Vintage Bike Advice

[TRM]

Hi, I'm a new guy here. :|
I have been involved with building custom vintage cruiser bikes for years, but have been giving thought to incorporating an electric motor into some future projects. Being new to e-bikes, I'm looking for advice on what type of electric system would work best for adapting to a vintage bike. I'm not looking for a plug and play solution and fully expect to take on some fabrication to achieve my goals.

Here's one of my bikes that I'm considering using.

 

[emco5]

It depends upon how you plan to use the bike. Do you like to pedal and just want a power nudge to get you over hills? Are you considering converting it into a moped, or is maintaining the bike's vintage integrity important?

The minimalist approach with the least amount of clutter would be something like Clean Republic's 350-watt front hub. It has no carousel display, just a thumb throttle, and the battery/BMS/controller are all tucked into a bag. Makes a very clean installation that is quickly reversible if you want to revert to vintage.

Otherwise, you can lace up more visibly obvious larger hubs, or go with a mid-drive like the Bafang options, and others. You can engineer and build your own drive, too, but the proven 'systems' have already done the homework. There will be lots of opinions here.

 

[nutnspecial]

Hey nice bike!

Yep, if you're just looking for more of E-assist a very basic hub kit would not only fit well but sometimes not cost much. Unless you can find one to match your rim you might want to lace the motor in, and front would be less 'destructive' to a vintage like that. I'm sure you don't want to drop the igh or switch to fixie or deraileur.

I'm not familar with the 350w emco mentions, I used a cheap simple ebay kit (with wheel & tire) on mine. >1kw = 210$. More tasteful and fitting just may be a smaller direct drive or geared hub though. A lot of people talk about xionga on here as a nice small geared hub. You can pair any hub like these to alot of controllers and get as much or as little extra controls/monitoring you are going for. Alot of preferences possible from your end on power, speed, control, monitor. . . including battery too!

There has got to be a few on here that have done similar to draw from, with either highly customized, stock, or more naked control/display, at varying power levels and supply?!?!

 

[spinningmagnets]

If you have a couple frames laying around, you would be doing a lot of readers a huge favor if you could post the precise measurements of the bottom bracket shell. The ID, and the width?

I'd think there would be two ways to go. Mid drive and hubmotor.

For a mid sized rear hubmotor, Justin at ebikes.ca (Grin Tech) is the first North American vendor to carry the TDCM rear direct drive hub, which has a 5-speed IGH built into its center. That would allow you to keep a single chain, and a single driven sprocket. Its a mid-sized hub, so....it's not very stealthy, unless you mount panniers over both sides of the rear cargo rack. However, it would run virtually silent on any of the modern controllers that have come out this past year (featuring sine wave).

http://www.ebikes.ca/shop/ebike-parts/motors/igh-305.html

If you don't need a lot of power and speed, and also don't have steep hills, you might use a small silver-cased front geared hub. That way you might even be able to make it "look like" an aluminum finned drum brake, or a dynamo, both of which would appear to be "period correct". This might be the best option due to issues with getting some kind of brake to work with the other ideas...

A mid drive would allow you to keep the wheels completely stock. If you added side panels to the frame triangle, it could hide the motor, controller and wiring. It would involve swapping-in a freewheeling bottom bracket crankset, one that has two chainrings. The motor (in the triangle) would drive one short chain to the outer chainring, and then...the inner chainring would drive the stock chain to the rear wheel. Of course you'd have to source an aluminum adapter sleeve to take the stock BB shell and convert it to the common BSA threads.

There may be other ways, but those were the first that came to mind...

 

[The fingers]

Keeping the vintage appearance when electric, and ease of converting it back to original would be cool. 8)

 

[TRM]

Thanks everyone for bringing up great points. There are pros and cons every way I turn!
I"m not looking for something with a huge amount of power or top end speed. More speed equals more brakes and I really don't want to stray too far from the typical vintage set up. Coaster brakes possibly paired with a front drum brake would be all of the stopping power that I would have to keep the vintage vibe if I went with a mid drive. Unless there are any rear hub motors with integrated brakes, I'm thinking that would present more issues with providing brakes. The smaller front hub motor would probably blend visually and I could keep the rear coaster brake if it would have enough power for hill climbing.

