Help deciding gears / brakes - Bafang 750 Cargo

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Moustachemiks   1 mW

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Help deciding gears / brakes - Bafang 750 Cargo

Post by Moustachemiks » Jul 26 2021 11:37am

Hi all,

So I've went through a lot of thinking in relation to designing my new cargo long john bike. However, I've come to a crossroad (again), where I'd appreciate all the input from experienced builders that I can get.

Info:
Long John cargo bike
Bafang 750W
20" front wheel
26" rear wheel

So, I'm deciding on gears & brakes and have spoken to a few bike mechanics in the process. As of now, I'm torn between getting an internal hubs with roller brakes, an internal hub with disc brakes or external gears with disc brakes. A bike mechanic advised me to get disc brakes, since traveling on a cargo bike with roller brakes will increase my break distance greatly compared to disc brakes. Also, the bafang 750W goes above the legal EU limitation, hence, he thought it might be a good idea to not take any chances in that regard. I agree with this, however, let's list the pros and cons to give you some insight to my thought process.

Pros & Cons from what i've gathered:

Internal hub with rollerbrakes:
Pro:
- Easy maintenance
- Cheapest option
- Can buy a complete rear wheel
Con:
- Brakes are not as powerful as disc brakes.

Internal hub with disc brakes:
Pro:
- Easy maintenance
- Best break potential
Con:
- Expensive and can't buy a complete wheel, hence need someone to build it.
- Cost half of IH with rollerbrakes

External hub with disc brakes:
Pro:
- Cheaper than internal hub with disc brakes.
- Still more powerful than roller brakes.
Con:
- Higher maintenance
- I read a lot of people have issues with chain line and changing gears? i.e. lowering number of gears.

What I'm currently looking at in relation to internal hubs are;
Nexus 8 speed w/ disc: https://bike.shimano.com/en-EU/product/ ... 00-8D.html
Nexus 7 speed w/ roller: https://www.bike24.com/p2285613.html

I'm really into the idea of getting disc brakes, but perhaps some of you can tell me it's a bad idea or advise for an alternative - or simply tell me that it's the only right solution :bigthumb:

RunForTheHills   100 W

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by RunForTheHills » Jul 26 2021 12:33pm

While IGHs are great, a regular derailleur with a cassette is easier to service than an IGH. You just need a couple of inexpensive tools and a few minutes to replace the cassette. Also, Shimano makes an ebike specific IGH. It is expensive, but might hold up better to the stress of a Bafang motor on a cargo bike.

https://bike.shimano.com/en-EU/product/ ... 00-5D.html

I agree that disc brakes are a better idea than roller brakes, particularly on a heavy cargo bike.

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MoneyPit   100 mW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by MoneyPit » Jul 26 2021 3:44pm

So I assume when you say the motor is a "Bafang 750w" that means a BBS02 limited to 750w? Not a 750w hub. And since 750w is considered to be a lot, necessitating "stronger" brakes to rein in all that power, you must be in the EU?

I would ONLY consider disc brakes in your application. In part I would make that recommendation regardless for any ebike, but in this specific case I also have my own frontloader/long john that I ride daily.

I found I needed to make the fronts kinder/gentler (lockups on a frontloader are entertaining to passersby) so I used 2-pc comfort pads in the front and my usual 4-pc sport pads in the back (Magura MT5e's). Also I used extra thick downhill rotors (Tektro Type 17's) as they'll live longer and happier despite getting their ass beat slowing down a 400+ lb bike.

Image

If you are riding a Bafang mid drive, Then unless you are doing a bunch of extra work, you'll be using a 1x up front. I am as well and I opted for an 11s in the back. Specifically a Sunrace CSMS7 11-46 cluster which is steel cogs on a steel spider. Underneath that, a DT350 hub with ratchet engagement. Pretty much indestructible even at the higher power levels I am running in the USA. Derailleur and shifters are SRAM GX.

