Widening Brompton rear triangle

Widening Brompton rear triangle

I've got to that dicey part of a Brompton 8 speed conversion where I open up the rear triangle to take an Alfine 8 hub. As posted elsewhere, the dropouts on a Brompton are 112mm apart. Shimano hubs are typically 135mm, so that's asking the tubes of the rear triangle to bend apart by 23mm - quite an ask when the tubes themselves are only 180mm long from the point where they are braced together, to their rear end at the dropout. On this job I'm experimenting with swapping the large serrated 10.7mm locknut on the non-drive side for a much smaller 4.4mm one. (From SJS Cycles).   This saving of 6.3mm width brings down the requirement to widen the triangle to just under 129mm. The good news is, I've achieved this already - well nearly. By opening up the triangle to 150mm under compression, I found it sprang back to 128mm - nearly there! However, I decided to try a little experiment. Intuitively,...
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The B75 – review

The B75 – review

My's son's Brompton was stolen in London last week. It's his main mode of transport, and was a gift to him nearly 5 years ago when he left for Uni. It's a very unique bike - converted to an Alfine 8 speed hub, with 32 spokes in the rear wheel.       If you come across it, look for the frame number: 436821 Thankfully the bike was insured - but how to replace something quite so unique? I decided to buy the stripped down version of the Brompton - the B75 - and use this as the basis to recreate the old bike. The B75 first came on the market at £750 - pretty reasonable for a three-speed Brompton - but has since gone up to £850. (Pandemic? Brexit? More people cycling?) At the same time, other Brompton versions have also shot up in price. I bought my M6L 4 years ago through cycle to work, and the shop price was around £1000. Today, a typical price...
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Brompton Explore – suburbia in a pith-helmet

Brompton Explore – suburbia in a pith-helmet

Perhaps Brompton Suburbia would have been a better name for this new edition, which looks like it's dressed up for a fancy dress party, not for serious touring. Donning a pith helmet and plus-fours doesn't make you an explorer. I'm disappointed because I'd hoped that Brompton would have used their engineering genius to solve some basic problems that make the Brompton inadequate for touring. Like the fact that the rack can't take panniers. And the gearing is too narrow and still too high. And there are no mudguards. And I'm frustrated, because the Brompton has a lot going for it as a tourer. I've taken mine twice round the Scottish isles of Mull and Iona, and wild camped on remote beaches and hillsides. It's not  a fast touring bike, but with its small wheels it doesn't tire you out (getting going is always easy), and its frame suspension keeps you comfortable. And I'm suspicious, because this edition feels more like a marketing ploy...
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Bikes, batteries and bumps

Bikes, batteries and bumps

Much as I'd love to have an electric Brompton, they are well outside my budget (and probably most people's). So this post is looking at alternatives, and particularly, at what I did with my ten year-old bike to turn it into an electric workhorse at a fraction of the cost of a new electric bike. (There are ways to convert your Brompton to electric too - some people swear by these.) Three Power Options I started by trying a number of off-the-peg models at a local e-bike shop. The three basic options for powering an ebike are to put a motor in the front wheel, the rear wheel, or in the bottom bracket. Most of these work on the basis that when you begin to pedal, this activates the motor, though some have a manual throttle. Each have their pros and cons. Bottom bracket (BB): I tested some state of the art e-bikes with a BB motor. Powering the bottom bracket makes sense because...
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New Brompton cover from October 2018 – what’s to like?

I've been looking for a new Brompton cover and saddlebag, and discovered that Brompton have changed the design - not for the better, in my opinion. My old bag was stolen from the bike about a year ago - ever since I've done without, getting by on the odd bus trip by pleading with the driver to let me on without one. After all, I can't see why a Brompton is any more of a dirt hazard than a wheelchair, buggy, shoe...  especially if your chainwheel is smaller and not protruding enough from the fold to come in contact with anything. And you don't need a bag for the train! But the old bag (above) is useful - flexibility on public transport, and a bit of spare carrying capacity - on warm summer days when you've no coat or pockets, and you want to spin along unencumbered by bags of any sort, the old-style saddle-bag (or sack, more accurately) can hold a...
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New triggers, old dimensions

With my Alfine 8 conversion nearly complete, it seemed only right to replace my 10-year-old trigger with a new one for the Brompton. (top) I wondered whether the change in shape of the new one would mean more space on the handlebar - one of the less good aspects of the Alfine 8 when you have the M-type bars. Alas, the dimensions that matter are the same. It means that in order to accommodate the width of the trigger, the cable has to come down on the inside of the bar, meaning the trigger points more downward than usual. Still, it works, and you soon get used to it. But if you're thinking of buying a Brompton to convert, can I suggest getting a flat-bar S type one? More room for the controls! Having said that, with the gripshift version of the Ergon2 grips, you can still finish off the bars very nicely. Mine are in the post!   UPDATE: Ergon grips have arrived a work beautifully...
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When the best way forward is back – an Alfine 11 conversion

When the best way forward is back – an Alfine 11 conversion

When I saw an Alfine 11 hub online for less than half price, I couldn't resist. I had hoped to do an Alfine 11 Brompton conversion at some point, and the opportunity to buy a cheaper Brompton through cycle-to-work brought hub and bike together. I used the bike as a commuter for 18 months, getting used to the Brompton 6-speed set-up. I knew that Bromptons had been converted to Alfine 11 hubs by others, but in one case with a seriously modified rear triangle. Perhaps that should have been a warning sign. My Alfine 8 conversions had gone like a dream, and I hadn't anticipated that the 11 would be much different. So I set about working out my gear ratios using the magnificent Brompton Gear Calculator coming up with an ideal spread (for me) using a 16T rear sprocket, and a 40T front chainwheel - made by Stronglight, but Brompton compatible. For the Alfine hubs, the over-locknut width between the rear dropouts...
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