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Luna X2.6 - how to get 40 mph?

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    Luna X2.6 - how to get 40 mph?

    I got a Luna X2.5 and would love to be able to hit 40 mph with it but it doesn't seem to be geared to hit that. I'm wondering if I need a bigger front sprocket? Fastest I've really hit level is ~35 mph.

    I haven't messed with the tuning app yet and I want to but it seems like it won't help raise the top pedal assist speed since at 34-35 the pedaling cadence seems already. Any advice would be great. I'm a noob when it comes to bikes so if I should change the front sprocket any info as to what to change it to would be super. Thanks!

    Some discussion already posted:

    Just bought the X 2.5 E Bike with the m600 and Ludacris controller on the description of Luna Cycles it says the bike will run 40 miles per hour 20% faster than X2 Ludacris because of the 60 bolt battery. I got it to run 34 mph but cannot get it to 40 has anybody run it at 40 and what parameters have you use on the vesc app?

    To get up around 40, aero is going to be a huge component. Learn to crouch and tuck down, swap out any baggy street clothes for spandex bike kit, get rid of your fat knobby tires for some thin street slicks. A bigger front sprocket will help if you feel you've maxed out your cadence, but not your power. I've run as big as 46T. If you adjust your B screw perfectly so the chain doesn't skip, then you can do momentary bursts of 40. (46x11 with the 27.5x2.8 tires = ~115rpm cadence at 40mph, so flying along pretty good) To maintain that for any length of time, you'd probably need to rework the bike into a road racer... dropped handlebars, 700x28 or 30 tires, thin carbon rims, rework the battery to get near the 80V limit, maybe even larger on the front ring, etc.
    Last edited by K442; 1 week ago.


    • Barrett
      Barrett commented
      Editing a comment
      Thanks! Yea I think it's a maxxed out cadence issue.

    Originally posted by Barrett View Post
    I got a Luna X2.5 and would love to be able to hit 40 mph..
    40-mph on a bicycle. Are the wheels, tires, chain & brakes rated for 40-mph.??


      Grin Technology has a bicycle dynamometer on their website. Mid drives are kind of hidden in the custom menus there. But you can play around with different variables and see what will improve things. One thing to keep in mind before going to skinny tires is that it will reduce braking right when you need more of it.
      Our ebike motor simulator allows you to easily simulate the different performance characteristics of different ebike setups - with a wide selection of hub motors modeled, and the ability to add custom batteries and controllers and set a wide variety of vehicle parameters you'll be able to see how factors such as throttle level, bike weight, hill grade and many more directly affect the performance of an ebike. You can even compare two different setups at a glance and at higher power levels and hill grades you'll even get an estimation of how long it would take the motor to overheat!

      You have to select mid drive, then scroll to the bottom of the menu and select show all.


        Thanks for posting the link to the simulator.

        Always interesting to plug in some numbers and see what comes out. In this specific case it seems they don't have the Bafang M600, [I substituted BBSHD], threw a 'custom' 2500 watt controller on it, 46T front ring, 11T rear, 200watts of human power and called it a 29 inch "wheel" because 27.5x2.8 is closer to a 29er in overall circumference, and said "mountain bike tuck" position That puts max efficiency right at 39 mph on flat/level ground and has the motor overheat in about 5 minutes. I'd say that is fairly accurate.

        Though the biggest use might not be in the exact accuracy, but seeing what changes make the biggest relative effect. Just changing to an 80V battery boosts the top speed to 43mph ...but the motor is predicted to overheat in under 3 minutes. Interestingly going much smaller or larger on the chain ring seems to hurt top speed. Hard to add meaningful power at 130+ rpm cadence on smaller chain rings and you just don't have enough torque to swing anything larger.

        The simulator doesn't seem to have many inputs to change the aero conditions... you can't even put in 'true' tire circumference, it seems. But given the drag equation has a "velocity2" term, reducing frontal area and decreasing Cd are going to be huge factors.


        • Retrorockit
          Retrorockit commented
          Editing a comment
          To some extent it's just about the only factor. Going small to get Cd is probably going to hurt braking also. Considering the expense in reliability, cost and weigh of trying to go that fast at some point an actual Emoto makes more sense.