Simple but relatively expensive BBS02 fat bike solution

[Ade]

I wanted an all weather commuting bike to be used summer and winter even in the snow - I live several Km up a mountain. So I bought one of these http://www.nakamura.no/portfolio/big-bob-4-0/ , ordered a fat bike modified Bafang BBS02 from Doug at http://california-ebike.com/ and a 48v 10Ah Battery pack with Samsung 25R cells from Custom Ebikes http://www.custom-ebikes.com/48v-samsung-25r-cell-high-power-10ah-battery-pack/. I also got custom full fenders from Big O http://stores.bigomfg.com/fender-kits/. Doug was nice enough to throw in a chainring adapter and some brake sensors I could use on the hydraulic brakes too.

There are some issues with the chain line on the 9 speed - it was a dual chain ring bike but I took off the granny in favour of the 36t - so the effective number of gears is now is probably 7. I haven't tested the lowest 2 gears in earnest though so perhaps they can be used; time will tell.

I used bullet connectors to attach the battery to the motor - for weather proofing, I first painted the connections with liquid tape, then shrink tubing and finally I sealed the shrink tubing with liquid tape. All the other connections look water tight to me - the display and the throttle are a concern but what's there to do about them besides bagging them?

I've been otherwise occupied so the bike has had light testing so far but first impressions are, "Awesome!"

 

[Jrmnet]

N'ice build! I'm hoping to put together something similar with my fatbike. The expense of the modified BBS02 is what's been holding me back for now.
Did you include PAS?
When you get a chance to get some more miles in, I'd be interested to hear what type of range you are getting with rides that include hills. Also, is the shifting smooth?

 

[litespeed]

Bike looks excellent and should serve you well.

Tom

 

[Ade]

N'ice build! I'm hoping to put together something similar with my fatbike. The expense of the modified BBS02 is what's been holding me back for now.
Did you include PAS?
When you get a chance to get some more miles in, I'd be interested to hear what type of range you are getting with rides that include hills. Also, is the shifting smooth?

By PAS I guess you mean the speed sensor? If so, yes, I don't see any reason not to have it and if you don't, the console doesn't work. One problem is the wheel build is asymmetric so the distance between the chainstay and spokes is quite large as the wheels are 102mm wide - the sensor is only just long enough at its greatest extension. Of course worse case you could place something between the sensor and chainstay to get the length. The default PAS settings were 3 assist levels and that's too little IMO - 9 is too much though so I settled on 5.

Also, the BBS02 that I received allows the throttle to work in assist mode 0 which is very nice - that would have been the main reason I would have built a programming cable but I'll not bother to now.

One of the biggest pita was to fix the brake sensor magnet. There is only one spot that works well and there's no nice way to attach the magnet there - so, it's currently attached with double sided tape. LOL. I'm thinking of gluing it with JB Weld instead which will be a neater finish. Oh, and routing the cables took me forever as I was trying to get the neatest look.

I wish, and I guess I'm not alone, Bafang would provide greater options in terms of chain rings though - it's a pity that using the adapter messes with the chain line so much.

Biggest surprises so far are;
- How much torque the motor seems to generate - going up hill at 30kph without peddling on a 23kg bike with wheels like this is something else and is extremely grin-worthy.
- How abruptly the power kicks in in PAS mode. It's not very subtle. I thought I would be able to set the assist mode to some level and forget it more or less but I found myself turning it to 0 and using the throttle when I wanted much finer control.

First real commute to work tomorrow so I will see how the battery holds up - it still shows full bars on its first charge even with all my playing around.

 

[Ade]

Also, is the shifting smooth?

Missed this - well, it shifts, kinda loudly. It seems smooth enough though but I haven't stressed it yet and I certainly haven't shifted into the two largest sprockets under power as the chain line is so extreme. I will report more with use - the main problem could be shifting under power going up steep hills. There's always the brake lever to cut power before shifting though as that cuts power way before the brakes kick in.

 

[Jrmnet]

Yes, I meant the speed sensor for the PAS, glad to hear that PAS works even if the power transition isn't subtle. That hill comment is what I hope to get out if the BBS02. Enjoy, and let us know how a full commute to work turns out.

 

[Warren]

In my experience, with motor running through the gears, shifting into bigger cogs under power will eventually bust the quick link. No problem shifting under power into smaller cogs though.

 

[Ade]

In my experience, with motor running through the gears, shifting into bigger cogs under power will eventually bust the quick link. No problem shifting under power into smaller cogs though.

Good to know.

 

[Ade]

Yes, I meant the speed sensor for the PAS, glad to hear that PAS works even if the power transition isn't subtle. That hill comment is what I hope to get out if the BBS02. Enjoy, and let us know how a full commute to work turns out.

