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Discussion Starter #1
Not sure if this is in the right section, but I think I’ve seen some electric pedal cycle chat before?

Anyway, I had a test ride last year of a full sus Scott electric mtb with a nice Bosch motor and a frame integrated 9Ah battery.

It was a pedal assist bike, rather than an out and out electric bike, and I really liked the way you still had to pedal, but it felt like you had bionic legs up hills etc.

I wanted one, but then the £5k+ price tag put me off somewhat.

Nevertheless, I made a note to revisit this at some point in the future. I have a couple of mtbs in the shed from when I was a keen mountain biker, they were pretty high end machines at the time but technology has overtaken them somewhat. However, I did feel I could make something similar to what I experienced with a factory e-bike and at a fraction of the cost via some kind of DIY route.

Fast forward lots of internet research, and I settled on the Tonsheng TSDZ2 mid drive. I discounted the hub drive motors although they were cheaper and easier to fit because I still wanted it to be a useable mountain bike and not have too much unsprung weight. I also stuck with a 250w motor, the legal limit for use on the public road.

I had a number of challenges when deciding on a fit, I wanted to keep my disc brakes and levers, and the pedal assist setups aid this as there is no throttle and therefore you don’t need a brake setup that cuts the motor if you brake. If you stop pedalling, the motor stops assisting too.

Next thing was there isn’t much room in the frame triangle for a battery, so whatever I used would have to be small but that would limit my range a bit. I settled on 2 x 5s 5200 mAh RC batteries in series that give me a nominal 36v 5.2Ah battery. Fully charged it’s about 42v. I mount it in an under seat bag I had knocking about the shed, and they just fit in nicely. The bag is also water proof to a degree.

I went for a handlebar mounted controller with the twist grip for varying the amount of pedal assist from off to level 4, my handlebars are already crowded with lockout levers for the front shock, and off road lights for this time of year. There is also a ‘walk assist’ mode that self propels the bike at walking pace should you suffer a mechanical. The motor, crank and batteries do add a bit of weight! The controller also acts as a cycle computer and will also power 6v lights via a switch if you so desire.

Fitting was pretty straightforward, I shed a gentle tear as I removed the light alloy race face cranks and replaced them with the anvil-like motor crank. It fits any standard 68 or 73mm bottom bracket shell.

I wired some RC model connectors to the factory battery wire, and although I still need to waterproof the connectors properly I managed to route it through the frame easily enough.

I’ve only ridden it about 4 miles since I got it setup, but already I’m reminded of the feel I had with the test ride last year. Mine is a bit more Heath Robinson and the motor is noisier than I remember the Bosch one being, but the effect is the same, I produce some torque and the motor does too. I didn’t want the electric moped feel, and I can lick it along at 25mph easily on the flat with the motor only assisting mildly in line with my torque inputs.

Longevity and reliability I have no idea of yet, but those who use the TSDZ2 have good things to say although the blue nylon transfer gear can wear if you’re clumsy with the gear changes.

Downsides? Well, the setup has added 4kgs, but I think the weight is in as good a place as it can be.

I also don’t know if adding range anxiety to another aspect of my life is a good thing, after the car and electric lawnmower!

On range, I estimate I’ll get about 25 miles of pedal assistance out of my battery pack, which should be plenty for my Sunday afternoon or evening jaunts. I could always invest in another couple of batteries and keep them in my back pack for longer rides.

My question is, will I be laughed out of the trail centres, I mean, it’s a DIY conversion with 26” wheels and I understand they’re old skool now?!

A few pics below, I’d be interested to see your e-bikes and happy to answer any questions for anybody thinking of doing similar?
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Don't B8FUN ( or similar name) make these mid drives with a large range of powers at more reasonable Chinese prices?
 

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Discussion Starter #3
Don't B8FUN ( or similar name) make these mid drives with a large range of powers at more reasonable Chinese prices?
They do, yes, and the Bafang BBS02 is a popular choice for e-bike conversions too.

The BBS02 works slightly differently though, in that the motor assists when you turn the pedals. If the pedals are turning, then the motor is doing most of the work.

The TSDZ2 has a torque sensor similar to the Bosch system fitted to a lot of the factory bikes, and it’s that setup I wanted. The motor only assists if I’m putting some effort in too, and it’s a simpler setup that doesn’t require a throttle or brake switches. The more you do, the more the motor does.

The BBS02 is good though, and very fine tuneable. You can get the TSDZ2 in up to 750w as well, which must be mad, as you definitely feel the assistance even at 250w, I’ve never cycled up the hill out of my village at 15mph before.

You can pick up the TSDZ2 from Ali Express etc, or an online retailer who dispatches from a German warehouse for less than $300 delivered, which is comparable to the Bafang.
 

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Discussion Starter #6
It’s very hard to say, and I’ve only ridden it a few miles.

I also need to establish if the speed sensor is accurate, I’ve programmed the controller with the correct wheel size etc, but I need to take it out with my phone mounted so I can measure the controllers speed be GPS.

