Phat rebirth - E-chopper build

[flemrasm]

a long time ago i bought a Phat choach chopper and rode it around for fun, i bought a set of 144 spoke wheels and changed them from single speed to 7 speed

after a while i lost interest in the bike, as i commute daily i got more focused on road bikes and commuters.. i took it apart and kept the bits and pieces..

some time ago i got the idea to rebuild it as an electric assist bike - but since money is short and electric assist kit costs a fortune in denmark, i kinda waited to get lucky on a deal on an used electric bike. last week that luck turned up, unfortunately one of my colleagues who had resently purchased a electric assist bike lent it to her daughter who crashed it into a car at high speed and was severely injured, the bike was damaged beyond repair and she let me have the remains for free
( her daughter is now recovering but still having issues with short term memory due to head injury - even though she was wearing a helmet ) so lucky for me, not so lucky for my colleague and her family

I took the bike apart and the front wheel electric motor and all electrics and battery are unharmed and ready to transfer to my phat - i knew i also wanted gears so this is what i came up with:

this is a sram i-motion 9 speed with disc brake mount, im planning on mounting a sprocket like this
in the disc mount and connecting to a rear hub with disc mount as well

the project will require some cutting and welding and as i dont have these facilities at home the build will probably go on for some time.. i´m thinking of making a chainguard for the front drive, any ideas are wellcome

regards
Flemming

 

[Green-Chain]

Re: Phat rebirth

Hi,

This is a good project, very interesting !!

Do you have a link to find this sprocket ?

this is a sram i-motion 9 speed with disc brake mount, im planning on mounting a sprocket like this
in the disc mount and connecting to a rear hub with disc mount as well

 

[flemrasm]

Re: Phat rebirth

the photo i posted is from velosolo.co.uk, after a bit of searching i found that in US, there is also a company called tomicog, google it and you can find his webpage..

i actually think i´ll try to drill my own( i do not have a big budget for bike parts) and if it turns out bad Í can always resort to buying

i´ll post updates as they happen

regards
Flemming

 

[iven]

Re: Phat rebirth

looks intresting, gonna watch this one

 

[Bicycle808]

Re: Phat rebirth

TomiCogs are hot and StainlesS, but the renthal-made velosolo cogs look nice too, in pictures. Probably going with the velosolo, as i am looking to get a hub from them anyway. (Shimano doesnt sell m756 fronts with 36h/silver in the States... :x )

Flem, that looks way interesting. what hub will you put in back? How bout rear brakes? Cant wait to see how this shapes up...
-rob

 

[flemrasm]

Re: Phat rebirth

hi Rob, i just got back from vacaton, and found a nice package from velosolo in the mail two 18t cogs that will go on the build regarding rear hub..i was planning on using a spaced out shimano front hub with disk mount for the cog, but as im going with a double rim setup ( becourse i dont have the $$ to buy wide rims ) i had to reconsider - as i think setting up V-brakes on double rims can be a bit tricky, so yesterday i took apart two old mtb wheels with disc mount and started making a dual flange rear hub
the front hub

goes in my mini lathe to make sure the cut with the hacksaw is clean

voila

did the same thing to the rear hub, but as they were different dimentions i had to turn it down a bit in the lathe
luckily its aluminium, the lathe is small and old - but it handeled this job good
now both are 29mm and fitting snug together

now is left to see how i will get them joined, i might need to call in a favor from an old colleague..orelse i will go with the alu brazing rods that i cant remember the name of right now
anyways, will post more as the build progresses

regards Flemming

 

[Bicycle808]

Re: Phat rebirth

This build is pretty fascinating. I'll check for updates regularly! Good luck!
-rob

 

[flemrasm]

Re: Phat rebirth

testsetup with the velosolo cogs

on with both and check clearance, it looks like it will just clear all places, ant the chainline is not so bad either

the sram imotion9 is extremely noisy in the high gears, anyone has this hub and can confirm that this is the case
or do i need to service it, its a loud, consistend clicking, i can imagine ill grow tired of this over time, but maby it will dull the noice of the electric front hub

next thing to ponder on is the placement of the battery, i´ve decided it is going on the front side of the seat tube

next thing will be to cut a part of the frame away to make room for the battery, i will weld in a piece of flat iron to form a square where the batteri can be placed
then i will make a support plate for the bottom plastic plate you see here with the batteri connections, i think the rest of the eletrics will be placed in some sort of box behind
the bottom bracket, below the chainstays


also started to think about my 2 rims 1 hub setup, as i do not have the skills to lace up two rims i will have to fixate them somehow, the rear rims are steel, so they will probably be welded
but i thought it´would look cool to make some kind of attachment that would bolt into the unused spokeholes to fixate the rims, maby in the shape of an X or a H, if anyone out there has ideas
pls share..



regards

flemming

 

[flemrasm]

Re: Phat rebirth

a short update - i got tired of waiting for a guy that can weld aluminium, so i came up with a different plan
i turned the two pieces of hub down to fit a 1 1/8 fork spacer, holes on 3 sides, will tap them and put in umbraco screws, i bet that will hold up nicely .. what do you think ?