Okay, well, I've been riding to work all week now and I was kinda disappointed to find out that the distance is only 4.2km one way (according to the trip computer). I guess it's the long, steep bada$$ hill that's at least half of it that makes it seem soooo much longer without power assistance.

But, the BBS02 takes that 2 and half km hill from hell without breaking a sweat even without peddling - 20 to 30kph up there no problem. It eats into the battery but still not as much as I'd feared. Starting from a full charge, after yesterdays's round trip and into work this morning, the battery is still better than 80% charged - but I have 25R cells remember so I guess that helps with the power draw on that hill.

I'm wondering if the 36T chaingring I have on is even necessary - perhaps I should switch it out with the stock chainring and test - it'll at least improve the chain line.

Had a tumble this morning though - lots and lots of black ice on the road and my tires, although a silica winter compound, just weren't enough at one point. The slide ripped my waterproofs and bent a peddle, not to mention bruised my leg. I've ordered a pair of tires with studs now which will hopefully arrive in a few days.

Even with all the nasty weather we've been having here - it's not real winter here this year, no snow, freezing fog, lots of rain freezing on the road so lots of ice, and it feels damp and chilly rather than the crisp sub zero temps we usually have - it's still very cool and incredibly fun to ride an ebike to work. 8)

 

[Ykick]

Yes, I meant the speed sensor for the PAS, glad to hear that PAS works even if the power transition isn't subtle. That hill comment is what I hope to get out if the BBS02. Enjoy, and let us know how a full commute to work turns out.

Okay, well, I've been riding to work all week now and I was kinda disappointed to find out that the distance is only 4.2km one way (according to the trip computer). I guess it's the long, steep bada$$ hill that's at least half of it that makes it seem soooo much longer without power assistance.

But, the BBS02 takes that 2 and half km hill from hell without breaking a sweat even without peddling - 20 to 30kph up there no problem. It eats into the battery but still not as much as I'd feared. Starting from a full charge, after yesterdays's round trip and into work this morning, the battery is still better than 80% charged - but I have 25R cells remember so I guess that helps with the power draw on that hill.

I'm wondering if the 36T chaingring I have on is even necessary - perhaps I should switch it out with the stock chainring and test - it'll at least improve the chain line.

Had a tumble this morning though - lots and lots of black ice on the road and my tires, although a silica winter compound, just weren't enough at one point. The slide ripped my waterproofs and bent a peddle, not to mention bruised my leg. I've ordered a pair of tires with studs now which will hopefully arrive in a few days.

Even with all the nasty weather we've been having here - it's not real winter here this year, no snow, freezing fog, lots of rain freezing on the road so lots of ice, and it feels damp and chilly rather than the crisp sub zero temps we usually have - it's still very cool and incredibly fun to ride an ebike to work. 8)

Thanks for your helpful thread. Yeah, even when I don't feel much like going to work, anticipation of the ride always tends to motivate me out of laze-ass mode.

 

[Jrmnet]

Bummer about the fall. Glad to see it gets you up that hill and that you are enjoying the ride.

 

[Ade]

Bummer about the fall. Glad to see it gets you up that hill and that you are enjoying the ride.

Yeah, I could have done without that. Until then I was amazed at how these vee snowshoe tires were managing with the icy conditions without studs - not one slip in 3 days, not even a little. But I guess it only takes one time...

I took off the turvativ downhill pedals I had on my other bike and they feel great on the ebike - much better than the little el-cheapo pedals that came with it and I don't think they will bend in a fall either.

I was a bit confused on the battery readout on the Bafang yesterday - near the top of the hill it started to show about 20% charge then when the load lightened up, the indicator went back to 60% or so. Is this normal?

 

[--freeride--]

Nice bike.

Please show som pics of your adapter where you can see the offset between the motor and the Chainring.
I made my own adapter and if you do that right, the chainline with a 36T is just about 3.2mm more outside than with the stock chainring. With a 38T up front you can reduce it to 2.4mm

I allthoug threw out the 11T in the back and moved the hole chassette out with a spacer on the inside. Those little improvments help to get the chainline right and I am shure you could use all gears.

The 11T any way won't last long with the big wheels and a BBS pulling the chain, so why keep it.

 

[leelorr]

I have been waiting (and waiting) for Bafang to come out with an adapter kit or different model for the Fatbike 100mm BB's for quite a while. I know about the $550 ($499 plus $50 tool rental plus shipping both ways?) adapter that you used, but have been hesitant to pull the trigger because of the price. Now that "Bikes Direct" has a new Fatbike with the Bluto front suspension fork for a reasonable price I am getting frustrated with the fact that there has been no clean, reasonably priced way to put the BBS02 on a Fatbike. Like the previous poster, I would love to see more details and photos of the problem you ran into with the chain line, etc.

