Brompton C Line 4-Speed Review: The Explore’s Replacement, With Half the Range
We set out to review the Brompton C Line Explore, the 6-speed steel Brompton most people picture. Brompton no longer makes it — or the 2-speed Urban. The mainstream C Line is now a 4-speed, and the number that matters is not the gear count but the range: 163% where the Explore had 300%. Here is what that means on a hill, and who should still buy one.
Where the reviews line up
No UK title has yet published a full test of the new 4-speed, so this page leans on three sources and is open about the gaps: road.cc, whose tester Matt Swaine scored the outgoing C Line Explore 9/10 on the same frame and fold; CycleChat, where owners of Brompton’s 4-speed derailleur bikes discuss what the gearing is like to live with; and buyer ratings at Trustpilot and REI, which are honest but tiny — 4.3/5 from 3 reviews at each, checked 5 October 2026.
Everyone agrees on the fold. road.cc calls it a design classic and “a cinch”; it packs to 58.5 × 56.5 × 27 cm in about 20 seconds, small enough to take on a train without a reservation. Nobody has a bad word for it, and it has not changed.
The disagreement is the gearing. The Explore’s 6 speeds gave a 300% range, enough for road.cc to climb a 9.4% road and cruise at 28 km/h. The 4-speed uses a single 11–18 tooth cluster with no hub gear, which Brompton itself puts at 163%. On a CycleChat thread about the 4-speed P Line and T Line, the complaint is spinning out at the top while still wanting the low end for hills. That is the trade: simpler, lighter, cheaper, and less range at both ends.
The buying decision is 4-speed or 12-speed, now that nothing sits in between. On 5 October 2026 the 4-speed cost £1,399 at Sigma Sports and Condor Cycles, £1,449 at SJS Cycles and £1,509 direct from Brompton. If your ride is flat and short, the 4-speed is enough. If it involves real hills or a long day, budget for the 12-speed.
The three reviews this summary is built from
- road.ccEditorial ride test of the outgoing 6-speed C Line Explore, February 2023. 9/10. Same frame and fold; different gears.
- CycleChatUK rider forum. A 2023 thread of 15-plus posts on living with Brompton’s 4-speed derailleur gearing.
- Trustpilot & REI4.3/5 from 3 reviews at each, checked 5 October 2026. Too few to lean on, and we say so.
Before the review: the C Line Explore and Urban are discontinued
Condor Cycles’ 2026 Brompton range guide states plainly that the previous 2-speed and 6-speed C Line folding bikes are discontinued. The C Line now comes as a 4-speed and a 12-speed, each with Low, Mid or High handlebars. Some listings blur this — one retailer titles a 2026 bike “C Line Explore 2026 … 4 speed”, and John Lewis still has a C Line Explore page marked no longer available. Brompton’s own subscription C Line is still listed as a 6-speed with a 300% range. If you are buying outright, check the gear count on the listing in front of you, and if you find a new 6-speed Explore at a run-out price, the road.cc test below applies to it in full.
