Intermittent cut out

[Faz]

Hi all, new to this site.
I wonder if anyone can help me please? I have a Freego folding bike (4 years old) We were out on a ride yesterday and everything was working ok. However, as I was going up a particularly steep hill the bike's assist started intermittently cutting out. This continued for the rest of the ride (in every gear and at all 5 levels of assist) The cut outs coincide directly with the rotation of the pedals. Can you offer any advice please? The battery was full of life as my bike's throttle is enabled and it worked fine when engaged.

 

[Nealh]

Two issues spring to mind;
1. Pedal assist has been knocked out of alignment check the BB area for a magnetic disc and wired sensor, the disc magnet gap to sensor should be about 1- 2mm also the disc should be firm on the BB axle. If the disc rotates on the axle by hand then it needs securing, often the plastic tangs that hold it in place break or lose their grip.
A couple of wraps of insulating tape or amalgam tape around the axle and then push disc firmly on to tape to stop movement.
2. The battery could be showing ageing, voltage sag on hills is a common feature of this esp under higher assist level and current load.

One can also check the phase wire connections to the controller to check for burning/heat build up on the plastic insulator sleeves.

 

[vfr400]

Have a look at the pedal sensor behind the chainwheel. there are two potential problems which would cause what you describe: Firstly, the magnet disc could be slipping on the shaft. Put some light finger pressure on it while you turn the crank. If that stops the magnet disc from turning, then you need to take the crank off and put a couple of turns of tape on the shaft to make the grip tighter. Secondly, the disc might have been knocked out of line. There should be a constant gap to the sensor of about 1mm while the disc rotate. If it's a bit crooked, straighten it up. if the gap is too big, wiggle the disc closer to the sensor.

 

[Faz]

Two issues spring to mind;
1. Pedal assist has been knocked out of alignment check the BB area for a magnetic disc and wired sensor, the disc magnet gap to sensor should be about 1- 2mm also the disc should be firm on the BB axle. If the disc rotates on the axle by hand then it needs securing, often the plastic tangs that hold it in place break or lose their grip.
A couple of wraps of insulating tape or amalgam tape around the axle and then push disc firmly on to tape to stop movement.
2. The battery could be showing ageing, voltage sag on hills is a common feature of this esp under higher assist level and current load.

One can also check the phase wire connections to the controller to check for burning/heat build up on the plastic insulator sleeves.

Many thanks for the Info.
Have checked and this bike doesn't have sensor on the spokes so must be a different type of mechanism?
The battery seems to be fine as it "flew" on the last mile back to the car on throttle.
I think I will check the controller as this seems to be the only option left to me.
Cheers

Faz

 

[Faz]

Have a look at the pedal sensor behind the chainwheel. there are two potential problems which would cause what you describe: Firstly, the magnet disc could be slipping on the shaft. Put some light finger pressure on it while you turn the crank. If that stops the magnet disc from turning, then you need to take the crank off and put a couple of turns of tape on the shaft to make the grip tighter. Secondly, the disc might have been knocked out of line. There should be a constant gap to the sensor of about 1mm while the disc rotate. If it's a bit crooked, straighten it up. if the gap is too big, wiggle the disc closer to the sensor.

 

[wheeliepete]

Have checked and this bike doesn't have sensor on the spokes so must be a different type of mechanism?

The PAS sensor and disc are on the crank of the bike, not the wheel/spokes.

 

[Faz]

Thanks for your advice.....found the culprit! The ring holding the magnets has fractured with at least 2" of the section missing (2 magnets as well) great advice from you both thank you! All I need to find out now is where to get the parts!

 

[Faz]

The PAS sensor and disc are on the crank of the bike, not the wheel/spokes.

Found it thanks, its smashed!

 

[Nealh]

One can use/buy any generic 3 wired pedal sensor/disc, have a look on ebay for 8 or 10 pole ones. Discs can be bought on there own but it often works out cheaper to buy the pair as one unit and only fit the disc, as one only needs the disc buy the cheapest you can find as the discs all do the same thing.

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One will need to extract the crank arm and chain rings to fit the new disc so buy a cheap crank puller.

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[Faz]

One can use/buy any generic 3 wired pedal sensor/disc, have a look on ebay for 8 or 10 pole ones. Discs can be bought on there own but it often works out cheaper to buy the pair as one unit and only fit the disc, as one only needs the disc buy the cheapest you can find as the discs all do the same thing.

