Rail (750Wh) Bosch Smart V5 update Mileage/Speed error

timohe

New Member
Feb 16, 2023
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Finland
Meaning all the 9.8:s and 9.9:s 750 Smart System Trek bikes must be modified with Bosch sensors. There must be thousands of them. At the same time they are selling new Gen 3 or Gen 4 Treks like no worrys knownig the bike is a mess after the first Flow update?
 

Jeremybub

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Jan 17, 2021
78
51
California
Meaning all the 9.8:s and 9.9:s 750 Smart System Trek bikes must be modified with Bosch sensors. There must be thousands of them. At the same time they are selling new Gen 3 or Gen 4 Treks like no worrys knownig the bike is a mess after the first Flow update?
Yeah, my bike is less then 2 months old and I am feeling the pain of a $10000 including tax sitting at a Trek shop with no confirmed correction in site,
& yes I would say TBD at this point. If the Bosch parts fix my bike we’ll all know what needs to be done. How Trek deals with the rear triangle modification or they work with Bosch to develop a speed sensor cable that fits the cut out is the unknown.
 

Paul Mac

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The truth of the matter is it is a quick fix if Trek just acknowledge it.
The valve magnet is £14 and then you just delete the hard wired speed sensor and enable the built-in sensor which is already in the motor, via the Bosch dealer computer.
No additional hardware is needed.
 

Jeremybub

Member
Jan 17, 2021
78
51
California
The truth of the matter is it is a quick fix if Trek just acknowledge it.
The valve magnet is £14 and then you just delete the hard wired speed sensor and enable the built-in sensor which is already in the motor, via the Bosch dealer computer.
No additional hardware is needed.
Interesting, Do you have a link to that information on the built-in sensor?
 

JP-NZ

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Feb 17, 2022
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Christchurch - New Zealand
Meaning all the 9.8:s and 9.9:s 750 Smart System Trek bikes must be modified with Bosch sensors. There must be thousands of them. At the same time they are selling new Gen 3 or Gen 4 Treks like no worrys knownig the bike is a mess after the first Flow update?
Thats my issue.

Why did Bosch not test the update on Trek magnets (if that is indeed the issue) before pushing the update out. They know Trek have thousands of Bosch smart system bikes out there.
 

Jeremybub

Member
Jan 17, 2021
78
51
California
🧐Why the heck is Trek not using this magnet!!!


I’ve been chatting with the Pole folks for a couple weeks now about a bike build, now it looks like I’ll be pulling the trigger on a Voima.
 
Last edited:

Paul Mac

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🧐Why the heck is Trek not using this magnet!!!


I’ve been chatting with the Pole for a couple weeks now about a bike build, now it looks like I’ll be pulling the trigger on a Voima.
You and me both for the Voima
 

Zimmerframe

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Jun 12, 2019
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I thought we started speaking about the motor/rim magnet option in post 67 ... ?

1676983155185.png
 

Jeremybub

Member
Jan 17, 2021
78
51
California
I thought we started speaking about the motor/rim magnet option in post 67 ... ?

View attachment 107321
I thought we started speaking about the motor/rim magnet option in post 67 ... ?

View attachment 107321
Hey ZimmerFrame
So your thoughts are Bosch enabled the magnet sensor in the motor, & Trek has its own magnet/speed sensor cable and a 6 bolt magnet on the hub, so as the wheel rotates the motor and speed/mile sensor cable is picking up the Trek oddly oblong magnet on the hub doubling the speed and miles?
 

Zimmerframe

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Hey ZimmerFrame
So your thoughts are Bosch enabled the magnet sensor in the motor, & Trek has its own magnet/speed sensor cable and a 6 bolt magnet on the hub, so as the wheel rotates the motor and speed/mile sensor cable is picking up the Trek oddly oblong magnet on the hub doubling the speed and miles?
It's a possibility - obviously unlikely though. I'm sure people would have noticed if there was a magic magnet mounted somewhere inside their Rim's. Just drop your bike in a huge box of paperclips and see where they're attached to afterwards ;-)

Wasn't sure if any of the rails used the rim magnet as standard or not or if anyone had tried it as an easy fix. The sensor option had to be changed by a dealer previously unless they have enabled both by default with the latest update.

Things to keep in mind with the rim magnet.