Specification at a glance
| Spec | Figure | Confidence |
|---|---|---|
| Gearing | 4-speed derailleur, 11-13-15-18 tooth sprockets, 50T chainring, trigger shifter | Brompton UK, Condor, SJS; chainring from Sigma Sports |
| Gear range | 163% (the old 6-speed Explore: 300%) | Brompton US and SJS for 163%; Brompton and road.cc for 300% (road.cc news gives 302%) |
| Weight | From 11.3 kg or from 12 kg — sources differ | 11.3 kg Brompton UK; 12 kg Condor and Sigma; 26.12 lb (about 11.85 kg) Brompton US. Mudguards included, no rack. road.cc weighed the 6-speed Explore at 12.3 kg |
| Folded size | 58.5 × 56.5 × 27 cm (25.3 × 23 × 10.6 in), H × W × D | Brompton; Condor matches |
| Fold time | About 20 seconds | Brompton and Edinburgh Bicycle Co-op |
| Handlebars | Low: straight bar, sporty and forward · Mid: riser, natural and relaxed, the most popular · High: riser with extra height, most upright, for taller riders | Sigma Sports and Condor descriptions |
| Frame | Hand-brazed heat-treated steel main frame, steel rear frame, carbon fork | Brompton |
| Tyres | Schwalbe Marathon Racer 349 × 35C, puncture-resistant, reflective sidewall | Brompton UK |
| Included | Mudguards, front carrier block for Brompton bags. Rack and lights not included | Brompton UK, Condor, Edinburgh Bicycle |
| Where made | Main frame hand-brazed in London | Brompton’s claim; component origin not stated |
| Frame warranty | 7 years, unlimited mileage, if registered; 2 years if not. Non-wearing parts 2 years | Brompton support page |
| Servicing | First service at 100 miles, then at least once a year | Brompton’s recommendation |
| Cycle to Work | Yes — Brompton lists Cyclescheme; Sigma Sports takes all major providers | Brompton UK, Sigma Sports |
| UK price | £1,399–£1,509 | Sigma & Condor £1,399, SJS £1,449, Brompton direct £1,509, 5 October 2026 |
road.cc
This is the review of the bike Brompton has just replaced, and we use it for what it can still tell you. The frame, fold, wheels, tyres and riding position carry over to the 4-speed; the gears do not. road.cc rode the High-bar Explore, weighed it at 12.3 kg and paid £1,640 for it in 2023, which makes today’s £1,399 4-speed look better value than it first appears.
The praise is for the fold, which it calls a design classic, and for a ride it describes as nippy and fun once you adjust to the quick steering of 16-inch wheels. It found the frame’s flex surprisingly comfortable on longer rides, rated the Schwalbe Marathon Racer tyres for puncture resistance, and climbed a 9.4% gradient on the 300% gearing. The criticisms are worth carrying over too: big jumps between ratios, a saddle that is easy to remove and therefore easy to steal, a harsh feel from small high-pressure tyres on poor roads, and reports of stock parts wearing under heavy mileage. How the 4-speed’s narrower spread compares on that same climb, nobody has yet published.
Watch: Brompton Gears Explained [New C-Line 12 speed - Rev.2025 ]
A walk-through of the 2025 Brompton gearing line-up. Useful for seeing exactly what the 4-speed gives up against the 12-speed, which is the decision this page comes down to.
Watch on YouTube ↗CycleChat
This thread is about the 4-speed P Line and T Line, the bikes that introduced Brompton’s 4-speed derailleur, not the new C Line itself. We include it because it is the only sustained owner discussion we found of what four sprockets with no hub gear feel like day to day, and because the C Line 4-speed uses the same 11-13-15-18 cluster. We could not confirm whether the chainrings match.
The original poster’s complaint is specific: spinning out too easily at the top end while wanting to keep the low gear for hills, and finding a cadence above 80 rpm hard to hold on a Brompton. Replies suggest a larger chainring (58 tooth against the stock 50), a second chainring changed by hand, or a Schlumpf two-speed bottom bracket, which widens the range but adds weight and cost. None of that is a fault. It is a reminder that a narrow range forces a choice — high enough for speed or low enough for climbs, not both — and that a dealer can change the chainring at purchase if you know which end you need.
Watch: Brompton 4 speed derailleur gear adjustment
A short home-maintenance clip on indexing the 4-speed derailleur. Worth a look before you decide whether to service it yourself between dealer visits.
Watch on YouTube ↗Trustpilot and REI
Six reviews across two sites is not evidence of anything on its own, and we would not normally print a source this thin. We do so because the bike is new and these are the only owner ratings we found: Sigma Sports, SJS Cycles and Edinburgh Bicycle Co-op had no reviews at all on their 4-speed pages. Treat what follows as colour, not proof.
