Thursday, October 21, 2010

Storm in a H cup

Certainly they had a go at wrenching it off
Finally, a few moments to work on the bike today. Boy does it take a long time to complete the work when you only go at each stage bit by bit. The frame came with a set of FSA cups still fitted, but they looked pretty beat up. I guess the previous owner had tried to remove them, but without the correct tool. Cups are an integral part of the headset of the bike, this is for want of a better description the linkage between the bike and the forks that hold the wheels and the steering bars. Without them, you are going to have a pole that rattles around inside a tube. It is quite a clever bit of engineering linkage, and overtime has evolved different methods of holding the fork steerer to, eventually, the handlebars. The setup we are going to use is a threadless headset, I am not going into the details, of stuff you can look it up on Wikepedia and several other websites if you are interested, but the whole process is, in theory, quite simple.

not a wing pylon, but a cup remover inserted into the steerer column
First you need the correct tool, the cups are simply slotted in the frame, so you could rip them out with a strong arm and a pair of pliers, something I think the previous owner had tried. As alternative, you could tap them out using a hammer and and an old screwdriver. It would be a slow job as you would need to go round moving each side evenly to prevent the whole thing getting wedged. Otherwise buy and cup removal tool, or borrow one. The cost a tenner, which isn't so bad. It's about the same amount you would pay the workshop to do the job for you. The tool is simply a split tube that fits in the steerer column, but the split will flange out to rest on the internal face of the cup to allow you to tap it out with a hammer. How simple is that? Feed in, tap and off it comes, the repeat for the otherside.

Two removed H cups
Now the problem comes in not planning for fitting the otherones on to the frame. Simple investigation of the the cup and the frame reveals, that these are going to have to be set level and true. That means, you guessed it, another specialist tool. Simple enough to build, as it is only two flat plates on a screw column with some method of pressing both cups onto the frame e.g. a wingnut. The parts though probably cost as much as a secondhand precision engineered one. So I will need to look into that for the future, and see if I can borrow what is needed to get off the ground sooner. In fact, borrowing appears to be the order of the day as, I am unsure of the quality of other parts of the headset assembly attached to the existing fork. My first idea was to replace the fork with a better one, sooner than later, but pennies predict that this will not be happening any time soon. So I will try and not change, star nuts and crown races, but you never know. See what happens when I have a go.

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