Help! Giant Fathom 2 2019 - Unrestriction via magnet move

maximusi

Just Joined
May 23, 2019
3
0
Dear All,

Wondered if you could help me. I tried unrestricting a brand new Fathom 2 2019 by moving the magnet to the pedals and a slight relocation of the receiver. This worked perfectly on my old Dirt-E+2 however for some reason the motor now cuts in and out ever second no matter the speed.

Has anyone tried this method or know what is going wrong? No error light flashes on the controls and the same happens when pressing walking mode.

Thanks in advance for any advice.
 

soundwave

Esteemed Pedelecer
May 23, 2015
12,052
4,947
they have upgraded the firmware so this will no longer work imo so only option now will be a dongle.
 

maximusi

Just Joined
May 23, 2019
3
0
Thanks. I have put it back to how it was however now it is giving an error light after a few seconds of cycling. Is this just saying the magnet is not quite in the right place?
 

flecc

Member
Oct 25, 2006
49,672
27,439
I don't know your model, but manufacturers are now being required to include anti-defeat software to prevent changes to the legality.

It may be that now you've tried it's recorded that so the maker or dealer sees the evidence. You could try fine adjustments to the magnet position, but if that doesn't work, check back with your dealer. They can get advice from Giant who are pretty good with dealer support.
.
 
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Fishy

Pedelecer
Nov 16, 2018
157
152
I don't know your model, but manufacturers are now being required to include anti-defeat software to prevent changes to the legality.

It may be that now you've tried it's recorded that so the maker or dealer sees the evidence. You could try fine adjustments to the magnet position, but if that doesn't work, check back with your dealer. They can get advice from Giant who are pretty good with dealer support.
.
Is this effectively the end of "dongling" then?
 

maximusi

Just Joined
May 23, 2019
3
0
I hope that I can get it working again we are going away tonight with the bikes for a long weekend!
 

soundwave

Esteemed Pedelecer
May 23, 2015
12,052
4,947
i cant see how just moving the sensor and magnet has stopped it working as the software is not that clever yet lol.

giant have there own displays and software tho so check the manual if you have one.
 

flecc

Member
Oct 25, 2006
49,672
27,439
Is this effectively the end of "dongling" then?
Not yet, the legal intentions are to stop makers incorporating defeat systems, such as button push changes in the handlebar units. It's not passed into law yet but some makers have already planned for it with current units.

Externals like dongles may still find ways round it.
.
 
D

Deleted member 25121

Guest
Your bike seems to use a Yamaha motor and Yamaha and/or Giant controller. As Flecc says, I suspect that the controller has detected that the system has been modified and has gone into what would be known as "limp mode" on a car. Hopefully your dealer will be able to reset it.

This raises the question as to how the controller could detect that the system has been modified since it doesn't know the gear you're in or the terrain. Your bike uses the "Giant PedalPlus 4-sensor technology" and
"The system uses speed and torque sensors along with motor and pedal rotation sensors to produce even power across the entire gear range. " Maybe its detected an anomaly between the sensors and has gone into limp mode to protect the system.

I'm told that the latest Bosch system can detect if modifications have been made and this is stored on the controller for the dealer and possibly Bosch to view.
 
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vfr400

Esteemed Pedelecer
Jun 12, 2011
9,822
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Basildon
Your bike seems to use a Yamaha motor and Yamaha and/or Giant controller. As Flecc says, I suspect that the controller has detected that the system has been modified and has gone into what would be known as "limp mode" on a car. Hopefully your dealer will be able to reset it.

This raises the question as to how the controller could detect that the system has been modified since it doesn't know the gear you're in or the terrain. Your bike uses the "Giant PedalPlus 4-sensor technology" and
"The system uses speed and torque sensors along with motor and pedal rotation sensors to produce even power across the entire gear range. " Maybe its detected an anomaly between the sensors and has gone into limp mode to protect the system.

I'm told that the latest Bosch system can detect if modifications have been made and this is stored on the controller for the dealer and possibly Bosch to view.
It's simple. The system already measures the crank rotation speed. When the wheel speed sensor gives out the same rpm as the crank sensor for a period of time, it can give an error code.
 

soundwave

Esteemed Pedelecer
May 23, 2015
12,052
4,947
It's simple. The system already measures the crank rotation speed. When the wheel speed sensor gives out the same rpm as the crank sensor for a period of time, it can give an error code.
seems a bit crap if that is what has happen but if your out riding and the magnet slips gets a error code and shuts off till a dealer can reset it seems a bit stupid tbh lol
 
D

Deleted member 25121

Guest
It's simple. The system already measures the crank rotation speed. When the wheel speed sensor gives out the same rpm as the crank sensor for a period of time, it can give an error code.
Good point vfr, could wheel rpm and crank rpm be the same, or very close, in normal use with one of the 10 derailleur gears selected I wonder????
 
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D

Deleted member 25121

Guest
Good point vfr, could wheel rpm and crank rpm be the same, or very close, in normal use with one of the 10 derailleur gears selected I wonder????
Answer - yes it could, I've looked at the Fathom 2 ebike details. The crankset has 36 teeth and the largest cassette gear also has 36 teeth, so one turn of the crank will produce 1 turn of the wheel.
 

Andy-Mat

Esteemed Pedelecer
Oct 26, 2018
1,861
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75
Dear All,

Wondered if you could help me. I tried unrestricting a brand new Fathom 2 2019 by moving the magnet to the pedals and a slight relocation of the receiver. This worked perfectly on my old Dirt-E+2 however for some reason the motor now cuts in and out ever second no matter the speed.

Has anyone tried this method or know what is going wrong? No error light flashes on the controls and the same happens when pressing walking mode.

Thanks in advance for any advice.
Some controllers are made for many/several wheel sizes, so selecting a smaller wheel should make the bike faster.....
But not all controllers are made for such changes I am told.
Maybe even replacing the controller with one with programming for different wheel sizes, might be a better option....new controllers are cheap.....
regards
Andy