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Posts Tagged ‘folding bicycle’

Sizing up the competition near Beaumont St.

Today I had a chance to ride the rebuilt Dahon around Broadmeadow and Hamilton, via the back streets (except for Beaumont Street).  As you would expect, the extended steering column and seat posts mean that this type of bike doesn’t have the structural integrity of a full sized bike. It feels wobbly-flexy at first but that feeling is accommodated as the bike is ridden further.

It is, however, nimble and a lot of fun, with quick steering and a tight turning circle and can whizz along at a reasonable pace thanks to the good leg extension possible with this design. You feel the bumps and road level changes more, which might have something to do with the stiffness of the short spokes, the small diameter and the lack of gyroscopic effect of a 16″ wheel, as the tyres are quite generous at 1.75″ wide. It’s not as rough in this respect as I thought it would be, and I am glad it’s a steel and not an alloy frame from a ride comfort point of view at least. Also, it is not a bike for stunt riding or stressful manoeuvres, at least not for people who have some mechanical sympathy anyway.

Attempting street cred - Broadmeadow.

For the level ground around Newcastle three speeds are easily enough. I had contemplated fitting a larger rear sprocket so that third was the normal gear but I think the 13 tooth is OK. I only have a spare 16T at home and I think this would make it too low – 14 or 15 would be better, though I don’t even plan on trying this until I get more used to the bike.

Diesel spotting, near Broadmeadow Rail

Although I have a van that will take a full sized bike and there is no need to fold it up, I found that folding down the steering column makes the Dahon a bit less likely to move around while transporting it.  The folder is a lot less bulky and hassle-free to carry, even when still unfolded. This could be the start of  new multi-modal bicycle adventures on occasions when I have to use the car.

No need to remove the front wheel here ...

The toy-like Dahon is a bike that seems to attract a bit of attention from onlookers – and I am also now wondering where I could get hold of an old model Brompton for comparison ?

At Scots Kirk, Hamilton.

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The past several days of heat and humidity and paralysis tick dramas with the cat have stopped me from riding this week. However, today I started to re-assemble the little Dahon folder. I find it helpful when doing bike rebuilds to keep the large parts organised  in large foam boxes and use smaller sealed food containers for bearings, bolts and small part groups.

Photographing the bike before disassembly helps remind me where cables run and how components should look when assembled, otherwise it’s easy to gradually forget where everything goes as the weeks or months go by, and that’s frustration I don’t need.

Things fell into place reasonably well today, but there were the usual struggles with the play in various bearings, adjusting the brakes, shortening and fitting a new chain, re-adjusting the gears and so on. I had to remove the folding castor wheel and refit it too, as the crank won’t go through the bottom bracket otherwise ….

 

 

The bell has polished up well and I made a new simplified indicator cover for the trigger shifter. The brake cables were OK so I just hung them up and ran cable lube through them over a few days. I fitted new brake shoes as well. The gear cable was broken, so I replaced it. I filed down a Shimano cable as I didn’t have a Sturmey Archer cable at hand – the nipple is smaller on the S-A .

 

wooden gear selector cover

"Ding ! "

wing nuts

 

The frame hinge locking levers and folding castor bolts use tiny circlips that don’t accept pliers and have a tendency to spring off into the blue while being fitted. Phew – I was lucky to find that one !  A Selle Royale gel saddle seemed a good choice of seat for this bike, so I will give it a try.

 

A shiny Dahon ...

 

I have fitted a front guard that isn’t quite the right size but I really wanted to keep the road muck out of the front brake and steering head bearings. It seems to hold steady without stays so far. I’ll think about it …

Gave it a quick ride to see how it felt.  “Flexy”, “frivolous” and “fun” seem to be the right words.  A little more detail fiddling and tweaking and I’ll do a ride report in the near future.

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I found myself wandering about in Long Jetty on the NSW Central Coast today – there weren’t too many bikes around, which is a shame, because The Entrance and Long Jetty are ideal riding spots with their seaside holiday ambience and moderate terrain (apart from the unpleasant traffic-heavy through roads).  Maybe I just chose the wrong day.

There are many shops selling old wares, craft, antiques and clothes in Long Jetty and outside one of them was this classic Raleigh Stowaway folding bike, decorated with flowers, as an attraction to passing shoppers. It looks as though it is mostly original and useable which is how I like to see old bikes … I am also sure that it was “not for sale”.

I have been on the lookout out for interesting folding bikes to photograph since recently acquiring a used Dahon to restore. These little central coast holiday towns would be great to explore on folding bikes, as they are too far for me to comfortably ride to, then back home from, in a day.

