Originally Posted by
DaveSSS
The biggest mistake that can be made when comparing two frames using reach and stack numbers is forgetting to make a correction to the reach when the stack heights are different.
If two frames have a large 20mm difference in stack, there will be an additional 6mm difference in reach between the two frames. I assume that the shorter frame would be set up with 20mm of spacer, which would reduce the reach by about 6mm, compared to the taller frame.
Good point. Of course, other factors will come into play that are related from standpoint of ergos as well that haven't even been discussed -- seatpost clamp setback req'd to keep same fore/aft position relative to BB, stock stem length for the given frame size. stem angle for the stock frame size, stock handlebar reach to the hoods, potentially different crankarm lengths, amount of handlebar drop. For the OP.. the net 7mm reach difference could be mitigated (or become greater issue) depending on lots of things.