Boost are a UK-based manufacturer of e-bike conversion kits. We have already taken a look at their rear wheel conversion kit for bikes with 26" or 700c sized wheels. Now comes news of the Boost for Brompton conversion system, which is billed as being, "a special version of Boost that fits snugly in the rear triangle of your Brompton. With 30km range and only 3kg added to the bike weight."
Judging by what little info is out there, the Boost Brompton kit looks to be a scaled-down version of their existing kit which we hailed as a, "Minimalist kit with pretty smooth performance for a great price."
We particularly liked the fact there is a single wire linking battery and motor with the handlebar control linking wirelessly to the control software to allow the rider to change power levels. That aspect of the system looks particularly well-suited to a Brompton folder where the elongated stem folds down which would potentially spell problems for a wired system.
As mentioned above, the total weight added to your existing unpowered Brompton is said to be in the region of 3kg, though no doubt it will feature a pretty small capacity battery. Apparently the motor is rated at 45Nm torque.
One thing not addressed on the Boost Brompton news page is how they will address the issue of replacing a rear wheel that contains gearing. You may effectively have to downgrade to a single speed machine, or it may be that a two-speed Brompton will be compatible with the new kit. Those with hub gears though will find themselves with fewer gear ratios.
Selected test riders are apparently trialling the system around London at present and Boost are aiming for production in late 2023 - though it sounds like significant funds are still required to make the Brompton-specific battery.
Normal pricing will be around £1,199 fully installed and they will offer a special discount for the the first orders to around £799 with the wireless handlebar control available for around £70 as an optional extra.
Those interested can sign up to be kept informed of the progress of the Boost Brompton system. It's notable that Boost offer both DIY fit and bike-shop fit options for their existing kit and it's assumed the Boost Brompton will follow the same sales model.
It's worth mentioning that kits fitted to Bromptons will void the warranty on the bike itself (frames have a seven-year warranty when registered and other non-wearing components two years), though we have yet to hear of any damage caused to Bromptons by kits we have recommended on ebiketips.