I don't need all those gears. I use the bike in flat country and I'm more interested in having the gears I want in a proper position to allow a straight chain line from my one front chainring, which is an offset Lekkie 52T. That overly large and inset chainring makes me stay off the bottom three cogs and start my riding on #4, which thanks to the front offset is still a little outboard on the fourth cog in. I use the next three inboard and thats pretty much as far as I want to go on my bike, which has a very tight/short rear triangle (its a Bullitt). I would use more cogs but I am cheating in a way as I also have a front hub motor that makes the bike AWD. That further reduces the number of gear changes I need to contemplate. So if no AWD I would be using one more gear down, and one more up, for a total of six.

https://talesontwowheels.com/2021/04/14 ... itt-cargo/

I would not use an IGH with a mid drive unless it was a Rohloff or a Kindernay since they are known to for-sure handle the torque that Bafang metes out (especially in a cargo bike application). And since those cost ransom... no IGH for me. I did give it strong consideration as the Bullitt has the frame cutouts for a belt drive, and a Rohloff with a belt would be sweet. But thats $2000 in parts when all is said and done.

The SRAM shifts like butter. Perfect alignment every time. Keep it simple and go with a derailleur.
Image

Moustachemiks   1 mW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by Moustachemiks » Jul 26 2021 5:43pm

MoneyPit wrote:
Jul 26 2021 3:44pm
So I assume when you say the motor is a "Bafang 750w" that means a BBS02 limited to 750w? Not a 750w hub. And since 750w is considered to be a lot, necessitating "stronger" brakes to rein in all that power, you must be in the EU?

I would ONLY consider disc brakes in your application. In part I would make that recommendation regardless for any ebike, but in this specific case I also have my own frontloader/long john that I ride daily.

I found I needed to make the fronts kinder/gentler (lockups on a frontloader are entertaining to passersby) so I used 2-pc comfort pads in the front and my usual 4-pc sport pads in the back (Magura MT5e's). Also I used extra thick downhill rotors (Tektro Type 17's) as they'll live longer and happier despite getting their ass beat slowing down a 400+ lb bike.

Image

If you are riding a Bafang mid drive, Then unless you are doing a bunch of extra work, you'll be using a 1x up front. I am as well and I opted for an 11s in the back. Specifically a Sunrace CSMS7 11-46 cluster which is steel cogs on a steel spider. Underneath that, a DT350 hub with ratchet engagement. Pretty much indestructible even at the higher power levels I am running in the USA. Derailleur and shifters are SRAM GX.

I don't need all those gears. I use the bike in flat country and I'm more interested in having the gears I want in a proper position to allow a straight chain line from my one front chainring, which is an offset Lekkie 52T. That overly large and inset chainring makes me stay off the bottom three cogs and start my riding on #4, which thanks to the front offset is still a little outboard on the fourth cog in. I use the next three inboard and thats pretty much as far as I want to go on my bike, which has a very tight/short rear triangle (its a Bullitt). I would use more cogs but I am cheating in a way as I also have a front hub motor that makes the bike AWD. That further reduces the number of gear changes I need to contemplate. So if no AWD I would be using one more gear down, and one more up, for a total of six.

https://talesontwowheels.com/2021/04/14 ... itt-cargo/

I would not use an IGH with a mid drive unless it was a Rohloff or a Kindernay since they are known to for-sure handle the torque that Bafang metes out (especially in a cargo bike application). And since those cost ransom... no IGH for me. I did give it strong consideration as the Bullitt has the frame cutouts for a belt drive, and a Rohloff with a belt would be sweet. But thats $2000 in parts when all is said and done.

The SRAM shifts like butter. Perfect alignment every time. Keep it simple and go with a derailleur.
Image
That is awesome advice! Thanks a lot. I am indeed in EU (Denmark) and The Bafang is indeed a BBS02.

This definitely has made me consider a a SRAM setup. It would be such a shame to ruin an IGH due to torque. It’s late here, so the research will continue tomorrow. I hope it’s alright if I get back to you with a few more questions in regards to your setup, once I’ve done my homework on the sram? :-)

Cheers!

