Would a 20" wheel vs a 26" wheel make much difference for torque?

Update:

my ebike currently freewheels at 65mph would a 20" freewheel at 50mph with 24% more torque?

Update 2:

Would the 3000w battery become equivalent to 3700w only reducing the freewheeling speed but increasing the riding speed and the torque?

Update 3:

the riding speed is currently 45mph

Update 4:

Is the top speed only reduced based on the top freewheel speed? (when it's only throttle)

Update 5:

*freewheeling

Update 6:

Basically my question is is a 20" wheel best suited to a 3t hub motor when the battery power will only carry me at 45mph.

5 Answers

Relevance
  • 7 months ago

    If you don't change your gearing to compensate for the smaller drive wheel, you'll be reducing your top speed but have more torque for take-offs.

    Edit: if it can go 65mph, then legally it's a motorcycle and this question should be posted in the motorcyle section.

  • David
    Lv 6
    7 months ago

    No, your bike does NOT "freewheel" at 65 mph.

    It's working as hard as it can, right up against whatever design feature that's holding it back

    There's usually a relationship for engines and motors regarding how much torque they can make at a certain rpm.

    So what's happening at 65 mph is that either it can't produce enough torque to overcome air drag any more, while theoretically being able to spin faster(if the load had been lower)

    Or it can't spin any faster, while theoretically being able to deliver more torque( if the RPM had been lower)

    Or, in a perfectly matched setup, it runs out of torque and RPM pretty much at the same time.

    Downshifting CAN increase your speed on flat ground if you've got RPM left but no torque left.

    Keep in mind that may equally well be the battery or controller that's the limit. Maybe your gearing ratio is OK, and you're already pulling all the amps the battery or controller can deliver, then that's it. Then you need another battery/controller to go faster.

    My first guess is that it's torque/amps drawn from the battery that is your limiting factor.

    Personally, I think you should stop being stupid.

    If you want to go at motorcycle speeds, get a motorcycle.

    An ebike, through and through designed to be safe and reliable at 65 mph would be expensive. And pretty much look like a motorcycle.

    And judging by your posts, I don't think you have an expensive ebike.

  • Carson
    Lv 6
    7 months ago

    It will make a big difference.

    If the bike has caliper brakes you won't have rear brakes too.

  • 7 months ago

    The “gear ratio” is higher with smaller wheels. It’s the same thing as downshifting.

    • Once you get in shape, your body will be most efficient with a cadence of 90-100 rpm. Downshift if you cannot sustain that rpm comfortably.

  • How do you think about the answers? You can sign in to vote the answer.
  • Anonymous
    7 months ago

    Yes

    Source(s): Science
Still have questions? Get your answers by asking now.