Bafang BBS02 750w off-roading and chain and gear set-ups

[TriggerGee]

I want to start a discussion about using the bafang mid drive on proper mountain bike trails and down hill/ jumps. I've knoticed there aren't many if any real off road riding vids on YouTube so I'd like to upload my own soon but right now the kits not up to it...

A month or so ago I got bafang mid drive with a frame mounted 11.6 ah battery and have covered 170miles on it so far mostly riding at around 10-17 mph on mounting bike trails in my local woodland and although it's bloody fantastic obviously the gearing is too high but more important is the constant chain derailing! My last 5 mile ride involved probably 10 derailments making it basically useless for fast bumpy trails and jumps. I had brought my rear derailed closer to the gears which seems to have slackened the chain enough to make it useless off road, I've moved it way out now and will see how it fairs tomorrow morning but even befor it was coming off 2-3 times over 5 miles and depending on when it comes off it can be slightly dangerious.

Is anyone using the kit for this kind of riding? What kind of chain guides/retainers can be used and what are the best gear setups? I guess 38t front as that's the lowest the bbs02 can take is that right? I've never been able to do this kind of riding except in my early teens due to a muscle wasting illness so I don't know much about proper mountain biking

 

[dbar]

I have a 750 watt motor in an old Marin Bolinas Ridge. I run a42 tooth front Bling ring and a 9 speed cassette at the rear . I have reduced this to 8 speed by taking off the smallest cog and putting a spacer on the wheel side of the cassette , lowest gear has 38 teeth. I left the front mech on as a chain guide. I have done some pretty extreme trails on it and not dropped the chain yet.

 

[ginekolog]

I have BBS02 750W on old GT aggressor. 44T front, 34 back (8 speed, deore cassette 34-11). Works great, I ride it hard and often in forrest steep hiking trails. It climbs very steep hills, but can be put to stop in uber steep ones. For that I would need 34 front hhich I dont want because I also enjoy pedaling at top speed (55 km/h on flats, 70 downhill). Not a single chain drop in 2600 km.

 

[TriggerGee]

I'll try loosing a gear at the rear and putting a spacer in by the wheel, that should help and I'll also try reinstalling the front derailer. The 42t front sproket would be a really nice additions do if I read right it has a thick thin tooth setup to help grip the chain, if only I could afford it...I don't know what's going on with my setup because my chain drops more waaaaaay more than you guys, if I peddle during or just after a very bumpy section at over 10mph when the bikes really getting jiggled the chain is very likely to slip of. It was better after moving the rear derailer back out away from the cassette as it took a bit of slack off the chain but it still slipped off a few times over 3 miles of woodland track with lots of roots, rocks and small jumps. Another question is what battery mount setup do you use for rough riding or do you prefer the battery in a backpack?

 

[nutnspecial]

The front deraileur as a guide sounds good. A chainguard helped on mine, but there may not be room on a serial middrive for that?

It sounds like you'd benefit from losing a few links of chain also?

 

[KINNINVIEKID]

My Cannondale runs a 44T front and 34-11T rear and has the front derailleur in place.
I ride Hamsterley forest a couple of times a week and have not dropped a single chain in 2800 miles.

 

[TriggerGee]

In the 180 miles I've covered since getting the kit a few weeks back I've dropped the chain more times than I can remember! Bloody 'ell...I tried losing a link but it made the chain so tight it actually got stuck on the high gear so after finally derailing it a had to put the link back in.

 

[MadRhino]

Get rid of the front derailer. A single chain ring for the front is enough, fit a proper bash guard and a DH chain guide. You might need a better derailer on the rear, tight and perfectly tuned. The harder you ride in mountain trails, the better the chain line and guiding need to be tuned.

 

[TriggerGee]

I've yet to try it but last night I put the front derailer back on and removed my lowest gear from the rear and fitted a spacer behind the high gear to move the whole cassette out a touch. I realise a chain guide/ guard would help a lot as well as I higher quality rear derailer but right now my budget is £0 so I have to use what I have or create my own bits.

It looks good after last nights changes so we'll see what happens when I take it out, might give it a try later...

 

[TriggerGee]

Well I did take it out and had my longest off road ride so far (partially because once I had ridden the 3 or so miles to the tracks and got going on the bumpy bits I realised I hadn't locked my frame battery in place so had to ride back home to lock it with the key before it flies off) it performed virtually faultlessly. I had jumps, rock docents, roots and stones at high speed and all the other things you might expect from a good mountain bike trail and not once did the chain drop! I felt confident using PAS or throttle when ever needed without worrying if it would derail the chain. This resulted in an overall increase in speed through the trails from around 12mph to 15-17mph average. I still need to sort a new from ring as the 48t just fails on steep technical uphill rock climbs, partially because it's impossible to peddle so I rely on the less precise control of the throttle. Also swapping the spacer I put in for a really high gear at the rear would be great.

Thanks chaps, massive improvements so far. Still would like to know how people carry their battery for hard riding?