Ideal chainwheel, cassette and and chain configuration.

[DodgyTicker]

Hello all, I'm new here and have a few questions.

I'm currently awaiting delivery of a Bafang mid drive kit and was wondering....

The bike that the kit is going is a hybrid with a compact double on the front which will obviously go into storage and a 11-34 ten speed cassette on the back.

My concern is how fragile the 10 speed chain will be and whether it would be worth retrofitting an 8 speed cassette, chain and shifter, stronger in my opinion (but may be wrong). Also if the bike is going to chew through chains and cassettes, an 8 speed setup is a lot cheaper to replace.

Is this worth doing, will I miss the additional 2 cogs, are my worries about 10 speed fragility unfounded?


The kit is arriving with a 44 tooth front and I've been reading about bling rings and chainlines! I've no idea if I need one but they are pretty to look at! I suppose the only way is to fit the kit and see where the chainline ends up?


Grease! I've read that it is worth cleaning out the factory grease off of the reduction gear and replacing it (and some) with Mobil 28 red grease. Is this worth doing?


I'm sure I'll have more questions but thanks in advance for any help or advice.

 

[Raboa]

Hi, I would buy a gear sensor, it is something I wish I had bought when I first got my kit.

After market bbsxx crank drive gear

1. Lekkie bling rings 2. The programming cable 3. The gear shift sensor 4. Eggrider LCD and programmable system 5. Lekkie buzz bars 6. Installation and maintenance tool 7. AeroShell Grease 22 (for final drive regreasing) 8. DPC-14 colour display (the voltage and current reading is a useful...

www.pedelecs.co.uk

 

[vfr400]

Which version Bafang motor is it?

 

[egroover]

I run a 10 speed sram setup on my BBS01, no gear sensor, 2700 miles on the cassette and chain so far in the last year or so, using the stock bafang 46t chainwheel. It clunks a bit when shifting when on full power, but drop the assist level down and its fine. I get the 10spd sram cassette from ebay for about 18 quid, and about 15 quid for the chain

 

[egroover]

forgot to add mine is a hybrid bike, and the cassette is 11-36 and the chainline is good just might have to adjust the derailleur for smooth shifting... offers a good range, but will be switching to a stock 44t bafang soon to give a little better climbing cadence

 

[DodgyTicker]

Thank you all for the replies so far.

In response to the questions you have had in return...

The kit is a BBS01b 250w with a 36v 17ah battery.

I've got both an inline gear sensor and hydraulic brake cut-outs coming with the kit along with a (bafang stock) 44 tooth front chainring, but those bling rings have really caught my eye!

Also, do you think the 44 front / 34 rear will be low enough for moderately steep hills (I don't care about speed, just want to get up them again) and is my chain likely to snap? I'm a big chap at about 120kg but before my latest drugs update and minor heart surgery in early September was a very active, but slow cyclist (despite the heart problems), covering about 2,000 leisure only miles a year.

 

[DodgyTicker]

The other things I've just thought of having pressed the post reply button are;

Clearance between the bottom bracket shell and the motor for the rear cable (the front cable will obviously be coming off) and more importantly the rear hyraulic brake line.

I'd obviously rather not have to re-route and move either of these, do you there will be room?

For reference, it is a 68mm standard square tapered BB setup.

And the grease on the final reduction gear, has anyone done it?

 

[jimriley]

The 11t rear cog will certainly take you above 15.5mph with a 46 front. I have a 34 x 11 x 7speed on mine with bbso1b. when running derestricted (in the grounds of my mansion) it will get to mid 20s mph. Can also cope with hills on normal roads. I'm now considering a 42 tooth rear to keep top speed down and better low gear off road.

 

[egroover]

I'll soon be moving my BBS01 350w to my 26" wheeled MTB. Just ordered a 11-40t rear cassette.

Do you think using the stock Bafang 44T front chainwheel and this new 11-40T on a 26" wheel will get me up hilly off road tracks with a bit of my own effort ?

 

[DodgyTicker]

Some feedback on this having now fitted the kit (almost).

No worries at all with chain alignment on a speed rear cassette (11-34). No chain-offs so far and I didn't even have to re-index the gears.

As to how long lived the chain will be, that remains to be seen.

And... I think the 44 tooth front makes the bike a little bit under geared but hopefully that will be resolved once I buy a programming cable and tweak the 'keep current'.

Thank you all for your help and suggestions.

 

[Deleted member 33385]

Some feedback on this having now fitted the kit (almost).

No worries at all with chain alignment on a speed rear cassette (11-34). No chain-offs so far and I didn't even have to re-index the gears.

As to how long lived the chain will be, that remains to be seen.

And... I think the 44 tooth front makes the bike a little bit under geared but hopefully that will be resolved once I buy a programming cable and tweak the 'keep current'.

Thank you all for your help and suggestions.

I switched out my 44T for a 52T to protect the controller, it really helps on very steep hills. It's best if you maintain at least a 60rpm cadence on hills, apparently:

https://electricbike-blog.com/2015/03/17/programming-the-bbs02-without-frying-your-controller-and-losing-your-sanity/

Who knows? Maybe I'll get a Lekkiewheel:

https://www.brightonebikes.co.uk/store/c11/Lekkie®_Bling_Rings.html

 

[DodgyTicker]

Surely a 52t up from a 44t front will put the controller under more stress with the higher gearing?

