30MPH Commuter : BBSHD vs QS205 24*5T

[michielk]

Hello!

I have build two ebikes so far, both using a basic PAS system.
Classic steel frame (no suspension) city bike with hub motor
- Using this to get around town (flat roads, cobblestones, ..)
- Crystalyte H4065 (High Torque motor in 28" wheel) @ 36V - 728Wh battery
- Good/fast acceleration up to its 20MPH top speed (legal for normal ebike over here). It has very poor brakes (Shimano roller brake in front, crappy vintage rim brake on rear). Unfortunately, no mounts or room for disc brakes. The bike is very heavy in the rear and bounces badly on bumpy roads. I used the steel frame for the classic looks, but am disappointed in handling and braking.

High quality aluminium downhill mountainbike with mid motor
- Using this for real off-road mountain biking (very steep hills, loose gravel, big rock gardens, etc.)
- BBSHD with 42T Lekkie chainring @ 52V - 1045Wh battery (in a backpack); DPC18 Display at the moment, just ordered an Eggrider V2
- Top speed 30MPH (legal for a high speed ebike over here). Long travel front & rear suspension, big 203mm hydraulic disc brakes make it a very comfortable and safe bike to ride. Very capable at climbing very steep hills, even on very loose or very rough terrain. Has a very natural balance to it, it's great on trails. I love this bike. Only thing missing is a torque-sensing PAS system

Now I would like to build a new bike for commuting 20 miles to/from work. Needs to be a legal (PAS, 30MPH) ebike. I will most likely use a Qulbix Q76R frame to keep the battery weight in the middle of the bike. Parts will come of a downhill mountainbike (triple front forks, big hydraulic disc brakes, 26" wheels. It needs to keep 30MPH for a while on flat roads without too much pedal effort.

Since I'm so happy with my downhill bike, I'm really considering getting a BBSHD again but with a 46T or 52T chainring to lower the cadence at 30MPH. I won't need all the climbing power, so this seems like a good trade-off. Since this bike is not for serious off-roading, I have no issues with a hub motor either. The QS205 is so popular, I'm doubting if I shouldn't consider this option as well. My biggest issue is that I want/need a PAS eBIKE, not a throttle-moped (although I have no problem with people wanting that). The QS has a single freewheel, so if I gear it for a comfortable cadence at 30MPH, it will be a very low cadence at 10-12mph).

Has anybody done a decent PAS integration with a QS? How naturally does it handle? Perhaps even a Torque sensing PAS system? Any suggestions on a Torque sensing BB that fits the Qulbix 76 Frame? (I believe it has a 83mm BSA BB)

All opinions, suggestions, information, experiences are welcome. But please don't turn this in another MID vs HUB discussion. I have both and aknowledge the advantages of both system. I'm just asking for opinions on which would better suit my current build (commuter bike that handles well with a natural feeling PAS).

thanks

 

[SlowCo]

20MPH top speed (legal for normal ebike over here)

- Top speed 30MPH (legal for a high speed ebike over here)

Needs to be a legal (PAS, 30MPH) ebike.

I saw you live in Belgium and wonder if you can actually have a legal ebike that fast in an EU country? Surely you need to comply with EU legislation and have such a high speed pedelec officially tested and registered in Belgium also?

 

[michielk]

Local law in Belgium
- Normal Ebike: 250W max, 25kmph max, PAS only
- Speed Pedelec (fast ebike) 4000W max, 45kmph max, main purpose: PAS

For a speed pedelec, you need to register the bike (license plate), wear a (bike)helmet, need a drivers license (moped or car) and if it has a throttle you also need a separate insurance. To register the bike you need a CoC (official certification) for the bike. However, they are working an approval process for people with a bike that comply's with the law but who don't have the CoC. Until the end of this year, a license plate is not yet required if you don't have a CoC for your bike.

I'm assuming that whatever bike I build that comply's with the law will receive official certification when they get around to organizing such approval. How is it in the Netherlands? Do you already have a homologation for older or DIY speed bikes?

thanks

 

[SlowCo]

There seems to come an individual approval test indeed. Good to know that it will stay possible to self build a speed pedelec and stay legal. Now we have to wait and see what the costs will be

More info I found:
https://www.bike-eu.com/laws-regula...0.1182063376.1532430708-2089157435.1532430708

https://www.tweewieler.nl/elektrisc...1.1182063376.1532430708-2089157435.1532430708

As to your original question: if you're considering such a heavy frame and use it for commuting I would advise a hub motor and a programmable sine wave controller. That will give you much less maintenance and the possibility to tune the drive train to your liking (good acceleration and regenerative braking i.e. less brake pad wearing) and the legal requirements (exact max speed regardless of battery pack voltage). For less weight and price I would also look at the new QS 260 cast wheel so you can use a moped rim that can use a moped tire (much more miles / less often changing tires/ less chance of a flat). That way you have a tubeless system that is easily repaired beside the road if you get a flat. The 2000W (peak much higher) 260 35H V1.2 would be ideal I think:
https://endless-sphere.com/forums/viewtopic.php?f=31&t=65972&start=1125 (towards bottom of page)

Edit to add: look at this controller for your build: https://endless-sphere.com/forums/viewtopic.php?f=31&t=81020

 

[quantumcloud509]

nevermind