Chain Falling Off

[richardg6paj]

I've just bought a Woosh Rio FB. I'm impressed so far. But one gremlin has just shown up. I've contacted Woosh, but it's the weekend so in the meantime thought I would ask for comments on here.
The problem is when first gear is selected the chain drops off the front sprocket, very annoying.
The Shimano Acera is working perfectly, but it seems to me that the chain is path is not central to the cassette meaning that the angle from first gear to the front sprocket is so severe that the chain comes off. I've noticed that 8th gear is perfectly aligned with the front sprocket. 2nd. gear is rough/noisy and as I said 1st. just doesn't work. So what's the answer to the problem apart from waiting to hear from Woosh. I thought maybe packing the front sprocket out to make it more central to the cassette, or could it be that the bottom bracket shaft is too long. Comments, please. Thanks.

 

[Deleted member 4366]

That's a big gap between the bottom bracket and the chain-wheel. I would get a bottom bracket with a much shorter spindle.

The jumping off will probably stop when the chain has worn a bit, but it doesn't look quite right being that far out of line. If you could claim back that 10 - 15 mm gap, or whatever it is, It would be a lot better. The next problem you'll have id the pedal sensor magnet disc drifting away from the sensor, especially if it gets knocked when the chain comes off.

 

[richardg6paj]

That's a big gap between the bottom bracket and the chain-wheel. I would get a bottom bracket with a much shorter spindle.

The jumping off will probably stop when the chain has worn a bit, but it doesn't look quite right being that far out of line. If you could claim back that 10 - 15 mm gap, or whatever it is, It would be a lot better. The next problem you'll have id the pedal sensor magnet disc drifting away from the sensor, especially if it gets knocked when the chain comes off.

Thanks, I'm pleased you agree it's not right. Obviously, nothing can be done at the wheel end. So it's either packing the sprocket out or like you say the bottom bracket is wrong. Yes, I'm aware of the magnet disk, looks a bit vulnerable, but not too worried about this at the moment.

 

[Woosh]

That's a big gap between the bottom bracket and the chain-wheel.

Richard has a fat bike, the choice of bottom brackets is limited.
Richard, could you post a picture of the chainline when you are on gear 8?

 

[richardg6paj]

Here's a picture of it in gear 8. Perfectly aligned. To my way of thinking it should be perfectly aligned on gear 4 or 5

 

[Woosh]

To my way of thinking it should be perfectly aligned on gear 4 or 5View attachment 20114

I see what you mean, Richard. I will look into this tomorrow.
Thank you for the pictures.

 

[richardg6paj]

So looks like in theory that the front sprocket needs moving 17mm for symmetrical alignment.

 

[Woosh]

Richard,

could you send some pictures at gear 1, 4 and 8 to support@wooshbikes.co.uk?

Many thanks

Tony