Almost to much information......

[Kevin.Mathers.1970]

Firstly post here, TIA.

I want to convert my wife's 2013 Specialized Vita to electric. It is a hybrid road bike, 9 speed with 700c wheels.

We love to ride together, but my wife has Multiple Sclerosis and the biggest affected area is her lower body. Riding any distance more than 8-10 miles is a struggle and takes days to recover from.

Specs
Rider weight ~210
Distance desired, 30 miles
Speed, avg 16 mph

What I "know" I want.
Rear wheel drive
Pedal sensing assist
Rear rack battery
Some type of display and assist level control
Throttle, in case she doesn't want to pedal.

My capabilities:

20 + years as a mechanical technician
Build my own wheels
Rebuild my bike with no issues.
My LBS calls me when he can't figure something out


There are just to many options to figure out what is the best set up for my wife.......

Help, please....

 

[jonathan75]

Firstly post here, TIA.

I want to convert my wife's 2013 Specialized Vita to electric. It is a hybrid road bike, 9 speed with 700c wheels.

We love to ride together, but my wife has Multiple Sclerosis and the biggest affected area is her lower body. Riding any distance more than 8-10 miles is a struggle and takes days to recover from.

Specs
Rider weight ~210
Distance desired, 30 miles
Speed, avg 16 mph

What I "know" I want.
Rear wheel drive
Pedal sensing assist
Rear rack battery
Some type of display and assist level control
Throttle, in case she doesn't want to pedal.

My capabilities:

20 + years as a mechanical technician
Build my own wheels
Rebuild my bike with no issues.
My LBS calls me when he can't figure something out


There are just to many options to figure out what is the best set up for my wife.......

Help, please....

The Oxydrive 13ah kit would tick all those boxes except for the rear battery (it's a bottle type). Its motor is very powerful. If you would be prepared to make do with front wheel drive the Woosh BPM kit might suit, albeit bottle battery again. If you wanted to reduce prices right down, you could order a rear BPM 350w, spokes, and your controller/display/PAS/brakes or HWBS (depending on if your gear shifters are integrated)/from chinese firms greenebikekit or bmsbattery, or elifebike - but I've heard mixed things about their batteries and it might be safer to buy the latter from the UK. Eclipsebikes do the cheapest quality batteries I'm aware of although bottle again. Or a Xiongda 2-speed motor direct from the company, they do a kit with the controller/display/pas etc for about £160 incl shipping, although it does require stretching the rear forks a little I gather.

 

[Deleted member 4366]

There's loads of options and they all work. Every time I look somewhere, I see another new kit supplier. It's easier to cross some off the list than put any on, so we can start with the big 500w/750w/1000w direct drive motors. They're very heavy and need big heavy batteries. They're only really suitable for constant high speed riding. Out of the rest, it depends whether you want support from the supplier or not and whether you're too bothered about weight. Then you need to consider the speed of the motor. 201 rpm = 15 mph in a 26" wheel. You have to do your sums for anything else. Nearly all the kits with LCDs give the posibility to set the maximum speed to 25km/h regardless of motor speed, but no point in having a 3o mph motor limited to 15mph. It'll be too inefficient. You have to choose one with a max speed just a bit more than what you want to travel at for best efficiency.

Why does it have to be a rack battery when downtube ones are much easier to fit and balance the bike better?

 

[Kevin.Mathers.1970]

The front forks are carbon, and not designed to take the fore and aft stress. I just assumed that a rack battery would be more apt to give my wife the 30 mile range.

 

[Deleted member 4366]

The for and aft force on the forks will be the same wherever you put the the battery. The downtube is always a good location as long as it's not carbon fibre too. You can get both 36v and 38v downtube batteries with 500wh capacity.

https://bmsbattery.com/ebike-battery/682-36v145ah-bottle-09-panasonic-battery-charger-battery.html

There's loads of places you can get them from - even some in UK.