The Shimano shifter flat bar series have the same cable pull length than the mountain bike shifters.
Is this series compatible with a mountain bike front derailleur, Deore, for example?
There's a great thread here that describes some of this. Here's the meat of it though:
Shimano's assertion that you need to use "flat-bar" front derailleurs with "flat-bar" shifters is false.
When working with Shimano, "flat-bar" shifters are really just mountain-bike shifters in different colors. This doesn't make a difference for the rear derailleur (Shimano has standardized the cable pull across all of their shifters), but there's two different cable pulls for the front derailleurs. "Road" front derailleurs require less cable movement than "mountain" front derailleurs for the same amount of lateral cage movement.
This has a couple consequences:
1: operating a "mountain" front derailleur with a "road" shifter will result in insufficient cage movement to make the shift. This is rare in the recumbent world.
2: operating a "road" front derailleur with a "mountain" shifter will result in the shifter jamming before the internal ratchet catches, meaning the chain will shift but immediately return to its starting position. In other words, the shift fails. If the shift succeeds, often the shifter will jam at that spot and not allow the shift in the other direction. This is very common in the recumbent world.
- the longer pull of the "flat-bar" or "mountain" front derailleurs makes for lighter pull at the shifter when using SRAM twist-grip shifters. This can be an advantage for people with slippery hands and/or weaker hands.
"Flat-bar" front derailleurs also have cages that better match the larger diameter chainrings typically installed on road bikes. "Mountain" chainrings are typically smaller, and trying to get a "mountain" front derailleur to work on larger chainrings often involves compromised adjustment or hand-modified cages.
My favorite "flat-bar" front derailleur is the Shimano FD-R443. (This is roughly Sora/Tiagra level parts: cheap, durable, and relatively attractive.) It's since been superceded by the FD-R453, which has a taller inner plate to match newer Shimano cranksets, but I like the FD-R443 for its greater adaptability to different chainring combinations.
I've been using the FD-R443 on several bikes, operated by Shimano Deore LX and XTR and SRAM Half-Pipe Attack shifters. It's always worked flawlessly.
So no, not really. You might be able to find a combination of gearing, derailleur, and cable pull that will work, but you're probably still better off finding a matching set.
I try these shifters with a Shimano Alivio front derailleur and it works very well. Rear i have a xt with a 11-32 casette and it works well too.
If somebody wants to upgrade an old bike with 8 speeds shifters, these is a good oportunity.
The Shimano 8 speed r440 road flat bar works with mountain bike front and rear derailleur.
I'm not sure people have this worked out. I purchased one of these 443 front derailleurs and discovered with my XT shifters it behaved exactly like a standard road and derailleur.
I think what is relevant is that there is a matching Shimano SL-R440 shifter that is flat bar shifter. Based on what I have experienced I have to suggest that it's the shifter in this odd group that does the magic of implementing the correct pull for a road bike derailleur