Disparity between Kiox speed & GPS

[sammcneill]

Hi guys,

SuperCharger 2 - love it.

I have noticed that the speed on the Kiox display is always approx 2km faster than my GPS either based on my Garmin Edge 530 or my Garmin Fenix 5.

I am wondering if anyone else noticed this? Could be be wheel circumference is set wrong?

cheers
Sam

 

[Deacon Blues]

I have a Purion, not a Kiox, but I'm having the same problem with my display reading a couple of km fast. I'd wish it was the other way around and that it read a couple of km slower. That way instead of the motor cutting out 2km early it would go past the 32km motor cut off by a couple of kms.

 

[fooferdoggie]

this is a known bosch issue. but even GPS's don't always match my gamins can be a little off from each other.

 

[Lumos]

I my first 2021 superdelite was 12% fast, its replacement only 5% fast. The only downside is that you lose some top speed you paid for.

 

[JVBulman]

If I recall correctly, there's an adjustment that can be made via the diagnostic program, but we've not had a chance to try it out yet.

 

[sammcneill]

I my first 2021 superdelite was 12% fast, its replacement only 5% fast. The only downside is that you lose some top speed you paid for.

That’s a good point .... the engine cutting out ahead of the advertised speed.....
My daughter joked that it’s just to make “old men” feel like they are going faster than they actually are ...

i know most cars Speedometers are similarly tuned a couple of kms faster than actual speed (presumably to help
Keep people slightly under the legal speed limit) but it’s a bit of a different story on an eBike really...

 

[fooferdoggie]

on our tandem with the Intuvia I changed the wheel diameter so it is maybe .1 off from the average miles of my garmin. but still at 8.5 or so we just have a small amount of assist and by 19 its gone.

 

[SteveBorough]

I think bike shops have a little play here and can adjust +/- 2 km/h, also wheel circumference, from my understanding, is an additional micro-adjustment you can make. I have struggled with this since becoming an R&M customer and have yet to receive clear definitive info on this from my LBS

 

[sammcneill]

Hi again
i did a 50km ride test yesterday and noticed this speed disparity a lot more, especially at the 40kph + range (I have a high speed SC2).

I also attached my new Garmin cadence sensor to more scientifically determine the very high cadence required to hit 40kph+ with my Enviolo hub.

data here if anyone interested

https://strava.app.link/xK7L9RG5efb

On the way home the Kiox was saying consistently 42-45kph but the Edge 530
Was showing 38-42kph. To achieve this needed a cadence of 95-105 which is too high in my mind and shows the Enviolo is “under geared” for top end speed at the 45kph range.

hence, my interest in a Rohloff for that extra gear range!

 

[Alaskan]

If you have a Nyon, Kiox or Intuvia you can set your wheel circumference within the parameters allowed by the bike manufacturer. The upper and low limits are controlled by the bike maker based on the gearing and tires that are approved to fit on the particular model of bike. If you need to set a smaller or larger circumference, you need to bring the bike into an authorized bike brand service facility that has certified Bosch test equipment and techs.

Getting someone at the bike maker's (not Bosch's) home office to sign in and expand the acceptable range is not an easy process but that is what has to happen. My Trek Allant would not actually accept the actual circumference of the stock tires that came on the bike. There was one person back at corporate in the midwest who had "the keys" and could expand the range sufficiently. Due to covid and people working at home it took a few weeks to convince them that it needed doing and then set a day when he could sign in with the local Trek store when my bike was on line with the Bosch cloud service.

 

[sammcneill]

Interesting ... thanks @Alaskan

I guess my question would be why? Why are these not being set correctly at factory at time of manufacturing....

Not the end of the world I guess. Just one of those things

 

[Alaskan]

Interesting ... thanks @Alaskan

I guess my question would be why? Why are these not being set correctly at factory at time of manufacturing....

Not the end of the world I guess. Just one of those things

Even the most careful, conscientious people (like you and me) screw up sometimes and have to go back and make things right. I often wonder about those who expect perfection from others. Do they beat themselves up when they mess up or do they only do that to others?

