Fouriers POWER UP

At Fouriers we admire other manufacturers for their innovations, but sometimes we can’t help to find some flaws and an urgent feeling to improve it. Thus we’ve done the same for the increasing popular 40t/42t sprocket. We’ve noticed a major issue for most 40t/42t sprockets when pedaling backwards the chain easily drops off. The MageSK (aka CR-DX004) is an improved design that doesn’t suffer the same problem and besides, it looks great.

Furthermore we’ve seen that upgrading the cassette to a 40/42T will suffers smooth shifting in the lower gears, due to the removal of the 15T or 17T sprocket. It is therefore recommended to also install a 16T sprocket along with the 40/42T sprocket on the cassette for the smoothest shifting. But we are Fouriers, we don’t want OK performance, we want YEAH performance.

 

Behold, our own designed (P.A.T) and manufactured 16T sprocket with additional chain lifts for swift and smooth shifting.

To complete the story we want to give everybody the complete package instead of a single sprocket. So when you buy our MageSK 40/42T sprocket, it comes with a B-tension screw and our unique 16T sprocket at no cost.
 

Compatibilty

Fouriers MageSK (CR-DX004) and our 16T sprocket can be mounted on Shimano 10-speed (11-36t or 11-34t) cassettes. No matter if you ride a 1x or 2x system, the MageSK will run smoothly.  Note: We do not recommend it for SRAM 10 speed cassette yet, but you can give it a shot.
 

We recommend the following Shimano cassettes:
 
Deore
XTR

If you want to change to a 1x system, we recommend to take a look at our Narrow Wide chainrings (CR-DX003-AH) that have a unique wave design and mud clearance technology. Easy to install and great performance. (see below)

Pic: MageSK (CR-DX004) with CR-DX003-AH

Installation:

We recommend you let a local shop install our upgrade kit for the best performance, unless you are familiar with the components. The following is a short/simple description for the installation of the 42T MageSK on a Deore.
 

Step 1: Remove the rear cassette from your bike.

Pic: Shimano 10 speed Deore cassette

Step 2: Take out the 15t and 17t sprocket and its spacer.

pic: Upgradeded Shimano Deore

Step 3:  You just made space in your 10speed cassette for two new sprockets. Add our 16T sprocket in between the 13T and 19T and add the 40/42T sprocket on the back of the cassette. Now install the entire cassette back on to your bike as it was.

Step 4: For the best performance you have to install the supplied B-tension screw on your rear derailleur so that there is enough clearance between the upper pulley of the derailleur and the sprocket. Usually there is 5~8mm distance between the upper pulley and 40/42T sprocket.

Encountered a problem? Or need more detailed information? If you have any questions, you can always ask: info@fouriers-bike.com . We have our team of engineers ready to answers all your questions!

 

Recommended Rear Derailleur

The MageSK 40t/42t is compatible with most medium to long cage 10-speed MTB rear derailleurs.

You can check if your cage derailleur is compatible by applying the following formula:

(biggest chainring - smallest chainring) + (biggest sprocket - smallest sprocket) = rear derailleur capacity
Source: Sutherland’s Handbook for Bicycle Mechanics

If you run a 1x system you can get away with most medium cage rear derailleurs and with a 2x system a long cage rear derailleur.

The MageSK comes with a B-tension screw, so you can fine tune your read derailleur for the MageSK sprocket.

Spec:

For: 10-speed
Material: Alloy 7075-T651, Full CNC
Spec: 40T/42T
Color: S.B Black, S.B Blue, S.B Gold, S.B Pink, S.B Purple, S.B Red
Weight: 40T: 67g / 42T: 71g / 16T: 15g
Comes with 16T (CR-S005-16) sprocket and B-tension screw.