Moustachemiks   1 mW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by Moustachemiks » Jul 27 2021 2:29am

MoneyPit wrote:
Jul 26 2021 3:44pm

I found I needed to make the fronts kinder/gentler (lockups on a frontloader are entertaining to passersby) so I used 2-pc comfort pads in the front and my usual 4-pc sport pads in the back (Magura MT5e's). Also I used extra thick downhill rotors (Tektro Type 17's) as they'll live longer and happier despite getting their ass beat slowing down a 400+ lb bike.

Image

If you are riding a Bafang mid drive, Then unless you are doing a bunch of extra work, you'll be using a 1x up front. I am as well and I opted for an 11s in the back. Specifically a Sunrace CSMS7 11-46 cluster which is steel cogs on a steel spider. Underneath that, a DT350 hub with ratchet engagement. Pretty much indestructible even at the higher power levels I am running in the USA. Derailleur and shifters are SRAM GX.

The SRAM shifts like butter. Perfect alignment every time. Keep it simple and go with a derailleur.
Image

The more I look into it, I really like your setup.

I think I might opt to go for the SRAM derailleur, the 52t and the sundance cassette, however, I am pushing my budget a bit by doing so. I don’t believe you spared any expense on your gear and I wish I could do the same 😉

Can you link to the SRAM derailleur? Is it type 2,1?

Do you have any recommendations to something similar to the DT350/rear wheel and the disc brakes (Magura MT5s). I would still like to go for the Tektro 17s break disc on the rear and front like you.

Would any of these wheels in the lower price class suit my needs? Sorry if I’m asking too much 🙈

https://www.bike-discount.de/en/shop/wheel-26-507

One again, thanks for the input! :)

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Chalo   100 GW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by Chalo » Jul 27 2021 12:00pm

Enviolo is another internally geared hub that can accept BBS02 power without problems.

If I were in your situation, and I already owned the BBS02, I'd go for an 8-speed cassette hub so the sprockets would be resistant to bending and consumables as cheap as possible. In a flat landscape, 11-32 or 11-34 gearing should give more than enough range. There are 11-40 (SunRace) and 12-42 (Microshift) 8-speed options available if that works better for you.

If I didn't already own the BBS02, I'd use a front hub motor instead. The small front wheel of a long john bike lets a hub motor perform its best, and separating the motor drive from the pedal drive allows you to choose whatever gears and brakes work best for you.
This is to express my gratitude to Justin of Grin Technologies for his extraordinary measures to save this forum for the benefit of all.

eMark   10 kW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by eMark » Jul 27 2021 1:39pm

Chalo wrote:
Jul 27 2021 12:00pm
If I didn't already own the BBS02, I'd use a front hub motor instead. The small front wheel of a long john bike lets a hub motor perform its best, and separating the motor drive from the pedal drive allows you to choose whatever gears and brakes work best for you.
Finally someone having something good to say about a front hub motor :thumb:

I've got over 3,000 miles on my cargo trike with its 20" front wheel and 750W hub motor. Would like to think that my 750W hub motor is just getting broke in after 3,095 miles. It should outlive most mid-drives considering it's only being powered by a 22A controller and either a 10S3P or 10S5P battery.

Opps: meant to say 16" instead of 20" ... wish it was 20" so i could cruise at 15mph instead of 12mph
Last edited by eMark on Jul 27 2021 2:23pm, edited 1 time in total.

