Help needed from those who have fitted the 8fun front wheel motor

[jackhandy]

Hi,
I want to 'lectify my Carrera Kraken mtb: It's fitted with XC (Suntour?) suspension forks (It's a few years old), which have 100mm between dropouts, but the fork legs above the dropouts have 90mm clearance.

8fun uk have replied to my query that they don't think the motor will fit without fouling the forks.

If any of you could check your installation against the attached pictures of my forks, I'd be most grateful: I'd like confirmation before I start researching all over again!

If opinion is that it will fit, should I need to go to a larger disc?

Thanks in advance

Pete

 

[amigafan2003]

What model Bafang?

There are some measurements here:-

QSWXK
http://bmsbattery.com/327-503-thickbox/qswxk-front-drive-brushless-hub-motor-for-ebike.jpg

Looks like it wil fit - you could always grind a little off the hub if it rubs on the left (left looking at the pic - right isyou're looking at it from the saddle ).

 

[Cyclezee]

Hi Pete,

An eZee motor would fit http://www.ebikes.ca/store/diagrams/MeZeeF.pdf

The Mk1 kit is currently on offer for £675

 

[JuicyBike]

Do your forks have fittings available for V Brakes? If so, you can use the QSWXB motor from Bafang (like we provide with our kits). See this diagram

 

[jackhandy]

What model Bafang?

There are some measurements here:-

QSWXK
http://bmsbattery.com/327-503-thickbox/qswxk-front-drive-brushless-hub-motor-for-ebike.jpg

Looks like it wil fit - you could always grind a little off the hub if it rubs on the left (left looking at the pic - right isyou're looking at it from the saddle ).

Yuss - That's the one (QSWXK), at least that's what 8fun's kit description says: It says it's the latest model, so maybe I can get away with it

It does look promising - I'd be grateful if anyone that's fitted one could confirm it.

Trouble is - Once I get started with the angle-grinder, I tends to "just nip a tad more off..... Ooer", and I'll be looking for lots of slopes to ride across, to level-up the bike!

Pete

 

[jackhandy]

Hi Pete,

An eZee motor would fit http://www.ebikes.ca/store/diagrams/MeZeeF.pdf

The Mk1 kit is currently on offer for £675

(Sharp-intake-of-breath).... Yes, I'd like be able to spend a bit more John, but funds is tight just now - One reason for biking a bit more

 

[jackhandy]

Do your forks have fittings available for V Brakes? If so, you can use the QSWXB motor from Bafang (like we provide with our kits). See this diagram

Yes, there are v-brake fittings, so that's a possibility.

I'd rather set my sights on the bottle battery, as I could manage a spare, but I'll have to go with what's feasible.

 

[jackhandy]

What model Bafang?

There are some measurements here:-

QSWXK
http://bmsbattery.com/327-503-thickbox/qswxk-front-drive-brushless-hub-motor-for-ebike.jpg

Looks like it wil fit - you could always grind a little off the hub if it rubs on the left (left looking at the pic - right isyou're looking at it from the saddle ).

I've got the bike on its back & done some further measuring:



Before going further - Can we establish Right & Left as: Bike right-way-up; viewed from the saddle: This makes the motor cable in the drawing exit by the r/h fork...?

The dotted forks in the Bafang drawing are pretty much exactly as mine are: The r/h side should clear OK. The l/h side is possibly an interference fit

The motor body section I've marked red scales @ about 50mm. diameter: My photo shows this will just, probably, contact the fork body above the dropout. (allowing 20mm from the top of the axle aperture).

1: Does this bit rotate?
2: How much clearance should be enough?
3: Can I safely grind this off the fork body? I'm assuming there's thick metal in that shoulder?

As before, I'll be grateful for any help & advice,

Pete

 

[amigafan2003]

Before going further - Can we establish Right & Left as: Bike right-way-up; viewed from the saddle: This makes the motor cable in the drawing exit by the r/h fork...?

Cable exits the LH side (if viewed from the saddle) - same side as the disc mount.

1: Does this bit rotate?

Yes.

2: How much clearance should be enough?

Can you see day light? Yes? Then it's enough I'll take a photo of the clearance on my Tongxin and carbon forks.

3: Can I safely grind this off the fork body? I'm assuming there's thick metal in that shoulder?

No! Grind it off the hub!

