing due to its 26 lbs steamroller weight.)
INDEXED raleigh pro 24.5" campy many thousands of miles (UK) raleigh comp 24.5" brampton many thousands of miles (?) trek 2300 tange < 3000, mi like-new (owner @0 mi)
NOT INDEXED trek 500 tange at least 12,000 miles (owner @0 mi) schwinn paramount 25" campy < 2000 mi (owner @150 mi)
raleigh 21.5"-23.5" campy, brampton (about 6 bikes) alan, schwinn, etc. campy sekai 23" tange
One surprising thing is that the TREK 2300, with a carbon head tube, indexed very quickly, before the tires, chain, or brake pads wore through. The TREK 500 with the overly stiff head tube, never indexed, despite hauling groceries through the rain in Vancouver for months on end, and 11 years of continuous service (1985-1996).
- Don Gillies
San Diego, CA, USA