New Brompton -- puzzle

[Bee]

Hello all,

I finally took the plunge after Christmas and ordered myself a Brompton M6L/R (44T), which I've had now for a month or so and am loving it. People said things to me like, "the Brompton is ok for short commutes but no good for doing distance". Well, after a 50 miler at the weekend, I am beginning to feel vindicated in doubting! For me the geometry seems to work rather well... which of course might say as much about me as does about the Brompton

I've added one or two bits: Ergon GP2 grips, Shimano A530 pedals, Zefal Spin mirror and a Garmin Edge 25 GPS -- all of which have turned out to be real winners.

The new Schwalbe Marathon Racer standard issue tyres are a bit light-weight -- had a rear puncture already, but the cuprit was a bent safety pin so quite likely a sturdier Marathon would have succumb also. The good thing is that these Racer tyres are pretty easy to get off and on with bare hands.

Any way, other than to say hello, and say what a useful forum this is for mining, I have a conundrum...
The left-hand (non-drive side) fork has a cylindrical braze-on on the rear edge - fixed with it's axis horizontal and perpendicular to the that of the bike at wheel-rim height. What the heck is it for???

 

[alicat]

Could you take a pic?

 

[alicat]

Hello and welcome.

I am glad the geometry of a Brompton works for you.

For me, I did a club run on one. I had to get off and walk for a while after 20 miles to shake out some pains. Oh and I was slower uphill than the 80 year olds on the ride.

 

[lazyfatgit]

Clips into the plastic clip on the frame when folded?

 

[raleighnut]

Like @alicat says hard to tell without a piccy but sounds like a bottle 'dyno' mount to me,

Oh and

 

[Poacher]

Today's prize goes to @raleighnut - I'm 99% sure that it's a throwback to when Bromptons were offered with an Axa dynamo, rather than the much preferable hub dynamo (choice of Son or Shimano - Son's better, 'cos it's much dearer ). Probably only retained for Brompton's legendary compatibility record.
It's a terrible aerodynamic drag, so probably best to saw it off flush with the fork. Please don't do this!

Welcome to the forum from a fellow M C Escher fan!

 

[Poacher]

Now having slight second thoughts - when I bought my Brompton back in 2009, the back of the order form had a list of prices for extras bought separately (i.e. not at time of ordering bike). This has:
Dynamo set (R version), c/w stay 69.00
Dynamo set (L version), c/w stay 70.25
Dynamo set (E version), c/w dynamo brackets 67.00

From what I can gather, the R version was for bikes with a rack, which would suggest the dynamo was powered from the rear wheel. L was for bikes with mudguards and E was for neither rack nor mudguards. It's a mystery:

 

[Pale Rider]

My Brompton had a bottle dynamo mounted on the rear non-drive side seat stay.

The cable broke due to the fold - as many did - so I took it off.

Can't recall exactly how it was mounted.

The OP says 'fork' and it's not clear if he means front or back, but if it's back, I reckon bottle dynamo mounting boss is a good shout.

 

[Poacher]

Definitely front fork. left hand side - I remember idly wondering what it was for myself, but then forgot all about it, to the extent that I unfolded mine just to check. As an aside, nearly all photos of Bromptons seem to be from the right hand side! I think it's threaded, but if it is, it's a very tight fit for an M6 machine screw, so tight that I didn't try forcing the issue, and an M5 rattles around inside it.


Edit: pic of several forks stolen off web, all being well, clearly shows the braze-on in question:

 

[Fab Foodie]

I’ve done a 100 miler on my S6L without any probs -and several 60 to 70 mile night rides. Have also toured the outer Hebs with bivvy for a spot of wild camping. If a Brommie works for you, it’s a hugely capable bike.

 

[simon.r]

I think it’s to mount a ‘cable fender disc’: https://www.sjscycles.co.uk/mudguards/brompton-cable-fender-disc/

On E Type (no mudguards) the front brake cable rubs on the tyre if this isn’t fitted.

Photo of one fitted here: https://item.rakuten.co.jp/gocycle/qcfdisc/

 

[Bee]

Excellent! First prize to Simon.r -- congratulations sir, to where should I send your prize of a new Brompton cable fender disc?
I was with the bottle dynamo idea for a while, but good sleuthing by Poacher revealed this to be a red herring.

Unable to decide between L and R models, in the end I bought an L and a rack set as a spare part (£15 uplift on buying an R). So if I invest in one of these cable fender discs, would I then have the complete set {E, L, R}?

 

[simon.r]

Excellent! First prize to Simon.r -- congratulations sir, to where should I send your prize of a new Brompton cable fender disc?
I was with the bottle dynamo idea for a while, but good sleuthing by Poacher revealed this to be a red herring.

Unable to decide between L and R models, in the end I bought an L and a rack set as a spare part (£15 uplift on buying an R). So if I invest in one of these cable fender discs, would I then have the complete set {E, L, R}?

You’ll also need a different hook https://brilliantbikes.co.uk/brompton-folding-detail/488-brompton-front-axle-hook-c-e-version.html for the E version! That should give you the option to have any version

Edit - thinking about it, the rear mudguard is also different on the L and R versions.

 

[Schwinnsta]

But was it needed at all? If so for what model? I was thinking dynamo, but on the front wheel, seemed unlikely.

 

[raleighnut]

But was it needed at all? If so for what model? I was thinking dynamo, but on the front wheel, seemed unlikely.

Quite common to stick em on the front wheel, easier to get at,