taller gearing for my n380 Rambler

Would like to hear from anyone who has switched to a Patterson crank, or other options to gain alittle more speed. Is the Patterson changeover something I can do myself?


  • What conditions do you usually ride on? How big are the hills?

    I had a used Patterson installed on my Rover with a Nexus i8 hub and found I seldom went into 8th gear anymore. I am now usually riding down a gear or two at the same speed. Also, I start in 1st or 2nd instead of 3rd. I had 155 mm crank arms before and went to the 170 mm with the Patterson which explains the harder starting. But I didn't see much more speed and that was on the larger Patterson gear. I have a whole other gear for climbing hills and use it, when needed.
  • edited January 23
    you might be disappointed with the effect of adding a stock patterson crankset, 80 g.i. compared to the oem 75 g.i. @ 60 rpm speed would rise from 13.5 to 14.4 mph.

    on the other hand, if you were to add $50 to the patterson cost for the 36-tooth chainring option, quite a different story. your gear-spread would now be 17-101 g.i. if blessed with an engine that can turn 60 rpm at 100 g.i. you would be doing 18 mph.

    a caveat (minor?) to the above is the nuvinci warranty regarding driving:driven sprocket ratios. on the other hand, since you cant stand on the pedals, that probably does not matter.

    self-install? go for it. requires 2 bottom bracket wrenches, torque wrench, 1.5 and 8mm hex wrenches. install the cable stop before mounting the crankset. lbs would probably charge you around $60 to do an install.

    good product, very good install instructions, excellent customer support.
  • James, I don't understand the calculations, but the numbers indicate my low gear would be slightly lower, but my high gear raises alot, like around 25%. Does that sound right? I'm content with my low gear, but am looking for more top speed.
  • 25% is a good number but falls into the ymmv category depending on condition of the engine.

    mph = gear-inch x pedal rpm x .003 so increase either gearing or cadence to increase speed.

    with the n-380 oem setup, increasing cadence from 60 rpm to 80 rpm will give you about the same 25% speed increase as increasing the gearing while turning the pedals at 60 rpm. either path is going to increase the load on knees and lungs.

    another aspect to this business is that speed gain much above 15 mph requires greater rider input to overcome increasing air resistance so fairing the trike now becomes part of the equation when contemplating increased speed.

    my humble - if running out of pedal on the flats is a problem, your engine is blessed and it is time to consider regearing.
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