Help! Carrera Crosscity - No pedal Drive

[Dashhouse]

I have a three-year old Carrera Crosscity.

Lately I have been experiencing a lack of drive whilst pedalling, i.e. using the chain and when not using the motor. On these occasions I have been able to continue under electric power alone, by merely moving the pedals. I’m assuming therefore that the problem is inside the Freehub, and that it will need replacing. I have not yet dismantled the rear-end.

My question is this: When I do dismantle the rear end and take off the cassette, will I find a conventional Freehub or will there be some special integrated Bafang unit?

I’m hoping the answer is the former, a conventional hub, and if that is the case, is anybody able to tell me which hub to order (the Crosscity is an 8-speed Shimano set-up)? If it helps, the cassette sprocket is a Shimano Acera CS-HG41-8 11-32T

All help/suggestions will be gratefully received

Thanks in advance.

 

[Nealh]

Whether the freehub is faulty, either bearings or pawls you won't know till the cassette is remove. Also you won't know if the freehub if faulty will come off easily.
With my bafang cst hub the freehub comes away easily but on my AKM hub the freehub is integrated in to the end plate, fortunately the end plate can be sourced for the AKM.

You won't know exactly which freehub to buy until you find out how it is affixed to the end plate, if like the AKM above you would have to source the complete end plate.

 

[vfr400]

The problem is that water has got in and made the pawls rusty, which has made them stick down.

You can probably solve it with oil. Get some 3-in-One. It must be that type of oil, not ordinary oil. Turn the bike on its side and drizzle the oil around the axle so that it goes down inside the gears. The stuck parts are at the back, so it will take a bit to get to them. wait a while for the oil to do its thing, then turn the bike upright and rotate the gears with the pedals to spread it around a bit. Give the gears a few taps to jog the pawls back into action if nothing happens.

If it doen't work, you'll need to see if you can dismantle the free-hub, which probably means taking the side off the motor.

I'm not sure, but I think the older ones might have freewheel gears, in which case you dion't need to dismantle the motor - just unscrew the gears and replace them.

 

[Nealh]

The CS HG41 is a freehub cassette, he has a cassette with the designation given.

 

[Dashhouse]

Whether the freehub is faulty, either bearings or pawls you won't know till the cassette is remove. Also you won't know if the freehub if faulty will come off easily.
With my bafang cst hub the freehub comes away easily but on my AKM hub the freehub is integrated in to the end plate, fortunately the end plate can be sourced for the AKM.

You won't know exactly which freehub to buy until you find out how it is affixed to the end plate, if like the AKM above you would have to source the complete end plate.

Thank you. The bike has a Bafang motor.

 

[Dashhouse]

The problem is that water has got in and made the pawls rusty, which has made them stick down.

You can probably solve it with oil. Get some 3-in-One. It must be that type of oil, not ordinary oil. Turn the bike on its side and drizzle the oil around the axle so that it goes down inside the gears. The stuck parts are at the back, so it will take a bit to get to them. wait a while for the oil to do its thing, then turn the bike upright and rotate the gears with the pedals to spread it around a bit. Give the gears a few taps to jog the pawls back into action if nothing happens.

If it doen't work, you'll need to see if you can dismantle the free-hub, which probably means taking the side off the motor.

I'm not sure, but I think the older ones might have freewheel gears, in which case you dion't need to dismantle the motor - just unscrew the gears and replace them.

Thanks. I’ll try the oil trick first. I know it is some sort of Freehub and I already have the replacement cassette sprocket, I just don’t know what sort of freehub I am going to find.

 

[vfr400]

Replacing the sprockets won't help if it's fre-hub gears as the pawls are in the hub. Free-wheel gears have the pawls in the gears. Show us a photo of your motor and gears if you're not sure what you have. The difference is that the free-hub gears have a retaining piece, like below, on the top gear, while as freewheel gears don't:

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[Dashhouse]

Here’s an update on what I found. After having modified my lock-ring removal tool to accommodate the motor wiring spindle, I eventually managed to undo the lock-ring, with the the help of my much stronger son; it needed an enormous amount of force and then let go with a loud click. It was an easy matter to remove the cassette, which revealed what looks like a standard Shimano freehub. After having applied liberal doses of oil as advised above, the pawls were now engaging, but there is no clicking sound from them when the freehub is spun. Also there is a fair amount of play, and I am sure it should be replaced. However, at this point I was stumped and could not work out how to remove it without taking off the side of the motor which would have required a special tool that I have not got (for bolts with a star-shaped hole with a pin in the middle). So I put everything back together with a new cassette and chain, and the bike is now useable (for a while), and rides very well, but I know I will still have to replace the freehub sometime.

 

[Dashhouse]

Incidentally, I wonder why the lock-ring should be tightened to 40 Nm. Is it a leftover from the days when all the rings were separate? Mine were all connected apart from the smallest one.

 

[Nealh]

Those security machine screws are T-hex, buy a set or one can buy single ones.
33PC SECURITY BIT SCREWDRIVER TOOL HOLDER TORX STAR HEX 60MM SPANNER SCREWS SET | eBay

 

[Nealh]

Incidentally, I wonder why the lock-ring should be tightened to 40 Nm. Is it a leftover from the days when all the rings were separate? Mine were all connected apart from the smallest one.

Smallest one is often 11t and wears the most, it is loose to easily replace. Also some prefer to have 12 or 13t high gear so again easy to swap out.

 

[vfr400]

Incidentally, I wonder why the lock-ring should be tightened to 40 Nm. Is it a leftover from the days when all the rings were separate? Mine were all connected apart from the smallest one.

I never tighten mine like that. I just nip them up by hand to something like 10Nm. I've never had one come undone, and they're a lot easier to undo.

 

[Dashhouse]

That’s what I thought. I just tightened mine up by hand in anticipation of having to remove it again soon, and I’ve ordered the TORX screwdriver bits.

Thank you, both, for your helpful and timely advice; it’s great to be able to talk to friendly experts, and always a pleasure to learn new skills.