Organic motor expectations

I have a 2014 Rover Nexus i8. It is my first trike and I bought it used from someone on the forum mid-June last year. At the time I was 66 years-old, diabetic, 6' tall and #250. Now 32 pounds lighter (#218 today, - thanks Rover) and a year older, I have installed a Bafang BBSHD electric assist motor. The motor weighs ~#13, the battery ~#8. Earlier this week, I was feeling great & left the battery at home and did a mostly flat ~7mi. course on a cool Michigan evening. Right off I decided to go for speed.

The course ended being 6.82 miles. I tried to keep stopping to a minimum, and pedaled as fast as I could without any breaks. My goal was at least 5 miles averaging 12-MPH. I felt it may have been my best ride ever. I ended up averaging 11.5 MPH, not too shabby, but I can't imagine where I could go faster. Are there 20" wheel trike riders out there who have a regular short track with a similar measured distance? I'd like to get a realistic idea of what others do when they push themselves over a 5+ mile course.

I realize the BBSHD adds #13, but the #30 I lost more than makes up for that, so I suppose I could have been a little faster, but doubtedly an average half mile per hour!?

Comments

  • Wait! If you lose weight, you should be able to go faster naturally. If not, forget dieting. My goal will be to keep my heart healthy, my bones strong, get fresh air and sunshine.
  • I have a 2014 Rover Nexus i8. It is my first trike and I bought it used from someone on the forum mid-June last year. At the time I was 66 years-old, diabetic, 6' tall and #250. Now 32 pounds lighter (#218 today, - thanks Rover) and a year older, I have installed a Bafang BBSHD electric assist motor. The motor weighs ~#13, the battery ~#8. Earlier this week, I was feeling great & left the battery at home and did a mostly flat ~7mi. course on a cool Michigan evening. Right off I decided to go for speed.

    The course ended being 6.82 miles. I tried to keep stopping to a minimum, and pedaled as fast as I could without any breaks. My goal was at least 5 miles averaging 12-MPH. I felt it may have been my best ride ever. I ended up averaging 11.5 MPH, not too shabby, but I can't imagine where I could go faster. Are there 20" wheel trike riders out there who have a regular short track with a similar measured distance? I'd like to get a realistic idea of what others do when they push themselves over a 5+ mile course.

    I realize the BBSHD adds #13, but the #30 I lost more than makes up for that, so I suppose I could have been a little faster, but doubtedly an average half mile per hour!?

    That is a impressive ride considering it was human powered and a first attempt at significant distance. Any idea what your cadence was ? Were you mashing or spinning out ?
    Others will chime in on drivetrain improvements/changes. I'd suggest continue working the engine.
  • Problem Solved!

    This really wasn't my first attempt at a 5+ mile human powered speed test on the Rover. All last year I worked on short bursts of maximum output, followed by longer periods of relaxed riding. I had read that for strength training and weight loss that alternating any workout in this way maximized weight loss and strength.

    So, it was really bothering me that my time for this distance was comparatively low. Last year I worked on increasing my comfortable cadence from ~55 initially to ~85-90 by autumns end. On this run, I actually did a combination of mashing and spinning- spinning close to 90 on the flats and parts of a long gradual incline, then mashing once I tired of making too little forward progress and also mashing on the downhills to get max speed quicker.

    As it turns out, I think I had at least two things working against me. First, my Rover is equipped with the BBSHD comes with a 46 tooth front sprocket, where as the stock Rover comes with a 32 tooth front sprocket! The other issue working against me was equal parts of laziness and stupidity. My pre-ride preparation includes properly adjusting by helmet so that it fits where it belongs, adjusting my glasses & mirrors, turning on the various trike lights, and squeezing the tires to assure adequate air pressure, and then off I go.

    Big Problem.

    From now on, I will use a tire gauge to check my tires. I run Schawlabe Marathon racers on my trike. They are 20"x1.5" and are rated for 55-100 PSI. I tend to keep my tires on the low side to better accommodate the bumps along my typical ride. Surprisingly to me, my most inflated tire only had #28- far from the #55 I normally fill them to. Shameful.

    Questions:
    Is it advisable to change from the 46" Bafang BBSHD chainring to something smaller.
    If so, I have 30t, 36t, or 40t available (Rover's stock chainring with Nexus i8 is 25t)?
    Would it be cheaper, easier, and/or better to go to a smaller rear cog - say 16t?

    Any other thoughts?
  • Innertubes/tires are a fickle thing. Found that checking the air pressure before a ride is the best option. Even if the tire is only 2 to 4 pounds off I fill to 70 PSI and maybe just a hair's breath more.
    Then too am carrying a heavier load that you no doubt.

    ¬ ITL
  • We pump tires before EVERY ride, 90psi.
  • Smaller rear cog means higher gearing. Larger cog lowers the gearing. I think the largest cog for the Nexus is a 24T and I only found one source for that and it wasn't available the last time I looked for it... Typical tooth counts for the Nexus is 16T, 18T, 20T and 22T. The stock cog is a 16T, so going to a 22T will lower you a ways. (Roughly 33%?)

    Lekkie makes a 36T chain ring for the BBSHD. You can find them here: https://lunacycle.com/lekkie-bbshd-bling-ring-chainring/ (Hope the link works this time...) This would lower the range better than 20% over what you have now.

    Or you could go with this 30T also from Lunacycle. https://lunacycle.com/parts/bafang-parts/bbshd-parts/luna-mighty-mini-30-tooth-bbshd-chain-ring/ This one would lower the range by about 33% as well.

    Either option on chain rings is going to cost you at least $50. Cogs run typically $6-$10 a shot. (In my mind, biggest bang for the buck is going with a larger cog...)

    Keep in mind, these are direct replacement parts, and they are going to take a bit of planning, chain splicing, etc. Since the BBSHD wants to spin at 180rpm at max throttle, you can figure out the top end while powered by any good gear calcs you want to use. I know the leg engine isn't going to be able to spin at that speed, but it can give you a base line to work from...

    It's possible with a small front and large back to get really low end gearing with the Bafang BBSHD and a Nexus-8. It's just going to take a small front and a large back to make it work.
  • Inner tubes tend to slip at those low pressures. Inviting a leak by cutting your valve stem. I know from experience!
  • Jrobiso2 wrote: »
    Inner tubes tend to slip at those low pressures. Inviting a leak by cutting your valve stem. I know from experience!

    Been there. Both on Rockhopper & Rover. Had green-stained t-shirt too.

    ¬ ITL
  • I have 40 psi tires and I thought I saw one stem angled Sunday when I aired them last. Better shift tube back b4 next
    ride. Glad I read all the posts.
  • Thank you all. This is all great info for all trikers to know. My pre-ride ritual will, from now on, include using an air gauge to check all tires. And I will make note of any valve stem that is not vertical and then correct it.

    And a special thank you to Elrique64, for helping me realize that I need a larger rear cog, not smaller to have lower gear inches. And I also really appreciate the Luna links.

    I would be lost without this Forum, so I guess this is a good time and place to thank TerraTrike once again for providing this wonderful Forum.
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