When Defiant set out to build an amazing board, we didn’t want to skimp on quality or use systems that require a lot of attention. We wanted a high performance board that required little to no maintenance. In the scope of that idea, all steel gear drives make sense. But where you trade maintenance and tinkering for reliability, you may also be trading the ability to modify things to your liking. Probably the best example of this is the fixed ratio in our gear drives. While they do accomplish the goal of providing a drive system that doesn’t have to be thought about often, they do present one unique limitation: choice in wheel type and size. Defiant’s compact precision gear drives are optimized for 100mm wheels, but will accept anything that fits the drive pins up to 125mm before the torque loss becomes irritating.
To address this issue we needed to back up and re-evaluate belt drives as an option. The biggest draw back to belt drives on electric skateboards is, not to mince words, the belts. Belts have a habit of wearing out and snapping. They pick up tiny rocks and debris which get compacted into the pulley grooves by the belt teeth causing damage to both the belt and the pulley, and if the belt tension and alignment isn’t properly adjusted after a swap they can add to motor stress, skip during braking, or start making a lot of noise as they rub up against the pulley flanges. They need to be cleaned after riding to avoid a lot of this, and most people carry spares and tools to swap them when riding any kind of distance.
But, and this is a huge but, belt drives pretty much let you have any kind of wheel and pulley combination you want. If you’re willing to put up with the maintenance, and most tinkerers and DIY enthusiasts are, they can open up a whole new world for you. And with the Defiant:One deck being capable of taking some pretty big wheels before getting any kind of bite (we haven’t tried it yet but up to a 7” wheel seems doable, definitely 6”) on the stock trucks, belt drives suddenly become something really worth rethinking.
With these thoughts in mind we reached out to our drive parts designer and started working on a belt drive system. Since we’re already working on AT wheels, we decided to have the first wheel pulleys that we test be a slightly higher ratio than the urethane gear drives. We also wanted the motor mounts to be 100% compatible with the trucks we’re already using, and we wanted the mount angles to be adjustable so that they could be tuned for ground clearance when the truck angles are set low. We also wanted them to be compatible with a well known brand of wheel pulleys so that the pulley ratio and wheel core type could be easily changed by the end user. Since Boardnamics designed our parts, that last bit was easy enough. They have multiple sizes of pulleys in stock for both ABEC and Kegel core types, and with a bearing replacement other brands of pulleys could be used as well. We could also add our own pulleys with additional tooth counts at any time, making things even more flexible, and often AT wheels have an option to include their own wheel pulleys at the time of purchase.
We’ve already received the first prototypes and they are performing well so far in our street testing. At the moment we’re using an 18/44 ratio with the new AT wheels, but will of course try out different tooth count wheel pulleys and different wheels to see how things shake out. We may stick with the larger motor pulley as it provides better tooth mesh to prevent slipping on hard braking, but end users are of course welcome to change things up on the bench. Our motors have an 8mm bore, and there’s a 10mm axle at the wheel pulley bearing, so replacements should be easy to find in a number of locations. If you’re anything like me, some of the ones you have in your drawer already might work.
We’ll keep you posted about our development progress and what this might mean as far as buying options for the Defiant:One. In the meantime, happy riding!