If you want to de-restrict - this will be CONSIDERABLY more difficult.

The field strength is monitored and can error if it thinks the strength is incorrect (too near/too far away) so it possibly needs to be calibrated as well as "enabled". (Hall effect)

Theoretically you could run a slightly smaller magnet if you mounted it inside the rim as it would be nearer the sensor, but this would lead to it's own issues.

Remember, if you buy one of these magnets (EB11200015) and run a presta valve (Which you probably do), you also need the sleeve (EB1120002S):

1676989152798.png
 

Zimmerframe

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Another thing to try, which I know is grasping at straws again ..

But if the problem is from the system compensating because it thinks there is spurious/de-restriction data/echo, is to re-align your magnet, as conveniently demonstrated in this thread to save me any work .. :-D


Standard fitting :

1676989692373.png


Modified install so the magnet runs directly past the sensor (you may need to put a washer behind the sensor so it cansit flush):

1676989724234.png


1676989749812.png
 

Jeremybub

Member
Jan 17, 2021
78
51
California
It's a possibility - obviously unlikely though. I'm sure people would have noticed if there was a magic magnet mounted somewhere inside their Rim's. Just drop your bike in a huge box of paperclips and see where they're attached to afterwards ;-)

Wasn't sure if any of the rails used the rim magnet as standard or not or if anyone had tried it as an easy fix. The sensor option had to be changed by a dealer previously unless they have enabled both by default with the latest update.

Things to keep in mind with the rim magnet.

If you want to de-restrict - this will be CONSIDERABLY more difficult.

The field strength is monitored and can error if it thinks the strength is incorrect (too near/too far away) so it possibly needs to be calibrated as well as "enabled". (Hall effect)

Theoretically you could run a slightly smaller magnet if you mounted it inside the rim as it would be nearer the sensor, but this would lead to it's own issues.

Remember, if you buy one of these magnets (EB11200015) and run a presta valve (Which you probably do), you also need the sleeve (EB1120002S):

View attachment 107323
You’re killing it with all this information.
I’ll let Trek and Bosch figure out what is going on first with my bike, maybe just maybe this is what Trek and Bosch are going to come up with to solve the issue.
Only issue is Trek will now need to come up with a problem solver for the gapping hole in the rear triangle where the Trek sensor is located.

BTW, no need to de-restrict I’m in the USA so 19.9mph is more the fast enough for me.
 

Mikerb

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May 16, 2019
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The speed sensor sends a signal per rotation and the motor software multiplies that by "pye" x the wheel diameter. So for a rim magnet signal being sensed by the motor that is 1 signal per wheel rotation. For a sensor/magnet arrangement on the brake disc there would be (probably) 2 signals per wheel rotation. So I wonder if the magnet used by Trek is powerful enough to be being picked up by the motor? Maybe some form of shield (tin foil) on the chainstay ( as a test..not permanent) would block the magnetic field from that magnet being sensed by the motor sensor?? That hypothesis would only make sense if the latest firmware update did indeed enable the speed sensor in the motor or overrided any option in the Bosch analysis software to have that sensor disabled.
 

Jeremybub

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Jan 17, 2021
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The speed sensor sends a signal per rotation and the motor software multiplies that by "pye" x the wheel diameter. So for a rim magnet signal being sensed by the motor that is 1 signal per wheel rotation. For a sensor/magnet arrangement on the brake disc there would be (probably) 2 signals per wheel rotation. So I wonder if the magnet used by Trek is powerful enough to be being picked up by the motor? Maybe some form of shield (tin foil) on the chainstay ( as a test..not permanent) would block the magnetic field from that magnet being sensed by the motor sensor?? That hypothesis would only make sense if the latest firmware update did indeed enable the speed sensor in the motor or overrided any option in the Bosch analysis software to have that sensor disabled.
FYI,
One of the other per Bosch which make since

Bosch eBike Systems
Good Morning Jeremy,

The drive unit on your eBike has basically two different ways that is can measure speed. Your eBike is programed for a wired speed sensor and a rotor magnet. This is the most common way.

The other way is for the drive unit to read the speed with a magnet that is mounted on the value stem. Your eBike is capable of this but you would need a Valve Stem magnet and Trek would need to reprogram the eBike remotely in order for this to work.