@spinningmagnets, the BB is the typical press fit American size, roughly 55mm ID and 68mm width.

 

[spinningmagnets]

Thanks for the BB measurements, TRM. I will make a note of it. Do you have the stock drop-outs widths handy, front and rear? (assuming that these are fairly common for most bikes of that era?)

There is a speed-sensing "Pedal Assist Sensor" (PAS) that can be attached behind the drive sprocket, so it would be very discrete. When you pedal, a small disc with several magnets at its rim will have the magnets pass by a sensor that is attached to the frame. When the sensor picks up that you are pedaling, a pre-programmed amount of power would be applied to the drive-wheel. doing it like this (as opposed to a hand-throttle) would help to keep the handlebars clear and uncluttered.

This is starting to sound like you might find a 2-speed Xiongda useful. I have a silver one, and it's small (NIB). I was curious to see how much it could take before melting down, but I never got around to it, with so many other projects to do first...

 

[TRM]

Thanks for the BB measurements, TRM. I will make a note of it. Do you have the stock drop-outs widths handy, front and rear? (assuming that these are fairly common for most bikes of that era?)

They are common but are typically narrower than modern widths. I'll check that tomorrow and post it then. The good thing is that they are steel frames so cold setting is acceptable and can be spread pretty easily.

 

[amberwolf]

I'd guess they are 110mm, or 100mm.

 

[Chalo]

Single speed coaster brakes are 110mm across locknuts with few exceptions. The only wider ones I've seen are modern-- intended for track bikes (120mm), choppers (135mm), or fatbikes (170mm).

I'd recommend a small, shiny finished geared hub motor in front. Maybe a Q100 or Q128. Lace it to a vintage or vintage-looking steel rim with the thinnest spokes you can, to get a reliable wheel with relatively low spoke tension (to avoid puckering the holes in a thin steel rim).

Danscomp has 14-17ga Sapim Laser double butted spokes that work well with as little as 50kg of static tension, and closely resemble the highly butted spokes that were common on nicer balloon tire bikes in the '50s and '60s. When I bought some recently, they cost less than $0.80 each. You might or might not be able to get them cut to a length suitable for cross-one lacing on a hub motor. You'll have to call Danscomp and ask, once you know what length you need.

The bike in your photo doesn't have a hole in the fork crown for a front caliper brake, which would be my first resort for an old cruiser bike that I wanted to keep looking true to period. Many such bikes do have a mounting hole, though.

If you use a small direct drive hub (not geared), you can set the motor up as an e-brake as long as you use a controller with that function. That would help maintain a cleaner look and allow you to avoid using an anachronistic brake.

 

[dogman dan]

For that particular bike,, this is exactly why they still make front hubs. I get the front or rear hub motor question several times a day at my job, and the answer is nearly always buy a rear hub.

The exceptions to the rule are bikes that cannot (without modifications) use a rear hub. Coaster brakes, internal gear rear shifter hubs, or most delta trikes cannot use a regular rear hub motor.

So front hub it is. The forks may be odd width, but as said above, you can bend em cold just a bit in or out, to make them fit a 100 mm wide front motor. A small 350w motor that will just look a bit like a vintage drum brake should be plenty of power. ( the motor is rated 350w,, but likely it runs at 750 peak) It will get you up to 20 mph, and likely that it quite fast enough for coaster brake only. I'd keep the wiring to a minimum, perhaps by carrying a very small battery in a front basket or bag.

That bike is too vintage to consider cluttering it up any more, with added brakes or other permanent modifications, IMO. If it was a 1995 Schwinn, different story. Then break out the welder and add rear hub, rear disc brakes, and front disk. Or at least some good v brakes. Also maybe 7 gears.

Re mid drive, most mid drives have a freewheel crank, so your feet don't tangle in the pedals if the motor is running. This means no way to apply a coaster brake. So again,, for mid drive, modifications.

