Newbie Electrifying a Bullitt

[Narcine]

Found this community whilst investigating DIY electric bike conversion.

Only been lurking a couple of days but been considering an electric cargo bike for a year or so and a few weeks ago got a Larry vs Harry Bullitt second hand that I'm thinking of electrifying myself.

Current thoughts are to figure out if a 250W 48V Tongsheng kit will fit correctly, I'd prefer no throttle and the torque sensing bikes seem more natural than the bafangs. The hub width looks fine but I need to reroute the rear gear cable that goes under the bottom bracket. There's no braze-ons directly in the way but there's one perhaps 7cm forward of the center of the hub I'm a bit wary of.

If anyone has any advice or some good threads for me to follow let me know!

 

[Fat Rat]

Welcome and have fun with your build

 

[Woosh]

Hi,

I don't think it's going to work.

Here is the drawing of the TSDZ2:

Basically, you need to draw a horizonal line, more or less flush with the bottom bracket shell.
You need clear space for the motor below the horizontal line.

This is your Bullitt:

I think you will have to look at the BBS01B kit instead.

Best regards

Tony

 

[Narcine]

That is my bullitt!

Thanks for the response. I hadn't even considered the slight lump under the bottom bracket.

It's a bit of a shame. The torque sensing, open source firmware and no need for brake and shift sensors made the TSDZ2 the winner for me.

Do you think the BBS01B would fit then?

 

[Woosh]

yes, I think it will.

 

[KirstinS]

That is my bullitt!

Thanks for the response. I hadn't even considered the slight lump under the bottom bracket.

It's a bit of a shame. The torque sensing, open source firmware and no need for brake and shift sensors made the TSDZ2 the winner for me.

Do you think the BBS01B would fit then?

You don't really need gear or brake sensors on. Bbs01 just on the higher power (and road illegal models)

I have never fitted either to a bbs01 (yes on bbs02)

Firmware for bbs has multiple apps to play with with if you choose.

But the big one for me. What is so good about torque sensing please? Especially on a cargo bike I'd want the bike to do the work. Like I put in 1w and bike adds 10w. With torque the system only adds power as you do. You can't ghost pedal or get full use of the motor power

For me a torque sensor on a road bike or a bike that is used by a fit, experienced cyclist wanting a natural feel. For a cargo bike that just doesn't compute for me. Have you tried both systems?

 

[Nosweat]

I just installed a Woosh front hub motor with torque sensor. Sensor Is in chainset so no bottom bracket to foul on. Would that fit your bike?

 

[Narcine]

You don't really need gear or brake sensors on. Bbs01 just on the higher power (and road illegal models)

I have never fitted either to a bbs01 (yes on bbs02)

Firmware for bbs has multiple apps to play with with if you choose.

But the big one for me. What is so good about torque sensing please? Especially on a cargo bike I'd want the bike to do the work. Like I put in 1w and bike adds 10w. With torque the system only adds power as you do. You can't ghost pedal or get full use of the motor power

For me a torque sensor on a road bike or a bike that is used by a fit, experienced cyclist wanting a natural feel. For a cargo bike that just doesn't compute for me. Have you tried both systems?

I haven't tried Tongsheng or the Bafang crank drive. I've tried a couple of electric cargo bikes, Babboe City-E (rear hub motor) and the Urban arrow (Bosch). I was told the Babboe was a Bafang, but I can't confirm that now, either way it was a rear hub motor not the crank drive.

I much preferred the feel of the Bosch, but then it's a much more expensive bike, the rear hub motor kind of kicked you after you started cycling rather than smoothly accelerating. I read that the smooth accelerating is what I'd get from a torque sensing system. So it was just that it felt more natural.

I figured in both cases the motor would do the work for us, I like to cycle so I'm happy to pedal, just with the distance + added weight I think it would be used a lot more if there was some assistance.

That's good to hear about the brake / gear sensors. I guess I can always start with them not fitted and see how it goes.

 

[Narcine]

I just installed a Woosh front hub motor with torque sensor. Sensor Is in chainset so no bottom bracket to foul on. Would that fit your bike?

The TS kit with an XF07? My front wheel is 20" and they have 20/26/700C ones available so that should fit. But since it's a cargo bike not a foldable the distance from me to the front wheel is rather far, probably just means longer wires. I don't know what the handling would be like though, being pulled by something over a meter in front of me.

