According to tribal knowledge and mystic folklore, if I want to convert a 26” mountain bike to a drop bar gravel bike; I want to go a size down to adjust for the longer top tube of these older bikes.
If I want to convert a 29” XC hardtail to a drop bar gravel bike, does the same rule apply?
Thanks in advance
by Returning2Riding
1 Comment
Probably the most reliable thing to do is to find the geometry chart (geometry geeks might have it). Make the effective top tube match your drop bar size. That’s easy and probably pretty good as a first estimate. If you want to put in some more work, you can do the full stack and reach calculation and then account for the fact that the seat is probably more forward on the XC than on your desired drop bar. In the middle, there is a bike geometry comparison site and you could load your drop bar fitting bike as white and your proposed XC donor as black and see how they overlap.
Just in case you don’t know, road shifters and mtb deraillers don’t play nice together and you can only rarely put a 2x road setup on an mtb frame and have a workable chainline.