Originally Posted by
Iride01
On my son's Trek Emonda with Tiagra, it shifts fast and very well to all the gears. 11-32 with a 52/36 up front. And the jockey wheel was very close to the cogs. I am sort of wondering if that hanger is putting the RD too far down. But it's not much if it is.
The hanger is around 25mm, so, within requested limits.I bet mine would also work nice with 11-32. Finally, B screw does adjust the pulley up, but not more than total 3-4 mm (therefore, I did not observe at the beginning). But 3-4 mm is not enough to cover the interval of large cogs (25 to 34 teeth) for which Tiagra was designed. Thus, it was optimized for upper range (30-34 teeth) on a standard hanger. Once you go toward cassettes with the large cog of 25, B screw can not compensate and shifting starts to deteriorate. I think this is rather a poor B adjustment design than a malfunction.
SRAM solution is way, way better: I regularly switch between wheels with 11-26 and 11-32 cassettes and all I must do is to rotate B screw +/- 8 complete rounds to adjust upper pulley position, then shifting is crisp with selected wheel. And I still have “B adjustment” unused.
With Tiagra I must re-optimize around my big cog of 26. But since “B adjustment” is not enough, I must find another hanger (around 1.5 cm height instead of recommended 2.4-2.6), so the upper pulley will be closer to the cassette. I do not even know whether such hanger exists…