New eBike or convert old bike, latter how to select?

Discussion in 'Electric Bikes' started by ericmark, 1 Apr 2019.

  1. ericmark

    ericmark Regular

    North Wales
    Moving house new one up hill from main road so to get home seems ebike is the way to go, wife has an ebike centre motor from halfords the Carrera Crosspath Electric Hybrid Bike - 18" which I have tried and like, however it is £1600 which is not cheap, I already have quite a good bike, so question is do I convert that bike or buy new?

    Looked at kits, the Bafang BBS01 seen at £350 to £450 and battery another £175 so even a conversion not cheap, and I can't really work out why a range in the price, it seems I remove the crank bearings and the kit replaces them I lose the three cogs at front and have to select, and to be frank I am a little uncertain about getting a kit which does not then do as expected, I see why to use kit for non road legal so one can in essence build an electric motor bike, but I am looking at street legal so not so sure if worth modifying existing bike?

    OK existing bike old but good quality reasonable light but no disc brakes and looking at Halfords prices mid motor ebike start at £850 or £950 with disc brakes, and suspension and I can get a folding ebike for £500 with no gears which would mean could take on the bus, but not as good for riding.

    At the moment the Carrera Vengeance E Mens Electric Mountain Bike seems about right as larger wheels more suitable for canal tow path however not mid motor so motor does not drive through gears like wife's. hers does seem the first in Halford range with centre motor, disc brakes, suspension however converting my mountain bike is heavy and cheap both wheels with suspension and disc brakes but so heavy with motor added could not carry on bike rack, and road bike calliper brakes no suspension already broke a rear wheel I assume because I am too heavy, so with extra weight of motor and battery would it take it?

    Clearly no answer expected saying do this, but would like some feed back from people who have fitted mid motor kits, or used other ebikes, specially considering complete ebike has a frame designed to take the mid motor so alloy constructed frame rather than steel.

    Thoughts please.
  2. roadrash

    roadrash cycle chatterer

    @raleighnut and @Pale Rider may be of help to you
    raleighnut likes this.
  3. Ffoeg

    Ffoeg .

    The Isle of Carl
    The Bafang has a cadence sensor to control the motor assistance which I find quite brutal in operation as it's either on or off. Plus you'l need the brake lever mounted cut offs so the motor doesn't try to get you back up to speed if you move the pedals whilst braking. This can be quite scary

    I'd recommend the TSDZ2 which has a torque sensor so it only put the power on if there is resistance in the crankset, which makes the power delivery far mor 'normal'. Plus as it doesn't require the brake lever cutoffs, it's a far neater install.

    Both the TSDZ2 and BBS motors are crank mounted which means the motor can keep to a reasonably constant RPM (cadence) and the road speed is governed by the gears. Hub mounted motors don't have that advantage and need to accommodate all road speeds which motors don't like.

    If you're feeling brave the TSDZ2 is a simple fit and should take the average home bike mechanic just a couple of hours using basic bike tools.
    • The battery fixes to the down tube using the bottle cage bosses - 2 bolts.
    • The motor assembly replaces the bottom bracket (standard 68/73 British thread)
    • Then put the display on the handlebars and put the speed sensor on the chain stay and magnet on the spokes
    • Finally connect the three cables to the battery unit - 1 to the motor, one to the display and one to the speed sensor
    And apart from normal bike fettling, that is all there is to it.

    Cost wise the motor kit was £295 delivered for the motor kit from China (via Germany, so no extra VAT no duty to pay) to my door. The battery (36v 14Ah with Panasonic cells) was sourced in the UK for £275.

    I used this shop on AliExpress... and selected the UPS delivery option (as instructed). The motor arrived within a week(ish), dispatched from Germany with no extra to pay. Going by all the documentation/labels etc I assume they have a warehouse in Germany and dispatch EU orders from there.

    Battery was UK Sourced, from here - But they've gone up in price since I bought mine :sad:

    eAlfine front (Custom).JPG

    @keithmac, @Mike_P and @WIGHTDIAMOND use the same motor too, so might offer some more advice
    Last edited: 1 Apr 2019
    Oldbloke, KneesUp, raleighnut and 5 others like this.
  4. Pale Rider

    Pale Rider Guru

    Kits aren't my thing, but I can tell @Ffoeg has done a tidy job on his crank kit, so he's worth listening to.

    A hub motor - front or rear - conversion would be cheaper.

    Reasonably pokey hub motors by the likes of Bafang are around £100.

    As regards batteries, you may be aware the packs are made up of cylindrical cells wired in series and parallel to give the desired voltage.

    A pack for £175 will likely use cheap cells - expect to pay double that for a decent pack.

    The Halfords crank bike - confusingly they are all branded Carrera - uses the well thought of Bosch crank system.

    Eclipse, as mentioned, is a reliable supplier of kit bits.

    The big Chinese name in this market is BMS Battery who have more motors, batteries, kits and motor wheels than you could shake several sticks at.

