bbs02 chain slipping. 8 speed?

[slickncghia]

G'day guys.

Ben from Melbourne Australia here.

I have a bbs02 750w.

Put it on my old crappy bigw 29er that I had shoe horned a 9 speed slx groupset on and it ran well but the bike was dangerous with $2 suspension and vbrakes.

I bough a new 29er with better gear all round except its running an 8 speed chain and cogset. I've been out doing some singletrack on it today for its first ride and the chain keeps slipping off the front sprocket every time it gets bumpy. It's happening regardless of what gear II'm in so I don't think it's a chainline or tension issue.

Could it be the chain? is it worth swapping over to the 9 speed setup?

Other option is to go 9 speed and swap over to a narrow wide sprocket. I have a 33t but that would limmit top speed a bit too much and I really don't want to have to buy another

Thoughts?

Mandatory photo. Apologies for the white Zip ties. they will be replaced

 

[tahustvedt]

The chainline will be really bad with a 33t sprocket.

Get a chain guide or install the front derailleur and adjust the screws so that it works as a chain guide.

 

[slickncghia]

Is that because it will be offset with an adapter?

I can't see how the amount of teeth effects the alignment of front and back sprockets.

I'm hearing you on the chain guide. I was hoping that wasnt necessary as I've been running. 1 x 9 for a couple of years without one.

Of note the slipping is not occurring when changing gears

 

[Overclocker]

yes chainguide or FD. 8-speed is great. prefer it over 9-speed

 

[slickncghia]

Cool ill whack the fd back on for the next ride.

If that dosent help I'll try the narrow wide aswell just to see.

Cheers
Ben

 

[tahustvedt]

Is that because it will be offset with an adapter?

I can't see how the amount of teeth effects the alignment of front and back sprockets.

I'm hearing you on the chain guide. I was hoping that wasnt necessary as I've been running. 1 x 9 for a couple of years without one.

Of note the slipping is not occurring when changing gears

Yes, the sprocket will be offset way too much, and you will not be able to use the larger cogs effectively.

 

[Tats]

Using a FD with no cable or selector on 9spd 29er - no chain slips - just works

 

[slickncghia]

thanks guys

 

[Abagrizzli]

Good chain doesn't slip. FD and chain guide are pretty much a patch to the existing problem, which is one of the following:

1. Worn chain
2. Too long chain
3. B-tension screw way off.

Now, since you have 8-speed cassette, i.e. you're using cheap and simple rear derailleur, without clutch (as we all), so there is no chain tension mechanism. Chain line with 8-speed is not really an issue, since the chain itself is very thick comparing to 10-speed, and the cassette's range is not wide enough to cause problems.

What would I do, without going into FD and chain guide:

1. Check that the chain is not worn over 75%.
2. If the chain is OK, shorten a link at a time. I mean cut one link off, if it still slips - cut another.
3. Adjust the B-tension screw to leave 5mm between the pulley and the largest cog at the lowest gear.

My wife is riding Ibis Mojo HD with BBS02 and 8-speed cassette without any chain related problems, and we ride singles as well. And on top of it this is a full suspension bike, which means the swingarm moves, unlike in hardtail.

 

[slickncghia]

Bike and chain are brand new.

Here is a pic of the chain tension in lowest gear. Too tight If anything. also the btenstion adjustment looks ok right?

When the chain slipped sometimes it was to the bottom bracket side and others it was to the crank side.

Again. Chain was slipping in multiple gears. Not when changing. Not only when using Pas

 

[Abagrizzli]

Chain + bike new - good, it eliminates some of the versions.

What would I do:

1. Ditch the Acera and change it to Sram X4. At this level Sram is better, it has larger pulleys, different cable alignment (like Shadow Plus in much more expensive XT) and a little firmer tension spring.
2. It looks like you have more than 5 mm between the pulley and the largest cog, although I can't say from the photo. If you do - use the B-tension screw to get it closer.
3. Check the rear gear alignment.
4. Cut a link

I mean, chain issues usually narrow down to few options. FD not really helping, 'cos it's not holding the chain to either side, it just helps it not to dance too much on rocky terrain. Since you're reporting the chain slips even when you're not switching gears, I don't think it will help. Chain guide helps to tense the chain, but in our case the chain moves too quickly due to the motor, and chain guide can wear the chain pretty quickly, and to be worn itself.

Most of the chain slips related to worn chains, too long chains, worn cogs, unaligned derailleurs and excessively faulty chain lines. In your case, the chain is new, the cogs are new, there is not front derailleur, and the chain line in 8-speed really has to be off in order to cause the chain to slip (and the chain itself also thicker). So we're staying with too long chain and unaligned rear der. That's my logic, but once again, I may be wrong and all I wrote is complete bullshit, I don't claim myself as a last word of wisdom )))))

 

[slickncghia]

I have an slx rear derailleur but that's 9/10 speed so I will have to swap everything.I might try that and see if it goes away also

 

[Ade]

G'day guys.

Ben from Melbourne Australia here.

I have a bbs02 750w.

Put it on my old crappy bigw 29er that I had shoe horned a 9 speed slx groupset on and it ran well but the bike was dangerous with $2 suspension and vbrakes.

I bough a new 29er with better gear all round except its running an 8 speed chain and cogset. I've been out doing some singletrack on it today for its first ride and the chain keeps slipping off the front sprocket every time it gets bumpy. It's happening regardless of what gear II'm in so I don't think it's a chainline or tension issue.

Could it be the chain? is it worth swapping over to the 9 speed setup?

Other option is to go 9 speed and swap over to a narrow wide sprocket. I have a 33t but that would limmit top speed a bit too much and I really don't want to have to buy another

Thoughts?

Mandatory photo. Apologies for the white Zip ties. they will be replaced

I had similar issues with the front chainring. I also had some slippage on the rear sprockets and spontaneous gear changes.

My chainline was definitely off by quite a bit though. I also damaged the chain by changing gear under high torque so that didn't help. I resolved all this by adding a Lekkie Bling Ring 42T narrow/wide chainring which fixed the chainline. I also changed the back cassette for a cheap shimano steel cassette and bought a KMC Ebike chain that's supposedly 30% harder than a normal chain.

And yes, I have a 9 speed.

 

[Samd]

Use a new anti-jump chain and it will reduce the issue. But if your chainline is bad it will need a chainkeeper.

Look between the side links of your chain. Are there small channels built into the side link walls to make room for the teeth?

When I install drives I always fit a nonjump MTB chain.

 

[allezdude]

That chain looks way too short. Also if you are running a double setup in the front, try to avoid cross-chaining. I.e., large in front, large in rear, or small in front, small in rear. That's just the road biker in me saying this stuff.

 

[gorndog]

I had the same chain line issues which I fixed by simply flipping the front 48t sprocket around. Totally fixed the issue of alignment for me.