Most reputable sellers of any ebike kits will offer you several options when it comes to a throttle. The 6 most common are:
- Right Thumb
- Left Thumb
- Right Half Twist
- Left Half Twist
- Right Full Twist
- Left Full Twist
For the uninitiated ebike builder this can be an intimidating choice. I’ve tried all of them and I’ll try to summarize my opinions about them in this article and make suggestions about which one I think is the best and why.
The standard BBS02 kit ships with a right thumb throttle. This is by a far margin my throttle of choice, but I never mount it on the right side. Why would I do something so crazy instead of just buying a left thumb throttle? Lets start by talking about single-track riding.
When riding single-track my usual hand position is two right hand fingers on the rear brake and one left hand thumb on the throttle and all the other piggies holding onto the handlebars for dear life. I never install an ebrake on the rear brake because it has an incredibly annoying 2 second cutout whenever you touch it at all. Normally there is only a span of milliseconds between when I am hitting the throttle and when I am hitting the brakes. I am constantly hammering on both of them and almost never just coasting along. Sometimes I even break the cardinal sin and hit both the brakes AND the throttle at the same time which you should absolutely never do. It puts a huge strain on the motor and is not advised, that being said I still do it by accident from time to time.
With only the thumb unfurled on my left hand my 4 other little piggies can hold on pretty tight to the handlebars, with my right hand I have 2 fingers and my thumb which again means I can hold on pretty well while the bike is plowing over roots at 16 mph. What doesn’t work well is when you have 2 fingers covering a brake AND try to use a thumb throttle. It sucks, believe me I’ve tried it. That leaves you only with your ring finger and pinky to keep that hand on the handlebars which in my opinion is not enough.
Why don’t I use the regular left side thumb throttle? That is a good question and one that is more about personal preference. With the right hand thumb throttle mounted on the left hand side you can rest your thumb against the main part of the throttle which doesn’t turn and lock in your speed like a cruise control. By rolling your thumb slightly up and down you can adjust your speed without removing your thumb from the throttle. Pushing against the throttle body, which doesn’t turn gives you a lot more stability and grip to keep that hand where you want it. The standard Bafang left hand thumb throttle ‘floats’ in midair and there is nothing to rest your thumb on to keep the speed steady. I find that the standard Bafang left hand thumb throttle works passably well for commuters, but is generally undesirable for riding single-track for that reason.
Lots of people complain about ‘thumb fatigue’ who try to commute with their thumb throttles. If these people spent more time doing ‘One Two Three Four I Declare a Thumb War’ then they wouldn’t have these chronic thumb fatigue problems. Clearly there is a bounty of pacifist thumbs out there that can’t take the strain of pushing against a throttle for extended periods of time which brings us to our next contender.
What about twist throttles?
Since motorcycles and scooters have standardized on the twist throttle then it must be superior to thumb throttles right? I’ve ridden all kinds of motorcycles for many years and I have no problems with the standard right hand twist throttle when on a motorcycle. However when I ride ebikes I find the twist throttles incredibly undesirable. On a motorcycle you are moving the twist throttle a tiny amount and getting an incredible amount of power. With an ebike you have to twist the throttle as far as it will go to get pretty much any power at all on my wimpy sub 1000W bikes. Moving your wrists down so far puts your riding position way off and makes grabbing the rear brakes awkward. The problem is slightly improved when you use a left side twist throttle since you rarely have to grab for the front brake when riding in the woods. However when you are riding on the street and you really want to stop you NEED to squeeze the front brakes and you need to squeeze it hard. The front brakes do most of your stopping for you and to have your wrist down and out of position makes it harder to get on the brakes quickly and confidently.
Another big problem with twist throttles is the shifters. In order to use the rear derailleur shifter properly you need your thumb to be in a very specific position. If you are using a right twist throttle then you have to make sure that your wrist and thumb line up with the shifter in order to shift which makes it hard to control the throttle and shift at the same time.
When installing a ‘half twist’ throttle make sure the 1/2 hand grip does not rub up against the twisting throttle body. This could ‘lock’ the throttle into the on position providing thrills, spills and chills for everyone. For ‘full twist’ throttles where the entire hand-grip twists this should not be an issue. I don’t recommend the full twist throttles because they are the easiest to accidentally accelerate while moving your bike around the garage. If you forget to turn the bike off and lean the throttle against something it can twist on its own making the bike take off without you.
The biggest disadvantage of mounting a right side thumb throttle on the left hand side is that the wire heads towards the outside of the bike and looks weird. I’ve found that once you install it, after a while you won’t even notice it anymore and neither will anyone else. If you loop the wire back on itself and zip-tie it to the throttle body then it is looks fine. The right hand thumb throttle is far more stealthy than the giant horizontal axis left hand thumb throttle and works much better for me than any half twist or full twist throttle I’ve tried.
To get your hand grips off to mount throttles I use a Flathead screwdriver wrapped in a rag that is soaked in isopropyl alcohol the jam it under the hand grip and try to spin it all the way around prying as I go. Once the hand grip is loose and there is some alcohol in there you should be able to spin and pull to get the hand grip off. If you can’t get it to come off just use a mat knife and cut it off and replace it with a brand new ESI Chunky Handgrip which is the best hand grip I’ve found yet.
Although the throttles shown in this article are ones specifically designed for the BBS02 most ebike throttles are similar and this article applies to pretty much any throttles out there on the market right now. Most throttles are pretty much the same, although the connectors can vary between different controllers. Many different brands of controllers have different throttle connectors so if you don’t buy the throttle with the controller then you may have to wire them up yourself. It is generally pretty straight forward with a power, ground and a hall effect wire that varies in voltage from about 0 to 4.2v or so based on the throttle position. BBS02 throttles use a Higo-style connector that is molded onto the cable and specifically designed for the BBS02 and mostly weather proof.
Have a favorite throttle? Post which one you like and why in the comments below.