The Folding Society

The SP - PHOTO REPORT ON the first 120 miles with the new Brompton-based folder

Probably the most immediately noticeable difference in the SP from a standard Brompton is the bars. The suspension seatpost which is used with standard flat bars gives better insulation from road shocks, but is also much more rigid, with virtually none of the flexing which occurs with the standard bars. The height of the bars can also be adjusted - the pictures show them in the lowest position, which is just over 1 inch lower than on my standard Brompton, which has the old pattern bars, in themselves a little lower than the current production models. Personally I would like them a bit lower still, as I am very short, but at least this is a move in the right direction. Taller riders can of course raise the bars to suit if required.

This view shows the handlebar stem, which is actually a Post Moderne seat post, more clearly.

The bars themselves are fairly standard lightweight ones. The use of a twist grip gear changer leaves the bars looking much less cluttered. The changer works well - very positive engagement of the gears, and very easy to operate. Steve usually tapes the bars and bar ends, but I prefer foam, and this also leaves the end of the flat part of the bars available for mounting a mirror.

The seven speed derailleur has an 11-28 cluster, which with the standard 50 tooth chainwheel gives a gear range of about 27 to 76 inches. The range is very well spaced, and eliminates the big jumps which are found at some points in most hub gear systems. Steve has had quite a struggle to squeeze the system into the very narrow standard Brompton rear triangle, and one inevitable consequence is that in bottom gear the mechanism is very close to the tyre. One of the bottom 3 gears should be engage before folding, so that there is no too much chain hanging loose. The arrangement in front of the bottom wheel of the tensioner is to hold the chain in place when the bike is folded, and is similar to that used on the Birdy. The XT changer works very smoothly, and gear changes are very positive.

The other big modification is the fitting of V-brakes front and rear. These are extremely powerful, but progressive. The substantial strengthening 'brake booster', in carbon fibre, helps to ensure the effectiveness. With these brakes you have to be careful in emergency braking not to grab the brakes hard, or it is easy to lock a wheel. The brakes and levers are Shimano XT.

This picture shows, not very clearly, the catch mounted on the end of the suspension block, which prevents the rear triangle folding under when the bike is lifted over kerbs, carried up or down steps, or is being manoeuvred in a limited space. A carbon fibre seat post is used, and for taller and heavier riders this is reinforced with an alloy tube inside - not necessary for a light rider like myself. A jubilee clip is normally fitted around the rear suspension rubber block to stiffen it, but due to my light weight I find that the ride is then quite harsh, so I have removed it. A lighter QR is also fitted to clamp the seat pillar in place.

My bike also has an option rear carrier with a quick release bracket which allows a standard Brompton front bag to be used at the back as well as the front.

There are lots of other nice details about the bike which I have not photographed (at least yet), such as the grease nipples for front and rear hubs and the suspension pivot, wires to prevent the frame clamp bolts coming out when the bike is being transported in a folded condition, and many other things.

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Copyright (C)1999 Ferrets Anonymous
Last updated: 15 August 1999
URL: http://www.whooper.demon.co.uk/foldsoc/sprep2.html