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After seeing how much grit was around the steering head bearings, I wanted to pull the whole bike down to clean and re-grease everything. I had some dramas at first, trying to undo the notched lock rings that hold the steering stem in place as they are difficult to access. After some penetrating catalyst and gentle taps with a hammer and punch they came free. The steering head itself has a similar lock ring which is easier to access with a C-spanner once the head stem is off.

Dahon steering head / front frame wishbone

The steering column and seat post that folders use are arrangements of sliding tubes with matching ridges and grooves that use plastic inserts to slide on when the quick releases are unlocked. This maintains the straight alignment of the handlebars and seat when folding/unfolding.The Dahon’s steering head itself is unusually squat, with large diameter caged bearings similar to a one-piece crank.

Telescopic seat post

I also disassembled, cleaned and re-greased the pedals then re-assembled them. Putting copper-slip compound on the threads makes them easier to remove for later servicing. I originally thought that the pedals were mismatched because one was not a folder, but have since discovered that some Dahons were made this way with one rigid and one folding pedal. The folding one has caged ball bearings while the fixed has loose ones. The pedals on a bicycle are are highly stressed components in a vulnerable position for dirt and water entry and subject to various knocks and scrapes, so it’s sometimes a wonder that they can last as well as they often do, without attention.

One rigid, one folding pedal

Side view

The front hub has now been rebuilt with new bearings. I think I was lucky here because it is unusually narrow and a replacement hub may have been hard to get, had I needed one. I have “pimped” the wheels with some blue anodised valve caps that I had, and some vintage wing nuts on the front wheel just for fun.

Wheels de-rusted, cleaned & hubs lubed

Here is the frame disassembled, to show how it breaks down. There was so much surface rust that I have had to repaint it with a close colour match and treat the inside with fish oil spray.

The frame and forks

The frame hinges

I hope this gives more of an idea of how this little folder works – it’s something new for me as well.

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I sometimes like to imagine the journey from prized new bike to unwanted sell off, and with this Dahon folder there are signs of rough use, perhaps from being folded and thrown into a car boot many times, clashing with the other luggage on long trips. The main folder hinges were very loose and the front wheel bearing cages had collapsed, but the cones and hub races are still in good condition.

The front wheel wobbling seems to be the final cause of abandonment following sometime after the fitting of a new front knobbly tyre.  Surface rust has dulled the appeal of once shiny metallic paintwork and chrome. The front wheel is also rusted more on one half due to being left standing a long time in the same spot, allowing rust to coat the upward facing side, another common effect of the local salty air.

I have dated the bike from the Sturmey-Archer “AW” model 3-speed hub, conveniently marked 91-6 manufacture ( i.e. June 1991 ), easily found once the oil coating had been removed from the shiny hub. The serial no. is B0011430– or “Boo” for short !

Bicycles, like most mechanical things, rely on regular usage, cleaning and occasional maintenance to age well, and though this seems obvious they are often expected to last forever with little or no care. The high cost of labour means that to have a bike in this condition repaired at a bike shop would be very expensive for the owner and not cost effective for most time-poor businesses either, and that’s where I come in !

Here is the main folder hinge, of which there are two, one passive and this one with the locking and safety mechanism, here showing the adjustment point for a loose hinge.

Now closed, with the plastic safety catch engaged – luckily this one and the steering safety catch are still in good condition, as they could be hard to locate new for a 20 year old bike.

The gearing would be massive on a normal sized wheel, with a count of 52 teeth on the chain wheel and only 13 on the rear cog, however on a 16″ this is fairly normal.

Dahons (and other folders) seem to have a cult following in some places, going by some of the flickr series I have seen while researching this one – some owners accessorising them in different and fun ways such as fitting them with Brooks leather saddles and accessories, or dozens of tiny glowing coloured LED lights for example. I am happy simply to begin making this one useful again – for now !

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I thought that I had run out of space for restored bicycle projects, so I really shouldn’t be going near garage sales. However, we were out on the tandem today and happened to come across a charity sale – there were a couple of kids bikes there that I ignored, but just as we were leaving I took a closer look. Wow ! – a steel framed 16″ wheeled Dahon folder with a 3-speed Sturmey Archer hub :

And at a price of about two cheap bicycle bells – I fell for it. I must say that I have previously had little interest in folders, but after looking over this one, I am fascinated – so clever and compact. The bike is basically sound but the finish has deteriorated, there are a few parts broken and one fold up pedal has been replaced with a non-folder. The front hub is acting as though the bearings are all missing, so that may be a problem. The gears appear to work well though the trigger shifter name plate has disappeared. I think it’s gorgeous !

Now I will have to do some research, regarding its age, SA hubs can be dated by their serial numbers apparently.

The seat is not original, and broken as well. All up there is plenty of work to be done. Having just finished a time consuming  restoration, this one will have to take a little bit longer to get through.

I am amazed how simple yet ingenious these things are – a folding trolley wheel :

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