Thanks,
leelorr

 

[Ade]

I have been waiting (and waiting) for Bafang to come out with an adapter kit or different model for the Fatbike 100mm BB's for quite a while. I know about the $550 ($499 plus $50 tool rental plus shipping both ways?) adapter that you used, but have been hesitant to pull the trigger because of the price. Now that "Bikes Direct" has a new Fatbike with the Bluto front suspension fork for a reasonable price I am getting frustrated with the fact that there has been no clean, reasonably priced way to put the BBS02 on a Fatbike. Like the previous poster, I would love to see more details and photos of the problem you ran into with the chain line, etc.

Thanks,
leelorr

Actually, I bought the ready made, fully converted 100mm BBS02 not the new kit made to modify a BBS02 - not that it makes much difference as the end result is the same, just one is more work. The adapter I mentioned is a chainring adapter so I could use the existing 36T chainring not the 48T chainring that comes with the BBS02. The problem is that the BBS02 chainring is dished so the teeth are closer to the bottom bracket compared to a normal chainring that you can fit with the adapter. Freeride below says this difference should only be a few mm - that surprises me as I remember the dishing on the stock chainring to be more than that but I could be wrong and I will check tomorrow. I'll also take some pictures so you can see.

Nice bike.

Please show som pics of your adapter where you can see the offset between the motor and the Chainring.
I made my own adapter and if you do that right, the chainline with a 36T is just about 3.2mm more outside than with the stock chainring. With a 38T up front you can reduce it to 2.4mm

I allthoug threw out the 11T in the back and moved the hole chassette out with a spacer on the inside. Those little improvments help to get the chainline right and I am shure you could use all gears.

The 11T any way won't last long with the big wheels and a BBS pulling the chain, so why keep it.

Hm, not sure I'd like to remove the smaller sprockets as I use them most on the flat - in fact, with the 36T chainring I've not felt the need to use any of the 3 larger sprockets even on my steep hill climb home.

One thing I noticed today as I was putting the bike away was what looks like a torn rubber washer starting to be pushed out from the left crank shaft - pretty weird as I can't remember fitting one of them in there when I put on the retaining bolts. I wonder if it's somehow worked its way out from inside the motor housing. I haven't had a chance to look at it properly but it's a little worrying. I'll check it out more tomorrow when I get a chance.

 

[Ade]

So here's the chainline - the picture form the top doesn't look too bad in the photo but it doesn't do it justice - the one taken from underneath shows it a little more clearly.

 

[--freeride--]

Thanks for your pics, thats what I thounght, your chainring is sitting at the outside of the adapter.

My adapter is made so that you put the Chainring on the Inside and have spacers to adjust the chainline the way you just about clear the plastik gearcover with the chainring bolts:

Here is a picture with two spacers liing on the adapter:


Here is my chainline with a 38T one spacer mounted up front:


With a 38T you need to grind a little bit of the nose of the Plastic Cover and get the tidest chainline. A 36T might just about fit if you grind more away or you use two Spacers without grinding.

On your pictrues I allthough seen that there is space between the right chainstay and your motor housing. I would recommend you take out the motor, go to a good bikeshop(check before if the got the tools) and let them mile down the right side of your BB housing by 5mm. (The frame could still be used with some spacers and the stock bb) Your motor is going to be more centered and has a better chainline.

You get at leased another 5mm with a adapter that is made like mine. This way you gain 10mm in the chainline and everything is perfekt

 

[Ade]

Thanks for your pics, thats what I thounght, your chainring is sitting at the outside of the adapter.

My adapter is made so that you put the Chainring on the Inside and have spacers to adjust the chainline the way you just about clear the plastik gearcover with the chainring bolts:

Here is a picture with two spacers liing on the adapter:
[snip]

Here is my chainline with a 38T one spacer mounted up front:
[snip]

With a 38T you need to grind a little bit of the nose of the Plastic Cover and get the tidest chainline. A 36T might just about fit if you grind more away or you use two Spacers without grinding.

On your pictrues I allthough seen that there is space between the right chainstay and your motor housing. I would recommend you take out the motor, go to a good bikeshop(check before if the got the tools) and let them mile down the right side of your BB housing by 5mm. (The frame could still be used with some spacers and the stock bb) Your motor is going to be more centered and has a better chainline.

You get at leased another 5mm with a adapter that is made like mine. This way you gain 10mm in the chainline and everything is perfekt

Ah, that's a lot of effort to try to use 3 sprockets I don't use. Thanks for the ideas though - maybe I'll take another look at the adapter and see what can be done.