I was pedalling it at an indicated 25mph on a flat road, and it felt like there was still some assistance at certain points of my cadence, but that could have been my imagination and/or noise from the motor as I was turning it. It certainly didn’t feel like I could get any faster, drag and wind resistance was equalling any forward motion it seemed to me.

Most e-bike bike shops seem to think that most ‘road legal’ e-bikes assist a little beyond the 15.5mph limit.

I think the bikes with a throttle are of more concern, you don’t need to pedal, and the only way I can get behind 15mph with this setup is if I’m pedalling too. I do cringe at the 750/1000W conversions on you tube etc that are just electric motorbikes really.
 

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Legally to be an ebike, assistance must stop at 15 mph. This seems a bit low to make it worthwhile, I know a lot of people mess with the speed sensor to stop the power cutting out. Your bike looks ideal for riding on bridleways where it would be a bit of a slog without assistance.
 

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Legally to be an ebike, assistance must stop at 15 mph. This seems a bit low to make it worthwhile, I know a lot of people mess with the speed sensor to stop the power cutting out. Your bike looks ideal for riding on bridleways where it would be a bit of a slog without assistance.

And under 250W motor.

I've had a Haibike Trekking for about 2.5 years (£3500) purely for commuting and done ~3,000 mile on it and not had to touch anything at all. Just runs sweet as the day it was new. Can get it chipped if I wanted to get peddle assist over 15mph but never felt the need. Now I'm over 50 I do really want to go over 20mph on a bicycle anyway !
 

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Cost?

My first bike was a Heinzmann Hub motor conversion of a Marin Commuter bike with 700C wheels about 15 year ago and that cost over £1,000 then. That was full assist though, not related to peddle but had a throttle and 350w motor.

The Haibike is pure "Road Warrior" class. Best bike I've had.
 

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I was expecting something horrific but that doesn't look too bad. Something like that could work nicely on my town bike.

Assistance up to 15mph is fine, it's just like having stronger legs when pulling away or going up hills. >15mph is going to be downhill where gravity is doing some of the work anyway.
 

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Cost?

My first bike was a Heinzmann Hub motor conversion of a Marin Commuter bike with 700C wheels about 15 year ago and that cost over £1,000 then. That was full assist though, not related to peddle but had a throttle and 350w motor.

The Haibike is pure "Road Warrior" class. Best bike I've had.
Web image of mine. Can go three days without re-charging covering around 60 mile.

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So I was thinking about ebikes and conversions for our existing bikes. Problem is I can afford to do one nicely but I can't afford to do all 5 to any standard.
Not sure what's possible but I got the impression the budget hub kits wouldn't be a great result. This looks very nice. Maybe not exactly a budget job however.
 

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Discussion Starter #14
Cost?

My first bike was a Heinzmann Hub motor conversion of a Marin Commuter bike with 700C wheels about 15 year ago and that cost over £1,000 then. That was full assist though, not related to peddle but had a throttle and 350w motor.

The Haibike is pure "Road Warrior" class. Best bike I've had.
Cost for the motor (with main chain wheel), controller, and crank arms was $300 delivered, the batteries were £60 each (so £120 total) from my local radio control shop. You can get much cheaper batteries from Hobbyking though.

This conversion cost about £360, I already have a suitable charger for the batteries but that would be another £25 or so.

I could probably sell the now redundant race face crankset and front derailleur to recover a bit of cost, but I’ll probably just keep them in case I revert it to standard.
 

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Discussion Starter #15
Legally to be an ebike, assistance must stop at 15 mph. This seems a bit low to make it worthwhile, I know a lot of people mess with the speed sensor to stop the power cutting out. Your bike looks ideal for riding on bridleways where it would be a bit of a slog without assistance.
I had the same reservations, but I’m surprised by how that low speed kick helps all round and I’ve no doubt it will save a lot of energy on a proper ride.

The Scott test bike I rode was on a route that I know well and have ridden previously, I went round it a heck of a lot quicker on the assisted bike and it was fun.

I’m riding it out at the weekend for a full test once I’ve sorted the battery cable connector waterproofing (old inner tube and zip ties I think).
 

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£2k will get you a nice Specialized HT Levo. You'd hardly know it was an ebike to look at it, until you pass folk breathing out their asshole on a steep incline and you breeze past still seated.
 

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I switched to a hybrid several years ago when I stopped doing less off road and more just commuting to work.

I have been tempted to dust off the old mountain bike and do something like this however, having the motor in the rear hub:



 

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Discussion Starter #18
I switched to a hybrid several years ago when I stopped doing less off road and more just commuting to work.

I have been tempted to dust off the old mountain bike and do something like this however, having the motor in the rear hub:



That looks a nice kit, and the rear hub motor would work well on a hard tail too.

With 1500W/2000W I bet it shifts as well!
 

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I have a Haibike SDuro Cross 6.0. One of THE best things I've ever bought. Of course there's no way I'd ever chip it and be able to do double the 15.5mph limit.
 

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Reading all these posts make me think I should resurrect this kudos eiger with da Vinci drive currently languishing in my garage. Yours looks great Tooks!
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