With these two sensors, it's basically a either/or situation so one is always working and the other way is always turned off. When Matt sent over the Diagnostic Report for your eBike we confirmed that everything is setup correctly for the wire wheel sensor.

The replacement Bosch magnet and Bosch Speed Sensor were sent out on Monday from our Minnesota warehouse and should arrive on Thursday. I'm very confident that this will fix the issue. I understand that this is a major hassle but we will get it fixed for you.
 

Mikerb

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Since the speed calculation maths built into the firmware must be unchanged ( otherwise the new firmware would impact on other bikes besides Treks), it seems the only thing that can be different with Trek is the type of Hall Effect sensor used (e.g. uni polar or bipolar). It suggests that the firmware update included some additional anti hacking change in terms of what form of signal it was prepared to accept, with the type of sensor being used by Trek delivering the same type of signal common to latest derestriction devices.
All just guesswork ( I love a mystery!!) and I doubt Bosch will ever be forthcoming in exposing the reason for the Trek issue, whilst fitting the Bosch sensor will indeed fix the problem.
 

Jeremybub

Member
Jan 17, 2021
78
51
California
Since the speed calculation maths built into the firmware must be unchanged ( otherwise the new firmware would impact on other bikes besides Treks), it seems the only thing that can be different with Trek is the type of Hall Effect sensor used (e.g. uni polar or bipolar). It suggests that the firmware update included some additional anti hacking change in terms of what form of signal it was prepared to accept, with the type of sensor being used by Trek delivering the same type of signal common to latest derestriction devices.
All just guesswork ( I love a mystery!!) and I doubt Bosch will ever be forthcoming in exposing the reason for the Trek issue, whilst fitting the Bosch sensor will indeed fix the problem.
Yeah, very intriguing, I’ve become over consumed with understanding this, my wife will be very happy when it’s all over so we can go back to snuggle time ❤️
 

blob

New Member
Feb 22, 2023
23
7
Croatia
Even if the valve magnet is a solution, I guess it's not the solution for bikes with Tyrewiz? Can they work together?

Btw, I have the same problem on my week old Trek Rail 9.9 (2022 model). :(
 

scooby82r

Member
Aug 15, 2020
81
47
Manchester, England
OK spoken to my dealer and they are willing to do an interim fix.
They can add a rim magnet and activate in the dealer software.
This has been tested and works.

Or wait for the Trek /Bosch fix which they've been told is imminent.
 

Rob Rides EMTB

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OK spoken to my dealer and they are willing to do an interim fix.
They can add a rim magnet and activate in the dealer software.
This has been tested and works.
I have also heard that this is the current fix for this issue. It seems at the moment that the Trek proprietary speed sensor magnet is causing this issue.
 

Rob Rides EMTB

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This is what is needed (along with the centre sleeve) - although I lost one on another bike, and purchased it and ran without the centre sleeve!


Then the dealer will need to activate this in their software..
 

Mikerb

E*POWAH Elite World Champion
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I have also heard that this is the current fix for this issue. It seems at the moment that the Trek proprietary speed sensor magnet is causing this issue.
I suspect it is the type of sensor rather than the magnet...............I think someone further up the thread tried using a different magnet and it made no difference.
 

Zimmerframe

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I suspect it is the type of sensor rather than the magnet...............I think someone further up the thread tried using a different magnet and it made no difference.
I suspect it's a combination.

Lets face it, Trek wouldn't go out of their way to develop their own sensor and alternative magnet when there are off the shelf items they can just procure from Bosch which will work.

Presumably when they were making the frame they realised that they couldn't use the standard sensor/magnet combination and had to develop their own.

This relies on a larger magnet on the disk and an offset sensor. This must of complied with the Bosch system at the time, but with the latest update, it operates outside of the parameters.

I suspect with the offset magnet the system now reads a magnet arriving signal and a magnet departing signal so it's doubling up.

By rotating the existing magnet on one bolt to line up with the signal it should just receive a single clear signal. You could even just unbolt the Trek magnet and stick a magnet on the disk to line up with the sensor.

With the single bolt magnet mount or the floating magnet, you run the risk that it could move/dislodge, so ideally someone will make a triangular magnet mount to offset the magnet from the standard disk holes, or 3d print a cage (triangle with a round hole in it) to hold the floating magnet in place against the disk.
 

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