 

[sjpt]

Woosh provided longer wires as needed for fitting an XF07 to the front of our tandem.

On a tandem the problem of low traction on the front wheel is not too serious because of the difference balance of weight over the wheels. Indeed, it is often helpful (eg slippery grass slightly uphill) to have motor drive at the front and human drive at the rear; quite often get slip on the rear while the motor continues pulling.

However, on a cargo bike you may have a different weight distribution that could mean relatively less weight at the front than a regular bike. That could be an issue. I think the handling would be fine apart from that.

 

[Narcine]

The front hub motor is an interesting idea, I'll look into it. I dismissed it after hearing of traction problems and the possibility of going head first over the handlebars if somehow the motor dislodged the wheel or broke your forks.

I'll see how much weight is at the front compared to the rear with some weighing scales and a rider with something in the front box.

If my front forks collapse there's no chance of me going over the front, I'd likely grind to a stop pretty quickly and my kid would be strapped in.

 

[Nosweat]

Haven't had an issue with slipping yet with my new XF07 torque sensor kit though that's only been on tarmac. I got the impression that's more relevant on gravel tracks though I doubt you would get far trying to go mountain biking on mud tracks on a cargo bike!

I would add that Woosh have been as fantastically helpful to me (and patient whilst I did my homework and felt like I was deluging them with questions!) as others on this forum have previously reported so I am sure they will be able to help you find a good solution.

 

[touringmark]

Found this community whilst investigating DIY electric bike conversion.

Only been lurking a couple of days but been considering an electric cargo bike for a year or so and a few weeks ago got a Larry vs Harry Bullitt second hand that I'm thinking of electrifying myself.

Current thoughts are to figure out if a 250W 48V Tongsheng kit will fit correctly, I'd prefer no throttle and the torque sensing bikes seem more natural than the bafangs. The hub width looks fine but I need to reroute the rear gear cable that goes under the bottom bracket. There's no braze-ons directly in the way but there's one perhaps 7cm forward of the center of the hub I'm a bit wary of.

If anyone has any advice or some good threads for me to follow let me know!

did you do this yet what did you finally go with as I am looking at doing this to a Bullitt cargo

 

[vfr400]

did you do this yet what did you finally go with as I am looking at doing this to a Bullitt cargo

It's not possible to fit that motor to that bike, nor is it possible to fit a bafang crank motor. You need to find a different system. maybe a GNG system or Cyclone if not a front motor.

 

[Narcine]

Yep, I completed it last May. I went with a Bafang 36V 250W BBS01B with 17.5Ah battery from Woosh. No problems fitting it. Apart from needing to add some washers to align the chainring adapter I got correctly.

There's a Facebook group called Bullitt The Dark Side that I've recently found where a number of people have converted Bullitts to electric in various different ways, so you might also find that useful.

The Tongsheng only fits if you're happy angle grinding away part of the frame.

Attaching the battery to the frame is the creative bit, I used metal bottle cage mounts (Topeak Alt-position Cage Mounts) with some big hose clamps. Some people use rivets, some people make custom metal brackets.

I got a 36T adaptor for the front gear to keep my gear ratio the same rather than running the ring that comes with it (42T?). The chain line is ok, I can just about use all 10 gears but the chain is very angled in the lowest ones.

I bought brake sensors since I have hydraulic brakes, but I haven't needed to fit them or a gear sensor. Although my wife has snapped the chain that came with the bike when shifting under load, so far the new chain has been fine though.

 

[Deleted member 33385]

gear sensor. Although my wife has snapped the chain that came with the bike when shifting under load, so far the new chain has been fine though.

Gear sensors allegedly prevent damage to chain and gears while shifting. I can stop the motor while shifting gear by lightly pressing the brakes, but I find that too much to remember when dodging cars. I'll be pulling a heavy bike trailer soon, which will put more strain on the drivechain... so I found this UK seller, and a gear sensor arrived via second class post:

https://www.ebay.co.uk/itm/Bafang-Mid-Drive-Gear-Sensor-Cut-Out-Switch-BBS01-BBS02-BBSHD/254655332719?hash=item3b4aa4016f:g:bhIAAOSwOfFer~Ss#shpCntId

...I don't know if it'd be suitable for your bike (hydraulic gears?), best ask Mr/Ms Woosh if you're unsure.

Must say, your Bullitt is a great looking bike! What a brilliant design! Do you know how much it weighs without the Bafang kit?