Distance measurement

[Swissrider]

I have done 390k on my H30 Rise, at least according to the on board STEPS computer. However, according to my Garmin edge I’ve done 337k. Yesterday I did a ride which according to my Rise was 33.9kk but my Edge said was 31.1k. Using a mapping program the route came out at 32.2k. I understand that there can be a discrepancy between GPS and measurements by wheel rotation but I’m surprised by how different the readings are - between 8% and 9% further than actual distance. I understand that there is no way of adjusting the wheel circumference to account for this difference, but is there anything else I can do?

 

[Richridesmtb]

STunlocker will help you.

 

[raymal]

I have done 390k on my H30 Rise, at least according to the on board STEPS computer. However, according to my Garmin edge I’ve done 337k. Yesterday I did a ride which according to my Rise was 33.9kk but my Edge said was 31.1k. Using a mapping program the route came out at 32.2k. I understand that there can be a discrepancy between GPS and measurements by wheel rotation but I’m surprised by how different the readings are - between 8% and 9% further than actual distance. I understand that there is no way of adjusting the wheel circumference to account for this difference, but is there anything else I can do?

Shimano / Madison (UK) will alter the wheel circumference via one of their dealers but they will need convincing that it's necessary due to the potential to circumvent the speed restriction (and to retain control of the aftermarket!). If you want to do it yourself - as Rich rides says - Stunlocker or one of the other similar apps

 

[Swissrider]

Thanks for replies. Is there a risk of invalidating the guarantee or bricking the motor with these apps? I was interested in whether other people had noticed that the distance measurement by the STEPS computer doesn’t seem to be accurate. However, if it is overestimating distance I think this means the circumference is too small (more rotations for a set distance so bike calculates it has gone further) but this also means that once the amount of rotations is reached that means the motor cuts out if wheel is bigger than set circumference one will be going faster than the 25k limit. Have I got this right? If yes, then maybe incorrect distance is a fair price to pay for higher speed cut out. I’ve read that there is a speed adjustment in the Shimano app but I can’t find it anywhere.

 

[Swissrider]

I’m fairly happy with GPS accuracy. Mountains are not problem as most important thing is clear view to the satellites. Trees and dense forest can be a problem but distances correspond well with mapping. I understand about slipping wheels but I don’t think my wheels have slipped nearly 60k in 400k! On my other bike I can adjust the wheel circumference and distance corresponds well with my Garmin, so I do think it’s the STEPS calculation which is wrong.

 

[Husky430]

Using STunlocker will definitely void your warranty after just checking the battery health on a mates bike and then him having motor issues and Shimano voiding the warranty because of STunlocker had been used on the bike. No amount of reasoning/pleading for sanity would change their mind, so just be careful. It's a real shame as it's such a better app than Shimano's Steps.

 

[vladej]

Distance measurement with Garmin Edge is much more accurate if you also have a speed sensor mounted on the front wheel hub.

 

[Swissrider]

Interesting. I’ve never heard of that. I’ll look into getting one.

 

[Longfellow78]

I have a galaxy watch and also a Garmin edge on my rise. The watch consistently shows I have ridden less than the distance on the Garmin. Also the distance on the Garmin appears to be derived from the shimano steps connection, not its own GPS for some reason.

I'm guessing the watch is more accurate, this would also suggest to me that the top speed of the bike is lower than it should be, as the assist will cut out earlier than it should if its over estimating distance.

 

[Swissrider]

If you are using the Orbea rise toolbox app the speed you get on that page is coming from the rise and will be the same as on the computer. There is only one page you can have with the Toolbox (with one data field - you choose the fields through the app or Garmin Express) but if you have another page and choose speed from the normal Garmin menu (rather than the IQ menu) you will find that the speed is no longer the same as you see on the on board computer. I think when I sync with connect it is taking the Garmin GPS distance, not the STEPS one as the distance is different to what the onboard computer is showing. If I check on the gear tab in Connect on my PC for the overall distance covered by my bike it is considerably less than the overall distance shown on the on board computer. Either the GPS (and your watch) is underestimating distance or the STEPS computer is overestimating. I tend to agree with you that it is the latter but I’m going to get the garmin device which fixes to the wheel to get a definitive answer as to which is the most accurate.

 

[neilo]

GPS may, depending on it's settings, be measuring only 2-dimensional distance travelled (X and Y axis), vs the wheel rotation which is measuring genuine distance over ground. If you ride a lot of steep hills, this could probably add up to a 10% difference in that direction (GPS showing a lower total distance). My Garmin (Fenix 6) has a setting to change to 3-d measurement but I haven't played with that myself.

 

[LeeS69]

I've always run an ant+ speed sensor on my mountain bikes as the gps can be flaky under trees etc. I haven't put one on the rise yet but I noticed last night the rise is measuring speed slightly under the wahoo, about 0.5 mph at 15mph. Might not seem much but it's notable... The Reckon is a low profile tyre, could it just be the reduced circumference over what orbea/shimano have specified??

 

[Swissrider]

Distance measurement with Garmin Edge is much more accurate if you also have a speed sensor mounted on the front wheel hub.

I’ve gone and bought a Garmin speed sensor. I calibrated it carefully (circumference 2280mm). When I’m riding I notice that the speed on the steps readout is between half and a full kph faster than the Garmin readout on my edge (I’m assuming that the Garmin will use the speed sensor rather than GPS), so it seems the Rise is reading too high which also means that assistance will cut out at a true 24kph. I guess there is no way of correcting the Rise reading as this comes from the sensor on the back disc and one cannot change the circumference of the wheel to correct over reading. Bummer!

 

[mak]

Is that 390km or 390k total distance? Just curious because that's a hell of a difference.
All 3 of my bikes onboard differ from my Garmin but to be fair the % is small, wheel slip is a good call ^^^^^^ .
Honestly, I don't think you would notice the extra help from the motor giving you that last 1kmph.

I think all manufactures have to go on the side of caution and go slightly below the legal limit. Same as a vehicle speedo.

 

[Swissrider]

That was 390km total distance. Odometer on bike now says 706Km but my Garmin says 631Km. Quite a difference! I take your point of manufactures being cautious but an 11% error seems too much. Sometimes, I have not started the Garmin the moment I've begun the ride but I would not think this would add up to more than a few Kms over the lifetime of the bike. As I said above, the speed reading is about 1 Kph lower. I believe that a Shimano service centre can change the circumference setting but have also heard that dealers have tried to do this but not been successful. Maybe I'm being a bit anal about this and it does not really matter but I like things to work the way they should. I'm using the original tyre on the rear wheel (maxis dissector) so it should be accurate. If I went for a smaller tyre, the error would be even worse. Bosch and Brose allow small changes to the wheel circumference, why not Shimano.