10-04-2020, 03:30 PM
I haven't tried it on an Ultegra, no. I've used Shimano Alivio (with a 14mm diameter, so 7mm radius) and Tourney derailleurs (15mm diameter) with very good results.
If you're indeed using a radius of 15mm, so 30mm diameter, it's perfectly normal the servo can't pull that.
If the Ultegra has a short travel of cable, you should try smaller (12 or 13mm diameter) horns, and see if you can get enough travel to cover all sprockets.
But:
On the other hand, there are a few things to check first:
- is the derailleur in good working order? Maybe it needs a lube
- is the cable flow good? I mean, is the bowden cable allowing a good fluid travel of the cable?
- is the servo getting good current flow? Try to measure it using a amp-meter. At the moment the servo isn't able to move the derailleur it should be drawing more than 1 amp. If amp is below that, either your battery isn't charged or there is something else limiting the current.
I suppose you're using the Shift4Me setup as described, including the 3D prints? If not, tell us more about your setup - it'll be easier to track down your problem.
If you're indeed using a radius of 15mm, so 30mm diameter, it's perfectly normal the servo can't pull that.
If the Ultegra has a short travel of cable, you should try smaller (12 or 13mm diameter) horns, and see if you can get enough travel to cover all sprockets.
But:
On the other hand, there are a few things to check first:
- is the derailleur in good working order? Maybe it needs a lube
- is the cable flow good? I mean, is the bowden cable allowing a good fluid travel of the cable?
- is the servo getting good current flow? Try to measure it using a amp-meter. At the moment the servo isn't able to move the derailleur it should be drawing more than 1 amp. If amp is below that, either your battery isn't charged or there is something else limiting the current.
I suppose you're using the Shift4Me setup as described, including the 3D prints? If not, tell us more about your setup - it'll be easier to track down your problem.