Tuesday, June 12, 2012

The Novice Bike Mechanic ( Part 1 )

I worked for one of the world’s premier engineering firms for over 35 years but my skills were much more theoretical than practical and I must be a contender for the world’s worst mechanic.
So it was with much trepidation that I decided to teach myself how a bike was put together by actually dismantling and rebuilding one rather than just study a maintenance manual.
I also have to recognize that as I get older those Derbyshire Peaks seem to be getting steeper and, whilst I can still climb as well as any on our Thursday Veterans ride, the others manage it by having a chainset which is much more suitable for the task than those on my bikes.
My 1961 Mercian still has its original Campagnola 52/42 chain rings  to which someone has later added a 30 tooth inner ring and these combined with a 12-28 cassette mean that all hills encountered to-date are manageable, but this will not always be the case.

So, I decided that my introductory bike mechanic project would be to change the chan rings to a more hill friendly set.  One of the great things about cycling is that people are always ready to give you recommendations and advice on how to proceed. After much discussion at many tea and cake shops, and looking what others had fitted, I determined on a 46/36/26 chainset with a strong recommendation to buy some proper tools to carry out the job and not bodge my way through.
My first lesson about bike upgrading was that it is very similar to my wife buying a dress for a wedding or any other event.. There is an inevitable creeping project scope as the dress needs complementing by a pair of shoes, handbag, jewellry, special hair cut etc, none of which were envisaged in the original scope spec that I had imagined.  The final cost makes the dress look a minor part of the whole ensemble!! Now bike scope creep is much more exciting as I discovered that I needed a new compatible Bottom Bracket and obviously (??? ) a new set of pedals so I could be firmly attached to the bike when hill climbing. I also needed some tools so purchased crank extractors, pedal removal spanner, 2 sets of bottom bracket sockets ( as new chain rings were not compatible with old BB )  and, as it turns out, a BIG spanner.

One of the amazing things about practical bike mechanics as opposed to the theoretical reading about it is that where in the instructions it says “ turn bolt anti-clockwise to remove “ it mentions nothing of the fact that after 50 years the original pedals were attached without greasing the threads ( see, I am learning! ) and now the things seem to have welded themselves together never to be separated from the cranks again in man’s lifetime. However, fortified by an extra piece of cake, and using what I considered to be excessive force, they eventually gave in to reason and the nuts loosened. This theme of very difficult to loosen nuts/bolts was a recurring feature of the dismantling process and the crank removal was a particularly frightening experience as everyone warned me that the combination of hardened steel tools and aluminium crank threads could have dire consequences if you got it wrong.

But eventually I managed to remove the cranks and exposed the bottom bracket.

Whoever had installed this had obviously not read the same articles that I had. It was meant to be inserted and then gently tightened until just firm. In order to remove this I needed not only the correct socket but an 18 inch spanner which was repeatedly thumped at the end with a rubber mallet before I could get the bolt to move.  But eventually it did and the bottom bracket could be extracted.

Part 1 of the project, disassembly and removal, is now complete and the next stage is just to clean things up before rebuilding with the new bits begins.

Or is it?

Now that I have got this far, the frame does looked a little scratched in places, and you can no longer get 27inch wheels, and the tyre choice for 27inch wheels are very limited and am I really happy with those brakes?

Time to ponder.

Better cycle to the cake shop and have a think...

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