Sunday, November 30, 2008

 

Rear cassette onto the rear wheel

This is the rear cassette I shall be using. It looks like a really heavy lump of metal, but in fact it is nice and light. It is mostly hollow inside, with what looks like the edges of a pyramid holding the cogs in position. Also as you can see in the picture, there are lots of little holes drilled in the cogs themselves to make it even lighter.


So off the bike comes the rear wheel, and onto the freewheel this cassette slides. These can be a bit of a pain to fit if you've not done it before as, although the splines look regular, they aren't, this is to ensure the whole arrangement only goes on in one way. There is a special tool to torque up the lock nut, and it is tempting to just grab the wheel when doing this, but one should use a chain whip on the cassette, otherwise you're damaging the freewheel and possibly taking you wheel out of true.


Shall I put the chain on now?


Nah, time for a beer.

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Saturday, November 29, 2008

 

Wheels and rim-tape

I open the delivery box with the wheels in and see what parts come with, and what I need that is missing. Rim-tape is missing. Rim-tape forms a barrier between the inner tube and the inside of the rim. If there was no rim tape the tube would press through the holes in the rims onto the spoke nipples or the tips of the spokes themselves, (if they protrude through the nipples,) these and the holes themselves are sharp and will puncture the tube in use.


Found some rim tape. I like plastic rim tape as the bicycle wheels will get quite a bit of water in them and cloth tape just rots, fails to protect the inner-tube and then you get a puncture that is unrepairable in the field.


There is a knack to installing rim-tape such as this as it is quite tight to get on. You first put a screwdriver through the valve hole in the rim-tape, and through the valve hole in the wheel. This ensures they start off more or less aligned. You then put another screwdriver on the rim and run it around to get the tape on. It is tricky and it feels like the tape will snap just before you get it all on, but it shouldn't. Now just before it is all on let the first screwdriver drop away, if it hasn't already, and get the tape all on the rim. Now the holes in the tape and the rim won't quite line up anymore, not to worry, just roll the screwdriver backwards and forwards and you'll see the holes come into alignment. When they're aligned, then take the screwdriver out.


Put the front wheel on.


And the back.


Looks more like a bicycle now.


Looks like a bike from this direction too!


Lots more parts to go on yet, so I'll have a beer as I decide what to do next.

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Friday, November 28, 2008

 

Installing the front derailleur

This is the front derailleur in it's box. I check first before opening the box to see if this one is the correct type. I need to see the key statements: "top-pull" and "31.8mm" written on the side. The down tube is 31.8 mm diameter, if the derailleur is narrower than this it won't go around the tube, and if it is wider then it won't grip. It needs to be top pull as that is the direction the control cable will pull from. This can be seen from the frame as there is a cable stop near the top of the seat tube.


I shall read the instructions this time, as I am not 100% sure on what the spacing should be from the large chain ring to the unit. Also it tells me how tight to torque up the retaining bolt.


And there it is. Notice the lump of creamy-white plastic inside the derailleur, it helps to put something like that in whilst setting it up, otherwise the derailleur cage sits over the smallest chain-ring and it is hard to set the clearance to the large chain-ring.


Well, that was so easy I think it deserves a beer.

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Thursday, November 27, 2008

 

Installing the rear derailleur

Bored with working at the front, now I shall do something to the rear of the bike. The black piece is a plastic spacer to prevent frame damage during delivery. I keep hold of things like this for when I transport my bikes anywhere and they don't have a wheel installed. Helps prevent damage from bending the frame due to over enthusiastic piling up of kit on top. The part furthest away is where the rear disc brake calliper screws on, and this side has the hanger where the rear dérailleur is fitted.


The rear derailleur screws into this hole here, on the hanger. Suppose it is called the hanger as it hangs down. If you look carefully it looks a little like a comma, the little 'tick' is a stop for a part on the derailleur that is used as a thrust plate to resist the twisting motion imparted when one tensions the cable to change gear. So it is important that the stop goes on the correct side, although it is usually difficult to get it wrong. On some derailleurs there is no plate, just a bolt. In that case the blot pushes against this tick.


