Bosch Performance Line CX

I have recently acquired a Bosch performance line CX and find it to be draggy like there is resistance to my pedalling. I find that eMTB mode is useless because it is hard to pedal, I have changed to custom modes on my NYON to overcome this. at certain rpms going up steep inclines the motor vibrates and a resonance can be felt through the pedals. In comparison the Bosch Active Line Plus is effortless quiet and smooth. Do you think I have a faulty motor? has anyone had the same experience?

Sounds like somethings wrong, I have a CX, and can't fault it.

I have recently acquired a Bosch performance line CX and find it to be draggy like there is resistance to my pedalling. I find that eMTB mode is useless because it is hard to pedal,

 

What is turbo mode like?

Turbo is fine, lots of acceleration. There's an oscillation at high rpm in low gear tho

Like Fishy, I have a CX and there is definitely no drag in any of the assisted modes; in fact the motor assistance is very marked. It can be heavy pedalling above the cut off with no assistance, though, due to the internal gearing. Sounds as if there is definitely a problem with the motor.

Just to check the obvious, is the clutch on that reduces chain slap over rough ground? This can be known to make it harder to pedal in certain circumstances like when you change to a bigger cog and the derailleur swings forward.

I have a Cx, no problems with drag or vibration........

I have recently acquired a Bosch performance line CX and find it to be draggy like there is resistance to my pedalling. I find that eMTB mode is useless because it is hard to pedal, I have changed to custom modes on my NYON to overcome this. at certain rpms going up steep inclines the motor vibrates and a resonance can be felt through the pedals. In comparison the Bosch Active Line Plus is effortless quiet and smooth. Do you think I have a faulty motor? has anyone had the same experience?

At what speeds do you notice this?

When going up steep hills try changing down a gear or two and using a higher cadence, if it still resonates you could have a motor problem. More spinning less pushing.

Turbo is fine, lots of acceleration. There's an oscillation at high rpm in low gear tho

 

Hmmm. What exactly is this 'oscillation' and what are you considering a high RPM?

 

I asked about turbo mode, because not that I'd want to cast dispersion on your leg strength, but in the past, my wife didn't get on with EMTB mode - found a distinct lack of power - even thought the bike was faulty! It was because EMTB mode is heavily biased towards taking input from the torque sensor. If you put out high power yourself, then EMTB mode will respond with oodles of assistance. However if your leg muscles aren't particularly strong, EMTB mode tends to give a very low assist.

(but you still don't really get a faulty 'oscillation' as such - not unless your legs are very 'bursty' strength wise, and aren't providing a smooth power output themselves)

The clutch is off. The vibration occurs mainly in first gear at higher cadence I'd say at 80rpm. The motor is dragging when in eMTB mode going up hills, one has to push on the pedals really hard to get the motor to respond. On the flat in tour mode the motor is quiet and seems to behave itself. But when going up hills in turbo the motor really screams and it feels notchy.

The oscillation feels like a resonance coming though the motor and pedals. It feels like it is causing resistance to the motor like a resonant spinning disc that won't spin faster because it it vibrating.

Does the bike have hub or derailleur gears?

The "oscillation" you feel sounds as though it is the chain vibration felt when using a high gear at high cadence/heavy loading. This is variously described as vibration through the frame, the bars or you saddle and sounds harsh. I think this is a characteristic of this drive system as many have described it. I surmise it is caused by sympathetic vibration of the chain when using a rear sprocket which has the same or similar number of teeth to the front sprocket. The two sprockets between them seem to set up a sympathetic vibration by the action of the links hitting the sprockets. Other than fitting an idler wheel over the top run of chain, I have found the best solution is to keep the chain well lubricated with a wet lube.

Hey all i have a similar issue, i have removed the worn 16 tooth sprocket and installed a new 20 tooth sprocket with a new chain and have alot of vibration under fair load regardless of rpm, the cassette is fairly worn in smaller sprockets but bigger sprockets are only mildly worn, so i think maybe a motor issue?

Hey all i have a similar issue, i have removed the worn 16 tooth sprocket and installed a new 20 tooth sprocket with a new chain and have alot of vibration under fair load regardless of rpm, the cassette is fairly worn in smaller sprockets but bigger sprockets are only mildly worn, so i think maybe a motor issue?

If the issue only became noticeable when you changed those parts, then there is a reasonable likelihood that it is related to that change.

 

I would refit the old bits if you still have them and see if the problem goes away. If not, I would suspect the combination of old cassette and new chain is a more likely cause than a motor fault happening at exactly this moment.

If the issue only became noticeable when you changed those parts, then there is a reasonable likelihood that it is related to that change.

 

I would refit the old bits if you still have them and see if the problem goes away. If not, I would suspect the combination of old cassette and new chain is a more likely cause than a motor fault happening at exactly this moment.

thanks for your quick reply, unfortunately i ground the teeth off the old sprocket and made it thinner to use as a spacer because the sprocket i bought was flat, i suspect it is the motor as i feel it through frame but there is no audble sound, cranks have no lateral play either so motor bearings should be fine, maybe the nylon teeth? but yes i will definitely be looking at cassette too, thanks again

i think it is the chain line and the sprocket is not in the right place on the motor and means the nylon transfer gear is twisting and that is the vibration you are feeling.

 

i still cant find any spacers but all you can do is try a sprocket that has a off set.

 

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