Shimano SLX M670 Rear Derailleur Review (2014)


Dedicated to all-mountain riding, the SLX groupset sits somewhere between Shimano’s Deore and Deore XT, and is, in the same time, quite of a competitor for these two, having a good balance between weight, performance, and price.

And it was about time the SLX reached such a level, because up until 2013, before Shimano upgraded the technology it featured or the materials being used for building it, we would have recommend at any given moment the XT in favour of the SLX. Nowadays, SLX has a front part manufactured out of alloy, but this doesn’t explain how the derailleur managed to gain 20 extra grams, despite not featuring the Shadow Plus technology, like the XT does.

However, SLX’s performances don’t fail to make themselves noticed. The enhancement represented by the Shadow Plus technology is unquestionable, providing a more silent ride among other things, but even without it, the SLX rear derailleur shifts with a speed almost the same as XT’s, and identical to that of Deore’s. Shifting under load is another place where Shimano got it right, but I wouldn’t push it too far if I were you.

Designed to function at its finest when coupled with a 10-speed cassette, the SLX rear derailleur also gets some help from its slim profile, which allows it to stay out the way of obstacles that could damage it. Without further ado, the new SLX is a fair-enough derailleur, that has undergone improvements in terms of materials used, and of shifting speed, even if it gained some extra weight, but, even so, it doesn’t manage to beat the value the Deore or XT have.

Weight: 278 grams