Bafang BBSHD - advice please

[TommyC]

I’ve just bought myself a Trek Marlin 7 and a 1000w 52v bafang conversion kit to go on it. I’ve done some research and feel I have a pretty good idea of what needs doing. But as a plumber I’m aware that some times a little knowledge is a dangerous thing! So I was just wondering if there was anything in particular I need to consider?

I’ve bought a DM03 display (newer sw102) and 52v 19.2ah battery. Will the standard controller suffice or do I need to upgrade to get the most out of the battery? If I put more power through it do I need to upgrade wiring/connectors?

Finally, what components/upgrades would you suggest? For instance, are the lekkie chainrings worth the extra money or is it just a bling thing?

My aim is just to make the thing as fast as possible! I’ve got a stereo 140 sl 750 for the technical stuff.

 

[dlatch]

I’ve just bought myself a Trek Marlin 7 and a 1000w 52v bafang conversion kit to go on it. I’ve done some research and feel I have a pretty good idea of what needs doing. But as a plumber I’m aware that some times a little knowledge is a dangerous thing! So I was just wondering if there was anything in particular I need to consider?

I’ve bought a DM03 display (newer sw102) and 52v 19.2ah battery. Will the standard controller suffice or do I need to upgrade to get the most out of the battery? If I put more power through it do I need to upgrade wiring/connectors?

Finally, what components/upgrades would you suggest? For instance, are the lekkie chainrings worth the extra money or is it just a bling thing?

My aim is just to make the thing as fast as possible! I’ve got a stereo 140 sl 750 for the technical stuff.

Definitely upgrade the chainring from the stock bafang lekkie are bloody expensive I put a grabring on mine for half the cost. 30amp limit and any of the popular controllers are more than enough for most drive trains to cope with.
Get yourself some spacer washers

 

[TommyC]

I’m slowly working it out! Got a 42t chainring with 24mm offset. Chainline is now 6mm further out so I’m looking to put 7/8 speed on to help with that. I did wonder if I could have a custom cassette made out of my 10 speed so I can retain the cog spacing of a 10 speed. But can I set my derailleur to work with an 8 speed shifter?

Had the bike out for a test at the weekend. Good for 35mph with the current 28a controller. Just got the shift sensor to fit, bigger rotors to go on and I want to run the main harness internally.

 

[Kiwi Giant]

My build last year was a large 2021 Trek Marlin 7 with a 36v 500w BB02 with a 864Wh (36v 24ah) battery fitted. I'm utilising the 10 speed 11-46T cassette and the Shimano MT200 disc brakes front & rear. I've fitted it with a Brand-X dropper seat, MTB alloy pedals DMR Defy 50mm Stem and Spank Spoon 60mm Bars. Also I've upgraded the forks to a Rockshox 35.

I’ve done the conversion with a 40t Lekkie Bling-Ring & Lekkie Onenut and Lekkie 160mm left offset Buzz-Bars. The chainline is good, I haven’t installed the shift sensor and so far haven’t noticed any issues with changing gear. The bike came originally with a 28t chainring and as I do a fair bit of hill climbing I may investigate a 36t or 38t Bling-Ring in the future, my only concern would be the offset issues.

I’ve used the SW102 Display as I wanted the smaller handlebar look and I already had a Garmin Edge 830 mounted so I don’t need much in the way of more data.

So far I’ve done around 2500km since September and it all seems to be working well, with only minor teething issues and the battery range is fantastic.

 

[TommyC]

Out of interest do you know how much further out your chain line is compared to standard? I’d really like to keep the 10 speed set up but not sure it’s going to be ok.

Before I go on I will explain I don’t know a lot about bikes, just applying my own logic. Please correct me if I say something stupid!

The bike won’t shift into the two biggest gears since I put the motor and new longer chain on. I assumed that’s just down to the chainline and the derailleur needs adjusting. Although I haven’t bothered trying it yet I’ve gone ahead and ordered an 8 speed 11-40t cassette that I’m going to take the 11 and 13 off and put a 12 on to make a 7 speed that, using info I found here:

Sheldon Brown's Bicycle Frame and Cassette Spacing Crib Sheet

Useful dimensions and conversions for the cyblist/mechanic: hub and sprocket cluster spacing

www.sheldonbrown.com

should bring that biggest gear out by 6.6mm. With the front chainline out by 6mm I’m thinking that should work fine?!?

Trouble I’m having is finding a decent 7 speed derailleur. Best I can find is the sram x5 but I’d have to pair with an x3 shifter?

I’ve put on some shimate RSX brakes that have the cutouts built in. Cheap Chinese stuff but I couldn’t find any with the correct 3 pin plugs from a reputable brand. They work just as well as the tektro that was on there. I went for the small display too as I want it to look as clean as possible.

I’ve got the bigger rotors and internal routing done now. Just a bit more tidying up of the wiring and the drivetrain to sort and it’s finished. Some better forks would be nice but not really got the funds for them right now.

 

[Kiwi Giant]

Remembering that I'm running a BBS02, not the BBHD. I'm using a 40t Lekkie Bling-Ring and because of this the low profile Lekkie Gear Cover. I run one spacer under the Bling-Ring so my offset is 9mm, the standard Bafang 46t chainring has an offset of 5.4mm. My chain runs straight about mid gears on the cassette and I have no problem getting all 11-46t on the 10 speed cassette. Lekkie says that there should be a 1.5mm gap between the ring and chain-stay to allow for flex, I'm running less than this but have not had a problem.

 

[TommyC]

So I took a look at the gears today. Turns out I just hadn’t tightened the cable properly! So now shifts through all the gears nicely. Chain does look a bit askew on the lowest gear but drivetrain isn’t too noisy. Think I’ll just leave as is for now and see how it rides.

 

[Kiwi Giant]

Great result.

 

[Chuy]

@TommyC How is the DM03 doing? The specs I saw for that display show it is fir a 24-36-48 volt systems. Any issues with it properly showing battery status? I also read the DM03 and SW102 are different models. They look similar, as dies the Eggrider, but they are all different models.

 

[TommyC]

Couldn’t tell you. I sold the bike pretty much as soon as I built it. Realised a hard tail with all that extra weight was no good for me. Sold it to a guy who wanted to ride 3 miles to work and back every day with minimal/no effort. Perfect for that!

Been on the lookout for a full sus frame do build up but can’t find anything I like that will allow the motor to sit up out of the way.