    Sales service is usually pretty good, but ultimately they are in China and you are in the UK.

    It's never going to be worth sending your £99 motor back if it breaks.
    raleighnut and ericmark like this.
  5. KneesUp

    KneesUp Veteran

    That's a neat install. I was looking at ebikes in Halfords yesterday because Mrs K wold like one to commute on - we work at the same place but the ride in - although short - is a choice between reasonably flat but very busy or reasonably quiet but quite lumpy, neither of which appeals to her. However, she would do the 'quiet but lumpy' route if she could arrive at work without being too hot, hence the ebike.

    Anyway - all the ones in Halfords looked less suitable than her current Raleigh Misty, which she loves. This kit is interesting because it's so neat and I'd imagine helps with weight distribution. Her bike is a mixte frame so there is no room for the battery where yours is, even if it had bottle cage mounts, so I'd be looking at one of the rack batteries and some cabling I guess. Mid drive also means the front wheel can have a dynamo so I can fit 'always on' lights.

    How much extra weight does it add minus the battery do you reckon? Mrs K would like sometimes to ride her bike without assistance (on family rides) I presume you can ride it without the battery without much penalty? Or is there resistance from the undriven motor?
  6. OP

    ericmark Regular

    North Wales
    I can only talk about the Carrera Crosspath Electric Hybrid Bike - 18" which is regular on special offer so £1,280 at moment, with the motor switched off it is still OK to ride, no worse than my heavy mountain bike also from Halfords, however the gearing is set so 16 MPH is about the maximum, the front cog is a single dished unit so you only have the 9 rear speeds, clearly heavy add says 24 kg of which 2.6 kg is battery.

    Looking at non electric weight drops to around 16 kg, however to compare I looked at Halfords web site for the cheapest ladies bike with front suspension, and Hydraulic Disc Brakes to compare weight and price, and simply did not find one under the price of the electric bike.

    First thing my wife did was change the seat to a large blow up suspension one from Lidi, second was fit panniers to carry lock and puncture outfit, actually got a tin of blow up and repair grunge. Not weighed it after, but now must be well over 24 kg and yet no problem riding with motor switched off.

    My concern however is the bike rack on car rated 40 kg so can't carry two electric bikes, unless we do some thing to reduce their weight. Although with disk brakes easy to remove wheel, question that comes to mind, is what happens to those discs when being shaken on a bike rack, would it need some thing to retain the pads? Why the Maypole NBC2040 3-Cycle Carrier Towbar Mounted is rated as a three bike carrier with max weight of 40 kg don't know, all three bikes would need to weigh less than 14 kg which seems unlikely, so would 42.8 kg for two bikes really be a problem? The car can take the weight, Kia Sorento but would I really need to remove wheels or would the extra 2.8 kg not matter?
  7. Pale Rider

    Pale Rider Guru

    A £1,000 mountain bike might weigh 12kg, a roadie bike a bit less, so your 40kg rated rack could carry three average bikes.

    Removing the batteries of your ebikes would bring the overall weight down to as near the limit as makes no difference.

    You could remove the front wheels, the disc pads are located by a pin so they will not fall out.

    What you need to avoid is squeezing the brake lever with the wheel removed.

    Some bikes come with a brightly coloured piece of plastic to shove between the pads to act as a spacer.

    Anything will do. I've used a lolly stick and a folded bit of cereal packet in the past.
    ericmark likes this.
  8. Ffoeg

    Ffoeg .

    The Isle of Carl
    Cheers :thumbsup: I have a long history of modifying cars where I was know for attention to detail :smile: Lucky with that kit most of the cables were pretty much the right length or can be easily shortened. The only 'extra' bit of cable (about 1½ft too long) is folded in 4, bound in some heat shrink and stuffed between the rear mudguard and seat post. Other cables are held to other normal bike cables (gears and brakes) with spiral wrap.

    Anywhoo, weights.... the motor kit is quoted at 3.6 kg, but I'm not sure what that quoted weight includes. Assuming that includes everything except the packaging (full parcel quoted at 5.4kg), then that's everything... motor, chainwheel , cranks, cables fittings and head unit. The Hailong battery on mine is quoted at approx 3.2kg all in (battery and mounting plate).

    So the complete conversion adds around 7kg to a bike, and mine as pictured is around 20kg with rack, mudguards, pedals and hub gear. Considering the Cube Hyde donor bike was 12.8Kg I'm happy the above maths is in the right ballpark.

    With the battery/motor off there is some resistance as you are still turning the motor, and it feels quite a heavy bike. But if you want to pedal unassisted then the lowest setting would more than compensate for the motor resistance and extra weight and feel more 'normal' except for the lower centre of gravity making the handling far better than a standard bike. On lowest setting then you'd be good for around 80k

    The latest kits have an extra wire to tap off a feed for 6v front and rear lights which can then be operated via the head unit, so there's no need for a dynamo adding more resistance :smile:
    Tenkaykev and KneesUp like this.
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