Originally Posted by
BikingGrad80
I need some advice on how to cheaply get some lower gears on an older bike.
I have a 90' Trek 1400 with 105 1055 series parts that I brought with me from Chicago. 42-23 is not cutting it as a lowest gear. It has a 1055 crankset nonbiopace with 52/42 double and 13-23 7 speed cassette.
I was looking for an economical way to get some lower gears. I am wondering if I can get a 39 or lower chainring that is compatible. I am also considering a 12-28 cassette. I have a spare 8/9/10 speed wheel that fits in the dropouts but don't want to spend the money on new shifters and chain and cassette.
Measure the bolt circle diameter of the bolts which hold the chainrings to the crank. The BCD determines compatibility.
I think there is a limit to how much difference between your high and low rings your front derailleur can handle so if you go much lower than 39 you will need to change the big ring too.
The cassette would probabaly make a bigger difference than the rings. 7s cassettes are still available new.