There is no difficulty in mounting the Shimano derailleurs. On the other hand, there are a few small gestures to know to settle them precisely!
To mount and adjust Shimano derailleurs you will need a 2 mm Allen key, a 4 mm and a 5 mm Allen key. It will also be necessary to add the allen wrench that tightens to screw the derailleur legs and a Phillips screwdriver for the races of the derailers. A torque wrench is also added to tighten the torque.
Pictures © Frédéric Iehl
Time and difficulty
It takes one hour of work to set up and adjust the Shimano derailleurs. It’s not that complex, except for the front derailleur. A small gap and the ascents and descents of chainrings will be less frank.
We start by checking the tightening of the rear leg. It is visually controlled that it is not twisted.
We do the same for the front derailleur. Little chance here that she twists.
The front derailleur is then positioned so as to adjust it in height. It must be slightly tight.
We start by positioning the derailleur in height. The fork must pass between 1 and 3 mm above the teeth.
Now we will orient the front derailleur so that its outer face is almost parallel to the teeth of the large plateau. The rear end of the derailleur can be shifted from 0.5 to 1 mm inwards.
The front derailleur is then tightened permanently.
We place a 5 mm allen wrench like this along the teeth of the tray and look at the gap with the fork.
We then play on this screw to bring closer (green) the fork or take it off (orange).
We start by greasing the derailleur hanger.
We tighten the derailleur thoroughly on the derailleur hanger
We avoid crushing this screw on the derailleur hanger.
We then make sure that the derailleur rotates freely on the derailleur hanger.
There are 3 screws on the back of the derailleur. The A is for the running of the small pinion, the B for the running of the large pinion and the C to manage the gap between the pulleys and the pinions.
Small chainring-big sprocket, we make sure that the derailleur does not touch the spokes. We then act on the B screw.
Large chainring-small spocket, we make sure that the chain runs without noise and does not rub on the frame. We then act on the A screw.
The pulleys train must also be as close as possible to the sprocket. Here we will reduce the distance a little.
We modulate the gap with the C screw. When we tighten (green) we move away, when we unscrew (orange) we bring…
On the front derailleur, the A screw is used for the race of the small chainring, the B screw for the race of the large plateau.
We put the chain on a small chainring and the large sprocket and look at how it goes.
We screw the A screw to bring the fork closer together, we unscrew it to keep it away. It must brush against the chain but without touching it.
We put the chain on the large chainring and the small sprocket. We look at where the fork goes. Here too, it must brush against the chain without touching it.
The B screw is then acted by screwing it closer to the fork of the chain, or by unscrewing it to move it away.
That’s it, it’s installed, all that remains is to adjust the Shimano indexation.