HairyOnion

Hi, hope you can help me with this issue I recently started having. The chain skips every 2 revolutions, teeth miss align and catch the rivets. Not sure how or why. Started happening last week. I have been manually cycling for 1 year with the bike. I converted the bike to an E-Bike, and carried on cycling for 6 months (done 1.5k miles so far I think with the ebike). Then the chain started to fall off the chainring. I replaced the chain but still had the same problem, I replaced the chainring and I still have the same problem. I will most likely buy a new cassette but can't see any problems or wear.

I made a video and put it on youtube but this site doesn't allow me add urls due to my post count

Trakhak

A chain falling off the chainring is almost always either an alignment problem (chain at too acute an angle between sprocket and chainring) or front derailleur adjustment/positioning problem (you didn't mention how many chainrings you have, which would be pertinent information).

Skipping almost always means that the teeth on the smallest one or two (rarely more than two) sprockets are worn. (Worn-out sprocket teeth look pretty much the same as teeth that aren't worn out.) Simple fix is to replace the cassette.

Also, resist the temptation to pedal around with the chain on the smallest sprocket in the back, which is what people seem to tend to do when they start riding an E-bike. For greatest cassette life, try to keep the chain mostly toward the middle of the cassette. Hope you have at least two chainrings, so that you can use the biggest ring when you're using E-power.

HairyOnion

Thanks, Trakhak for responding,

I have a 44 t chainring form the Bafang 750W 48V BBS02B kit, the cassette is a Shimano HG50, 10 speed, 11-36.

So to give a little more info the chain if I am in the center gears doesn't fall off but every 2 rotations raise up on top of the teeth and then slips back into the dips between the teeth.

This is the link to the video on youtube youtu be.com/shorts/a_DO3J0-Ljo

had to put a few spaces in the url for this forum to allow it through.

I have bought a new cassette that hopefully arrives Monday next week.

davidad

That's good because the cassette is worn out. You can inspect the teeth where the chain skips and see that the leading edge of the tooth is slightly upset.

Iride01 

How many miles or kilometers on the parts involved here? The chain ring might well be worn too and now the new chain exposes that issue since it's now correctly spaced.

This part is all IMO, but I think chain and sprocket wear on e-bikes is exacerbated by the riders not sensing how much force it's taking to actually move the bike. And therefore the gears used for accelerating and climbing are way too high a ratio that puts more stress on the cogs chain and motor.

A gasoline engine would be bucking and stalling like when you try to start driving a manual transmission car in second gear instead of first. But the electric motor gives you a sensation that everything is okay when maybe it's not really okay.

Andrew R Stewart 

We are seeing far more chain/teeth wear per mile on the E bikes we have sold and serviced, compared to a bio motor bike. I would agree with the other's suggestions till shown different, they pretty much my assumptions.

Iride01 has a very good point. A gas engine tend to have greater torque in it's mid RPM range, pretty poor power when at low RPMs. On the other hand electric motors have max torque at the least RPMs. So the start ups are much harder on the drive system that any human could achieve. And the perception of overall power being used (from the E assist) is usually underestimated (or not even thought about).

Add to this is that most e conversions are a compromise between low cost and easy installation ability. Long term durability tends to be rather down on the list of goals. Andy

HairyOnion

When the Bafang kit arrived it had been configured to be quite aggressive so it would chew threw chains on a weekly basis, I bought a programming cable and set the motor to only start after 1 1/2 spins and have the 2nd from the slowest acceleration setting. Changing those settings solved everything. I know you won't believe it but I am very considerate of the gear I am in. Maybe the early days caused a lot of wear idk. Before the e-bike conversion I reckon I will have done over 2.5k miles and 1.5k with the electric motor.

I am hoping to get the new cassette tomorrow so will fit it on the weekend. I will let you guys know if it solves the problem.

HairyOnion

Guys, I put the new cassette on and I get the exact same issue, the teeth and the gaps between the chain rivets mis align causing the chain to rise and then fall back into place as the chainring continues to be turned.

So I have replaced the chain, cassette, and chainring and the problem still persists.

Do you have any other ideas? Because I don't know what else can cause this.

Iride01 

Put the bike in the middle cog on the rear stack, if you have an even number of cogs, then pick one near the middle.

Get behind your bike and look over the cassette and sight down the chain all the way to the front sprocket. If it isn't reasonably straight then you might have for some reason just gotten your chain line too messed up for your chain to want to stay on the cogs that are giving you trouble.

You did get the correct speed chain for your rear number of cogs didn't you?

Which cogs is this an issue on?

If the cogs on either end of the cassette, then maybe your limits aren't set correctly. But make sure you know that it's the limits before you muck with them. The manual for your rear DR model will tell you how to correctly set them.

ClydeClydeson

The description of the chain skipping every certain number of crank revolutions sounds a lot like a stiff link (or links) in the chain. This is most often caused by less-than-perfect installation, but rough shifting can cause it, as can riding with a bent tooth on a chainring or cog.

If it is a stiff link (telltale sign is that the derailleur jumps as the stiff link passes through wen backpedalling) the solution is often to use your hands to pur a bending force on the sides of the links - put your thumbs on either side of the stiff link and try to bend it sideways back and forth, which will spread the chain's plates slightly and free things up. It could also be a twisted or otherwise damaged link, and these generally cannot be fixed by hand - you need to remove the damaged link and splice the ends of the chain back together (or add a quick link)

HairyOnion

OMG, it was the new chain. The link was a little stiff. Because the old chain was behaving like this when I put the new chain on and it behaved the same , I thought the problem must have been elsewhere.

Thank you for all the comments and help guys. I can leave the escooter at home now and carry on cycling