Convert Road Bike to Ebike - Advice!

[cdb5]

Hi All --

I'm thinking about converting an old touring bike into an ebike with a BBS02 mid-drive. Bafang USA Direct is having a presale on kits. But I'm a novice & need advice!

Here's the deal: I have a short (~3.5m each way) commute to/from work, and I pull my daughter in a Burley Bee trailer to day care on the way. I'd like to be less sweaty when I arrive. But more importantly, I live on top of a really steep hill, and I struggle to get up it. It's only a half-mile climb, but it averages a 12% gradient, peaking at 16.5%. So I'm looking for something powerful enough to get up that with only casual levels of exertion from me. And my budget is only around $1,000, give or take. A mid-drive kit for my old Raleigh touring bike seems like the best bet.

Two questions for you experts:

1 - Is that conversion a good/safe idea? The touring bike has rim brakes & narrow wheels. And I'm pulling precious cargo, so safety is a priority. Will I be putting us at risk (well, more risk than biking in a road inherently has) by putting so much power into that kind of setup (as opposed to something with fatter tires, disc brakes, etc.)

2 - What sort of specs should I aim for? These kits have tons of options & I can't tell what's necessary and what isn't. Specifically:
- Will 750W motor be enough? Passenger/cargo payload will be about 240 lbs.
- What chainring size should I pick? 44T has the most torque, but I'd like to have some speed for the rest of the commute (or if I go for a separate joyride).
- Can I get away with a 48V battery, or is 52V necessary for the hill? Is 11.6 Ah enough (Ultra Slim), or should I spring for more (Mini Shark or Jumbo Shark)?
- Are gear sensors really necessary? Seems like a gimmick, but I don't want to break a chain.

Thanks in advance!

 

[Dewey]

Can you provide more information about your bike, how old, model name, gearing type, etc. In general yes even vintage Raleigh bikes can be converted, but to give you better stopping power there are options, for example my wife and I have two 1973 Raleigh Sports 3-speed Sturmey IGH pedal bikes I have not converted to an ebike, on mine I had my bike shop rebuild both wheels with Sun CR18 aluminum 26" rims and keeping the original Raleigh hub due to the proprietary hub width sizing, the shop also fit Kool Stop Salmon brake pads, the result is not only is the bike lighter but it stops much better, and should cost around $250 per wheel depending on your bike shops labor costs, you may only need the front wheel done as most of your braking power will be on the front. I would recommend fitting an ebrake sensor to the front brake lever.

A gearsensor is not manadatory, you can pause pedalling to stop the motor, or fit a kill switch, I had my shop fit a gearsensor as I have a Nexus 8 IGH which is a bit fragile, I've heard the Sturmey 3-speed IGH are stronger particularly in 2nd gear which is the direct drive 1:1 gear. Shimano recommend a 2:1 gear ratio so I run a 42t chainring front, 21t sprocket rear. I don't know what the Sturmey needs but I expect you can fit a bigger chainring on your stronger Sturmey 3 IGH

 

[Deacon Blues]

I've been mulling over the idea of converting my old 1990 Kona commuter bike to an ebike, but it has rim brakes, which (I think) may not give me enough stopping power.

With the added weight, added power, and precious cargo I'd recommend starting with a bike that has disc brakes. It's a personal decision. Some will say braking on your converting your present bike with rim brakes will be fine. If it was me, I wouldn't do it.

 

[indianajo]

I lift 340 lb gross up 15% grades with a 500 w mac12 geared hub motor. 3 of those & 74 other hills on my 30 mile commute to summer camp. I carry food & ag supplies out there from town on the cargo bike left. No chain wearing mid drive required. No welding, everything was bolt on. Grades of that pitch that last an hour can burn a geared hub motor, but in 3.5 miles you don't have enough time. My motor is 48 v, but most geared hub motor vendors have moved to 36 v only. Probably too many warrenty replacements in Califonia & Oregon, where 90% of the electric bike sales are. And lots of 10% 15 mile grades are.
Old Sturmey archer 3 speed IGH was direct, 1:2, 1:3. No torque multiplying speeds. I have owned 2 from the UK days. New ones from taiwan are different.
Different pads help rim brakes in the dry, but after you run through a puddle all bets are off. I hit a car in the rain that ran the 4 way stop, after I stopped & restarted. 2 mph? I've hated rim brakes since being forced into them in 1966 by theft of my 2 speed bendix coaster brake bike, but now you can buy disk brakes. I have the cable pull 160 mm tektros, they stop fine down 15% with 340 lb. 5" brake handles that come with geared hub motor kits help the force problem caused by the 3.5" handles they sell cable pull brakes with. Hydraulic disk brakes are a big fad now, solve the force problem but require much more difficult maintenance at pad replacement time. I adjust my pads ~1000 miles, takes 2 minutes with an allen wrench.
Really, a used disk brake bike off craigslist is probably better than converting a rim brake survivor. Will have modern crank too, instead one of 4 possible crank designs on old bikes that are not supported by the mid-drive kits.

 

[RunForTheHills]

I think that it would be a shame to convert a collectable vintage Raleigh. I have a 1974 International (the copper color) and I would never do that to the bike, although I have updated it with modern components. I never had the original campy components as my Dad built it for me from a frame when I went away to college around 1981 with spare parts he had lying around. Rim brakes are fine unless you are riding really fast (like 30MPH +). And even then they are probably fine. If you are comfortable stopping the bike from 20-25MPH without a motor, it will be the same with a motor. You could switch to Kool Stop pads and give yourself more time to stop if it is raining.

You have a short commute and could get away with a smaller battery, but I would get a 52V jumbo shark. 48V will work fine also and will run the motor at just a slightly slower speed than the 52V.

 

[RunForTheHills]

Really, a used disk brake bike off craigslist is probably better than converting a rim brake survivor. Will have modern crank too, instead one of 4 possible crank designs on old bikes that are not supported by the mid-drive kits.

That is a good point. The older Raleighs with cottered cranks used a non-standard 26tpi threading on the bottom bracket. The higher end Raleighs had a 68mm 24tpi (BSA) bottom bracket.

 

[harryS]

Piece of cake, except it's easier on a comfort or mountain style bike made after 2000, The brake levers and throttle will fit better on upright bars, rather than dropped bars. Otherwise, you have to buy the brake sensor and glue them onto the road bike levers. Unless you go crazy towing your kids in torrential rain at mid drive speeds, rim brakes are fine.

I used to tow my grand daughter with an Instep trailer using a BBS02 powered department store Diamondback. Could probably tow 2x her weight, but would have to drive defensively. If you're already towing then, you know,

Don't need a lot of battery for a 15 mile range.

 

[Dewey]

That is a good point. The older Raleighs with cottered cranks used a non-standard 26tpi threading on the bottom bracket. The higher end Raleighs had a 68mm 24tpi (BSA) bottom bracket.

I thought that might be a problem too until recently someone reminded me you don't use the threading as the motor slides into the bottom bracket, here's a photo of a 1951 Raleigh DL converted with a BBS01

 

[Dewey]

Here's my 1973 Raleigh Sports after the rim/brake pad upgrade towing a trailer. There is just enough thread on the left axle to fit the Thule/Chariot hitch cup

 

[cdb5]

Can you provide more information about your bike, how old, model name, gearing type, etc.

Sorry all, I meant 'old' as in 'not new,' not as in 'vintage collectible.' It's a Cadent 1.0 from 2006. Gear is SRAM PG850 8-speed (12-26t). I love it since I biked coast-to-coast on it. But it's not anything special & it would be more useful to me now in this capacity.

Crank should be compatible with the kit, right? It's listed as Truvativ ISO Flow Road.

The brake levers and throttle will fit better on upright bars, rather than dropped bars. Otherwise, you have to buy the brake sensor and glue them onto the road bike levers.

Hadn't thought about the difficulty of mounting throttle/brake sensors on dropbars with the road bike levers. But it's possible, right -- just annoying?

So sounds like rim brakes aren't ideal, but okay, as long as I steer clear of foul weather. My understanding is that it would be expensive to convert to disc brakes. I appreciate that a used bike with disc brakes would be better in theory, but hard to beat the price of $0 for the one I already own.

Thanks for the reccs on batteries.

I lift 340 lb gross up 15% grades with a 500 w mac12 geared hub motor.

Indianajo, you must have insane quads. I tried a RadMission w/ 500W hub motor (I know their specs are trash, but still) and couldn't make it up without an insane workout. The hub motor just doesn't have enough torque at those low wheel RPMs.

 

[Dewey]

Crank should be compatible with the kit, right? It's listed as Truvativ ISO Flow Road.

