Wednesday, 7 December 2016

Which sprocket(s) do I need for my Brompton?

Which sprocket(s) do I need for my Brompton?

Over time chains and sprockets wear out. Due to the workhorse nature of the Brompton and the fact that the drivetrain is closer to the ground than on larger bikes (it picks up more dirt / grit), and the fact that it only has one or two sprockets to pared to 7-11 on a mountain bike for example,  they can wear even quicker.

If you are replacing your rear sprocket(s) then we recommend replacing both the chain and the sprocket. We describe it as an old married couple - they get comfortable with each other and wear at about the same rate.

So remember - if you replace the chain alone then the chain may well slip - and the same if you replace just the chain.

Which sprocket(s) do I need?

Well, as you are changing the chain AND sprocket, then it's the 3/32 sprocket you'll be wanting!

Note: If you fit a narrow chain 3/32 to a wide sprocket 1/8, the chain may not sit properly on the sprocket - so the chain will appear to be too short.

The sprocket you need depends upon your rear wheel and on whether you also want to replace the chain guard and circlip (which holds the sprocket / sprockets) in place.

Which splines?

Brompton sprockets come in two possible spline fittings:
3 spline / ISO sprockets - as shown here, are used on the SRAM 3 and SRAM 6 speed rear wheels, and on the Sturmey Archer 3 speed rear wheels.

They are available available with 13 teeth (13T) -  (standard on the 3 speed BSR - Brompton Standard Ratio rear wheel, and used on the Sachs/SRAM 3 and 6 speeds).

The 14T sprocket was a minor gearing option change for the Sturmey Archer rear wheels - but only in conjunction with a 1/8 inch chain - which is pretty much unused any longer.

The 15T sprocket was used on the Sachs/SRAM 6 speed rear wheels along side the 13T.  


Shimano style splines, as shown here use 9 splines spaced so that the sprocket can not be put onto the hub the wrong way around.

12T - used on single speed Bromptons and in conjunction with the 16T on the two speed Brompton.

13T - used in conjunction with the 16T sprocket on the 6 speed BWR - Brompton Wide Ratio - equipped Brompton Sturmey Archer rear wheel.

16T - used in conjunction with the 12T on the 2 speed and the 13T on the BWR 6 speed rear wheel.

Which width Sprocket?


Sprocket size Sprocket Sprocket stack Splines Note
12t QRSPR12 QRSPRSTACK12 ISO 3 Spline Single speed
13t QRSPR13 QRSPRSTACK13 ISO 3 Spline 3 speed BSR
14t QRSPR14 QRSPRSTACK14-SA ISO 3 Spline 3 speed BSR
15t QRSPR15 QRSPRSTACK15 ISO 3 Spline 3 speed SRAM

 To be continued ......

Tuesday, 4 October 2016

Brompton 2016 Black edition

Following the success of the BLACK Edition last year, Brompton have released another limited run of the Brompton BLACK Edition folding bike. They are the first 2017 specification Bromptons available.

 

Black edition features

The BLACK edition special features include*:
  • Black Wheel Rims, spokes and hubs (braking surface is still silver)
  • Black Pedals (both the folding left hand and fixed right)
  • Black rear reflector bracket
  • Black mudguards
  • Black brake levers (the standard ones have black levers - but the body is also black on these ones)
  • Black saddle rails and pentaclip (fixes the saddle to the seatpost)
  • Black seatpost
  • Black chainring and cranks
  • Black handlebars
  • Black hinge clamps 
  • Black mudguard roller wheel
* We could have missed some!

 

Brompton BLACK edition colours

They are available in a limited choice of colours - to highlight the black features
  • Black
  • Orange
  • Lime Green
  • Lagoon Blue
Brompton Black Edition - Orange
And unlike most Brompton where the main frame is one colour and the extremities are another, these have the main frame and handlebar stem as one of the four colours above, and the front forks and rear triangle in black.

The black colour bikes (so all-black) have an almost black decal not used on any of the other bikes in the Brompton range

Unfortunately the photo to to the right doesn't do it justice - we'll try again soon!

 

Brompton 2017 new features

The BLACK edition Bromptons are the first of the 2017 models produced.

