COSMIC BIKES BROMPTON GUIDE

BROMPTON CONVERSIONS & MODIFICATIONS

What if you change your mind?

You may wonder whether any of the selections you make in your initial Brompton purchase can be modified or replaced with other stock Brompton parts if you change your mind after riding for awhile.

The answer is that some things are changed a lot more easily than others. Hopefully, these guidelines, based on our many years’ experience, will help you make the right choice.

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Easy and inexpensive changes

If you’ve purchased your Brompton from us and are covered by your one-year or extended service package, these modifications will basically add the modest cost of your desired parts, and we cover the labor. If you’re not covered by one of our service plans, the labor to install these is fairly minimal.

  • Gear ratio. You’re not changing the number of speeds, but simply adjusting the gear ratio up or down. This usually involves only replacing the main chainring (and in some cases also the rear cogs).

  • Saddle type. Any standard bicycle saddle is compatible with the Brompton.

  • Seatpost height. We can easily swap the standard or extended seatpost for the telescopic one to give you more extension, and for easier removal of the saddle for packing.

  • Tires. We usually stock a few different tire options for Bromptons if you wish to modify your bike for a different handling and riding style.

  • Adding EZ Wheels is a simple upgrade that replaces the stock frame and rack rollers, and will make the bike easier to roll in the folded position.

Somewhat complex and expensive changes

These procedures require more expensive parts, and will incur additional labor charges due to complexity of installation. These modifications are quite a bit more expensive when added after-purchase, than they are if ordered initially with the bike.

  • Adding fenders (changing from version E to L) OR adding fenders and rack (changing from version E to R). If you have a bike without any fenders, adding these options is time-consuming but fairly straightforward. The parts are quite a bit more expensive than if purchased when ordering your bike.

  • Adding or removing a rack (changing from version L to R, or R to L) is more complex than it sounds, because the rack is coupled with a special fender configuration. So installing or removing the rack requires replacing your existing rear fender.

  • Adding generator lighting. The complete lighting kit installation requires replacing your front wheel with one equipped with the generator hub, and wiring the lights.

Complex and expensive changes

We recommend that you carefully consider your handlebar choice and number of gears desired at the time you purchase your Brompton, since these changes can add up to several hundred dollars. These modifications can be made, and we have done them for customers, but they generally make sense on bikes that have been ridden for some years, and need to be adapted to the owners’ changing needs. In some cases, it might be better to sell the existing bike, and start over with a new bike built to your current preferences.

  • Changing the gearing (from 2 to 6, 3 to 6, 1 to 3, etc). This is a very involved procedure that requires the purchase of a new rear wheel, a number of the drivetrain components, new control levers, and all cables. It will easily run several hundred dollars.

  • Changing the handlebar. This sounds simple, but is definitely not. Each Brompton handlebar type utilizes a different stem (see this article on handlebars). It is possible to change this configuration, but it requires special ordering a color-matched stem in addition to replacing the handlebar and all the cables. (NOTE: due to supply chain changes in the last few seasons, ordering a stem may not be possible.)

It’s possible to make modifications using non-Brompton parts, but many such changes will affect your Brompton warranty, and therefore may not be advisable on bikes still covered by the 7-year warranty. For a list of other Brompton services we offer, click here.

It is not possible to convert a standard Brompton to electric, or vice versa. There are after-market suppliers of electric systems for Brompton, but, as noted above, installing one will void your Brompton warranty.

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