 

[kingfish254]

Re: Phat rebirth

This thing is wild! gonna be fun to follow!

 

[Bicycle808]

Re: Phat rebirth

Flem,

Looks great; i hope it holds up. Gotta ask: where are you? That lil car in the background looks like a VW polo or somesuch... not something we see in the States too much...

 

[flemrasm]

Re: Phat rebirth

Report this postReply with quoteRe: Phat rebirth
by Bicycle808 on Fri Aug 24, 2012 7:43 pm

Flem,

Looks great; i hope it holds up. Gotta ask: where are you? That lil car in the background looks like a VW polo or somesuch... not something we see in the States too much...

Hi, i think it will hold up, the spokes will take alot of the tention, and the axel will keep it together , this weekend i got the wheels laced up, got the frame welded & decided to change the mid drive hub to a 3sp shimano with rollerbrake, so now im fabricating parts to turn the rollerbrake hub into a disc brake hub..its alot of fun, and i get to play around with the tiny lathe again .. pictures tonight - promise

I´m located in Denmark - where the taxes are high and the cars are small.. the car is a VW golf, a bit larger than a polo, that goes for around 45.000 USD over here

Regards
Flemming

 

[flemrasm]

so, as promised a few progress pics, things are comming along nicely

i got the rear rims welded & laced to the homemade dual disc mount hub..still need to be trued though

the front wheel( dual rim as well ) is also laced up to the motorhub - also needs truing

as i had no means of welding the alu rims, i have made 70 2mm holes around the rims and tied them together with
steelwire ( dont know if thats the correct word), and then spokes from each side of the hub goes to both rims
i have no idea if i can true it, or if it will hold up.. if you have an opinion on this, or a piece of advise, pls share

last weekend i was at a colleagues house and did some work on the frame, we made a bottom plate for the battery base
and got a cage welded in to support the frame where i cut it.. it worked out pretty good i think

bottom plate

support structure

battery in

 

[flemrasm]

i also decided to ditch the I9 hub, its simply too noisy, so now im going with a shimano 3 speed..
that then gives some other challenges as it dose not have a disc mount for my disc cog, rather a rollerbrake
so i´we started fabricating an adaptor, not quite there yet - but a little teaser

started with this..its a display unit that was thrown out in the dumpster at work, the ends are solid aluminum

took them to my mini lathe, made ALOT of alu-scrap

had alot of cutting oil ( for me)

so far i ended up with this

now i´m waiting for monday where i can get to a drill press to make some holes for the disc cog

regards
Flemming

 

[wheelbender6]

Wow. You've done a lot more than bolt on a hub motor and put some batteries on a cargo rack. Not much room in that Phat frame.

 

[flemrasm]

build update, i spend a few days finishing my mid drive with disk mount adaptor, turned out pretty good i think, i got the wheels mounted today
back is dual rim 26x2,35 and front is dual rim 700cx50,
first mockup for a mechanical testride( all electrics besides front wheel motor hasent gone on yet

and also missing another important piece of equipment - brakes

here´s a few pics

chain goes to rear wheel left side

crank to mid drive

view from cockpit

mid drive to rear wheel - chain just clears the battery

front wheel with 700x50 schwalbe big apple tire..

regards
flemming

 

[Endlesschain]

that rear hub is awesome looking,interesting build and its come together better than I thought it would,looks like it was a technical build,I said it before and will say again europeans have a certain style of technical/styleistic way of building

 

[flemrasm]

little Progress has been made, most of the wireing are done, but i messed up some wires, so i had to take it apart again
and i got som safety features installed..

rear disc brake

i have no idea how it will function in wet conditions - it being upsidedown... anybody has any thoughts on that ? will rain be a bigger issue when its sitting as it does ?

i have had some difficulties figuring out the front brake, as i´m using double rims, a normal V-brake cluster from a mountainbike fork will not work, it will pulle the brakes too close to the rims, so roaming my parts stash i came across a bmx stem that i purchased at a flea marked a couple of years ago, the guy said it was oversize, and i thought 31.8mm, but apparently bmx oversize is about 29mm..so i just kept it in a drawer..

i found out that the bar -end of it would fit the fork legs perfect, so i cut them out, drilled and tapped them to accept the V-brake bosses
and voila.. v-brakes on fromt wheel

sorry about the lousy quality..

more updates after the weekend, hopefully after the first testride

regards
Flemming