Short review: Conv-E kit (mid 2012)
The Conv-E kit promises an easy conversion for any standard bike, creating an electric-assist machine in minutes. We fitted one to try it out! Read the review in full.
Posted by Peter Eland on Thursday 6 Sep 2012
This review appeared in Electric Bike magazine Issue 5. You can download it as a high resolution PDF. Or click the viewer below to read the review with the original print layout - or scroll down for the full text and images online!
Short review: Conv-E kit
The Conv-E kit promises an easy conversion for any standard bike, creating an electric-assist machine in minutes. We fitted one to try it out!
Conv-E was formed in 2010 by Keith Palmer, formerly head of long-established e-bike company Powabyke. Its first product is the electric bike conversion kit; more recently they've also taken on distribution of a USA-designed, (and usually non-electric) folding bike, the Swift.
The kit's recommended price is £699, and it's available only via around 25 cycle dealers who have signed up as 'Conversion Centres': they will fit the system to your bike "typically in less than half an hour"; presumably that's by appointment rather than while you wait! The labour cost for fitting may be included in the cost of the kit, but confirm this first. Warranty is one year.
The kit consists of three main parts. First is a replacement front wheel, available in 26" or 700c (28") sizes as standard, and 24" and 20" to special order. It's built with stainless spokes and a decent alloy rim. A disk brake version of the hub motor is also available.
Next there's the 36V, 6Ah battery pack in its smart aluminium casing, complete with bracket to fit it to bottle cage mounts on your frame - this is very like the system on the Powabyke we reviewed in Issue 3, with a small Allen key to lock the battery in place via a wedge system.
The battery pack itself has a neat recessed button with blue LED status light for on/off, and connectors for the charger (with a captive cover), throttle and motor.
Finally, there's a throttle for the handlebars; both twist grip and thumb throttle types are available, and at our request our kit came with the thumb version. Finally, cables and various mounting hardware are also supplied, as is a mains charger in a tidy carry case, a nice touch to keep its cables from tangling up in your bag.
As an alternative to the bottle cage battery mount, Conv-E offer a carrier rack adaptor, which puts the battery on the top surface of a rear rack.
There's an adaptor available to fit the battery pack to a rear carrier rack.
The battery can of course also be carried in panniers or the like. 1m extension cables for both throttle and motor leads are available. All of the cables use good quality waterproof connectors, which snap firmly into place. Our kit was supplied as it would be to a Conversion Centre, so much of what follows is what the mechanic would encounter, rather than the customer.
I first tried fitting the kit to a very nice hand-built frame. Unfortunately, although it did have bottle cage mounts in just the right place to fit the battery, the mounts were a couple of millimetres further apart than they should be, and the screws just wouldn't go through the mounting plate. Hardly the Conv-E's fault, but the mount system should perhaps have some leeway built in. Many bottle cages have one bolt hole elongated into a slot for this very reason - to accommodate some variation in mount spacing.
The Conv-E battery wouldn't fit onto the bosses on my hand made frame, so I tried mounting it via an adaptor. Problems fitting the motor then made me try another bike.
The second hitch was also down to the handmade nature of the bike, I'm fairly sure: I just couldn't get the new wheel's axle into the fork dropouts; the slots were too narrow. I did file excess paint out but that didn't help, and I didn't want to remove any metal in this safety critical area. So it was on to Plan B, and another bike.
This was my scrappy old Saracen Tufftrax workhorse, an MTB from the '90s. Not such a shiny showcase for the Conv-E, sadly… but an easier conversion, perhaps because factory manufacturing is more consistent than hand-made. The wheel popped in straight away, and adding the throttle to the already rather cluttered handlebars was also simple.
The thumb throttle incorporates a three level battery status indicator.
I did hit a minor snag again fitting the battery: the mount fitted fine on both sets of bosses, but in neither position was there space to fit the battery pack. In the end I used a Topeak bottle cage adaptor to suspend it from the top tube.
With all three parts in place, all that remains is to tidy the cable runs, check front brake adjustment (in case the new wheel's rim isn't the same width or height as your old one) and plug the cables in.
The motor dropped straight into the forks on my scrappy old mountain bike.
The Conv-E is currently a 'pure throttle' system, although Conv-E are apparently working on a version with pedal rotation sensor. So turn the throttle and it goes whenever the battery's switched on. With no brake lever contacts, it won't cut out when you brake - something to be aware of as you ride.
On the road the system was quite impressive, pulling away strongly from a standstill and coping with most hills well too. It's not silent, although the buzz is only moderate.
The throttle provides good control, from just a trickle of power to full on.
So you can match speed with other riders quite easily.
I certainly noticed the additional weight (around 5 kg, less the weight of the front wheel it replaced) from the Conv-E system: it did make riding the bike unassisted feel rather stolid.
Another niggle is that the 'pure throttle' system means you lose power whenever you lift your throttle hand to indicate a turn.
As batteries these days go the 36V, 6Ah model fitted isn't huge: doubtless the size was chosen to keep weight down. Conv-E claim 10-15 miles with no pedalling, which is fine for most everyday trips. The three-level battery status on the throttle gives a rough idea of how the battery is doing, and it took me the flattish 10 miles to work and back without a problem (with just a little pedalling) before a charge overnight.
Overall, the Conv-E kit seems like an effective way to add basic electric assist. It's good that the fitting work is now being handled by bike shops - as my experience shows, minor snags can crop up. But the Conv-E is about as simple as it comes for installation, and the build quality of battery pack and connectors in particular inspires confidence.
There are of course a good number of competing kits, and we'll review more in due course. At £699 the Conv-E isn't either the cheapest or the most sophisticated, but build quality seems good, and it's far from the most pricey. If you have a cherished bike you want to electrify, it might be just the ticket.
I presume that you didnt choose to mention that the batteries are NiCad. Cheap batteries from the far east are what gave the whole Ebike industry a bad name. What other important facts have you not mentioned?
Just seen this comment. You are mistaken re the batteries - just checked and they are lithium ones supplied by Samsung.
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