Is 60rpm the optimum cadence for the BBS01b ?

I'm still waiting for my cable to arrive and once I've messed about with the settings i'll report back. I have a funny feeling that my current 44t front will be fine once the settings are tweaked as per the links you provided above.

 

[Deleted member 33385]

Surely

"Don't call me Shirley", lol:

52t up from a 44t front will put the controller under more stress with the higher gearing?

Without installing a temperature sensor in the motor contoller, there's no way of monitoring how much stress it is experiencing (is heat produced the best indicator of stress?), and I don't fancy trying to do that quite yet. That being said, my battery indicator drops sharply (recovers on the flat) when the motor is working very hard on hills (setting on the C18 controller), even with 52T driving 32T - it was working even harder at 48T, those 4 extra teeth made a big difference, surprisingly. I don't tend to need much assistance when using the higher gears, and if the C18 battery indicator is any indication, the motor/controller isn't working anywhere nearly as hard - if at all - as it does on hills using lower gearing. I'm too old for 48T or 44T regardless. Call me lazy, I do.

Is 60rpm the optimum cadence for the BBS01b ?

Your guess is as good as mine. As far as I know, there have only been minimal changes from the BBS01. I'm sticking to 60rpm when the motor is under stress, and when it's likelihood is indicated by the battery on the C18 controller.

 

[egroover]

The 44t chainwheel will result in lower gearing, easier to pedal, higher motor cadence, less strain on the motor and you.. you've done the opposite by switching to the 52t chainwheel

 

[Deleted member 33385]

The 44t chainwheel will result in lower gearing, easier to pedal, higher motor cadence, less strain on the motor and you.. you've done the opposite by switching to the 52t chainwheel

I have 44T, 48T and 52T to experiment with - two of them were free (sent later, because he was terrified of my legal threats), because the seller had limited stock to send with the initial kit. For me - it's striking a balance between being able to tackle hills without risking the controller too much, while also being being fast on the straights. I can't be doing with a bike which is much slower than my 80s racer. Right now, with the 52T up front driving 11T, it's quick enough.

 

[egroover]

I have 44T, 48T and 52T to experiment with - two of them were free because the seller had limited stock to send. For me - it's striking a balance between being able to tackle hills without risking the controller too much, while also being being fast on the straights. I can't be doing with a bike which is much slower than my 80s racer. Right now, with the 52T up front driving 11T, it's quick enough.

The faster the motor spins the less stress on it especially on hills. Really struggling to see your logic

 

[Deleted member 33385]

The faster the motor spins the less stress on it especially on hills. Really struggling to see your logic

...but I also need it to be fast on level ground - can't have both. I managed 25.3mph the other night on the flat on PAS 9 (speed limit de-restricted), that's something I'm quite pleased with, but the effort nearly gave me a heart attack. Plus I had a flat front tyre at the time (slow leak). I should manage much faster after I build up my leg muscles, which at the moment resemble both noodles and the utensils the Chinese use to eat them with.

 

[DodgyTicker]

I think I've sussed out the misunderstanding with the gearing has...

And that is wheel size, if the Dahon you ride, with say 20" wheels, a 52t front will not have nearly the same impact as running a 52t on a 700c wheel.

Using the calculator at BikeCalc.com

52f x 11r on a 20" wheel (assumed Dahon wheel size and an assumed 25c tyre) gives 84.17 gear inches.

Whereas on my bike with 700c x 32 tyre 52f x 11r gives 127.75 gear inches.

With that in mind, on a bike with 20" wheels, the 52t front isn't particularly overgeared. To match the 52f x 11r on a 20" a 700c bike would be running at 52f x 17r.

Now inputting what I've got, which is a 44t front with a 10 speed 11-34 rear, my top gear gives 108.03 gear inches which is significantly higher than the top gear on your Dahon.

To match your top gear I'd have to put mine 3 or 4 rear cogs up, 6th or 7th gear out of 10.

I'd conclude that anything less than a 52t front on that Dahon would make un-rideable because the gearing would be so low. Very good for hills though.


I could be wrong and am open to debate.

 

[egroover]

I think I've sussed out the misunderstanding with the gearing has...

And that is wheel size, if the Dahon you ride, with say 20" wheels, a 52t front will not have nearly the same impact as running a 52t on a 700c wheel.

Using the calculator at BikeCalc.com

52f x 11r on a 20" wheel (assumed Dahon wheel size and an assumed 25c tyre) gives 84.17 gear inches.

Whereas on my bike with 700c x 32 tyre 52f x 11r gives 127.75 gear inches.

With that in mind, on a bike with 20" wheels, the 52t front isn't particularly overgeared. To match the 52f x 11r on a 20" a 700c bike would be running at 52f x 17r.

Now inputting what I've got, which is a 44t front with a 10 speed 11-34 rear, my top gear gives 108.03 gear inches which is significantly higher than the top gear on your Dahon.

To match your top gear I'd have to put mine 3 or 4 rear cogs up, 6th or 7th gear out of 10.

I'd conclude that anything less than a 52t front on that Dahon would make un-rideable because the gearing would be so low. Very good for hills though.


I could be wrong and am open to debate.

Ahh yes of course, assumed the bike in question was 26/28 wheel. All makes sense now.

 

[Deleted member 33385]

I could be wrong and am open to debate.

In contrast - I'm like a slimy politician, I'm never ever willing to be wrong! And debate must be ruthlessly suppressed!