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MoneyPit   100 mW

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Re: Help deciding gears / brakes - Bafang 750 Cargo

Post by MoneyPit » Jul 27 2021 2:17pm

Moustachemiks wrote:
Jul 27 2021 2:29am

I think I might opt to go for the SRAM derailleur, the 52t and the sundance cassette, however, I am pushing my budget a bit by doing so. I don’t believe you spared any expense on your gear and I wish I could do the same 😉
Remember the 52T is specifically there as part of an overall assessment of chain alignment, my frame, my routes and knowing my desired cadence. in a vacuum, 52T on a Bafang mid is too big even on flat ground. It will bog a 30a BBSHD and it certainly will bog any BBS02. BUT the Lekkie chainring insets the chain by quite a bit, and on this bike that means my straight chain line is well into my cluster, so for a straight or near-straight chain line with a Lekkie's 42T+ offset I am 4-7 cogs in and I'm spinning - unless I go up to 52T and then cadence on PAS is perfect at the effort level I want.

I have several chainrings for the BBSHD (Luna Eclipse and Lekkie in multiple sizes each) and a 103 BCD adapter as well so I took the time to experiment quite a bit thanks to having all those parts available. The 52T ring was my third or fourth refinement about a month into taking the bike onto the road.

You should budget in some experimentation on this front as well.
Moustachemiks wrote:
Jul 27 2021 2:29am
Can you link to the SRAM derailleur? Is it type 2,1?
Yup. Not because I felt a need for a clutch. As you know parts aren't the easiest to come by right now and that one was available. And yeah this was a bucket-list bike and I built it frame-up to be all it can be.

But if you are in Denmark, you need 3-4 gears, tops. If possible look at a SRAM 9-spd. I have a couple of those on other builds and they are great. I prefer SRAM because the shifters allow more choices for throttles and knicknacks on the handlebars vs. Shimano or even Microshift shifters. But if thats not an issue for you, a Shimano RD-M591 is what I have used in the past for 9 spd and they are flawless. For 9 spd all the parts are cheaper too. If 9 spd you can use a steel 1-pc HG-400 cluster for durability. I like the nickel-plated 12-30's as 11T on a single-motor bike is too small (bogs the motor, again). 9 spd KMC 'e' chain with nickel finish is nowhere near as expensive as any quality 11s chain.
Moustachemiks wrote:
Jul 27 2021 2:29am
Do you have any recommendations to something similar to the DT350/rear wheel and the disc brakes (Magura MT5s). I would still like to go for the Tektro 17s break disc on the rear and front like you.
ZTTO hubs on AliExpress have the DT ratchet engagement mech (supposedly the patent ran out but they may just be chinesing it and doing a shameless copy) which is so good for a mid drive, and they are relatively inexpensive. I can't vouch for their quality level personally but I have heard good things from people who have used them. I would ask around here to see what people say about them.

I have bought MT5's from bike-discount.de before cheap. Also Ebay has takeoffs from a bike shop on occasion. Especially German bike shops. You don't need the cutoffs although they are very nice. But you cannot use the Type 17 rotors on normal brake calipers as they are too thick. They only work on tektro calipers meant for them and the Maguras that are made for 2.1mm rotors. You can get away with the 2.3mm Tektros on Magura calipers barely. I use Maguras on all my bikes, so I can swap in a set of half-worn pads from one bike onto one with new rotors and that works. Then by the time the pads are worn down, that rotor is worn just a bit and will work with new pads.
Moustachemiks wrote:
Jul 27 2021 2:29am
Would any of these wheels in the lower price class suit my needs?
I don't have a clue about these. I use built wheels on my bikes and I spec all the bits on them. You want strong hoops and quality spokes for a cargo application. 36H if you can but not necessary if you go hi quality across the board. I have used Sunringle MTX39's on my 26" 'normal wheel' builds and really like them. Not expensive but not easy to get hold of anymore. Spokes on one were DT Alpines which are astronomically priced but worked great (mid tail cargo application). On the frontloader discussed here they were Sapim Strongs which are plenty good for what you want. Both used brass nipples. Both used DT 350 Hybrid hubs cuz they are beefed up all around and come with steel cassette bodies. Do NOT use Chinese XL single-gauge spokes that are super stiff. I broke this rule on my front wheel and went 12ga Sapim Leader. Never again. 13ga tops.

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