Brompton C Line 4-speed folding bike (2027)

Brompton C Line 4-speed folding bike

The 4-speed version of the C Line was originally introduced in the autumn of 2024 for the 2025 model year (replacing the 2-speed)

Gearing wise it uses the new 4-speed derailleur system introduced with the P Line and the T Line to save weight over the internally geared 3-speed Sturmey Archer hub

The changes for model year 2027 are just 

1/ a reduction in the number of colours to the following:

• Matt Black
• Plum Red
• Lunar Ice
• Racing Green

2/ The renaming of the models from low, mid and high to sporty, standard and comfort

Brompton C Line 4-speed specification:

All steel:

• Steel Main frame and stem
• Steel forks
• Steel advance rear triangle

Folded size: 585mm wide x 565mm tall by 270mm deep

For the 2027 model year the C Line range of colours are:

• Matt Black
• Plum Red
• Lunar Ice
• Racing Green

There is no longer the option to have a main frame a different colour to the extremities

Decal colour: Depending upon main frame colour

Detailing (mudguards, hubs, handlebars, brake levers etc): Black

There is a choice of three handlebar styles:

• Low rise / straight bars (previously known as the S type)
• Mid rise / classic Brompton style bars (previously known as the M type)
• High rise for a more upright ride (previously known as the H type)

Brompton 4-speed advance derailleur system
Derailleur chain tensioner
54T front chainring - black
106 link Brompton advance chain with connecting link
Folding left hand pedal - black
Non-removable right hand pedal - black
4 rear rear sprockets 
Integrated 4-speed gear shifter on left side of bars - black - for derailleur

The C line comes with the front carrier block fitted to allow for carrying of the Brompton luggage range, in turn allowing you to carry your stuff without affecting the steering of the bike

This bike comes with black advance mudguards (front and rear)
No rack / roller frame is included - though it can be retro-fitted

This bike comes with two advance roller wheels fitted to the rear frame and one on the rear mudguard

Marathon racer tyres - black / reflective - new 2027 Schwalbe branding
Low rolling resistance and good puncture protection 

16 inch (ETRTO size 349) wheels with double wall rim

• 28 spokes  on the rear
• 28 spokes on the front

The wheels have black hubs, silver spokes and black rims (the braking surface is still silver)

Schrader / car type 8mm valve 

Brompton standard saddle - 147mm wide

This saddle features chromoly rails and the fixing point for the Brompton Cateye or Be Seen rear light 

The seatpost is now dictated by the handlebar type

Low bars come with a standard seatpost
Mid bars come with an extended seatpost
High bars come with a telescopic seatpost

If you would like to swap between standard and extended, we can do that free of charge
If you would like to swap to a telescopic seatpost we can do that for an extra cost

Saddle height insert is included - we recommend you fit that after riding the bike for a while

Along with the new C Line comes a new advance suspension block

Front and rear reflectors are included

It's easy to retrofit battery lighting such as:

• Brompton dynamo lighting
• Brompton Spanning solo rear light
• Brompton CatEye 500lm front light
• Brompton Be Seen light set

This is the 2027 model year bike introduced in autumn 2026

We made this short YouTube video to show the features / changes for the 2027 model year (spoiler alert - mostly just colour)