The Trustpilot reviews, written between December 2025 and January 2026, split two five-star to one three-star. Owners rate the quality and ride — “Beautiful ride. Love it!” — and Brompton’s customer support. The three-star complaint is value: that the bike is too expensive for what it is and that accessories, which most people need, have to be bought separately. That chimes with the spec: no rack, no lights and no bag come in the box. At REI an owner called it life-changing for flat living and commuting; the one three-star review hints at durability without saying what failed.
Watch: Brompton Bike Review and Initial Upgrades: Our first week with a new C-Line Brompton
An owner’s first week with a new C Line and the accessories they added straight away. The listing does not say which gearing the bike has, so watch it for the fold, fit and add-ons rather than the gears.
Watch on YouTube ↗Strengths and weak points
What holds up
- The fold: about 20 seconds to 58.5 × 56.5 × 27 cm, praised by every source.
- Cheaper than the Explore was: £1,399 at two dealers against road.cc’s £1,640 test price in 2023.
- Lighter than the Explore on Brompton’s own figure — from 11.3 kg, with mudguards.
- Simple gearing: one shifter, four sprockets, no hub to service.
- Puncture-resistant Schwalbe Marathon Racer tyres as standard.
- 7-year frame warranty once registered, and Cycle to Work eligible.
What people complain about
- Gear range falls from 300% to 163% — a real loss for hills or speed.
- No rack, lights or bag included, and Brompton accessories are not cheap.
- Saddle is quick-release and easy to steal (road.cc).
- Small high-pressure tyres feel harsh on broken roads.
- Weight figures disagree: 11.3 kg from Brompton UK, 12 kg from two dealers.
- No full UK editorial test of the 4-speed yet.
Who it actually suits
Buy it if your riding is a train-and-bike commute or a few flat miles across town, you need to carry the bike up stairs or store it under a desk, and you want the simplest Brompton to own. Pick the Mid bar if you are unsure; Low if you like a forward, sporty position; High if you are tall or want to sit bolt upright. Put it through Cycle to Work if your employer runs a scheme, and budget for a lock and lights from day one — our reviews of the Kryptonite Evolution Mini-7 D-lock and the Cateye AMPP 800 light cover both.
Look elsewhere if you live somewhere hilly, ride long distances, or want to keep up with traffic on fast roads: the 12-speed C Line costs more but restores the range the Explore had and more. And if you find a new 6-speed Explore being cleared at a good price, it is the better-geared bike for most riders.
What we could not check
- The videos were confirmed by search listing, not by opening them. youtube.com will not load for us, so each video ID and title was verified by finding the same watch URL in two differently-worded searches. None of the listings named the channel. We have not watched them.
- A full editorial test of the 4-speed C Line. We found none from road.cc, BikeRadar, Cycling Weekly or any UK title. The road.cc test is of the outgoing 6-speed Explore.
- The true weight. Brompton UK says from 11.3 kg, Condor and Sigma Sports from 12 kg, Brompton US 26.12 lb. Nobody we read weighed a 4-speed, or said which handlebar the figure is for.
- Gear inches, lowest and highest. Brompton publishes the 163% range but we could not find the actual low and high gears, so we cannot say how much of the loss is at the climbing end.
- Whether the CycleChat owners’ 4-speed matches the C Line’s. The sprockets are the same; we could not confirm the chainring on the P Line and T Line bikes in that thread.
- Why Brompton direct is dearer. Brompton listed £1,509 against £1,399 at two dealers on the same day. It may depend on colour or handlebar; we could not confirm.
- How much of the bike is made in London. Brompton says the frame is hand-brazed there; it does not say where the components come from.
- Brompton’s full warranty terms for UK buyers. We read the support summary, not the full terms document, so check what voids the frame warranty before modifying the bike.
Sources last checked 5 October 2026. Brompton prices vary by colour and handlebar — check the listing in front of you before ordering.