Originally Posted by
CafeVelo
Get whatever speed you'd like to reuse, pull one cog out somewhere, and pop it on the 7 speed hub. It should fit fine. That's assuming a cheap bike has a cassette hub. If it's thread on then you're out of luck. Nobody made a 7 speed integrated shifter till shimano came out with tourney for low end bikes.
Beg to differ with you. Shimano made STI Brifters with 7-speeds in the RX100, 105, and RSX model lines. Trek built bikes with 7-speed STI with all three Shimano Product lines. My 97 Trek 1400 has 7-speeds and STI RSX. Trek 1500 came with 105. Trek 1200 and 1220 came with 7-speed RX100 and RSX different model years.
There's a 98 Cannondale R600 8-speed STI with a small frame (tape measure looks like 16", Seller says it 17 1/2"). For $56, plus shipping (located in AZ).