Brompton 8-spd Instructions
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.
– Take off the original tensioner, and all gear cables, including the pulley for the gear cable on the right side.
– 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. Important: use the new washers supplied with the kit, not the original ones from your old wheel. 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. Only do this nut up hand-tight, you’ll want to take it off again when you fit the cable.
– Pump up the tyre.
Fitting the chainset and chain:
– Take off the pedals and chainset.
– Fit the new chainset, and fit the pedals.
– the chain may not be the right length – with the standard 20t sprocket, 33t chainring, and latest tensioner, the chain should be 100 links long.
– 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.
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. If space is cramped, you can usually move the brake lever inboard a bit too. Make sure the shifter doesn’t restrict movement of the brake lever.
– 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 square 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 cable 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 😉