Price and advice for mid drive conversion

[Stephenmacleod]

hi all.

looking at a specialized pitch tomorrow to get me back into biking. Light trails but mostly path and soft road use.
was thinking of making it a commuter on my 25 mile round trip daily work commute of 90% flat roads. The bike itself is a 2015 and used, but it's really cheap so.

I've been told mid drive is best really, and I'm aware of bafang being a very good setup. But I'm wanting to keep costs down as once I'm used to an ebike after a conversion I'd invest more in a better setup or a factory e bike.

what would I need, and what should I expect to pay? I'll be able to fit it myself, or certainly with the help of a mechanic relative.

thanks,

steve

Reply

 

[Jonah]

For commuting on flattish roads I think a hub motor might well be your best option. Have a look at the Woosh website for various options of both hub and crank offerings and their relative costs. You can expect cost to be in the region of £500 including a decent battery. You should find a link on this forum as Woosh are a supporter and regular contributor. It is of course possible to do it a bit cheaper.

 

[sjpt]

As Jonah says, try Woosh, and expect £500 up. http://wooshbikes.co.uk/cart/#/category/uid-3/cd-conversion-kits. If you get all the bits from different places you might save a bit, but buy from Woosh and you know it will be a complete kit that works together, with excellent pre and post sales support.

You won't benefit that much from crank drive for that distance commute. A 13ah battery will do the 25 miles return easily, but will need charging every evening. A 17ah battery will give longer, should give a 2 return trips if you use the motor pretty lightly; but I think I'd recharge it every evening all the same.

Torque sensors are nice and give a more natural feeling ride, but cadence sensors are quite a bit cheaper and (to me) more than adequate, with the advantage you can ghost pedal if you are tired ... just keep the pedals turning but without actually pushing.

 

[KirstinS]

Agree with above. A rear hub kit will be cheaper, better and less maintenance for your use. I have a mid drive on my bike that is used mostly for proper off-road but hub for the bike used for mostly road

Woosh have always been good for me and particularly in sorting out the odd issue but you can buy cheaper from China direct. You get zero support or warranty for that though of course . Horses for courses really but I value the warrzty/support .

Personally I buy full kits in the UK and the odd cheap part from China when I'm in no hurry.

 

[Nealh]

A hub bike in my view is a better commute option, it looks nicer with the hub in the rear wheel. The clunky mid drive look is just down right ugly with its horrible bulky looking BB area which once would have had a tidy look to it and sticks out like a sore thumb. For commuting you need the bike to do the work and get there as fresh as possible with mid drive you are going to have to work at it to get the best out of it and that means more sweat, ok if you can shower at work if not you might be niffy all day.

 

[Stephenmacleod]

do the rear hub options usually have a throttle for no pedalling? just im wanting to have the option of no pedalling when im shattered after going up a hill.

 

[sjpt]

If you have cadence sensors (which most hub drives have) you can ghost pedal, where you pedal slowly with no effort and the motor does the work. In some ways more relaxing than a throttle.

 

[Nealh]

do the rear hub options usually have a throttle for no pedalling? just im wanting to have the option of no pedalling when im shattered after going up a hill.

Depending on the bike it may be possible to retrofit one.

 

[SexyHyde]

Don't get the mid drive, from someone in a really similar situation that got a bbs02 750w kit.
reasons against mid drives:
Bottom brackets are all different, so sometimes you can't get a perfect fit easily.
Chainline is off with anything other than a bling ring, and thats better but not great.
Power goes through your drive train, so you will be adjusting, maintaining and replacing things a lot more (10 months for me is 3 chainrings, 3 chains, 2 derailleurs [sram holds up better than shimano imho] countless adjusting of gears).
The controllers on the bafang are built in and run at their limit, you can use an aftermarket controller if you want, but thats a lot of hassle making the mid drive waterproof.

I came to the same conclusion about mid drives after doing my research, but having owned one, I'd say go for a hub.

imho I would want a mid drive with a gear box, or an ebike specific IGH. Just waiting for someone to make it and price it in my price range.

 

[SexyHyde]

do the rear hub options usually have a throttle for no pedalling? just im wanting to have the option of no pedalling when im shattered after going up a hill.

I was only ever shattered on my ebike if i wanted to be.
Going to work was a leisurely ride in high assistance.
Going home was making my heart and lungs bleed in low / no assistance.
You think you want a throttle, but just get used to the assistance levels, and pedalling is much more natural.

 

[Woosh]

was thinking of making it a commuter on my 25 mile round trip daily

what would I need, and what should I expect to pay?