New features for 2017 are*:

2017 model lock on Brompton grips and gear changer
  • Lock on grips. It seems that the lock on Brompton grips have finally been released by Brompton. They are still foam, but fixed on with a lock on clip at the inside end.
  •  New gear triggers. Both the 3 speed (for the hub gear) and 2 speed (for derailleur system) have new gear triggers. They are similar to the Shimano trigger style changers. 
  • New brake levers? The gear triggers / shifters (whatever you would prefer to call them) integrate with the brake lever. We haven't taken them apart to see, but the existing levers don't seem to have the mounting holes.
  • New gear cables. The new gear shifters use new gear cables - so you will have to select the correct one - for the Brompton 2016 BLACK edition it is the 2017 model cables!

*Again - we could have missed some

You can see our range of Brompton BLACK edition bikes here.

Tuesday, 4 August 2015

Is my Brompton a long or short wheelbase?

Pre 2004 Bromptons are referred to as short (as opposed to long) wheelbase.

But often we are asked "How do I know of my ?Brompton is long or short wheelbase?"

The easy guess is 'it's a long wheelbase' - as the majority of Bromptons out there are the long wheelbase model - but to be 100% sure there are these two ways to see.

Method 1: Tape measure 

The long wheelbase Brompton is only 3cm / 30mm longer than the short wheelbase version - but this makes enough difference that different cables should ideally be used (rear brakes and hub/derailleur gear cables) to make the fold work optimally.

You can measure (with the Brompton unfolded) from the centre of the front wheel to the centre of the rear wheel.

The long wheelbase Brompton has a length of 1045cm
The short wheelbase Brompton has a length of 1015cm

Measure the distance from front to rear wheel nut to determine if its a long or short wheelbase Brompton



Method 2: Distinguishing features / characteristics - main hinge

Main hinge construction

One of the improvements made to the long wheelbase Brompton was the quality of the main hinge. Instead if being brazed by hand it is now done by machine to make it more consistent and robust in its construction.

The below picture shows the main hinge on a short wheelbase Brompton - you can see that the main hinge is not quite as tidy as the machine brazed version on the long wheelbase model.

Red Brompton folding bike showing older hand brazed main hinge
Brompton folding bike - short wheelbase model with hand brazed main hinge
The hand brazed main Brompton main hinge gives the appearance that the hinge is narrower - as the slope up is thicker, but the hinge clamp required is actually the same width.

The picture below shows the main hinge on a long wheelbase Brompton - you can see the much smoother join made by machine brazed hinge.

Blue Brompton folding bike showing newer machine brazed main hinge
Brompton folding bike - long wheelbase model with machine brazed main hinge
Out of interest - both of the bikes shown above (the long and short wheelbase model) feature the older hinge clamps, which are now available in various colours (yellow, red, lime green and yellow) as well as the traditional black.

More info on hinge clamps - Brilliant Bikes








Wednesday, 29 July 2015

Brompton Hub Gear Cable Pulley Assembly - part update

In July (we think) 2015 there has been a small update to Brompton components

The picture below shows the old and new Brompton hub gear cable pulley assembly - it is used to route the hub gear cable (used on Sturmey Archer and SRAM / Sachs 3, 5 and 6 speed setups) through a ninety degree bend (using a pulley wheel inside the assembly to ensure smooth motion of the cable) just before it attaches to the cable anchor and the gear indicator chain.

New look Brompton Gear Cable Pulley Assembly

Not to worry - the new pulley assembly is compatible with Bromptons old and new. Below shows the difference between the old and new version - it's just a change to the look really.

Old (on the left) and New (on the right) Gear cable assembly
Just in case you are not quite sure where it fits - the below picture shows it in position on the Brompton.

Brompton gear cable pulley assembly in place
Brompton Gear Cable Pulley Assemble in place
You can see more and buy it at Brilliant Bikes - here:

Thursday, 25 June 2015

More Brompton colour - handlebar clamps

Ready for summer - to brighten up your Brompton, there are some new colour Brompton clamps now available.

Each Brompton has two clamps to lock the frame in place when in the unfolded position as shown in the picture below (it's not the best picture - we used the Brompton bike builder to grab it - sorry!)

