Printing with TPE on a bowden is said to be impossible. Not anymore: The modification to the compact bowden extruder allows the rubber filament to be forced into the feeding hole without allowing it to twist out of the feed. The filament I used was hardnes 45D and is called semi flexible TPE rubber 1,7mm thickness.
After printing the part you need to drill the feeding hole open with a 1,5mm or 2mm dril. This hole where the filament is feeded into needs to be smooth and must be perfectly aligned with the pulley.
Maximum printing speed is +-2cm/s although if the extruder is dirty or old you will reach the most reliable result at 5mm/s. Its not fast but it works. Temperature of filament =240'C. Make sure the bowden tube has no sharp kinks or bends. The trick is to smooth the path to the head as much as possible.
Make sure you are not feeding faster than what is needed. Measure the actual feed length for a 100mm feed and adjust the speed accordingly. Rubber parts will need to be printed solid. I found that printing with a infill density of 95%, is solid enough and allows for excess feed to find a spot to settle.
IMPORTANT: flexible filament can not retract. The retraction needs to be switched off.
Let me know if you had success or if you are struggling and you need help.