The Mechanic Speaks

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Oxydrive Ebike Kit Review

I installed an Oxydrive ebike kit on my commuter bike a few months ago and have put enough miles on it (just over 450 so far) to have given it a thorough evaluation.  Overall, I’m totally happy with my electrified bike.  I can leave the battery at home and it still rides like a normal bike.  Or, for my commute, the electric assist takes the sting out of the hills along my route and I arrive less sweaty.

P1040335

The finished product

I chose the Oxydrive kit over the other alternatives for one primary reason: it has pedal assist and I could make it work with drop bars.  Most other ebike kits lack pedal assist and are thumb throttle operation only.  A thumb throttle is less efficient than pedal assist, which is reflected in the manufacturer’s advertised range.  Further complicating things is that all the thumb throttles are made to fit 22.2mm flat bars, and will not fit on 23.8mm drop bars.  I *love* the Salsa Woodchipper drop bars on my bike and didn’t want to lose them to get e-juice.  The Oxydrive is also unique in that the brake cut-out switches it uses install in-line on the brake cables instead of being integrated with the levers.  This also works with my drop-bar requirement.  Oxygen Bikes is a British company with no US distributors, so shipping is from the UK.

edit

It’s like Christmas!

Installation isn’t tough but required a bit of work on several parts:

  • The fork dropouts have to be filed from 9mm to 10mm.  I was really nervous about doing this to my precious bike, but with a bit of careful work and patience it turned out fine.  A normal 9mm quick release wheel is supposed to still work fine, though I haven’t refitted one yet to check this.
  • The bottom bracket senor for the pedal assist was originally a concern for me as I really didn’t want to widen up the pedal stance or throw off my chainline.  I installed the sensor on the non-drive side which requires a flanged BB ring.  You might have to buy one from a bike shop if your bike doesn’t already have one (most don’t).  I happened to already have one that was made of plastic so I filed the flange down thinner to help with clearance.  I also filed down the bulge on the outside of the plastic magnet disc to help with clearance too.  These two minor filing modifications made it possible for me to continue using my original 110mm bottom bracket, which is fantastic.
  • The wiring harness is plenty long.  I use a Jandd frame bag which works nicely for hiding the bundle of excess cable.

Bottom bracket sensor for pedal assist

Problems & Minor Gripes:

  • Within the first 10 miles of riding I started having problems with the pedal assist cutting out.  I checked and rechecked every connection and made sure the magnet disk was properly spaced from the sensor.  The problem persisted and gradually got worse, so I called Oxygen’s customer service.  They said it was probably a bad pedal sensor, and shipped a new one out to me free of charge.  I popped the new sensor in place of the old one and have had no troubles since.  This was a great opportunity to test out Oxygen’s customer service, and I give them an enthusiastic A+.
  • The included documentation is terrible.  The only paper manual included is from the Chinese manufacturer of the LCD display, and it’s barely intelligible.  Oxydrive has a couple manuals in PDF form on their webpage but they’re not particularly useful either.
  • Because of the poorly-written documentation (above), I had been plugging the charger into the battery before plugging it into the wall.  The connector makes a big spark when you do this.  I called customer service about this and they explained that I just needed to do the opposite: plug the charger into the wall to ground it before plugging it into the battery.  Problem solved, but be advised that the manuals really are rather crap.
  • I tried disconnecting the thumb throttle since I use the pedal-assist mode exclusively, but disconnecting it caused problems with the computer.  Apparently it needs to be connected for proper operation.  I reconnected it and everything was back to normal.  This isn’t really a problem with the kit, just be advised that if you’re doing a drop-bar install like mine that you will need to find a place to mount the thumb throttle even if you don’t plan to use it.
  • The included wall-cord for the battery charger had a British-style plug!  I didn’t even bother calling Oxygen about this since it was a $2 fix thru Amazon to get a US-style cord, and having such a small item shipped over the Atlantic when I could get one locally seemed a bit absurd anyways.
  • The wheel was *waaay* out of true and also out of round.  Four spoke nipples were totally loose and spun by hand.  This was an easy fix, a few minutes on the truing stand and it was good to go, but still a bit disappointing.  Save yourself some time and check the wheel before installing it.
  • The brake cut-off switches can be a bit sticky.  Sometimes they engage and then don’t disengage when I release the brake lever.  This is usually fixed by jiggling the brake lever, but it’s an annoying problem.  The front worked fine and it was mostly the rear switch that was sticking, so I just disconnected it.  If the front switch had been sticking too then it would have been more of an issue.
  • Fixing a flat on the front wheel is now a big pain.  The motor axle nut is a 19mm, which means carrying a full-size wrench around everywhere.  Eventually I plan to cut a regular 19mm wrench in half so it will fit in a seat bag, right now it lives in my Jandd frame bag.
  • The speedometer/odometer on the LCD display only works when the system is powered on.  I still ride my bike without the battery for shorter trips quite often, so no speedo for those rides.

Thumb throttle mounted on custom bracket in front of handlebar

Likes:

  • Battery life is excellent.  I’ve been reliably getting 25 miles or more with assist at level 3 on my mildly hilly commute (see elevation profile below).  Good for 30 miles on a slightly smoother route.  Lowering the assist level or finding a flatter route would obviously extend the range.  So I’d say that Oxygen’s 35 mile range estimate is reasonable and possibly a bit conservative.

GPS indicates just over 1,000ft elevation gain on this route (one-way). Over 2,100ft for the 25 mile round-trip.

  • The programmable speed limit was a surprise, this is possibly my favorite feature.  I have it set at 18mph (can be set at up to 25mph), at that speed the boost fades out gradually.  This helps conserve battery power and helps me to only use the battery when I really need it, which is primarily at lower speeds.
  • The overall quality of the cables and connectors is outstanding.  Each one has its own pin pattern, so it’s impossible to mix them up.  Quality cables make the whole install look professional.
  • The LCD display is great.  It looks sleek and is easy to read.  It is not intended to be removable, but the wire simply unplugs from the harness so it should be easy to modify the mounting bracket to make the display removable.  This will require fixing the assist selector button to the side of the display, but I think it should be doable.  I’ll experiment with that eventually.  (edit: there is a new LCD unit for 2013, the picture below is the old one)

LCD display

Final thoughts:

As far as I am aware there is not a single Ebike, kit or complete bike, available with drop bars (anyone want to corner a niche market!?!?).  Even though Oxygen intends their kit to work with flat bars, I think it’s probably the best kit available for a drop bar build.  The system has a few small flaws, but with a bit of mechanical know-how it can be built into a fantastic commuting tool.

—> Edit July 2013:  Maintenance report on motor problem.

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2 Comments

  1. nice review, I only have one question about this conversion kit, is it possible to let the engine fully take over so you do not have the peddle yourself. On the website of Oxydrive I can not find a clear answer.

    Thx

    • you *can* do that, but only on mostly flat ground, and it will drastically reduce the battery range. the motor can’t pull you up a hill by itself. the motor is rated for 250W of continuous power, and a hill will cause it to draw over 500W. it can handle that for short periods of time, but after maybe 30-45 seconds it will get hot and the protection circuit will cut the motor out. this is really meant to be a pedal assist kit. look for motors rated at 500-750W if you want to be able to ride on e-juice alone. hope this helps!

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