Location if Brompton Hinge Clamps


The hinge clamp assembly (QHCA) consists of two parts - the hinge clamp plate (QHCPL) and the hinge clamp lever / bolt assembly (QHCLEVA) - see left.

The hinge clamp plate is available in silver or silver (though we have heard of some people getting them anodised to give extra colour there)

The hinge clamp lever / bolt is easily removed for replacing - no tools required.

It simply unscrews / screws into the frame (you already partially unscrew it when folding the bike)


The new (for 2015) Brompton coloured hinge clamp levers

Now - for the first time ever, the hinge clamp lever / bolt assembly is available in colours other than black ....

Blue
Red
Sunflower yellow
Lime green (though we think it's a bit light for lime - more like mint!)


They come display packaged (on re-cycled card of course)

For the full range of hinge clamps - click here


Wednesday, 24 June 2015

Which Brompton handlebar type do I have?

It may be simple for those us who have worked on and with Bromptons for years - but many of our Brompton spares and accessories are for specific handlebar types.

If you are not sure which type you have, then it makes ordering the right replacements difficult (gear and brake cables for example are pre-cut to the correct length based upon the type of handlebar your Brompton has)

So here we are ... There are 4 types of handlebar type

The original was the classic M-type, still the most popular with our customers.

Brompton with classic M-type handlebars
Brompton straight / S-type handlebars
Then in May 2005 the S-type and P-type were introduced

The S-type handlebars (shown to the right) give a sporty feel to the ride, with your head down ready for racing away from the lights during the rush hour.
Brompton P-type handlebars
The P-type handlebars (shown to the left) give the rider a variety of riding positions - hence P-type for multi position.

They are generally most popular for long distance touring where, when spending hours in the saddle, being able to ride in different positions can be beneficial.










Brompton H-type handlebars



Last but in no means least was the H-type  - introduced in Janyary 2012 - to cater for taller riders and
the Northern European markets (Holland, Germany, Denmark and Sweden) where a more upright riding style is preferred.

The handlebars used are exactly the same as on the M-type, the difference is that the handlebar stem is approx 2cm / 1 inch longer just below the hinge.

Each Brompton handlebar type has it's own handlebar stem and cable lengths - which means you can;t just change handlebar types if you want the fold to function correctly.



If you are looking to buy a new Brompton  - then why not use the Brompton website - it will help guide you through making the right choice (click here) or come and visit Brilliant Bikes in Chobham where we have a large range of Bromptons including a demo in stock - you can see our list of in-stock Bromptons by clicking here.

Tuesday, 5 May 2015

Brompton 10 degree brake lever

About Brompton 10 degree brake levers and new cable end


In 2012 Brompton changed the size of the nipple used on their brake cables from a proprietary size to a standard brake nipple size.

The new (standard - as you would find on a Hybrid / MTB bicycle for example) nipple is slightly smaller than the previous one used by Brompton.

This is good if you want to use non-Brompton brake cables but bad if you have some of the older 10 degree Brompton brake levers.

Open clevis

Brompton 10 degree brake lever - Open Clevis

Because of the reduced nipple size, some of the older levers (those with an open clevis) must be replaced. These are so called 10 degree levers (this is the angle at which the cable fed out from the lever). They can be identified as they have a double metal band where the lever is secured to the handlebars. See picture

Some older 10 degree brake levers had an open clevis as shown in the below picture:

(the clevis is circled in red - it's the part into which the nipple sits)

Brake clevis on Brompton 10 degree lever


Closed Clevis

The closed clevis brake lever was introduced in August 2008

Some 10 degree levers (as shown below) and the newer 30 degree levers and (introduced in 2013) aluminium brake levers from Brompton have what is known as a closed clevis.
Brompton 10 degree lever with closed clevis
With the closed clevis (even in conjunction with the smaller brake nipple) there is no risk that when the cable is slack that the nipple falls out rendering the brake useless.

As you can see from the picture - with the closed clevis the cable has to be fed through a hole, meaning it can't fall out.

Brompton with the 10 degree brake levers with an open clevis should be replaced with either the 30 degree or new aluminium brake levers.

All Brompton brake parts (cables, callipers and levers) for sale can be found here: