jrickards

My wife has a Specialized Myka 29er (hard tail) that she loves because it fits her and it took many bikes to find this one, a few years back. She would now like an ebike but, living in a smaller city, there aren't a lot of choices and none of them were as comfortable fitting as her 29er. Therefore, I suggested we convert her bike and she's happy with that.

I actually started looking at this last year but with COVID, I stopped. However, what I found was a nice 29er conversion kit but it turns out that the company has since gone belly up. I'm now having difficulty finding one and the more I look, the more confused I'm getting.

One tricky item about her bike that the previously found kit accommodated is that the top tube is very low, so low in fact that the small front triangle has only space and mounts for a single water bottle and the only cage and bottle that works is a side-loading cage and a 500ml bottle. The ebike kit I found last year came with a rear rack (double decker) where the battery sits in the lower level. A triangle mounted battery won't fit, even if we removed the bottle and cage.

Ignore whether or not a kit is difficult to install, I'm quite fine with handing that duty off to my local bike shop.

It was a rear wheel conversion kit but I don't know if front wheel or "chainring style" are better. Likely, my wife will never travel more than 30km at a time so that might affect the motor and battery options. Our city can have hills in a few areas and she's about 200lb/90kg (but consistently dropping these last few years and she's continuing to make progress, congrats honey!)

What can you recommend? Front/chainring/rear style? Motor wattage? Battery capacity? I think the finished kit should have a double decker rack, even if the rack is bought separately, as she plans to commute with the bike and will need access to the rack.

I think it should be pedal assist but if it is also a throttle (not throttle only), I'm fine with that.

Finally, we live in Canada.

Thanks

2old

Lots of options, but will the bike be used in hilly areas? If so, a mid-drive is the best option IMO. If not, look at Swytch (I don't like handlebar bags (in this case fro batteries). Otherwise Luna has an attachment system that would permit the battery to be installed in many places on the bike or purchase a rear rack and mount the battery there. The photo shows where I mounted a battery on my daughter's bike and works well for her.

2old

2nd photo shows a rear rack with a rectangular battery, but other types could be mounted there. The battery, which was insulated from vibration with dense foam and strapped on, didn't exhibit any bad characteristics in the five years it powered this 1000w, 52V system or a BBS02 mid-drive off road. Procured a larger battery and gave it away. I had mounted the battery in numerous places on the bike; surprisingly, it handled best (and perfectly) in this configuration even though having a massive rear weight bias.

creativepart

I converted my 2018 Specialized Crosstrail Sport Disc with a hubdrive kit from Dillenger Bikes. It was an easy one day project. The kit cost $750 and had every part I needed - except the Dillenger kit required a Freewheel and the Specialized came with a Cassette/Freehub so I couldn't move it from the donor bike to the electric. Also the Specialized has a disc brake rotor that is a center mount style and the Dillenger wheel uses a disc brake rotor that affixes with screws. Both were minor items that cost less than $40 for both combined.

It works great and I'm happy with the bike. I've put over 600 miles on it since the conversion in January.

A Mid-Drive might be even easier to convert as you use the Specialized wheel in stock form. Mid-Drive kits cost a bit more and are just as easy to convert but you need a few special bike tools to remove the crankset and bottom bracket of your donor bike.

As to battery mounting. You can put it below the downtube and use hose clamps to hold the battery mount to the tube. Like this:

Chuckles1

Make sure a mid-drive will fit your bike before buying a kit. I wanted to do a mid-drive, but both candidate bikes had too wide chainstays that would have precluded proper fitting of mid-drive. I put a geared rear hub drive on instead, and enjoy it. There are threads on the forum and on endless-sphere.com about chainstay interference and required clearances.

2old

^^^ Good point; with the large seat stays in the bottom bracket area, good chance for interference. Also, probably 73 mm bottom bracket which doesn't permit use of the "jam" nut on a BBS02, so adds to the complexity IMO.

Doc_Wui

I converted a bike 5 years ago to a Bafang BBS02 48V 750W middrive. I hadn't ridden it for two years and recently started using it regularly. I had forgotten how nice it is to have a bike with quick release wheels front and rear. as I have been changing tires on my hubmotor bikes. The hubmotors have 17mm nuts and often have torque washers.

In addition when converting a bike, the controller in a Bafang is inside the motor, so there is no need tp figure out where to put a box on the frame, dress up wires, and make it look presentable. While more and more hub motor kits are moving to plug-n-play connectors, some of the kits are a distressing jumble of connectors to sort out. In contrast, a bafang is fairly quick to wire.

Luna has the potted batteries which might work, although they are 52V and I believe the latest Bafang motors are quite touchy about going that high.


Diamondback Wildwood with BBS02.

Looking down at the chain line.

2old

Mine worked well too, but on a steel frame. The battery is on the downtube now secured magnetically.

Riveting

Not sure if it checks all your boxes, but I had great success with this conversion kit: Hilltopper Conversion Kit

linberl

Things to also consider with conversion: (1) final weight of the bike, if you have to lift or carry it or pedal it without juice, (2) front hubs aren't great if you are doing a lot of hill climbing but rear hubs work okay as do mid-drives, (3) try to stick with non-proprietary builds or companies that have been around a relatively long time, (4) try to find one with a fairly standard battery connection or one that can be adapted easily so when you replace the batteries you're not stuck if the original supplier is history.