Goes on really easy. I just screw the derailleur hanger bolt into the hanger. I check several times to make sure it is correct as it went on way too easy. Then I torque the hanger bolt up as per the instructions.


I prefer the SRAM system for the rear derailleur as they use a parallelogram arrangement for moving across the cassette, this ensures the cage can never contact the cassette. On other systems they rely on the chain tension to pull the cage down. When a MTB gets really dirty in a race you can forget about chain tension doing anything like when you set the bike up, so I don't bother with anything less.

Reckon it is time for another beer.

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Installing the chainset

This part is big and has lots of teeth on it. I shall read the instructions first this time. They say I should put some grease on and just slide it in.


So I put some grease on and slide it in. I let go and it swings down and sort of hangs there, kinda lifeless and forlorn looking. Looks sort of sad, doesn't it, like it is missing it's partner.


The instructions then say I put the other side on and with a hex bolt tighten it up. There are many ways to put the other crank arm on. I shall put it pointing away from the other so it looks like most other bicycles. Much happier looking now.


There are a couple of parts left over, look like little felt washers. The instructions say they are for the pedals.


Hmm, have to dig out some pedals, sure I have some laying about, but I think I'll have a beer whilst I think about where they might be.

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Wednesday, November 26, 2008

 

Installing the bottom bracket

This is a bottom bracket and bearing. It's known as an external bottom bracket. Somehow the bearings screw into that tube at the bottom, but the bearing part stays outside, hence the name external bottom bracket bearing. I reason that it screws in because of the thread on the outside of the bottom bracket bearings and the internal thread on the corresponding part, the bottom bracket.


I wonder how it comes apart, pull at it, and with a pop it falls to pieces, bits flying all over. The middle part is some plastic tube with rubber rings to act as seals. Luckily I find all the parts. Hmm, I think I found them all.


I get it to pieces. This side won't screw in at first, so I do the otherside first. I try this side again, it won't go it, keeps skipping. In desperation I try screwing it backwards to try and find the thread start. Woo hoo, it starts to screw on. I read the instructions and it tells me that English thread is counter-clockwise on this side.



I screw it on with the spacers. There is a chart in the instructions about how to place the spacers for such and such chain line. I reckon that if I put the spacers in then if it isn't correct I can always take them back out, whereas if I don't put them in then I've used up future grip on the thread needlessly. Also, if I put the spacers on then I won't need to go hunting about for them some time in the future when I've forgetten where I put them to keep them safe for if I needed them at some future point. Or, something like that.


I torque it up and it's time for another beer.

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Tuesday, November 25, 2008

 

Installing the forks

In the box where I got the headset from there are some other parts.


On reading the instructions there is a bearing thing that goes on neck of the fork.


It won't go all the way down on it's own, you need a bit of pipe, a little larger diameter than the neck of the fork so it fits over it, that you will hit with a hammer, and something so that the bearing thing doesn't go squiffy through being hit off angle.


What with a few other parts I can now put the forks on the frame.


Doesn't look quite right does it, and there are some parts left over. Think I'll put them on too. Looks much better now.


Time for another beer.

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Monday, November 24, 2008

 

Building myself a new MTB

It's snowing. Think I'll build myself a winter bicycle. I've built up quite a collection of spare parts, and wonder how far I'll get before reaching a stopper.


First off, have to find somewhere to build it. Somewhere quiet so I'm not disturbed too often. The dog's shed will do.


Clear some space, set up the stand, and install a couple of shopping bags of beer in a place close to hand, but not where I'll be tripping over it every five minutes.


Frame on the stand, installing the headset. Time for a beer. Hmm, maybe I should have read the instructions first. Why? It kinda looks right, but better safe than sorry.


More to follow...

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