Kinetics – the blog…

Berkut trike, originally uploaded by Ben Cooper.

A customer trade-in, soon to be listed on eBay, along with a Birdy Black, a Bike Friday Sat’r'day (is that how it’s spelled?) and a child’s trailer.

It’s a remarkable piece of engineering – front-wheel drive with a differential…

8-spd kits, originally uploaded by Ben Cooper.

Building another batch – these ones are using a Shimano external-bearing chainset. I’m still hunting for the perfect chainset for this kit, but these are very good

Got another 8 kits to build, as soon as more hubs arrive…

Brompton spares…, originally uploaded by Ben Cooper.

I’ve got loads of Brompton spares going, erm, spare. So if you need a replacement part, maybe this’ll help – here’s what I’ve got:

14 x 54t chainset – latest version with the knobble on the back of the LH crank arm. RRP: £65 – now £40 each.
1 x same as above, without the knobble – £35
1 x same as above, older version with cut-away back – £20
1 x 50t chainset, latest shape without knobble – £35
1 x 50t chainset, RH only – £20
1 x 50t chainset, older version with cut-away back – £20
1 x LH crankarm, cutaway back – RRP £11.50, now £5
1 x LH crankarm, flat faced version (even older) – £5

5 x singlespeed rear wheel, latest version, with 12t sprocket. RRP £75, now £50 each.

6 x Bottom bracket – removed from brand new bikes. RRP £19, now £10

12 x chain tensioner for singlespeed and 3-speed – RRP £15, now £10 each

Online ordering is now set up here:

http://www.kinetics-online.co.uk/html/spares.shtml

Arm-powered ’30s Car, originally uploaded by Ben Cooper.

A local pedal-car collector brought this to the shop to show me – it’s
French, branded l’Etoile, and it’s powered by pulling on the
handlebars – you steer with your feet.

For general reference, here’s the instructions I wrote for fitting the 8-speed. The chainset bit might vary depending on what chainset I can get hold of.

Fitting the back wheel:

- Take off your old back wheel, and swap the tyre, tube and rim tape onto the new wheel.
- Slide the new wheel into the dropouts – it should go with the cable guide pointing upwards – it can only go in one of two ways, so it should be obvious which way is right.
- Slide the two tabbed washers onto the axle, with the tabs going in to the slots in the dropouts. Fit a Sturmey nut on the left side, and the plain nut on the right, and tighten.
- Slide the chain tensioner on on the right, then fit the thin washer, and the other Sturmey nut, and tighten.
- Pump up the tyre.

Fitting the chainset and chain:

- Take off the pedals, chainset, and bottom bracket.
- Fit the new bottom bracket cups – there’s a Shimano tool to do this, or there’s an equivalent Park one which I use, the BBT-9
- Fit the new chainset, sliding it in, and tensioning the bearings with the BBT-9 and tighten the allen bolts on the left crank arm.
- the chain will now be too long – to get the right length, thread it through the tensioner, and pull it so that the axle and both tensioner pulley wheels are in line, and shorten the chain to that length.
- if you fit a new chain, fit either a 7/8-speed derailleur chain, or a narrow single-speed one like the SRAM PC-1.
- Re-fit the pedals.

Fitting the shifter and cables:

- Fit the shifter to the right handlebar – you’ll need to cut down the handlebar grip a bit, and it should go with the cable to the front of the brake lever, not behind.
- Remove all the gear cables, shifters, tensioners, etc. Also remove the plastic pulley wheel that the gear cable goes through just before the back wheel.
- Thread the outer gear cable through the plastic cable gatherer behind the stem, down alongside the other cables, behind the chainset and through the cable guide there, through the cable guide on the chainstay (going from outside to inside, like the brake cable) and up through the tube that used to hold the plastic pulley, before curving down towards the cable guide on the hub – depending on your handlebars, you will probably need to cut a bit off the cable to make it the right length.
- Thread the gear cable through the outer cable. It’s easiest if you don’t put the outer cable into the cabel guide on the hub yet, you can do this later.
- Fit the cable clamp as in the Sturmey instructions – put the shifter into 8th, and fit the clamp 105mm along from the end of the outer cable. Cut off the spare cable.
- It’s easiest if you take the tensioner off again for this bit – push the plastic cable clip on the hub backwards so you have some slack, and clip the cable clamp in place. Try operating the shifter to make sure the cable clip rotates around the hub correctly.
- Adjust the gears as per the Sturmey instructions – in 4th gear, make sure the yellow dot is in the centre of the window, on the back of the hub on the right-hand side.
- Re-fit the tensioner, and try again – operate the shifter a few times while pedaling, and check again that the yellow dot is in the centre of the window – adjust the barrel adjuster on the gear shifter if necessary.

That should be it

Update for the latest version: The latest chainset uses the standard Brompton bottom bracket, so you don’t need to replace the bottom bracket. The new chain tensioner has the lower pulley a bit lower than before – a chain 100 links long is the perfect size.