Converting Gazelle HeavyDutyNL to electric

[Dutch Bob Bike Builder]

Here I have converting a Gazelle HeavyDutyNL, Shimano Nexus7V Rollerbrakehubs woman's bike to electric for a customer.

Used a Bafang BBS02B 36V 500W Mid Drive Motor,68mm, 44t front chainwheel, P850C display, rear rack battery 36V 20Ah, chainglider 44 front + 18/22 back, Front+rear lights. Upgrade the front Rollerbrake to e-bike version for better brake power. Outlined the rear hub for good chain line.

Customer is very happy with it.

[Retrorockit]

There are rear roller brakes with big heatsinks also. Since overheating cooks the lubricant in those it might be worth adding one.

Since you're converting customers bikes there is a setup I like for urban riding and that is the old Shimano Rapid Rise (low normal) derailer with a proper Rapid Rise Revoshifter. This allows downshifting several gears at once even when stopped. This ability gets lost when the front (low normal) derailer is removed for the mid drive conversion. I own a Nexus bike , and a Rapid Rise bike. They shift very similarly in traffic. Maybe this is common knowledge in NL, but in the US it's a secret.

[Dutch Bob Bike Builder]

Hello Retrorockit;

The gears is not a derailleur system, but a closed gear hub with 7 gears inside, and the shifter is a grip shift, witch can shift from 1 to 7 gear and from 7 to 1 when you standing still, no paddling. you can't do that with a derailleur, you need to paddle to let the derailleur chance the chain on the rear sprockets. We use here (Netherlands) more the hub gears for the normal daily bicycle's, derailleur system we use for racing and mountain bikes and we don't have mountains in the Netherlands, so we do not need that many gears as 21 or 24 or even 27 gears.

[Retrorockit]

I understand that. I own a Trek navigator 400 that has an 8 speed Nexus with Revoshift. I made the mistake of using a TSDZ2 thinking it was a torque sensing Bafang motor. I just added the info. about the Rapid Rise because you mentioned converting the bike for a customer., I thought you might be doing more bikes in the future.
With a Rapid Rise derailer you CAN downshift w/o pedalling. The shift will occur when you do pedal. That's the secret! Where I live it's just as flat as NL.
I can go from high speed to a sudden stop and not be caught in a high gear. Urban riding and flat terrain here. I run an XTR Rapid Rise derailer and 8 speed Revoshifter with an 11-40 casette.

[josd777]

Hi Dutch Bob, i have the same bike but male version frame .How did you solve the fitting of the BBS02 into the Gazelle bottom bracket. Did you use bushes for that .I think the driveshaft of the BBS02 is the same as the BBS01 . It seems the Gazelle BB diameter is to big. I have a nexus 3 speed and already placed a "wider"rear sprocket but i still feel my chainline is not good. How did you solve that. Best regards Jos

[Dutch Bob Bike Builder]

Hallo Jos, i fitted a thin hard plastic tube around the drive shaft, so it just fit in the bottom bracket house.
To align you're rear nexus 3 hub, you can change the locknut on the right side for a smaller nut, or file down locknut, if you don't have one. What you have taken off (measure it) and put on the left side. After that you have to align the rim to the hub/frame, otherwise you're wheels aren't aligned. And put on the right side the chain tensioner outside the frame if it is necessary.

Best regards Bob

[josd777]

Thx Bob. I just found an old hard plastic water vacuüm cleaner pipe that did the job .I first tried to bend a 2mm alunium strip in a circle but i need 2.5mm so still to much play. I hope the forces on the plastic bushes will not compress the bushes. And for the nut,i did that as well. My first plan was to reduce the size of the bottom bracket . That would be a tricky job and the bike would be an ebike forever.. Chainline is straight now. Did not need to put the chain tensioner to the outside of the frame. It looks like the alignment is ok but i will measure it more exactly . How can i adjust the rim? Trim the spokes a bit so the wheel will move a bit to the left and aligns in the middle of the frame? I never did that ,its about 1.5 mm now. What tolerance is normal for alignment? Thx again Bob. Best regards Jos

[josd777]

Here is the chainline before

[josd777]

Chain is not tensioned on the image

[Dutch Bob Bike Builder]

Josd777, to move the rim, you unscrew 2 quarter turns to right side spoke's nipple's and you tide 2 quarter turn the left side spoke nipple's, and look if the rim is in the middle of you're frame. Use good tools and if you don't want to do it your self ask you're local bicycle shop to do it for you.

[josd777]

Thanks for the advice Bob. I just made new bushes from ppc so much harder material and modified it to a excact fit. Put it all together and i had a straight chainline. Frame was checked on straightness. I removed a little material from the nexus locking nut on the right side. So yesterday made my first test drive. It was succesfull. Bike was driving straight and balanced with driving without hands. Not my ussaly way of driving but to check if the bike was balanced. So not needed to adjust the rear wheel and hub. Best regards Jos

[EmilyS]

Hi there, thanks so much for your helpful post. I have just purchased a Gazelle Heavy Duty NL with the hope of converting it to electric using a Bafang BBS02 like you have done here. How do you get the motor to fit on the bike? We are struggling to see how it will work without cutting away some of the frame. Do you have any close up photos which you could share?