No, the kit will come with square taper aluminum crank arms that deform easily on the steel motor spindle, also you will be converting your drivetrain to a 1x. I wanted to go down to 42t so I replaced the kit chainring with a Luna chainring adapter for 104bcd chainrings, and the Bafang crank arms with a steel unicycle crankset because steel is real - although folk on other forums recommend the Shimano Steps FC-e6000 square taper crank arms.

 

[RunForTheHills]

The Grin motor simulator is fun to play with to try different battery and motor combinations. You have to choose the "Show All" option at the bottom of the motor list to choose the BBSO2 motor.

https://ebikes.ca/tools/simulator.html

 

[indianajo]

Indianajo, you must have insane quads. I tried a RadMission w/ 500W hub motor (I know their specs are trash, but still) and couldn't make it up without an insane workout. The hub motor just doesn't have enough torque at those low wheel RPMs.

The 500 w Mac12 will start 340 lb on a 15% grade with no help. Will pull up to 8 mph without help. The previous $221 ebikeling 1300 w geared hubmotor would start 340 lb without help and pull up to 6 mph without help. I can pedal that weight up without power in 32:28 although I have 32:32 available. I only weigh 160-170 lb. BTW the $221 hubmotor wore out at 4500 miles, 2 1/2 years. Took me 2 afternoons to convert over, since the luna controller could not be mounted where the ebikeling controller was, under the seat. Still using the first $630 luna battery, no problems in 3 1/3 years.
Rad has been known for playing games with wattage specs.

 

[cdb5]

Still using the first $630 luna battery, no problems in 3 1/3 years.

Seems like Luna has a solid rep on these boards. Is there a significant advantage to them over Bafang USA Direct? Their website suggests their version of the BBS02 is different/better, but it's hard for me to tell whether any of those differences matter for a rookie like me. Prices aren't that far apart, although they're out of stock of the BBS02 at the moment.

 

[Dewey]

Seems like Luna has a solid rep on these boards. Is there a significant advantage to them over Bafang USA Direct? Their website suggests their version of the BBS02 is different/better, but it's hard for me to tell whether any of those differences matter for a rookie like me. Prices aren't that far apart, although they're out of stock of the BBS02 at the moment.

Another forum member whose opinion I trust posted a response from Bafang on another thread ‘Bafang USA Direct’ have no connection to Bafang. In 2016 I bought my battery from Luna and it’s still keeping a charge 5 years on, I bought my BBS01 motor from California Ebike and have had good parts support from them, battery and motor are connected with crimp on Anderson connectors I bought from Grin Tech.

 

[indianajo]

Seems like Luna has a solid rep on these boards. Is there a significant advantage to them over Bafang USA Direct?

Last time I checked luna had dropped support of 48 v products, emphasizing the high speed 52 v line. I don't ride at high speeds and probably would be happy with a 36 v product. They have also frequently not stocked normal width tire power wheels, keeping a line of fat tires power wheels, in which I am also not interested. The management is still okay, but they make their money on exotic almost motorcycle products. I don't know who else is a US based reliable source of batteries. Ebikeling has whole kits sometimes, but his products are rather low end. My power wheel from him lasted ~4500 miles before plastic gears wore out. I tried to buy a Mac12 power wheel from electricbikes.com in 2018 at $200 over Luna, and he cancelled my order because we have hills in Indiana. He accused me of running a pedicab service because my load with supplies is 340 lb. In 2018 Luna had the Mac12 front wheel kit, but not anymore.
Many here will direct you outside the USA, for those that wish to spread their debit card numbers & bank details around the planet on servers not covered by the FBI fraud rules.

 

[WattsUpDude]

paging @PedalUma

 

[tomjasz]

Their website suggests their version of the BBS02 is different/better,

Luna has made all sorts of exaggerated claims over the years. Every reseller has the same BBS02B motors. Try calling your prospective sources. Who responds in a timely fashion? Installing a kit won’t damage a frame or vintage frame.

 

[PedalUma]

@WattsUpDude!
I have been off EBR for a while because I have been working on a lot of bikes. Some cool stuff. I think I just pulled off the cleanest 1Kw HD build to date. It is not stealthy but it is not a rat's nest either and it is solid.

For my rim brake bikes I always use 945mm brake pads. These double the surface area and can lock up if needed.

 

[tomjasz]

Road bikes are very fast even with BBS02.

HACKED BBS02. Not an off-the-shelf motor. And don't expect a long service life.