Brompton Gearing Options
While the choice of handlebar on a Brompton does not affect the price, the choice of gears does, and it’s the second most important option that will affect the user experience with your new Brompton.
Brompton bicycles are offered with 2, 3 or 6 speeds (and a number of further variations), and each option has its unique advantages and optimal applications. The single-speed option has been eliminated for 2021, but we include it here for anyone purchasing a Brompton second-hand.
As with the handlebar choice, it makes sense to decide on your gearing before making your purchase, since chainging the number of gears on the Brompton can add unnecessarily high expense. We hope this guide will help yo with that decision. Of course we're happy to answer any specific questions you may have, and we always encourage you to come in for a test ride to try out the various options.
(Not available for 2021)
The single speed Brompton is the most affordable, lightest and least maintenance-intensive option available. It is geared similarly to a single-speed urban bike, so it is relatively easy to start from a dead stop, and capable of decent cruising speed with a reasonable pedaling cadence. The single speed lacks some versatility, and is ideally suited to relatively short trips over mostly flat terrain (and considerably less so to cross-country treks over diverse topography). However, because of its low-weight, compactness and lower assortment of moving parts, it’s also a wonderful companion for out-of-state and international travel, so you are never stranded without your own personal transport. Read more about what else is there to love about the single-speed Brompton.
The two-speed drivetrain is comprised of a proprietary 2-speed derailleur which switches the chain between two cogs affixed to the rear hub, and is activated by a small left-hand shifter. This arrangement adds $80, a negligible amount of weight, and an easier gear that turns out to be very useful for going up bridges and overpasses, while retaining most of the simplicity you get with the single-speed. Brompton touts the two-speed configuration as being the most versatile option for urban commuting and multimodal travel, giving the rider a bit more versatility, while still keeping the weight of the bike low.
The 3-speed option does add about 1.5lbs of weight and $140 over the cost of the single speed, but the venerable 3-speed Sturmey Archer hub is easy to operate and virtually bomb-proof. The Brompton Standard Gear Range (BSR) provides three evenly spaced gears, so you can climb hills, cruise in normal traffic or haul ass when you have a tailwind or when being chased by your neighbor’s dog.
Unlike derailleur gears, internal gears may be changed when you are at a stop, so if you forget to downshift at a stoplight, no prob — just push the shift lever down, and you’ll be good to go in gear 1 when the light turns green. I love, love, love the three-speed option for it’s versatility and simplicity, and I don’t mind the extra weight. However. I have found that on longer rides (exceeding 10-15 miles) I do miss the middle gear between the cruising one and the pushing one. It may be a small inconvenience if you take longer trips infrequently, but if you plan to do world tour on your 16” wheel steed, see below.
The 6-speed Brompton offers the ultimate in gearing versatility, and if you intend to take longer pedaling trips with your new folder, put away any thoughts about keeping it simple and light, and go for the full monty. Yes, it adds more money, yes, it adds more weight. Yes, the two shifters are somewhat more cumbersome and initially confusing (one will shift while you’re at a stop, the other will not). Yes, you have to think about what gear you’re in and actually look at the dang shifters. But at mile 34.3 you will be happy that you don’t have to constantly shift between your cruising gear and your pushing gear, and instead find yourself comfortably pedaling in the “+” version of one or the “-” version of the other.
The confusion over the 6-speed system may ease when you realize that the gears are not a linear arrangement of gears 1 through 6. Instead, the 6-speed system is a combination of a 2-speed derailleur and a 3-speed hub, resulting in two distinct sets of 3 gears. Your right hand operates the 3-speed internal hub, the left hand operated the 2-speed derailleur. In the “+” position, this shifter will allow the 3-speed hub to perform just as it does on the standard 3-speed Brompton. However, when you push the left-hand shifter into the “-” position, it brings the whole 3-speed system into a lower range, resulting in 3 lower gears that dovetail with the standard three. The effective range of all six gears is similar to the span of gears you get on a typical urban hybrid. It takes a little getting used to, but the versatility is well worth mastering the slightly steeper learning curve.
To make things a little more confusing, the 2, 3 and 6-speed Brompton drivetrains can be ordered with modified gearing (reduced or increased) to further customize the bike to your riding preferences. The reduced gearing options are appropriate for very hilly areas, or for riders who are less athletic, older or very petite. The increased gearing options may be appropriate for riders accustomed to pushing harder gears.
Most of our customers find that in Chicago’s flat topography standard gearing works just fine. A -12% reduction makes sense on 6-speeds, which feature Brompton Wide Range (BWR) Sturmey Archer hub on the rear wheel. The standard 6-speed comes with a 50-tooth chainring, while a reduced 6-speed comes with a 44-tooth chainring. Because of the wide gear range of the hub, the smaller chainring may give the average rider a more fully usable range of 6 gears, but it remains a matter of personal preference of the rider.
Fortunately, these modifications are accomplished by substituting different size front chainrings (in the case of the 3-speed, the rear sprocket may also be replaced), and are relatively simple to perform by a Brompton dealer after your bike purchase, should you happen to want to modify your gearing in the future.