Electric Bike 12 Magnet PAS Pedal Assist Sensor Cadence Replacement Uprated Disc | eBay

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One will need to extract the crank arm and chain rings to fit the new disc so buy a cheap crank puller.

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Thank so much for your brilliant advice, parts ordered! cheers, Faz

 

[vfr400]

Thank so much for your brilliant advice, parts ordered! cheers, Faz

Hold on there, you're too quick. Can you measure the diameter of the disc? The one I fixed with the same problem on a Freego had a larger than usual one (about 80 - 90 mm), which is why I had to bodge the only one I had that size (see below). Normal discs are about 65mm, so the magnets don't line up with the sensor and it won't work. The one you ordered looks like a 65mm one

If you can't get the right size disc, you have to replace the sensor as well as the disc, which is a bit more work because you have to remove the bottom bracket assembly.

You will probably find that 12 magnets swamps the sensor. Try it first, and if it doesn't work, press out every other magnet to leave 6. That's what I had to do when fitting a 12 magnet disc to a Freego.

When you try the new disc, don't forget that it only works one way up. Test it forwards and backwards. if it works backwards, flip the disc. Test it before you reassemble the crank to avoid a lot of work.

This one is 76mm:

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IIRC, I used one of these, which is 88mm:

Pardon our interruption...

 

[Nealh]

12 pole stock Freego disc on ebikes direct is 65mm, though out of stock.

 

[vfr400]

12 pole stock Freego disc on ebikes direct is 65mm, though out of stock.

As I said, the Freego I fixed that had a section broken out of the disc had a very large disc. All will be resolved when they measures theirs. It's easy to check. I'm only warning of a potential problem. There are a lot of different models and versions of Freegos.

 

[Faz]

Hold on there, you're too quick. Can you measure the diameter of the disc? The one I fixed with the same problem on a Freego had a larger than usual one (about 80 - 90 mm), which is why I had to bodge the only one I had that size (see below). Normal discs are about 65mm, so the magnets don't line up with the sensor and it won't work. The one you ordered looks like a 65mm one

If you can't get the right size disc, you have to replace the sensor as well as the disc, which is a bit more work because you have to remove the bottom bracket assembly.

You will probably find that 12 magnets swamps the sensor. Try it first, and if it doesn't work, press out every other magnet to leave 6. That's what I had to do when fitting a 12 magnet disc to a Freego.

When you try the new disc, don't forget that it only works one way up. Test it forwards and backwards. if it works backwards, flip the disc. Test it before you reassemble the crank to avoid a lot of work.

This one is 76mm:

Electric Bike 12 Magnet PAS Pedal Assist Sensor Cadence Replacement Disc - XL | eBay

Find many great new & used options and get the best deals for Electric Bike 12 Magnet PAS Pedal Assist Sensor Cadence Replacement Disc - XL at the best online prices at eBay! Free delivery for many products!

www.ebay.co.uk

IIRC, I used one of these, which is 88mm:

Pardon our interruption...

Hi, that's me impulsive! I measured the existing disk which is approximately 70mm and ordered the official Freego version which is expensive at £14, and also the cheaper version suggested as "back up". The existing disk is 12 magnets (as are the replacements). Being "non techno" I am perpexed as to what swamping the sensor means? Is it that it hasn't got chance to recognise connection as the magnets are too close together? The original seemed to work fine? Sorry but this is way beyond my knowledge.
am really appreciating the knowledge you have and advice being given

 

[vfr400]

Hi, that's me impulsive! I measured the existing disk which is approximately 70mm and ordered the official Freego version which is expensive at £14, and also the cheaper version suggested as "back up". The existing disk is 12 magnets (as are the replacements). Being "non techno" I am perpexed as to what swamping the sensor means? Is it that it hasn't got chance to recognise connection as the magnets are too close together? The original seemed to work fine? Sorry but this is way beyond my knowledge.
am really appreciating the knowledge you have and advice being given

If you have a normal sized disc, you'll be fine. 70mm is normal. Panic over.

 

[Faz]

If you have a normal sized disc, you'll be fine. 70mm is normal. Panic over.

If you have a normal sized disc, you'll be fine. 70mm is normal. Panic over.

If you have a normal sized disc, you'll be fine. 70mm is normal. Panic over.

Phew! a steep learning curve! Thanks for all the advice, next step will be fitting it, that said, I have the tools so no excuses!

 

[Nealh]

All you have to do is fit the disc correctly, it should indicate outer or inner face. If fitted incorrectly the PAS will work when you pedal backwards so if that occurs one simply swaps the disc facing.