Them’s The Brakes
Harry Wills - Bo CTO - November 2025
- Premium scooter brake options
- Best scooter braking experience as a rider
- Stopping Bo in a hurry
Zero ai: Bo does not use Ai to write, because we believe you’ve come here to speak to humans not Nvidia GPUs. That will mean that some of our language has errors, and we feel that’s a price worth paying.
Bo front wheel next to a leading Chinese brand
There are several ‘Easter-Eggs’ in Bo, and one of the most well-hidden and enjoyable is the braking system.
Bo is a slightly unusual ‘every-day’ scooter insofar as it has two brake levers. You’re probably used to this on bicycles, or even small motorbikes, however in the scooter world everything is normally designed to the lowest cost possible. Obviously two brake levers costs twice as much as one brake lever, so normally one of them is removed.
That is only possible because one of the brakes on a scooter is normally an ‘e-brake’ and as a result you can have both the wire cable for the mechanical brake and the electric cable for the e-brake, both going to the same lever.
However, as a riding experience it is sub-prime. Because scooters have small wheels, they tend to have small-diameter brakes. This makes sense - you can’t have a disc bigger than your wheel, it would hit the ground.
The issue is that small discs do tend to be ‘grabby’. That is because you need to be able to apply a powerful stopping force over a small moment (the distance from the brake caliper to the wheel). This lack of leverage means that the calipers have to be able to apply a high clamping force on the disc, which often results in the initial ‘bite’ being aggressive - even when you carefully apply your braking at the lever.
In contrast, e-brakes are lovely, silky smooth braking experiences. Especially when you have a high quality motor controller, the e-brake gives superb modulation and feels incredibly natural.
When a manufacturer decides to blend both braking systems into one lever, you lose these great e-brake attributes. The e-brake becomes an accompaniment, chipping in a few Watts of force to the disc brake. You lose the full riding benefit of such a refined system.
Additionally, because the disc brake kicks in so early on a blended brake system you lose out on the potential regenerative braking benefits. A good e-brake will return as much as 20% of your energy over a full battery cycle, but blend it with the disc brake and the vast majority of that is lost.
So, returning to Bo - the double brake system. We chose this because it gives you back control. On your left hand, you have an e-brake system with up to 22Amps of force. That is directly regenerating your battery pack, which means if you only ride on the e-brake you’ll recover the maximum energy possible.
It also has the silky e-brake feel, so when you just want to modulate speed (rather than coming to a full stop) it’s perfect. Even a novice scooter rider quickly becomes adept at tickling-off a few mph for a corner, or gently reining it in down a hill. Also, the satisfaction of regenerating power back into the battery is addictive.
On the right hand side of your controls is a second brake lever, controlling a powerful drum brake. This is used for fast and full stopping.
That rear wheel motor is both propulsion and braking, in one unit.
Drum brakes may seem like old technology, but that is automotive marketing at work rather than reality. A good drum brake can give incredible stopping power, and they have the advantage of being completely protected and requiring zero maintenance.
The only way to improve stopping over a cable operated drum brake is to upgrade to a hydraulic disc brake - and on a vehicle like a Bo scooter where reliability and ease of maintenance is the number one priority that has other downsides that we did not feel were acceptable.
If you’ve read this far you now have a good understanding of the Bo brake system, but you’re probably wondering what became of the ‘Easter egg’ I referred to at the start…
One of the most curious bits of testing on the prototype Bo vehicles was how much people disliked the e-brake. ‘It doesn’t work’, ‘I don’t feel confident in it’, ‘The left brake is broken’ were the sort of comments we received. Objectively as engineers we knew that the e-brake was nicer to ride, but for some reason scooter riders were not enjoying it.
Eventually our brilliant and resourceful CEO made the observation that because it was operated by an electric wire, the left hand lever did not have an obvious ‘brake cable’ attached to it. The electric wire snuck in through a hole in the handlebars, and as such the brake looked like there was nothing attached to it.
Additionally, because it was not pulling on a brake system the lever did not give proper ‘resistance’. Sure - it was braking the scooter - but to your hand it felt like you were pulling on air.
In response to this we launched a project to create a system which was code-named ‘fake-brake’. The aim was to replicate the feel of a braking system, without actually having a brake caliper to pull on. We also ran the cable to actuate this through a proper brake-line, so the left hand lever now appeared to be attached to something.
The results were immediate and astounding. The very same people who previously had said the left lever was broken, or they did not like using it, returned from their test rides singing the praises of our improved brake system - despite zero actual change being made to the e-brake itself. The ‘feel’ of using the brake was now tactile and premium, and as such the rider could ignore the actual lever action and just observe the braking experience.
With both brakes in place, it 'feels' right...
Across thousands of test rides, we have only had three people question the action of the left hand lever. In all those instances it has turned out that the fake-brake was incorrectly adjusted, allowing the lever to pull closer to the bar than intended. When set correctly it is indistinguishable from the feel of a ‘real’ mechanical brake.
HW.
If you're interested in reading more - Link to Articles
If you'd like to look at Bo M more closely - Link to Model M
If you'd like to read about The Turbo Land-speed scooter - Link to Turbo
