Help replacing front derailleur

Question

Evening, total newb question maybe but it’s driving me mad.

I have a Carrera Vulcan 2015 model which I bought second hand to aid my physiotherapy. From what I can work out by the spec sheet the front derailleuris a Shimano Tourney FD-M190 (I think, I say that as spec sheet says 27.5 inch wheel which is 💩).

What could I replace this with? I haven’t got a clue and the lad in the bike shop literally said “dunno” and shrugged his shoulders.

Rear derailleur is a SRAM x4 with a 8 speed Shimano cassette (which could do with replacing (I assume all 8 speed cassettes are the same).

Thank you for listening and any help would be hugely appreciated.

Paul

Answer 1

As far as I can tell the 2015 Carrera Vulcan came with SRAM X4 all round. If the front derailleur is a Shimano unit it definitely was not original. I would guess the previous owner swapped it in. A Shimano unit will have 'Shimano' and 'Tourney' written on it. A picture of the derailleur added to you question will help us provide a good answer.

In general SRAM and Shinano derailleurs and shifters are not compatible because they use a different cable pull ratio (how much cable is pulled to move the derailleur a certain amount).

You options for replacement depend on what front shifter you have. If the shifter was also replaced with a Shimano unit you'll need a Shimano derailleur replacement. I'd avoid the Tourney range and upgrade slightly to something in Altus or Acera ranges. The exact model you want depends on if the the cable routing comes from the top or bottom of the frame.

If the shifter is still a SRAM unit you the obvious choice for a replacement is a SRAM X4 unit as was originally fitted. I don't think SRAM makes these anymore but they are available from Ebay, Amazon etc.

Answer 2

Shimano and Sram derailleurs are generally not cross compatible. Sram rear derailleurs require you use Sram shifters. Shimano rear derailleurs require you use Shimano shifter. There are some exceptions though. The front shifters from Sram and Shimano use the same cable pull ratio on at least the 7 and 8 speed models. So you can in fact use a Sram shifter with a Shimano front derailleur or a Shimano Shifter with a Sram front derailleur as long as you are running a 7 or 8 speed drive train. As far as what will work on your bike there are many varieties of front derailleurs. Sheldon Browns' site has an excellent tutorial on identifying the characteristics of each type. They include mount type (clamp on, direct mount, E type) mount location (high mount, low mount), cable pull direction (does the cable pull down from the bottom bracket or up from near the seatpost clamp), Number of teeth on the largest front chain ring, number of front chainrings.