Luna Fixed Stealth 400w torque sensing mid-drive bike

Discussions related to motors other than hub motors.
This includes R/C motors, botttom bracket, roller and geared drives.
Post Reply
Timelord   1 W

1 W
Posts: 61
Joined: Sep 10 2010 8:56pm

Luna Fixed Stealth 400w torque sensing mid-drive bike

Post by Timelord » May 19 2019 1:15pm

Having a bit of a hard time wrapping my head around this one.

https://lunacycle.com/luna-fixed-stealth-ebike

I assume the motor has a rotor and planetary gears mounted on the bottom bracket spindle. That's kind of neat. Beats having a separate, bulbous motor casing sticking out like Bafang, Cyclone or Tongsheng. But it does mean you're stuck with that motor, never to be upgraded, and if anything goes wrong with it and spare parts are unavailable or discontinued, the entire bike has to be written off. At least something like Bosch or STePs presumably has a standardized mounting bracket for each brand and available spare parts. Wonder why Luna didn't just use one of those systems if they were going to go closed system.

I don't get the battery design. Looks like it's a custom extrusion for 18650 cells. But how would you access it if it needs repair or replacement/rebuild? Through the oversize "bottom bracket" after removing the motor? With each block of four batteries connected by wiring so they can be bent out of the way during extraction and insertion? Really like the clean look with all internal wiring, but again, if anything needs to be fixed, seems like it would be a pain in the neck to work on concealed wires.

User avatar
Chalo   100 GW

100 GW
Posts: 7961
Joined: Apr 29 2009 11:29pm
Location: Austin, Texas

Re: Luna Fixed Stealth 400w torque sensing mid-drive bike

Post by Chalo » May 19 2019 1:25pm

It's Luna's answer to everything-tucked-away e-bikes like Van Moof etc.

They call it "fixed", but it's not a fixed gear and it's far too chunky and ugly to recall the fixed gear fashion bikes of a few years ago.

Yes, it will be a huge nuisance to work on or even do basic troubleshooting.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

LowkeeRider   100 mW

100 mW
Posts: 46
Joined: Jul 18 2012 1:32am

Re: Luna Fixed Stealth 400w torque sensing mid-drive bike

Post by LowkeeRider » Oct 30 2019 7:38pm

Any ES members bought this bike, could you share your experience here?

My commute is 30km and flat but I am not a strong rider, could this bike do it?

Wish they design it to accept a small external bottle battery.

AngryBob   100 W

100 W
Posts: 199
Joined: Jul 10 2019 4:37pm

Re: Luna Fixed Stealth 400w torque sensing mid-drive bike

Post by AngryBob » Oct 31 2019 7:08am

20 miles on a 7ah battery is going to require quite a bit of pedaling with minimal assist, and will need to be charged for the return trip.

That bike, with a standard BB, no motor and no battery, at a dramatically lower price, might make a good candidate for a decent conversion to do your commute, but as it stands now, for someone not a strong pedaler, NO.

User avatar
fechter   100 GW

100 GW
Posts: 14647
Joined: Dec 31 2006 3:23pm
Location: California Bay Area, USA

Re: Luna Fixed Stealth 400w torque sensing mid-drive bike

Post by fechter » Oct 31 2019 8:59am

LowkeeRider wrote:
Oct 30 2019 7:38pm
Any ES members bought this bike, could you share your experience here?

My commute is 30km and flat but I am not a strong rider, could this bike do it?

Wish they design it to accept a small external bottle battery.
I test rode one but not long enough to see what the range is. Power consumption is largely affected by speed. If you ride slow enough, it would make it no problem.

I'm sure there is some way to modify it for an external battery but it might take a lot of work. I have not seen how it comes apart.
"One test is worth a thousand opinions"

Post Reply