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After some time, I go back to publishing a more technical-themed post for my Towards the Bikend initiative. I renamed this section of the project as INSTRUCTIONS BEFORE USE. Before getting down to our focal points, a quick summary.
Towards the Bikend is a column that includes the publication of various posts, all centered on the theme of the "bike world". In the past, I had published a few posts, but never too formal. Instead, I decided to give a more structured face, finding myself disassembling an old road bike from top to bottom, and thinking I could show - with the help of some photos taken during the different passages - a "sketch" of how to proceed. However, the project plans to go beyond this boundary through contents that concern multiple aspects of the bike world, from homemade training methods to local initiatives, perhaps also passing through training itineraries.
Today I will resume the theme of the last episode, the one relating to DISASSEMBLY of a CRANKSET branded Shimano, Ultegra series. You can find the first part of the disassembly, CLICKING ON THIS LINK. In that post, you will find the steps I took to remove the crankset mounted on a road bike.
Once disassembled, the crankset will appear as in the image you see below.
On this occasion, I didn't remove the pedal, but I advise you to remove this kind of accessory BEFORE removing the crankset. The procedure is simpler, especially if there were oxides formed over time and which would certainly make more difficult the movement in the screwing area.
As we have seen previously, the CRANKSET is the portion of the bike essentially consisting of the cranks, the chainrings, the various connection points between these elements, and what allows them to be stably placed. In the figure below, I indicated with an arrow the two parts on which today I will focus my post: the front CROWNS.
On this occasion, there were two, one bigger and one smaller. However, there are many bikes with a single crown or with three crowns... and maybe who knows how many else. These portions are placed on the other parts of the crankset by means of some specific screws, four on my occasion.
In the case of Shimano Ultegra series that I had, and of which more recent models exist today, the screws are inserted in special spaces created at the level of the right crank arm: unlike the left crank arm, the right one widens and has a very particular shape, which allows it to perform its role, furthermore creating a retention and support area for the crowns that are mounted on it.
To loosen the fixing screws of the crowns, I used a hand tool which, however, proved to be inefficient. It all depends on the forces with which the screws have been tightened, which could also be excessive compared to first-price tools on the market. Mine broke almost immediately, being blocked by a simple and not very strong plastic handle.
I managed to remedy this problem with the help of a screwdriver drill. However, I show you the steps taken with the first manual tool, to make you understand where to insert what. There you have it, the screw to loosen has a head into which the tip of the tool fits.
And a little closer:
Once all screws are removed, the crowns will be movable. I don't have a photo available to show you the various parts, the last one I took represents the two lonely crowns after disassembly.
Be careful!
The crowns are set on each other. Once the screws are loosened, you will need to apply little pressure to create a slight wobble. This will lighten the interlocking force, then you can pull out the crowns one by one. The larger chainring needs some extra attention, being wedged on the crank through a retention game between the external and internal sides. In the case of fairly old cranksets, the forces to be exerted to slide the crowns after removing the screws could be more substantial. However, I have carried out this “disaster” step manually and successfully.
Finished, yes, and this time for real. At least as regards the crankset. For the other parts of the bicycle, I'll see you in the coming weeks and maybe months. At the moment I have reduced the posts of my daily activities on the bike, I am thinking of something more useful that I will reveal soon. You will find everything as always on the #bikend tag.
