Hi Andi need advice please

Hi, new to this forum but need some advice.

I have a custom built e-bike that I built myself using the bbshd, 52v 18ah battery (Samsung q30 cells), stock/unlocked controller, gearshift sensor on a Voodoo canzo MTB.

This issue I've got is with the bike and not the motor, the bike was bought new and I only rode it 2 or 3 times before adding the motor. The issue I've had I've had from the day I bought it, when I change to certain gears like say 5th, 6th, or 7th my chain seems to skip if I pedal hard. So I adjusted the gears/derailleur so that the 5th, 6rh and 7th no longer skip but then issue seems to move to either 1st second and 3rd or it will go to the last 3 cogs?
Does anyone know why this is happening?
I've changed the chain, front cog, had the derailleur set up and checked for been bent at a cycle shop and all was ok However I've never changed the cassette? Do you think this would cause this issue? Also if I'm going to change the cassette is it worth me changing the derailleur system to a internally geared hub like the shimino Alfine 11?.

I use the bike to mainly commute to work and occasionally go on bike trails at weekends.

Any help is appreciated
Thanks

A worn cassette or freewheel will skip under load. If the chain is elongated more than 0.75%, the sprocket teeth will be reshaped enough that is necessary to replace them. Usually, wear of the front chainring is less of a concern (meaning it can be ignored until it's more severe).

Note that if you run a new chain on a worn-out cassette, the cassette will rapidly transfer its wear to the new chain.

Mid drives chow through drivetrain parts like that's their job, so get used to the idea of replacing both chain and cassette frequently. Get a chain checker, cassette tool and chain whip, and spare components to keep on hand. That's the downside to using a mid drive that runs through the bike's gears.

Cassettes are cheap and easy to replace. They're consumable maintenance items. There's no comparison between switching to an internally geared wheel, which is a several hundred dollar operation that requires reconfiguring your bike, and replacing a worn cassette. Also, BBSHD will crunch up an Alfine 8 hub if you try to use them together.

If your reason to have a mid drive is for fun recreational riding, I suggest putting together a cheap and simple hub motor bike for going to work. That way your fun bike will be in fresher shape when it's time to play. You can opt for things like heavy puncture resistant tires, direct drive front hub, drum or rim brakes, and internal gearing that will increase your commuter bike's reliability and decrease maintenance.

Another thing that can cause the chain to skip is not enough tension from the derailleur. Some have an adjustment for this. Removing a few chain links will also help if the chain can still fit on the largest cog.

fechter said:

Another thing that can cause the chain to skip is not enough tension from the derailleur. Some have an adjustment for this. Removing a few chain links will also help if the chain can still fit on the largest cog.

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B-tension adjusting screws are not for changing chain tension. They're for making the jockey pulley track close to the sprockets for clean shifting. Don't use them to increase chain tension or shifting will deteriorate markedly.

Using the shortest chain that will fit over the largest sprocket and chainring without pulling the derailleur to its limit is a good way to maximize chain tension with a given derailleur. But if insufficient chain tension is a problem, switching to a derailleur with a stronger tension spring, or with a clutch, is a better remedy.

You could restack your cassette so that the 4 gears you use the most fall within the sweet spot.

Guess I am not clear on 'skipping' - do you mean the chain slipping over a single cog allowing the pedal to slip forward, or do you mean the chain trying to skip up to the next bigger cog or drop to a lower cog?

You say the bike is nearly new, so not likely anything is too terribly worn yet. If the chain is skipping forward, that is typically a B screw adjustment to make the chain wrap tighter around the cog. But the way you mention dialing in the lower set of gears, only to have the upper set start skipping, that sounds more like indexing of the shifter. There are lots of tutorials out there which go into much more detail than I can here. The only comment I can add is that when adding an electric motor, it seems like all the adjustments need to be 'spot on' for good shifting. When pedaling with leg power, a certain amount of misalignment may never be noticed. But add the power of the electric motor and you might be dialing in the chain with 1/4 or even 1/8th turns of the screws.

Also. what does your chain line look like? is it fairly 'normal' or has it been pushed out one way or the other with the addition of the motor?

4πr^2 said:

The only comment I can add is that when adding an electric motor, it seems like all the adjustments need to be 'spot on' for good shifting. When pedaling with leg power, a certain amount of misalignment may never be noticed. But add the power of the electric motor and you might be dialing in the chain with 1/4 or even 1/8th turns of the screws.

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AFAICT in my limited middrive experiences, this isnt' because of the power itself, it's because when pedalling you "naturally" change cadence during shifting (after some practice) but the motor doesn't do this (even if you have a gearsensor of sometype to detect gear shift changes, it doesn't react the same way or the same timing that you do, so it may not shift the same either). The pedal sensing and even throttle may have some delay that is enough to throw off the shifting from what's needed...so a more precise alignment may accomodate the timing/power issue.

Chalo said:

... BBSHD will crunch up an Alfine 8 hub if you try to use them together.

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Hi Chalo - is this from personal experience or references? I ask, because I've used almost exclusively the older SG-S501 Alfine 8 hubs on my bikes (~six, BBSHD/BBS02), and have not experienced a failure. If there are references to what failed, I'd really like to know, for proactive sake.

ncmired said:

Chalo said:

... BBSHD will crunch up an Alfine 8 hub if you try to use them together.

Click to expand...

Hi Chalo - is this from personal experience or references? I ask, because I've used almost exclusively the older SG-S501 Alfine 8 hubs on my bikes (~six, BBSHD/BBS02), and have not experienced a failure. If there are references to what failed, I'd really like to know, for proactive sake.

Click to expand...

Because Shimano doesn't supply replacement parts, I've never done a postmortem on a crapped out Alfine 8 or Nexus 7 or 8. I just order a new core and install it. But even on pedal-only bikes, Shimano gearhubs don't especially like heavy riders or low gear ratios.