no mph or mileage reading on purion

B Mac

New Member
Region
USA
We just purchased an Allant 7 ebike. After 26 miles the speedometer stopped working. I get the message Error 503, which means speed sensor error. I believe the speed sensor is built into the disc for the rear brakes but I don't see it or know how it works. Has anyone had this happen? I will call LBS on Monday to see what they say, if it is not an easy fix. Thanks in advance.
 
Last edited:

Luv2ride

Active Member
I ride a Trek Super Commuter, (not sure if it is the same) there is a magnet on a spoke of the rear wheel, make sure it is lined up with the sensor on the chain stay.
 

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Alaskan

Well-Known Member
Don't even try messing with this on your own. It is a warranty issue and you messing with it might preclude getting it fixed under warranty.

It is just a magnet in the rear disk rotor. If things are not working right, the magnet fell out or the sensor has an issue. The older versions had the magnet affixed to a spoke and could slide out of place if the screw was not adequately tightened. The sensor is built into the frame back there and senses how frequently the magnet goes past it. You have a great new bike, let the Trek people fix it. Our local Trek store has great people who take excellent care of my Allant+9.9S.
 

B Mac

New Member
Region
USA
I ride a Trek Super Commuter, (not sure if it is the same) there is a magnet on a spoke of the rear wheel, make sure it is lined up with the sensor on the chain stay.

Thanks for the picture. I see nothing like that on my bike, perhaps it fell off.
 

B Mac

New Member
Region
USA
Don't even try messing with this on your own. It is a warranty issue and you messing with it might preclude getting it fixed under warranty.

It is just a magnet in the rear disk rotor. If things are not working right, the magnet fell out or the sensor has an issue. The older versions had the magnet affixed to a spoke and could slide out of place if the screw was not adequately tightened. The sensor is built into the frame back there and senses how frequently the magnet goes past it. You have a great new bike, let the Trek people fix it. Our local Trek store has great people who take excellent care of my Allant+9.9S.
I don't see the magnet. I am heading to the LBS for something else next week so I will bring the bike in. Thanks for your input.
 

Alaskan

Well-Known Member
It is very hard to see on the inside of your rear brake rotor. It is a small magnetic disk, less than 1/2" in diameter, embedded in the the rotor concentric with the ring of rivets that attach the steel to the aluminum center lock spider. It is the small black thing at 6:30 in this photo

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PedalUma

Well-Known Member
Region
USA
Just curious. How does the bike feel? Does it ride nicer than when the sensor was working?
This is regardless of the readout.
 

B Mac

New Member
Region
USA
It is very hard to see on the inside of your rear brake rotor. It is a small magnetic disk, less than 1/2" in diameter, embedded in the the rotor concentric with the ring of rivets that attach the steel to the aluminum center lock spider. It is the small black thing at 6:30 in this photo

View attachment 81612
Thanks for the good picture. It is there and seems secure. I will let the LBS figure it out.
 

PedalUma

Well-Known Member
Region
USA
Thank you for the confirmation. I remove them from my builds to enhance the ride feel and to remove governors and limiters. These bikes ride great without the sensor!
 

Dallant

Well-Known Member
Remember there are lots of folks on this forum that do work on their ebikes. Some because they want to and others because they can’t afford one with the backing of a network like Trek. You bought one has that network/warranty and I highly recommend you use it and not try to work on yours. Welcome to the Allant family.
B9BCEE3F-8F43-472E-A24A-910402B25DEB.jpeg
 

B Mac

New Member
Region
USA
You remove the speed sensor from your Bosch bikes?
Remember there are lots of folks on this forum that do work on their ebikes. Some because they want to and others because they can’t afford one with the backing of a network like Trek. You bought one has that network/warranty and I highly recommend you use it and not try to work on yours. Welcome to the Allant family.View attachment 81765
Thanks for the advice. I will be taking the bike into the LBS.
 

Dallant

Well-Known Member
This is what my speed sensor looks like on my dirty Allant+7.
 

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Alaskan

Well-Known Member
This is what my speed sensor looks like on my dirty Allant+7.
That is actually the magnet attached to the brake rotor. The sensor itself is incorporated inside the left chain stay, directly inside where the kickstand mounts. You will see a short length of cable emerging from the chain stay attached to the sensor. It senses rate at which the magnet spins past it.
 

B Mac

New Member
Region
USA
I‘m very curious what’s happening so please let us know.
The LBS is 50 miles away. They are expecting a Thule Easy Fold bike rack to be coming into stock soon. I am planning to take the bike in at that time and check out the rack. I will let you know what they discover about the speedometer problem at that time. Thanks for your interest.