Review: Shimano SLX Shadow Plus Mech

Ali Todd Ali Todd

Words and photos: Dave Arthur

Thank God (or rather, Shimano) the days of noisy, chain-slapping bikes are through. First introduced a couple of years ago, and now put as standard on pretty much every new bike, clutch mechs are an example of trickle-down technology in action. They’ve now reached the very affordable SLX groupset, which Dave recently put through its paces. Here’s what he had to say…

See that grey switch? The answer to all your chain and noise-related problems.
See that grey switch? The answer to all your chain and noise-related problems.

The introduction of clutch-style rear mechs has been a real game changer for mountain biking, and is right up there with the dropper seatpost in the “how did we ever manage before” category of products.

Shimano first introduced the Shadow Plus clutch-style mech to its XTR groupset, but it’s since trickled down to SLX (RD-M675 to give it its full and proper name(, making it far more affordable. SLX is arguably the Japanese company’s best groupset in terms of value for money with all the performance, and a smidgen extra weight, of the more expensive XT and XTR.

I’ve been running this SLX rear mech for a good few months now, right through the depths of winter, and it’s still ticking along as nicely as the first day I bolted it to the bike. Little discernable slack or looseness has developed in that time and the slim design means rock strikes are much less likely, and despite a few close calls it has shrugged off the abuse well. It’s a tough mech that’s for sure.

Shifting performance is typical Shimano fare, that is to say slick and flawless. Compared to a non-Shadow Plus mech, shifting is a touch heavier at the paddle, but you quickly get used to it within a few shifts. For note I was using an XTR shifter.

Setting the mech up is a doddle, just bolt it on, set the high and low limit screws, tension the gear cable and away you go. The lack of cable adjuster is something I missed but the adjuster on the shifter is easier to access for adjustments on the go anyway, and at least you don’t have the big loop of cable that can be a snag hazard.

To remove the rear wheel you simply flick the lever down – this disengages the clutch so the mech can pull forwards as you drop the wheel out of the frame. It’s an easier system than SRAM’s Type 2, which requires the cage to be pushed forward and the lock activated.

Riding with clutch mechs is something you get used to very quickly. Jump on a bike without one and you notice how noisy the bike is, the chain slapping at the chainstays over rough ground. Dropped chains are now a thing of the past too, none of those dropped chains moments half way down descents.

For £55 (less if you shop around) it’s a bargain. Unless you’re racing at a top level or a weight weenie, there’s little reason to spend any more.

Verdict

An affordable high performance derailleur that’ll keep your chain in place

Price:  £54.99

Link here

What Shimano says: 

Tough, aggressive and light weight Dyna-Sys 10-speed SLX rear derailleur using revolutionary features from XT and XTR at an affordable price point

Shimano’s new Direct Mount Rear Derailleur system gives more space around the rear frame dropout resulting in easier rear wheel removal but also allows frame designers to shorten chain stays, increase axel sizes and move suspension pivots

Shadow Plus features a super low profile design that reduces the risk of damage from trail side hazards
Single tension spring prevents contact with the chainstay resulting in a silent ride
Shadow Plus uses a chain stabilising switch that when on will reduce chain bounce in rough terrain
Direct cable routing prevents snagging from any trail side hazards
Alloy and steel construction leads to lower weight
Two fluorine-coated link pin bushings aid slick shifting
High rigidity wide outer link braces the pulley body to increase pivot joint rigidity
Strong return spring for a positive shifting feel
Improved cable pull ratio provides a more accurate shift action
Dyna-Sys 10-speed compatible only
35T capacity GS cage
Top normal spring uses the spring to select higher gears