by Agent041 on Mon Jan 15, 2024 8:14 pm
I have a strange problem with my Addict Gravel 30 2023, and hopefully someone can help me.
I have problematic front derailleur alignment. Crank Praxis Alba 48/32 (gravel crank). Front derailour GRX600. Already from the start the chain rubs on the first 3 gears (34T,-30T-27T) on a small chainring. I have tried to adjust the L (low) limit screw, but it appears that it was already to the end. As I unscrew the limit screw it goes out away from the "wall". So the derailleur cage does not move to the frame. But when I tighten the L screw in, then the cage also goes nowhere, until I reach the "wall" with the screw, and then starts to move inside even more towards the chain. So the derailer L screw works as it should. But when unscrewing it again, it goes outwards, but unfortunately not out enough. As said, still rubbing on the first 3 gears. Have later then added a chain catcher and again mounted the derailer, but unfortunately it stayed the same. Wanted to adjust it with the center bolt toward the frame hanger and change the angle of the cage towards the chainring, but it was correctly parallel to the chainring from the beginning, so did not do that. I do not understand, why is this? As I investigated, the chainline for Alba and GRX600 are the same (47mm).
As the Praxis bottom bracket (BB) was done after second wash and did not want to buy another Praxis BB for 80eur, and had Ultegra 12speed PowerMeter crank I mounted Shimano BB and Ultegra 50/34 12speed crank. And additionally today also 105 12speed front deraileur, as it has the same chainline as Ultegra (44,5mm). But the result was the same. The low limit screw does not move the cage inner enougf for small gears. Also 1-2-3 gears rub a bit.
Does someone know what the problem is? If I would get 105 11speed with 43,5mm chainline it would be probably OK, but in couple of months I plan to upgrade to 105 Di2 12speed and need to fix this problem as it is. The shop where I bought the bike (online) simply do not care and are ignoring me.