One worry I have now is this broken washer that's working itself out from the crank axle;


I've asked Doug at California e-bike if it'll be an issue - I just hope it's not intended to stop water to getting in and rusting everything up. The salt on the roads here at the moment is awful and the BBS has some surface rust starting on the exterior nuts and bolts already. :|

 

[--freeride--]

Have a look if you can mount your chainring to the inside of your adapter, if that is to tide, put one washer under each screw and so on untill it fitts. that will improove things and does not cost anything

I saw that rubber seel come of on other pictures befor, that might be a standard BBS problem. So ask california-ebikes what to do, they definitly mounted that part.

Without it there could be dirt going straight into the needlebearings and distroy it.

 

[Ade]

Have a look if you can mount your chainring to the inside of your adapter, if that is to tide, put one washer under each screw and so on untill it fitts. that will improove things and does not cost anything

I saw that rubber seel come of on other pictures befor, that might be a standard BBS problem. So ask california-ebikes what to do, they definitly mounted that part.

Without it there could be dirt going straight into the needlebearings and distroy it.

Doug got back to me and said it's a dust shield for the needle bearings and I should just make a new one out of soft plastic or rubber. I'll see if I can get the time this weekend - I probably have some old silicone something or other around I can use.

I pretty sure I tried it to mount the chainring the other way when I was putting it all together but I will check it out again when I have a chance - life and 2 year old kids have a habit of limiting my spare time these days though.

Oh, and if anyone is interested, the Dillinger 4 studded tires I put on have been great - no more falls or even slips even on wet ice. Fantastic purchase even if they cost a silly amount of money for a bit of rubber.

 

[--freeride--]

You need to put washers between the adapter and the motor, to get the adapter a little out, then you can fit the chainring on the inside. with one set(5) of washers the chainring will fit, but the chain will rub and grind on the nose of the plastik cover, grind 1,5mm of the nose of the plastik cover and everything will fit.

 

[Ade]

You need to put washers between the adapter and the motor, to get the adapter a little out, then you can fit the chainring on the inside. with one set(5) of washers the chainring will fit, but the chain will rub and grind on the nose of the plastik cover, grind 1,5mm of the nose of the plastik cover and everything will fit.

In case you've missed this;
http://endless-sphere.com/forums/viewtopic.php?f=31&t=65946

Quite cool solution even if it's 42T I thin it may be okay for me as it'll fix my chain line and allow my to use my larger sprockets.

 

[--freeride--]

You are right, some Italiens made a similar one. But 42T is to big for me (you could easily hit 35miles with 42T/11T) and it is expensive.
Putting some washers under your adapter and flipping the Chainring to the other side is no big deal and will do the job...

If you are not planing to climb steep grades at low speed, then go with the 42T und throw the smaller gears in the back out(11-12T), that will help to make your drivetrain more durable. The bigger the Chainrings and sprockets you use, the less chain force you have that is wearing your chain and sprockets.

With a 100$ chainring I really recommend to have a chaincaliber, a worn chain will kill your chainring and thats not cool.

 

[Ade]

You are right, some Italiens made a similar one. But 42T is to big for me (you could easily hit 35miles with 42T/11T) and it is expensive.
Putting some washers under your adapter and flipping the Chainring to the other side is no big deal and will do the job...

If you are not planing to climb steep grades at low speed, then go with the 42T und throw the smaller gears in the back out(11-12T), that will help to make your drivetrain more durable. The bigger the Chainrings and sprockets you use, the less chain force you have that is wearing your chain and sprockets.

With a 100$ chainring I really recommend to have a chaincaliber, a worn chain will kill your chainring and thats not cool.

So, after several incidents - slipping in/out of gear and twice losing the chain altogether, I've ordered the 42T bling ring from em3ev ($80) which will correct my chain line and hopefully help with the chain coming off as it's purportedly a narrow/wide design. I've also ordered a KMC X9E e-bike chain which will help with chain wear I hope. I'm looking around for a simple chain tensioner too.

These rutted winter roads are a major PITA and I've come to the conclusion that heavy, deep porridge-like snow that's thrown off snowploughs is not just a PITA for cars - especially at junctions!

 

[--freeride--]

Get a damped derailleur, the narrow wide is opimized for 10speed so i don't think it helps a lot with 9 Speed...

although the e Bike chain is just for getting some more Money for exaktly the same thing.

A German MTB Magazine did some testing where they tried diffrend chains and shimano was by far the best. I would recomend a Shimano XT 93 with hardened bolts.

The Salt in the snow is the problem that kills your drivedrain.

What would help a lot is to keep the Saltwater away from your drivedrain. I run a long Budflap on the front fender, that is nearly at the ground. So my feet stay dry and there is less spray that goes on the chain. You could although build a shield or somthing that covers the chain from the water and mud that the rear tires throws on top...