Allez: Chain And Gear Indexing

Last step in the drive train mashup is the chain and of course the indexing later on. In the first step of installation I will go for the Shimano Dura Ace chain (CN-HG901) with quick-link/master-link, again. Maybe I will change the chain to more “bling” one =)

These tools are needed:

  • Bike Stand
  • 2mm Allen
  • CT-3.2
  • MLP-1.2
  • CN-10
  • DP-2

Official Service Manual:

Service/Spare Part:

  • Shimano CN-HG901
    • I-CNHG90111116
  • Jagwire Cable Tip (1,2mm)
    • BOT117-AB (black)

Post as guidance? No warranty in ANY case of damage!

I cut the length of the new chain to my needs, measured by the old one. The new weight of the CN-HG901 is 231,4 grams. Seems to me ok.

The assembly of the chain is quite simple. First you need to know the direction. This is based on the logos branded into the chain (they must face outside). Then put it on the smallest cogs through the rear derailleur pulleys and straight to the small chain ring on front. Set the quick-link/master-link in the right direction and close the connection.

Now its time for indexing… Rear first. Shift to the smallest cog and the largest chain ring on front, then undo the cable – this is for the general index of the chain and the idler pulleys which must be set in line (done by the high limit screw). If everything is correct tighten the cable again with 6-7NM, cut it and seal it with an end cap (1,2mm). After that the general rear indexing is happening via the adjustment screw(s). Finally the low limit, shift to the largest cog and the smaller chain ring and set the low limit…. rear derailleur is done when everything runs smooth (especially the noise of the chain).

Similar procedure on the front. Lowest cog and large chain ring for the high limit (h-screw). The gap should be around 0,5mm to the outer cage of the front derailleur (=no grinding sound). Same for the low limit (l-screw): largest cog and smallest chain ring , same inner gap to the cage of 0,5mm (=no grinding sound).

To complete the indexing a walk through all gears is recommended… maybe there is some need for fine tuning.