Ebike conversion for my 1987 Schwinn Voyaguer

[Puzzlewuzzle]

My 1987 Schwinn Voyaguer currently sports a useless hunk of Copenhagen Wheel rear hub drive.
Suoerpedestrian will no longer support the app needed to use the Wheel.
I am considering conversion to a mid drive CYC Photon.

My Schwinn has a Biopace triple front chainring with 50-44-28 teeth.
I am in hilly Central Pennsylvania Appalachian Mountains and 72 years old.
The CYC Photon is available with a front single chainring with either 42 or 38 teeth.
I usually would ride the Schwinn using the 44 tooth ring while shifting with the 30-26-22-19-16-14 rear cassette.

I am looking for recommendations concerning the 42 vs 38 tooth front ring.
As I indicated I have some steep hills to travel.
I am leaning toward the 38 tooth front chainring for hills however I also wish to maintain speed on the 35 mph roads I travel.



Picture of the Schwinn with the useless Copenhagen Wheel




Cheers,
David

 

[Annieolnie]

It really is a trade off. You also have to consider that you don't want to over stress a midrive with too big a front chainring when you are starting up from a full stop, I don’t actually know how too small a front chainring feels when you have a torque sensor, but my BBso2b would be ghost pedaling with 38 teeth. My Bafang came with a 46 tooth, that has been a good fit for me, but that's on 26 inch wheels, which have inherently more torque. I don’t know if this is your first build or not, but 750 watts with 110nm of torque, you are going to get up those hills just fine, with or without your feet and it is also something that is not hard to change later on. I wish I could be more decisive, but it is a somewhat subjective kind of thing. Welcome to the forum, by the way.

 

[Puzzlewuzzle]

The rear hub drive I am replacing was 350 watts, 48 volts, 5.8 amp hours.

A 750 watt, 52 volt, 10 amp hour mid drive motor will be a powerhouse in comparison.

I decided to get the 42 tooth chainring for my road bike e-fit.

 

[Puzzlewuzzle]

I have the Photon installed in my 38 year old touring bike.
The disassembly of the bottom bracket aka BB had some challenges. They don't make em like that anymore...
Things were fairly straightforward till I discovered the need for a special BB locknut removal tool. A six tooth nut confronted me as I tried a 16 tooth wrench to fit.
A visit to the local bike shop led to my purchase of a proper Japanese made wrench stated to "last me a lifetime" even though I only needed it once (at least so far). Another tool in the bike tool kit is always a good thing I tell myself as I fork over 27$.
The excellent vids available for a CYC Photon install led me through the few step by step procedures concerning spacers etc.
I found some threading to be tight so caution advised against potential cross threading. Take it slow & easy.

On to a rear wheel drive rebuild - Shimano 105 road bike sprockets, hubs, and derailleur.

42T 1X Photon
Shimano 105 11 speed 11-12-13-14-15-17-19-21-23-25-28T
T Gear Ratio
28 - 1.5
25 - 1.7
23 - 1.8
21 - 2.0
19 - 2.2
17 - 2.5
15 - 2.8
14 - 3.0
13 - 3.2
12 - 3.5
11 - 3.8

 

[Puzzlewuzzle]

Question on Chain alignment.
As the instruction vid suggested I placed a 3mm spacer on the drive side of the Photon crank and the 5mm & 7mm spacers on the left side to accommodate the uptake for a 68mm BB install. The Photon may be installed in BBs from 68mm to 83mm.
I checked the chain alignment with the Shimano 105 11 speed sprockets finding the chain would align with the #7 sprocket (counting from large to small).
A more true align would be to the #6 sprocket, a difference of about 3mm to the inside.
Is a disassembly to change the spacers worth the effort for a 3mm diff in "perfect" chain alignment?

 

[HumanPerson]

Depends on what you want.

Looks like you can move the sprocket over towards the frame a little bit...it really is up to you and how you ride

 

[HumanPerson]

Welcome to the forums, by the way!

 

[Annieolnie]

That's a really big cassette. If it were me, I'd be changing it to a 10 speed. People say it will work but those gears are pretty thinned out because there are so many of them. The photon is going to be stressing each sprocket. I think you are going to have to put the derrailleur on and play with it for a bit. I'm assuming you are using friction shifters and not indexing. There will definitely be some tinkering going on later, regardless.

 

[HumanPerson]

Maybe even a 7 speed cassette

 

[Annieolnie]

Yes, after all it will be an ebike that's a road bike. He won't be climbing Mt. Kilimonjaro, and if he does, he has a motor.

 

[Puzzlewuzzle]

I have a set of Shimano 105 rear parts - derailler, hub, and 11gear cassette. A 7 gear cassette is not compatible with the hub or derailleur.
If the 11 gear cassette does not work out I can go for a 10 or possibly 9.
The Schwinn Voyaguer was friction and index shift capable. I like friction shifting better than index and will only use friction shift with the Photon.
Any sprocket will have additional stress and wear and will eventually need replaced so on I go with the parts I have.
Enough $$ spent for now.

 

[Puzzlewuzzle]

I have completed the conversion of my Schwinn touring bike to electric assist with a mid-drive CYC Photon.
Love it in torque sensor pedal mode.
Still get a good workout on the hill and valley roads in the Central Appalachian Mountains with the pedal boost to help me up the grades.
I have completely rebuilt my 1987 Voyaguer except for the original cantilever brakes.
Electric Son generator hub on the front wheel for lights (and phone charger if needed).

The new Shimano rear derailleur, hub, and sprockets shift like a dream.
Gears 42T front 10 / 11-28 rear.

 

[Annieolnie]

Very pretty! I like that highly sprung, suspended seat.

 

[Puzzlewuzzle]

Very pretty! I like that highly sprung, suspended seat.

Brooks leather and springs ... just right for an up-right pedaling position.
The frame is Imperial Rose.
I love this metallic flecked deep red...but hard to match for touch ups on this classic 38 year old steel frame bike.

 

[Puzzlewuzzle]

Here a some photos of my Photon mid-drive install




The chain line came out a bit out of center.
I plan to disassemble the Photon and rearrange the spacers to adjust my chain line.
Spacers are necessary for install in the 68mm wide Schwinn bracket.

I installed the 3mm spacer is on the drive side and the 5mm and 7mm are on the non-drive side. Don't ask why but I will say anyway...instead of closely following the manufacturers recommendation on spacer location I followed a web vid suggestion.

I will be stacking all the spacers on the non-drive side to move the crank sprocket inward and adjust my chain line a bit.
Below are shown the three supplied spacers.

Close examination will also reveal my horrible touch up paint, supposedly red but looks orange on the lovely Imperial Rose red of the 1987 Schwinn Voyaguer frame - ouch. Oh where oh where has Imperial Rose paint availability gone?