 

[MadRhino]

I'd say there are 2 solutions building that frame: Vintage or Hot Rod.

Vintage: Keeping the bike completely original, restoring the paint job and fitting a small front hub. Batteries would then go on a custom rear rack matching the bike's style and color sheme.

Hot Rod: Reproduce the design of the top tube decorative metal work with Carbon Fiber, only bigger to hold and hide the batteries and controller. Lower the whole bike by the mean of 24" wheels, wide rims 72 spokes, widest tires that the frame will accept (maybe sread the rear to clear wider), shorter crank levers. Fitting a DD rear hub to use regen braking, and why not a springer fork and a chopper saddle...

 

[spinningmagnets]

Since you are new here, it may be difficult to decide which posters have the best advice. Dogmans post-count speaks for itself, and he has a record of being fair and non-partisan when it comes to "what works". Chalo seems to enjoy stirring up controversy, but...he has worked many years as a bike mechanic, and many posters have verified his advice when it comes to wheel-builds and bicycle brakes.

Since most vintage frames are steel, I personally believe they can take a "little more" than they were designed to survive, but...I wouldn't encourage anyone to hot rod them in a way that would endanger them or their rider, and i wouldn't suggest anything that would eliminate the possibility that the bike could be returned to stock classic vintage form (due to rarity).

That being said, European law stipulates the most common drive system is a 250W-500W power level, that can only supply power from a PAS system, and it can only add power up to 16-MPH. As a result, there are a wide variety of affordable EU-compliant systems to choose from, due to mass production. I will certainly be keeping an eye on whatever you decide, as I have a fondness for these classic vintage bikes.

 

[docw009]

This is for show right? If so, I also like the look of a small geared hub motor in front. The next problem is where to put the battery and then there are the controls.

You could try a bare twist throttle and skip the PAS. Or a twist throttle with the three button PAS control on it. I recall the tank is a sheet metal clam shell, big enough to hold two D batteries. Bet you could put the guts of a small controller inside. Speed control too. All you need is a heat sink for the transistors. Fab up a longer tank if it's too small.

Hide the battery in a front basket, or get someone to make a small custom one for that or a rear rack. To keep with the 50's styling, a finned rear fender with a battery inside. Ha ha.

 

[TRM]

Thanks everyone, this is very informative!

If you use a small direct drive hub (not geared), you can set the motor up as an e-brake as long as you use a controller with that function. That would help maintain a cleaner look and allow you to avoid using an anachronistic brake.

That's interesting, I need to look into e-brakes.

Re mid drive, most mid drives have a freewheel crank, so your feet don't tangle in the pedals if the motor is running. This means no way to apply a coaster brake. So again,, for mid drive, modifications.

Good point. I hadn't considered that the mid drive would negate using the coaster brake.

I'd say there are 2 solutions building that frame: Vintage or Hot Rod.

Vintage: Keeping the bike completely original, restoring the paint job and fitting a small front hub. Batteries would then go on a custom rear rack matching the bike's style and color sheme.

Hot Rod: Reproduce the design of the top tube decorative metal work with Carbon Fiber, only bigger to hold and hide the batteries and controller. Lower the whole bike by the mean of 24" wheels, wide rims 72 spokes, widest tires that the frame will accept (maybe sread the rear to clear wider), shorter crank levers. Fitting a DD rear hub to use regen braking, and why not a springer fork and a chopper saddle...

The regenerative braking sounds very interesting!

Both Vintage and Hot Rod are viable directions. I have built both styles in the past. The top tube (I call it a tank) is where I would hide as much as possible. I'm thinking the batteries would take up too much space as you pointed out, but I have some ideas for that also depending on what the final needs are. This bike is a guinea pig for testing ideas to see what will be necessary to make the most logical transition into e-bikes on vintage platforms.
I actually designed and made the tank that's on this bike out of fiberglass. The bike started as a girls step trough frame and the tank is for converting it into a men's bike.
Here's a picture of the bike when I started it:

This photo might give you an idea about how much space I have to work with inside of the tank.

