New Member & Planned Build

[nspr]

Morning all from the north of Essex,

Moving to a farm in the next 6 months or so and it's pressed a plan I've had for a while of building an e-bike for the shorter trips (pub, town, station etc) as opposed to putting more miles on the car on back lanes. Also would let me use some of the back tracks my car can't get through.
Any advice, warnings etc from those with a far better idea what they're doing than I have would be welcome.
Current plan is a 29er hardtail (Commencal Meta's or Nukeproof frames seem sensible money) single speed with a TSDZ02 motor on the open source firmware. Hydraulic disks, 48V.
I've got a triban road bike for exercise so this is solely supposed to be an easy quick way to get about; so plenty of assist at all times.

If this is in the wrong place, let me know.

 

[Nealh]

TSDZ2 might have an issue with single speed , depends on the gearing . If too high then won't be very good from a standing start. Initially for the motor to provide assistance I find it needs to be geared low first before climbing up through the gears.

 

[Zlatan]

TSDZ2 might have an issue with single speed , depends on the gearing . If too high then won't be very good from a standing start. Initially for the motor to provide assistance I find it needs to geared low first before climbing up through the gears.

I, d agree with above. Using mid drive on single speed is negating choice of mid drive straight away. It's main benefit is giving motor access to same range of gear as rider. On single speed, you may aswell spend less money and fit hub drive.???
Other thing to consider is with TD72 and a decent battery you are investing quite a bit of money and time into bike. My advice would be to go route you, ve planned but on a bike more capable of utilising what TD72 offers. (couple of years ago I put same unit on a Cube MTB and it's made a fantastic bike)
But to be fair TD72 is so easy to fit might be worth putting it on bike you suggested and trying it.??

 

[nspr]

Cheers both. I was a little worried about the gearing being too tall off the start, but I think the open source firmware has a few tricks here regards additional assist off a standing start? Was going to run a 750w. Although not sure if it's all the same motor under different firmware?
Originally wanted to do hub gears to keep the maintenance to a minimum but I don't think these are really available for boost width through axles?
I guess I can always try a few sprockets and worst case give up and go to a fairly simple 1x groupset?

 

[Zlatan]

Cheers both. I was a little worried about the gearing being too tall off the start, but I think the open source firmware has a few tricks here regards additional assist off a standing start? Was going to run a 750w. Although not sure if it's all the same motor under different firmware?
Originally wanted to do hub gears to keep the maintenance to a minimum but I don't think these are really available for boost width through axles?
I guess I can always try a few sprockets and worst case give up and go to a fairly simple 1x groupset?

You could go that route but dumping current into system to compensate for high gears will affect range and probably longevity of unit.?? .. Its also going beyond "pedelec" definition... But lots do.
Good luck.
Keep us informed.

 

[nspr]

I get the purpose of the 250w pedelec definition and the speed limit, but looking at the bosch / other "oem" units it seems the 250w definition is somewhat meaningless, untestable in practical application and being broken left right and centre in commercially available bikes from big name makers (bosch units happily sitting at 900w)... but I gather there's a thousand threads on here for this debate already!
Will do.

 

[nspr]

Planned to buy the motor from electric-bike-conversions.co.uk, is the best bet or can anyone recommend elsewhere? Would you use the battery they offer?

 

[Zlatan]

I get the purpose of the 250w pedelec definition and the speed limit, but looking at the bosch / other "oem" units it seems the 250w definition is somewhat meaningless, untestable in practical application and being broken left right and centre in commercially available bikes from big name makers (bosch units happily sitting at 900w)... but I gather there's a thousand threads on here for this debate already!
Will do.

No, that's not quite right.
Legal units do for short periods go beyond the 250w limit, but the motor/system is(should be) rated at 250w continuous.
My current GT often shows well over 250w (most I, ve seen is 604w,it has a built in power meter) but I have never used bike and it shown an average of over 250w.. Even under hard usage on long climbs average tends to be around 200w..(think highest I, ve seen is 220w,even when it's peaked at 450w)
I,m not playing police man but if something did go wrong for either of us... My GT would be deemed "a legal pedelec". A 750w Bafang wouldn't,because it obviously isn't.
The whole point of crank drives is to provide sufficient help over wide range of speeds on what is a very limited power capability and be within the pedelec limitations regarding the law.
But, as I said earlier, many do ignore the restrictions and apparently with little comeback. If I were you, I, d try a few before deciding. Both my Haibike and GT still amaze me on their climbing ability on so little power.


Note the reading of 460ish max but with an average of 80 or so. That's normal for this bike. (and makes sense with respect to range, if bike could use an average over 250w a 400wh battery (as on Haibike) isn't going to go far.
I only use bikes in highest setting. Both can do around 28 miles off road. (peak district)(with around 2000ft climbing) Haibike on 400wh,GT on 500wh.
The Tongshen and Bafang (pedelec legal) kits I built are almost identical to these figures.
Have a friend with a 750w Hub drive, he can empty his 600wh battery in 70 mins.. He can average around double the legal limit.???His bike is capable of averaging 514..Clearly not a pedelec.

 

[matthewslack]

Probably better with either cheap i.e. 7 or 8 speed not fancy gears, or a hub gear and a 250W motor to keep loads down.

Either way maintenance costs kept down and much nicer to ride.

 

[saneagle]

750w TDZ02 will burn out if you run it with single speed. If all you want is transport, a rear hub motor will be more reliable, more durable, cheaper, cheaper to run, lighter, simpler to install and give you many more options for power.

 

[nspr]

Thanks again for the input all, came to the conclusion building the bike up myself was always going to be a false economy. Ordered a Nukeproof Scout 290 hardtail with a 1x10 Deore. Due next week, then we shall see about the conversion.

 

[nspr]

Long time no progress, been enjoying the bike too much as is out the box! Got some nice chunky mudguards on, just in time for dry summer, obviously...




However, still want to crack on with a conversion. TSDZ2 still the way to go? I'm fairly convinced i want something torque sensing, and am happy screwing about with OSF. A tad concerned about space for the battery, do we think it will clear the top tube on the bottle mounts?

 

[egroover]

Those bottle mount holes are low down the frame so you will need to add an additional hole in the frame (rivnut) higher up if you plan to use a Hailong style downtube battery. Will be tight with the slimmest Hailong 1 type battery, get the dimensions and produce a cardboard template to test sizing. Alternatively. a frame bag type battery might be an better option or a a slim bottle style battery