I would recommend the Tongsheng TSDZ2T - crank drive with torque sensor and throttle.
If you are tired, there is the throttle to help you.
The 48V 12AH should be just about enough for two days at a push so if you forget to recharge overnight, it's still possible to use the bike the following day.
For those who have a stepthrough bikes, we have 48V 15AH rack battery, giving you a bit more miles.

https://wooshbikes.co.uk/cart/#/product/uid-208-tsdz2t-12ah/tsdz2-cd-kit-48v-12ah-with-throttle

 

[Nosweat]

Is there a reason why motors (either hub or crank) that have a candence sensor and throttle require a brake sensor to cut the power in an emergency whereas motors that don't have the throttle or use torque sensors don't seem to need a brake sensor? Could a torque sensor ever jamb fully on or isn't that possible?

 

[Woosh]

that's because the throttle has priority over the cadence sensor.
The controller does check for stuck throttle in its startup sequence but can't stop the throttle from jamming later on.
If the throttle accidentally gets stuck somewhere in the active state, it will start the motor. That's why you need the brake sensors as an insurance.

bikes with torque sensor have also a cadence sensor. You need both sensors to be activated to start the motor.

 

[Stephenmacleod]

Just to clarify then; what other options are there besides the swx02 by whoosh and the q128c for rear hub motors? The whoosh kit looks good but I would ideally like something a little more powerful like a 500w or something. I may still end up opting for the whoosh kit I'd just like to know what other options there are. Thanks

 

[Nealh]

Q128c is 500w .
The SWX02 at 48v with a 17a controller will be able to output 816w before inefficiency losses and about 650w at the wheel if required. 650w temporary should be more then ample for most people.
Any motor power comes via controller rating (Amps) and a suitable battery to deliver that power. High power drains the battery quickly and stresses the cells unless the best branded high amperage ones are used.
A typical 1000w hub will be a D/D hub and a 250w geared hub motor in most circumstances will be a better option.
For other hubs look at options from PSWPower,Greenbikekit, BMSBattery, Topbikekit or YosePower also Aliexpress or ebay hubs can be found.

 

[Stephenmacleod]

Are the swx02's restricted to 15.5mph though? I'm assuming that A. They can be unrestricted but B. That'll invalidate a warranty.

 

[Woosh]

we don't condone derestriction but legality aside, derestriction does not void the warranty on geared hub kits, only on crank drive kits.
That is because the geared hub kits do not get damaged by derestriction, the back EMF voltage goes up gradually as you go faster, reducing effectively the current flowing through the motor.
All our motors are optimised* for 15mph, so the noload speed* is about 20-22mph except the SWX02 on the Santana3, a bit higher. The 48V SWX02 is also optimised for 15mph, you get 30% more torque but it does not go any faster than the 36V SWX02.
On CD motors, you can have tall gears and run the motor at too low RPM, causing it to shed load of battery into heat, cooking your controller inside the motor.

* noload speed is when you lift up the motor wheel from the ground and push fully on the throttle. At that speed, the back EMF voltage is equal to the battery's voltage, effectively cancelling the weight of the motor but does not help you go faster. If you manage to ride over the noload speed, it's on your own steam.

*optimsed speed: that's the speed that your motor produces the maximum power, typically when you climb a 5%-7% hill at 15mph.

 

[esuark]

I`m 68 85kg and have a woosh 48v swx02 in an old Raleigh Aero Max mountain bike I can generally cruise along flattish roads at 18mph max assist 19mph with effort. I live in an area with quite a few climbs north downs, I can get up these with little effort compared to my analogue bikes, some I cant get up with the analogues. I was out yesterday, was windy and I passed a few on bikes. Riding my race bike I could cover a local circuit of 33 miles at an average of 15mph 8/10 years ago in good weather, yesterday in the wind with the old Raleigh with the swx on max assist I average about the same for the same circuit .For me it brings back the enjoyment even in adverse conditions. Other advantages minimal gear changing I never use the granny ring. My experience.

 

[GLJoe]

All our motors are optimised* for 15mph, so the noload speed* is about 20-22mph

That's interesting information. Seems sensible for bikes restricted to the 15mph limit. A couple of questions if I may:
1. Does this 'optimised' 15mph speed also mean you have the most efficient battery use (least amount of power wasted as heat at this speed - given you want as much oomph as possible)?
2. What about DD 28mph Spedelecs like the Stromer bikes. Any idea what the optimised and no load speeds would be for that type of implementation?

 

[sjpt]

Optimized for 10 or 12 mph might suit us better (even if it meant we lost most push before 15mph), but I can see why 15 is probably best for most people.