...i wouldn't suggest anything that would eliminate the possibility that the bike could be returned to stock classic vintage form (due to rarity). I will certainly be keeping an eye on whatever you decide, as I have a fondness for these classic vintage bikes.

That's one of my objectives, to come up with a system that I can bolt together without modifying the bike permanently. Spreading the drop outs is about as far as I'm willing to go. I believe I can work around everything else.

This is for show right? If so, I also like the look of a small geared hub motor in front.

Yes and no. The focus is on the aesthetics, but I do want the best performance that I can get at the same time. Given the restrictions on what will work, I agree with you and everyone else that the front hub motor is looking like the best solution.

 

[dogman dan]

IMO,, hot rodding that bike is not to be considered. It's too vintage for it, to valuable to ruin with big mods. Put a minimalist front hub on that one.

But you can take a cheap as modern Schwinn, and mod the hell out of it. Mine's not exactly hot rod, not by ES standards anyway. But It's lengthened 9 inches, and sports a pretty perky large rear hubmotor. Currently powered at 2000w, with 48v. 33 mph max speed. But pop a 72v battery on it, and it would go 40 mph plus with 3000w.

Dual disc brakes, with home made mounts welded to the frame. Front chain ring swapped for a 52 tooth, scavenged from a junk Schwinn Varsity 10 speed. Seven speed gears added simply by using a cheap bolt to the dropout derailleur. The bike was originally a single speed coaster brake bike.

No reason not to modify the hell out of a bike as common as an empty beer can.

 

[Drunkskunk]

That bike is awesome. I'd read about it over on ratrodbikes.com a while back. Really impressive stuff.

A mid drive kills your coaster brake, but mid drives work best with multi-geared bikes, so you could replace the rear hub with a 5 speed Sturmy Archer with an integrated drum brake. then add a matching drum brake to the front for added stopping power.

Since you built the tank, It shouldn't be too hard to make a version that would hold a battery. My old boardtrack style bike uses the tank to store a small battery, and it works out well.

 

[aroundqube]

https://endless-sphere.com/forums/viewtopic.php?f=3&t=82169&p=1206797#p1206797

 

[spinningmagnets]

This might be an opportunity to consider making vintage style cargo panniers? Even if they never existed in the past, your keen sense of style is obvious, and I'm certain you could come up with something that looks "period correct"? Not just for the battery and controller, but there would be left-over space usable for sunglasses, gloves, etc...

Leather, fiberglass, wicker, "X"...

 

[TRM]

This might be an opportunity to consider making vintage style cargo panniers? Even if they never existed in the past, your keen sense of style is obvious, and I'm certain you could come up with something that looks "period correct"? Not just for the battery and controller, but there would be left-over space usable for sunglasses, gloves, etc...

Leather, fiberglass, wicker, "X"...

I think you've been reading my mail! :lol:

 

[TRM]

That bike is awesome. I'd read about it over on ratrodbikes.com a while back. Really impressive stuff.

A mid drive kills your coaster brake, but mid drives work best with multi-geared bikes, so you could replace the rear hub with a 5 speed Sturmy Archer with an integrated drum brake. then add a matching drum brake to the front for added stopping power.

Since you built the tank, It shouldn't be too hard to make a version that would hold a battery. My old boardtrack style bike uses the tank to store a small battery, and it works out well.

Thanks Drunkskunk, I glad you like it! That's good thinking on the mid drive paired with a S-A hub. And FYI, I am exploring some ideas about some vintage styled battery and controller holders. Stay tuned!

https://endless-sphere.com/forums/viewtopic.php?f=3&t=82169&p=1206797#p1206797

I like that!

 

[dogman dan]

That little front motor I mentioned in that thread is still on sale BTW. But I think a naked of paint silver motor might look better on vintage.

Re paint to match the bike one possibility. Or give it something funky, like black box wrinkle paint.

 

[TRM]

Thanks Dogman Dan.