AlanKHG

Hi there—

I scored an old Brompton cheap. The prior owner says it was 15 years old, and it seems to have seen regular maintenance— it was originally 5-speed, and still has a 5s shifter, but now has a 3 speed BSR hub. It also has a dual-pivot front brake which may have been upgraded at some point? What model is it? And what would I need to do the locking rear wheel mod?

Here it is as I bought it:


And here it is after a new saddle and making some new mudflaps from sheet rubber:

berlinonaut

This is a Brompton Mk2, built until 2000. If it had a five gear it was an L5 model in it's original state. The brakes have been upgraded to the dual pivot model on the front - standard since 2000 and same as the ones until 2017 (just changed for 2018) - and an enhanced single pivot on the rear, used as standard from 2000 - ~ mid 2007 (then was changed to dual pivot as well). A common upgrade at that time as the older brakes are a nightmare and your's are still ok today, especially in combination with good brake shoes.

Brake levers are still worth upgrading to the current model, the model since 2013 before the current or 3rd party levers. It seems to have a 44t or 46t chainwheel (lower gearing option, useful on the 5-speed), standard for the 3 speed (as well as the 5 speed on the MK2) would have been 50t. The stock roller wheels have been replaced with easy wheels (not yet available at the time the bike was built).

Possibly the bars have been replaced as well - please check the shape as the old ones were affected by some breakages and there was a recall in 2002 for bikes made until 1999. Check here if you's is still affected. Grips and marathon tires are (relatively recent) retrofit as well. Left folding pedal was a paid extra on the MK2 (standard since the Mk3). Rear mudflap did not exist on the MK2 but was standard since the MK3 (2000) on. So either it has been retrofitted or the rear blade has been replaced at some point in time.

For the rear-frame clip there is a retrofit option available from Brompton.
Brompton Q part code: QRFCLIP-RETKIT
Brompton part number: 9040179

Here's a link: https://brilliantbikes.co.uk/brompto...-retrokit.html

Regarding the exact age: Tell us the frame number (on top of the frame at the rear-frame hinge. Then it is possible to date it very ecactly.

fietsbob

I guessed mine(MK2) by the year on the back hub S-A AW 3 speed..

I like the previous 3 speed shifter, the plastic over the bar one has a nice light action..

[Anecdotally ] Old steel triggers were work to get in 1st..

Plastic, over the bar 3 speed & BSR hub , are light action, combined..





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Schwinnsta

I never noticed this.

berlinonaut

Common way and generally valid for MK2 Bromptons with the old S/A-hubs with steel housing, but not for the OP as his rear wheel has been replaced with a newer one.

AlanKHG

Thanks for all the info!

The handlebars appear to have been replaced by the newer model?


Also a folding pedal was installed, and parts of the the sticker from the old US Brompton distributor remain:

fietsbob

last version used a cast steel hinge , tup inside 2nd & 3rd butt brazed tubes to forged steel hinged pieces.. skilled brazing required training people.


Mk2 bars , center sleeve, would not let 22.2mm/ 7/8" bar ends fit, the Mk 4 has a different bar, the Ergon Grip Bar Ends fit well .

asking about a used bike which the past owner changed stuff is , going to be entertaining, at least





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berlinonaut

Yes, looks good.

Yes, saw it in your first picture already, that's why I mentioned it. It became standard only with the MK3 but many MK2s got one already from the factory for an upgrade price - relatively expensive back then already but very useful as well.

fietsbob

Yes Mr Wasson, Foldabikes, was the only one in the USA for quite a while, in Palo Alto Cal, .. He retired recently ..

If he sold his house in today's real estate market, around Stanford Uni, Silicone valley's hub, he has plenty to live on.. travel, etc.

his site used to have a lot of users and his, travel pictures.. ..


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AlanKHG

So the handlebars seem to have come a bit loose on this bike and the nut on the clamp bolt is 13.4 mm across the flats which is approximately 17/32 in. Why on earth is that? Did Brompton have some sort of proprietary nut size made? Or is this some sort of obscure British standard like Whitworth?
https://en.wikipedia.org/wiki/Britis...dard_Whitworth

Schwinnsta

The clamp is threaded on modern Bromptons.

AlanKHG

This Brompton definitely isn't modern.

12boy

If your bars are loose a qr clamp will do just fine. I use a seatclamp qr.

berlinonaut

At that time: Yes, this is one of the obscure british standards from former times. This was changed with the MK3 in 2000. You still can use a metric tool to work on it - will not fit perfectly but good enough. Or you use one of those: KNIPEX - The Pliers Company. - Products - a highly recommended tool for your toolbox anyway.

fietsbob

my Mk2 3T, had the rack fitted bottle dynamo, black frame , was set up for left side 2nd pull chain,
for the then 5 speed ..

fillet brazed connection of tube to hinge parts .. Zn coated steel spokes, 20 spoke front wheel, steel hub.

AlanKHG

Interesting. Do you have a photo?

berlinonaut

Yes, you've mentioned this gazillion times and showed the according photo. But what has this to do with the topic or the question of the OP?

fietsbob

seat post quick release ?

fietsbob

and you tediously respond in the same way.


people redundantly ask the same question as if its never been asked before ..

AlanKHG

Ooh, I just realized I replaced my old seatpost QR as a part of installing the back-wheel-lock upgrade kit — so I have one sitting in my bin now! Thank you!

tds101 

Good job on the suggestion sir!!!