Thorn Me’n’U2 Electric Conversion – Conclusions

The motor is now fixed, the speed sensor wire is lengthened and the sensor fitted, and the rear brake sensor is now fitted. We’ve just done an 18 mile ride with lots of hills. How well does it work?

Background

I’m around 85kg, the kids are around 50kg between them, and the bike is around 35kg with the electric motor fitted. Plus luggage. Say 180kg total – quite a lot to haul up a hill.

Most of that weight is on the front wheel.

No more worries about hills

The biggest change is that hills are no longer a problem. I used to be aware of all the hills I would have to climb – not worried but I would always have them in the back of my mind and would choose a route to minimise hills. Now I don’t think about them.

I’ve normally got the power set on 3/5. This is enough to easily climb hills (almost any hill) at about 8mph with low battery consumption. If I increase the power to 5/5 (max) then the speed will increase to about 12-13mph but the battery drops fast.

I no longer use the small chainring at the front – it isn’t necessary. Bottom gear in the middle ring is low enough for any hill I’ve found so far.

Kids happy

The kids are happier to ride the bike. I think this is due to a couple of reasons:

  • We’re going a lot faster, particularly up the hills. They enjoy the ride more at higher speed.
  • They don’t get told to “pedal as hard as possible” any more – they can just chill.

Battery life seems good

On 3/5 power the battery doesn’t drop much. 18 miles dropped 1 or 2 bars on the power meter. If max power is used then the battery drops much faster.

The power level has a big effect on the speed of the bike but doesn’t seem to have much effect on low speed torque – it will still provide a hefty push at 1/5 power but only up to a few mph.

Front wheel drive works well

Fitting all the components at the front was the right thing to do:

  • All the cables are the standard length – apart from the speed sensor cable
  • The driving wheel has lots of weight on it
  • Front wheel drive is great in slippery conditions – the bike will pull itself wherever the wheel is turned.

However, there are downsides:

  • Having to change the forks and front brakes was expensive and hassle. I don’t have front paniers any more as there are no fittings for them on these forks (watch this space…)
  • Care needs to be taken with power cutting in at low speeds when manoevering. However this would probably be similar with rear wheel drive.

The disk-brake forks are much stronger than the rim-brake forks. There is a slight difference in ride quality but in a blind test it would be hard to spot.

Starting and junctions are easier

The smooth power when starting makes getting my feet into the toe clips much easier – the bike accelerates much faster. The acceleration is very useful at junctions – max power means the bike will accelerate fast when necessary.

Support from Woosh

Andy at Woosh was extremely good at answering my innumerable questions. The price is fair, everything works as stated, and support is second to none. I’m sure it would be possible to put a kit together yourself for less but there are so many things that could go wrong that it didn’t seem worth it to me.

Downsides

Weight

The bike is a bit heavier. This doesn’t matter on the road but lifting the bike in and out of the house is noticably harder.

Experience

In some way the electric motor does take away from the experience of riding the bike. I guess this is partly due to the lack of torque sensing – the power to the front wheel is either on or off. The Boardman hybrid feels much more natural. Possibly another reason is that motor is very noticeable particularly on full power – it is a bit too addictive!

If I lived somewhere flattish I think the bike would be nicer without the electric kit. However, in the hills, it makes a huge difference to usability.

Control glitches

First the good news – I’ve sorted out why the LCD was turning itself off. The LCD will turn itself off after 10 minutes if unused. Because I didn’t have the speed sensor working initially (the cable wasn’t long enough) the LCD didn’t know the bike was moving and would turn itself off 10 minutes after the last button press.

The PAS sensor works well. However there do seem to be some glitches. If the speed sensor has cut the motor and then the bike has slowed down it seems to be necessary to stop pedalling for a moment, then restart, to get the motor to work again. This is a minor irritation but does upset smooth pedalling when there are three people at the pedals!

Kit quality

Overall I’m very happy with the quality of the kit. The motor works well and internally seems well put together. The LCD, battery and controller are all good. I really like the connectors – they are easy to insert and remove and seem very waterproof. The motor is quiet – it makes just enough noise to let me know it is working.

There are some areas that could be improved:

  • Wire insulation – I broke the insulation of the motor wire without trying. I probably didn’t take enough care but the insulation is of a fairly brittle type. The wire core is good quality – tinned copper which prevents corrosion. Fixing the wire wasn’t too hard once I’d made a puller and figured out how to do it, but the fix does take a while.
  • Battery mount – this is a bit flimsy. I’ve mounted mine on custom brackets which makes it much stronger. I’m sure the standard mounts on water bottle fixings are ok but the plastic is thin and flexible.
  • Wheel – the spokes are not particularly tight which isn’t helped by the offset required by the disk brake. I’m going to ask a local wheel-builder to tighten it up or build the hub into a new rim.
  • As mentioned the connectors are very good indeed. While spare connectors wired into cables are readily available (“Bafang higo cable” on eBay) it isn’t possible to buy just the connector. This means cables have to be joined with solder and heat-shrink.
  • I’ve had a couple of instances where the brake sensor didn’t turn off when I released the brake. I needed to pull the brake again firmly to reset the sensor. Hopefully this will sort itself out as everything beds in.
  • It would be cool if there was a way to run lights off the eBike battery. There seems to be a function in the LCD to turn lights on and off but no connectors.

Overall

The motor makes the bike much more practical as a means of transport. The kids are happier and I’m happier. We can ride further and not worry about hills.

Future TODO list

Sort out the front wheel – tighten the spokes or rebuild with a new rim.

I need to make brackets for the front forks to mount the low-rider pannier racks and the dynamo. Front panniers are much easier to access on the road; otherwise everyone has to get off while I go round to the back of the bike.

I’d like to tidy up my brackets to make them a bit neater.

I’d like to shorten and tidy up the cables, getting rid of some of the cable ties.

1 thought on “Thorn Me’n’U2 Electric Conversion – Conclusions

  1. Pingback: Thorn Me’n’U2 Electric Conversion Part 3 | Martin's Blog

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