Kit options for Fat Bike

[tezdread]

Hey,

I've been looking for a kit for a fat bike that has a 120mm Bottom Bracket and 4" tyres but I don't seem to be able to find one. The wheel hubs are approx 6".

Ideally I guess would be a mid drive kit would be best but are they available for 120mm BB's? I've searched Google with various phrases but I can't find one and searching these forums doesn't give me anything either?

I'm thinking mid drive but if there are hub options that would work well then that would be fine.

Any help appreciated.
Thanks

 

[Cyclezee]

Hi Tezdread,

eZee have their own electric fat bike called the e-Rex and as the eZee suppliers for the UK we stock the same electrics in retro fit kit form as used on the e-Rex.

 

[Deleted member 4366]

Hey,

I've been looking for a kit for a fat bike that has a 120mm Bottom Bracket

What do you mean by that? What does the 120mm relate to?

 

[Cyclezee]

I guess Tezdread means the overall length of the BB rather than the width of the shell in which case we are talking 68mm.

 

[tezdread]

Hey,

Have I been looking at the BB sizes in the wrong way?

I first looked at the 8-Fun BBS01 CD Kit and it says "bikes with standard 64/68mm bottom bracket" so I measured the width of the BB by the crank arm and it's about 40mm, so thought they must mean the length from one side of the bike to the other and on 2 of my bikes, it's about 68mm, on the fatty it's about 120mm.

Hi John, I didn't see that bike on your site! Would it be easy enough to have the motor on the rear wheel and would it fit my wheel? Also would I be able to use my current battery with this kit?

This bike is strictly for off-road use and I would like something with a bit more power\speed for getting up the hills than what is road legal. Cycling up a muddy hill on this bike is damn hard work (and usually a walk!) but the ride down is really good and it kinda glides over mud patches that would normally get me well stuck.

As I already have the woosh front wheel hub motor on my work bike, and the fatty won't be used much I was thinking that a good option would be to use the battery that I currently have, for both bikes. If the 8-Fun BBS01 CD Kit would fit this bike, it seems like it's the best (and cheapest) option.

Thanks

 

[Cyclezee]

Hey,

Have I been looking at the BB sizes in the wrong way?

I first looked at the 8-Fun BBS01 CD Kit and it says "bikes with standard 64/68mm bottom bracket" so I measured the width of the BB by the crank arm and it's about 40mm, so thought they must mean the length from one side of the bike to the other and on 2 of my bikes, it's about 68mm, on the fatty it's about 120mm.

Hi John, I didn't see that bike on your site! Would it be easy enough to have the motor on the rear wheel and would it fit my wheel? Also would I be able to use my current battery with this kit?

This bike is strictly for off-road use and I would like something with a bit more power\speed for getting up the hills than what is road legal. Cycling up a muddy hill on this bike is damn hard work (and usually a walk!) but the ride down is really good and it kinda glides over mud patches that would normally get me well stuck.

As I already have the woosh front wheel hub motor on my work bike, and the fatty won't be used much I was thinking that a good option would be to use the battery that I currently have, for both bikes. If the 8-Fun BBS01 CD Kit would fit this bike, it seems like it's the best (and cheapest) option.

Thanks

The eZee e-Rex isn't on our website because it isn't in production yet.
We could supply a front or rear eZee kit and build the motor into the wheel supplied with a fat bike or supply a compatible one and if it is for off road use only it could be unrestricted 500w.

 

[tezdread]

Cheers John, just reading the fotboy prototype thread

Yup the 500w would be desirable and to have the motor built in to the current back wheel.

I'll post in the other thread any questions about that.

Where do you get the 68mm measurement from?

 

[Cyclezee]

If the total length of the bottom bracket is 120mm then the BB shell should be 68mm wide.

It is important to note that for a front eZee motor the dropouts need to be 100mm +/- 5mm and for a rear the dropouts 135mm +/- 5mm.

 

[tezdread]

A rough measurement of the dropouts puts them at about 150mm front and 180mm rear. I thought that this would be a problem for hub motors.

If the BB shell is 68mm, then it would seem that the mid drive options would work just fine. Is that correct?

 

[trex]

the BBS01 is the easiest kit to fit.

 

[tezdread]

the BBS01 is the easiest kit to fit.

That's what I was thinking but I didn't understand about the bottom bracket shell. It would also be compatible with my current battery, making it a fairly cheap conversion and for a bike that would only be used about 60 times a year (unless we have crazy snow over longer periods) that makes sense to me.

 

[Deleted member 4366]

Why don't you measure the BB shell with a rule? Then you'll know how long it is.

 

[tezdread]

Why don't you measure the BB shell with a rule? Then you'll know how long it is.

Because I would have to buy the tools and do it But I guess that's the best way and I do need to know before buying anything.

 

[Geebee]

All you need is a ruler to measure the BB.
If you want to spend a lot of money there is a BBS02 120mm conversion available http://california-ebike.com/product/bafang-fatbike-mid-drive-bbs-02-ebike-conversion-kit/

 

[tezdread]

Oh boy....In my second post I explained that I'd measured my other bikes and they had 68mm BB's...some confusion.

So as it is, my fat bike has a 120mm BB. I don't know what size the BB shell is and won't until I buy the tool(s) and take it apart and measure it. I don't know anything about BB's other than what I've looked at in 10 mins but having a 68mm shell in a 120mm BB seems odd and you can buy fat bike BB's and cranks that have 120mm BB's.

http://www.ebay.com/itm/Fat-Bike-Crankset-36-22T-170mm-Arm-Length-120mm-Bottom-Bracket-/131309813179

Anyhow, this

http://california-ebike.com/product/bafang-fatbike-mid-drive-bbs-02-ebike-conversion-kit/

is for a 100mm BB not a 120mm

Taking a better look at the contents of the BBS-0x kits, both the standard one on the woosh site and the one on the above site, my dumb guess is that none of them will work.

"This Bafang “Fatbike” Mid Drive consists of a modified Bafang BBS-02 drive with an extended axle to accommodate the installation on a bike with a 100mm bottom bracket." http://california-ebike.com/

It's in the axle right?

 

[Deleted member 4366]

You don't need any tools to measure the BB shell - just a ruler or tape measure. You don't have to dismantle anything. The length of the BB spindle is not important at this stage. You're getting confused between the BB shell and the BB spindle. The one in your link is for a 100mm shell. How long is your shell?

 

[tezdread]

Looking at the picture posted by Geebee, this is the first thing I measured. It is 120mm, as originally posted.

When it was mentioned that the shell was 68mm, I did a google images search and saw an inner metal sleeve so thought that it was being suggested that the shell could be smaller than the space in the frame that houses the BB.

It now looks like you're talking about the BB area on the frame....correct?

If so, it is 120mm (not including the crank arms)

 

[Cyclezee]

Hi Tezdread,

Can you give details of the bike in question, i.e. make, model, link to manufactrers website and if possible upload some photos.

 

[Cyclezee]

Is it by any chance one of these http://www.gooutdoors.co.uk/coyote-fatman-fat-bike-black-p328471 ?
Coincidentally I was in the local store yesterday while my wife was looking at the clothing and had a brief look at one.
The Coyote Fatman weighs 22Kg before you start adding electrics.
If anyone is interested we could supply them, but couldn't really sell for much less than Go Outdoors.

Here are some more photos.

 

[tezdread]

Hi John, it looks very similar but it's the fatfish bike from argos. Will post up link n pics when I get home.

Would a kit fit those from gooutdoors?