 

[chain]

If any of you could check your installation against the attached pictures of my forks, I'd be most grateful: I'd like confirmation before I start researching all over again!
PeteView attachment 3901View attachment 3902

Pictorial essay of fitting the kit you're discussing. Scroll down to the photo with the red background for the relationship of the hub to the fork, and use the dimensions on the same page to measure and get a scale. Building an electric bike 1: ELECTRIC MOTOR CHOICES FOR PEDELECS by Andre Jute

Andre Jute

 

[RedXair]

Hi Pete,

I fitted the 8fun kit to my Carrera Kraken a few weeks ago, the front wheel fitted ok although the clearence is very close I did not need to change my disc which is the standard one fitted (160mm I think).

All in all it was fairly easy to install with a few tweaks here I had to make a new hole in the battery holder as this did not line correctly with the bottle holder holes on the frame, the only problem I have is that I can not use the largest chainwheel on my crankset as with the pedelec sensor installed it seems the front deraileur will not push the chain over enough but I can live with this at the min but will eventually take it to a bike shop and see if they can figure a solution. I have attached a pic below.

I'm very happy with the kit so far for the money paid.

Good luck.

Martin

 

[jackhandy]

Pictorial essay of fitting the kit you're discussing. Scroll down to the photo with the red background for the relationship of the hub to the fork, and use the dimensions on the same page to measure and get a scale. Building an electric bike 1: ELECTRIC MOTOR CHOICES FOR PEDELECS by Andre Jute

Andre Jute

Thanks for taking the time to help-out, Andre: I had, in fact, read your essay but....

I'm getting more confused the further I go into this:

Your drawing is of a very different motor to the drawing Amigafan found on the BMS website, although both are labelled as QSWXK. I can't find a dimensioned drawing on the 8fun uk website, so I'll email them to confirm what actually comes with the current kit.

It looks unlikely I'll be able to keep the disk brake, so I'll just replace it with a V.

I may even have to replace the forks, although I don't know with what yet - All the suspension forks I've seen in the local bike shops look very similar to mine (I haven't had the nerve to get out the rule yet)

Pete

 

[chain]

It looks unlikely I'll be able to keep the disk brake, so I'll just replace it with a V.

I may even have to replace the forks, although I don't know with what yet - All the suspension forks I've seen in the local bike shops look very similar to mine (I haven't had the nerve to get out the rule yet)

Pete

Might be smart to buy the kit and see how it fits or not before you lash out on a fork. I found when I had the components to hand, a millimetre appeared magically on all sides, more than the most careful measurements from drawings indicated. It was just enough to make a comfortable rather than a paint-wrecking fit. Enough is as good as a mile.

If you like disc brakes, and your fork will take the forces, you could just go to a larger size disc. The cost is the larger disc and an extension for the calliper mount.

It might be worth asking 8FUN in the UK if they have any of the special, thin callipers that BMS advertised last year, which are no longer on their netsite. I haven't tried them, or even seen them in the metal, but from the advertising text it seemed that they were designed to solve this very problem of fat motors with 160mm disc brakes in 100mm forks. And they were cheap, at least at BMS, under £17 for a complete kit.

I note that the makers of my Utopia Kranich, a known-strong bike, object strongly to fitting brake discs larger than 160mm. There's a good reason for not fitting too large a disc to a steel fork unless it is specially designed for the purpose or strengthened for the stress.

Andre Jute

 

[jackhandy]

Hi Pete,

I fitted the 8fun kit to my Carrera Kraken a few weeks ago, the front wheel fitted ok although the clearence is very close I did not need to change my disc which is the standard one fitted (160mm I think).

Thanks, Martin, that's just the job

My Kraken is a bit older than yours & has the older XC forks: Could you tell me which model forks you have, so I'll know what to look for if mine are no go?

Thanks again,

Pete

 

[jackhandy]

Might be smart to buy the kit and see how it fits or not before you lash out on a fork. I found when I had the components to hand, a millimetre appeared magically on all sides, more than the most careful measurements from drawings indicated. It was just enough to make a comfortable rather than a paint-wrecking fit. Enough is as good as a mile.

It might be worth asking 8FUN in the UK if they have any of the special, thin callipers that BMS advertised last year, which are no longer on their netsite. I haven't tried them, or even seen them in the metal, but from the advertising text it seemed that they were designed to solve this very problem of fat motors with 160mm disc brakes in 100mm forks. And they were cheap, at least at BMS, under £17 for a complete kit.

Thanks again Andre - The more advice I get before taking the plunge, the better - I LIKE informed advice

8Fun uk are going to be glad when I finally buy the damn kit & stop asking awkward questions! But I'll get one ordered now that I know it will fit, one way or another.

Pete