 

[sammcneill]

Even the most careful, conscientious people (like you and me) screw up sometimes and have to go back and make things right. I often wonder about those who expect perfection from others. Do they beat themselves up when they mess up or do they only do that to others?

Well said and well reminded @Alaskan ! From what I've observed, the true perfectionists are more brutal on themselves than anyone else ever could be towards them.... I'd not wish perfectionist traits on my worst enemy.

 

[Johnny]

i know most cars Speedometers are similarly tuned a couple of kms faster than actual speed (presumably to help
Keep people slightly under the legal speed limit) but it’s a bit of a different story on an eBike really...

Although car speedometers also over-read, that is because there is no speed cut off in cars hence this gives companies buffer to avoid any liability in case of a speeding citation.

Bosch,(Mainstream mid drives in general) seems to over-read the speed by %5-10. May be they are trying to take into account the largest tire one can put on a specific model rather than the one that it comes with, to play it safe. However it is ridiculous that the circumference can not be properly adjusted by even by the Lbs. Also in my experience, the so called circumference adjustment on the menu does nothing to the cut off rpm(not speed, there seems to be a non-user changeable rpm limit) at the wheel. You can decrease it, the speedo will read less and get closer to gps, but your cut off speed also decreases in that case.

This deception works in manufacturers' favor. The riders feel like they can keep the advertised maximum speeds without hitting a cut off wall. The wall effect is where the motor cuts abruptly at the speed limit, it is quite frustrating. For example , a so called 28 mph limited bike actually begins to cut around 25-26mph linearly and completely turns off before reaching 28mph to prevent this effect but then the rider can never truly achieve 28mph unless it can ride at that speed without power. It is very likely that the people who think they can keep or exceed 28mph on their bikes, are actually going around 26mph at those instances.

 

[sammcneill]

Agreed Johnny....

 

[Deleted member 18083]

Ride with GPS versus Kiox …

Ride with GPS
Apple iPhone 12 Pro
Kiox / Bosch PL CX Gen1
EU specification : 25 km/h max​

• No problem with keeping GPS distance and Kiox distance in sync.
• RwGPS average speed and Kiox average speed for the full ride were exactly the same.
• Despite this, the Kiox speed was typically between 1 and 2 km/h faster than RwGPS speed!
• Motor support support fades out from just over 25 km/h and is gone by 27 km/h (as indicated by Kiox).
• And why was RwGPS indicating 0.8 km/h when the ebike was not moving? (I know: first world problem!)
  
  
• Duration (RwGPS) : time since setting off.
• Trip Time (Kiox) : time on the move.
• 5:28 – 4:44 = 44 minutes consuming coffee and snacks (and taking this photo).

 

[Johnny]

No problem with keeping GPS distance and Kiox distance in sync.

If they are synced kiox is probably using gps data to calculate average speed, distance etc. (but not the instantaneous speed).

RwGPS average speed and Kiox average speed for the full ride were exactly the same.

If they are synced as you have said then this is a direct result of the first one.

Despite this, the Kiox speed is typically between 1 and 2 km/h faster than RwGPS speed!

This is usually what many of us observe. Speed is overstated by %5-10.

Motor support support fades out from just over 25 km/h and is gone by 27 km/h (as indicated by Kiox).

How about the speed indicated by your gps at that moment? Is it 23kmh fade out to 25kmh cut off?(it should be according to your previous statement)

 

[Deleted member 18083]

It seems that I have used 'in sync' without sufficient clarification.

The distance recorded by RwGPS and by Kiox are in sync because I have set the wheel circumference in Kiox settings to achieve this.

The distance displayed by Kiox is determined by the wheel circumference setting; Ride with GPS uses satellite signals. (At least, that's my understanding.)

 

[Johnny]

The distance displayed by Kiox is determined by the wheel circumference setting; Ride with GPS uses satellite signals. (At least, that's my understanding.)

So you are saying that kiox reads 2km more for instantaneous speed but still records the correct total distance ? That is unlikely. I am not %100 certain, but it is most likely that when riding with gps kiox actually uses gps data for total distance.

 

[Deleted member 18083]

I doubt that there is any communication between RwGPS and Kiox.