# User filtered wheel speeds can't be used as driven/undriven/vehicle speed

**URL:** <https://community.ecumaster.com/t/user-filtered-wheel-speeds-cant-be-used-as-driven-undriven-vehicle-speed/6573>\
**Category:** EMU PRO\
**Created:** [September 25, 2026, 3:16am UTC](https://community.ecumaster.com/t/user-filtered-wheel-speeds-cant-be-used-as-driven-undriven-vehicle-speed/6573 "2026-09-25T03:16:17Z")\
**Posts on this page:** 1\
**Page:** 1

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**Author:** ![ScottSmith](https://avatars.discourse-cdn.com/v4/letter/s/cc9497/32.png) [@ScottSmith](https://community.ecumaster.com/u/ScottSmith)\
**Post date:** [September 25, 2026, 3:16am UTC](https://community.ecumaster.com/t/user-filtered-wheel-speeds-cant-be-used-as-driven-undriven-vehicle-speed/6573/1 "2026-09-25T03:16:17Z")

</div>

I have wired wheel speed inputs to four digital inputs of the PRO-8. Unfortunately I have an issue in hardware (wiring, frequency divider circuit, etc) that is causing sporadic 40+km/h jumps in speed for 10-15ms. This causes all sorts of havoc with the BMW DCT so I have needed to filter the wheel speeds before sending them to CANTCU.

Herein lies the problem:

1. Vehicle speed can (basically) only come from driven/undriven axle speed, which makes sense, except:
2. Driven/undriven axle speeds can only come from the individual wheel speeds, which makes sense, except:
3. The individual wheel speeds (LF/LR/RF/RR) can only come from a configured sensor, or from a specific CAN protocol, but NOT from a user channel. This is a problem because the filtering on Sensors 1-4 is insufficient.

I did try routing the wheel speeds through Turbo 1/2 freq and Gearbox input/output freq, then having sensors 1-4 use user channels, but unfortunately the resolution for turbo 1/2 frequency wasn’t sufficient for use as a wheel speed.

I guess ideally the wheel speeds (Sensors 1-4) could have stronger filtering (though I realize that would interfere with their effectiveness for traction control). Alternatively, can the individual corners (Wheel Speed / Front Left(etc) / Source) allow the use of a user variable? The consequences aren’t that bad, basically the pit limiter momentarily bounces to “Armed, speed high” state for 10ms due to the incorrect speed), so maybe this is just a “me” problem (the real answer would be to fix the wiring, or maybe connect to the MK60 ABS using CAN).

FWIW I ended up doing the following for filtering:

```auto
DeltaLF = ("sensors/wheelSpeed/sensor1/frequency" - FilteredLF)
FilteredLF = clamp(DeltaLF, -8, 8) * 0.200 + FilteredLF

```

I think I can loosen the filtering but this is working fine for me, mostly because I don’t use traction control. Here’s what the unfiltered axle speed looks like:

 ![Screenshot 2026-09-24 201217](https://europe1.discourse-cdn.com/flex013/uploads/ecumaster/original/2X/2/292620cf65635991a77ddc757dac5b916cfe79c2.png)