Giant Revive, planning a mid motor conversion

[Gazz]

Hi all,

First post here, i'm based in Nottingham, England, and have only just got back into cycling after discovering a style of bike i can actually ride for more than 5 minutes without being in severe pain,

That bike is a giant revive semi recumbent bike, it's a bit of a heavy beast, and i also pull a trailer for my dog to ride in when she gets tired, but i love the riding position with the crank forward and backrest seat, having back and joint problems, i just couldn't ride an upright bike anymore.

The version i have is the N7 as above, which has a 7 speed nexus rear hub, the chain runs in the swing arm, 48T chainwheel, chain wraps around about 80% of the chainwheel, bottom half goes over a tensioner that is just a derailleur sprocket on a spring mounted arm, so the chain return is running about half an inch from the power side of the chain (the return part of the chain is actually in a channel in the bottom of the swing arm)

Giant did make an electric version of this bike, mounting a panasonic motor behind the BB,i'm not sure exactly how it drove the bike, no photo's i can find of one with the plastic covers off.

Anyway, my plan is to mount a motor just behind the BB on the swing arm, and have the drive sprocket engage the chain where the tensioner used to, freewheel crank set, and 12x 15AH lifepo4 cells stuffed down the top tube of the frame.
Unfortunately the version of the bike i have has the round seat tube:

and thus prevents me using all the length of the top tube internally, as the seat tube goes thru the top tube, but i rekon i'll still have enough room, if not, i can always do a flat pack for rear rack mounting.

Has anyone ever done this kind of conversion before? i'm imagining a cyclone style motor would be best, or maybe the GNG V2,

I will only be using this bike to help me get fitter, going for rides with my GF and the dog (GF has a Raleigh pioneer 2, probably go for a hub motor in that) so 15-20 mph max is more than adequate for me, would prefer range over speed,
Road/cycle path and pretty well made off road cycle trails are my planned use, moderate hills i rekon.
i'm thinking maybe a 350 watt motor??
The bike has 20" wheels, i'm in the process of fitting an 18T rear sprocket and high pressure rear tyre (hence i've used photo's found on the net, will take my own photo's of the bike when it's back together)

I weigh 115 kilos, the bike stock is about 24 kilo's, dog trailer is prolly 10 kilos, and the dog is 30 kilos, so around 170 kg/375LBS!!! all up weight before adding electric bits.

Please feel free to pick my plans to bits and point out glaring errors (weight being the biggest issue i think)

 

[Gab]

Hi

I think the most compact and hence likely to fit under your bike on the swing arm and direct on the chain as you say is the Cyclone type kits, and the new AFT kits being the better quality version of the cyclone ones, but I think you may have to make up your own mounting to suit that unusual swing arm size .

So is your chain hanging down low or inside the frame ? if it's inside the frame that could get tricky to put the motor under the bottom bracket.

300w is not a lot of power for 170kg load, you may need more power, in any case a mid drive will definitely get the most out of the low power compared to a hub motor.

 

[Gazz]

Thanks for the reply, here's a photo of the 'rig':

The dog (a cross collie, shaved for summer) should weigh nearer 20 kilo's, but she's getting on a bit so can't be expected to run along side me for too long, especially if i am cheating with electric assist,

The bike was stored in a barn since it was bought direct from giant with the last of their stock of this model, around 2008, hence a mouse has eaten part of the backrest, and a few bits are missing, front of the chainwheel guard is on bit, but i rekon i'd have to make a new one anyway to cover the motor drive wheel,

A custom motor mount will definitely have to be made up by me,
I imagine i can make something up to go between the shock bottom mount and the spacer piece behind the bottom bracket,

The tape measure is showing the space between the bottom bracket and the rear wheel, quite a bit more than a normal upright bike

This is a view from the side, showing the chain tensioner wheel,


Only the top of the chain runs inside the swing arm, the bottom of it is hidden from view, but is in a channel on the bottom of the arm, so i rekon a motor will have plenty of space to reside somewhere along the swingarm, even if the bottom of the chain has to hang low a little,


The swing arm is 112mm across the outer edges, i think my bottom bracket is a 66mm one, hard to measure accurately with the inner chain wheel guard in place... need to pull the crank to get at the securing bolts, and i don't have a crank puller here,
There is 17mm between in inner face of the pedals and the swing arm, but i think i have to go for wider spaced crank anyway for a freewheel crank?

The top tube is 60mm wide by 80mm high, and is square, and there's about a foot of length from the seat post to where it begins to taper in height for the rear rack, so not sure if i can stuff many batteries down there or not,

Time to get some measurements of motors and batteries i think,

 

[shoalster]

Did you complete your project with your Revive? I noticed that your post is from a year and a half ago .
At any rate, I have a giant revive spirit factory electric bike . I purchased it two weeks ago and I really like it! I had to adjust the chain so I took pictures of the drivetrain . I tried to attach the pictures but they would not attach for some reason .
Before I bought mine I saw an ad for a giant revive with an aftermarket electric upgrade for sale for $650. He claimed that it could top out at over 30 miles per hour. In the picture it looked like it had a mid drive system .

 

[Cowardlyduck]

Sorry for digging up an old thread.

I started a new thread for everyone to discuss Giant Revive conversions in one place.
Giant Revive conversions

Feel free to jump over and update us on your build if you want.

Cheers