Our Rides in Words, Photos & Videos

[Deleted member 18083]

Home from the sea…

Scarborough Boat Harbour
Queensland​

I saw this prawn trawler coming in from the bay and pulled to the side of the bike earth to snap its entry. It must be a tough life being a trawler skipper but, I trust, one of the most interesting. No more dreaming.

 

[mschwett]

A distance from point A to B over a known route is a fixed and known value. My experience tells me GPS is doing measurement OK (otherwise car GPS navigation would make little sense). Most of speedometers/odometers for e-bikes produce values that are different from reality. Typically, the e-bike display reports longer distance ridden and higher cruising speed than is correct. Specifically, EVO displays for Giant e-bikes are notorious for overestimating the distance ridden and speed.

As Rab knows me, I'm really experienced in these matters. Interestingly, my Czech hub-drive motor e-bike on 42-622 tyres gives almost exact distance and speed as reported by GPS. My EU "speed" Vado is in agreement with GPS when ridden on stock Electrak 2.0 tyres. (The latter is the result of very accurate design by Specialized that had to prove the speedometer accuracy for EU Certificate of Conformity).

Rab, make an experiment. I'm sure there are radars with display in your area. Ride by such radar at constant speed and compare your speedometer readout with the radar readout. I'm gonna make a bet with you your EVO overestimates your speed

not to get too far off topic, but while a distance in a straight line between two points is known, vehicles don't travel in an exactly straight line at an exactly constant speed. a measurement at the wheel can take this into account, a position derived from GPS (with a meter of so of inaccuracy) every second does not. ride in a highly wiggly line at 20KPH and your gps will say you're going 18KPH because the sampling frequency is not high enough to capture "all" the motion.

as a further data point, i ride past the cycling path radar indicators on the golden gate bridge nearly every day, and while they have no decimals, they're usually the same as the mission control / creo speed indicator and often different than the relatively slowly changing GPS values in rideWithGPS or cyclemeter.

 

[Stefan Mikes]

I hate going OT but 1 or 2 km extra or even more on a long route as reported by the display is certainly wrong, compared to the actual road distance. On the last ride of Summer 2020, the EVO display on Giant Trance E+ reported 125 km; TCD-W display on Vado (with thinner tyres than certified) gave 122 km. Actual distance ridden was 121 km. Trust me, the number of tests done by several EBR members clearly proved e-bike displays are not to be trusted. Even different tyre inflation pressure gives different results!

Giant Trance E+, EVO display. The wheel circumference set by Giant is 2178 mm. Actual value (stock tyres) is 2250 mm.

Reality, by GPS.

 

[AlanDB]

My experience and observations with GPS and ebike speedometer/odometer pretty much matches what Stefan is saying. GPS inaccuracies of point positioning (sometimes referred to as GPS drift) when measuring an entire route would tend to give an inflated distance over the straighter line of travel, so you would expect the speed of the GPS to be inflated (greater distance in the same amount of time). But the opposite is true in my observations, where the ebike speedometer/distance travelled is always greater than the GPS measured distance/speed. This at least is true for the 3 ebikes I have.

 

[Deleted member 18083]

Ride with GPS: how logging interval affects recorded distance…

My experience:

• Ride with GPS set to a logging interval of one second does not result in an unacceptable track.
• At their 25 km/h pedal-assist limit my ebikes travel seven metres every second (25,000 metres ÷ 60 ÷ 60).

 

[mschwett]

i suppose it depends what you’re trying to measure! i’m more interested with how far i actually rolled, not the straightest distance on the map or between the GPS samples. a sweeping left turn (an arc) become an oddly chamfered corner of straight lines, a curb to curb zigzag up a crazy steep 20% city hill becomes an irregular wiggle down the middle of the road, riding in circles waiting for something or someone is a few fidgety starburst lines. in all cases the calibrated measurement of wheel rotations x circumference is far more accurate (and longer) than the 1 second interval GPS trace.

since we’re so far OT here, is there an existing thread to discuss this? i would love to see all the experiments that have been done!

 

[Anna]

A distance from point A to B over a known route is a fixed and known value. My experience tells me GPS is doing measurement OK (otherwise car GPS navigation would make little sense). Most of speedometers/odometers for e-bikes produce values that are different from reality. Typically, the e-bike display reports longer distance ridden and higher cruising speed than is correct. Specifically, EVO displays for Giant e-bikes are notorious for overestimating the distance ridden and speed.

As Rab knows me, I'm really experienced in these matters. Interestingly, my Czech hub-drive motor e-bike on 42-622 tyres gives almost exact distance and speed as reported by GPS. My EU "speed" Vado is in agreement with GPS when ridden on stock Electrak 2.0 tyres. (The latter is the result of very accurate design by Specialized that had to prove the speedometer accuracy for EU Certificate of Conformity).

Rab, make an experiment. I'm sure there are radars with display in your area. Ride by such radar at constant speed and compare your speedometer readout with the radar readout. I'm gonna make a bet with you your EVO overestimates your speed

Stefan I think you are right...my ride Control app for my Liv Pro said I was traveling at a record 45.7mph flying down a steep hill. Too fast...but doubt it was accurate.

 

[steve mercier]

After a trip to Burnaby mtn my overpriced TOPEAK bag , carrying a spare powerpack 500, flew out of my overpriced TOPEAK rack in the crosswalk of a major intersection. Thankfully I had insulated the heck out of inside of the bag so the battery took a licking and kept on ticking. The part that irks me is that I do not know how it came loose ,so now I cannot trust it at all. I know it is a bag that is meant for touring that I took on some blue trails but at that price it should have a better locking system.

 

[steve mercier]

May these kids grow up without remembering Covid.

 

[steve mercier]

 

[steve mercier]

 

[steve mercier]

Not a cloud in the sky over old Raincouver!

 

[steve mercier]

Race or some sort of performance horses I bet. Salt water is good for their legs or so I've heard. Notice the eyes of the horse on our left. He's a bit scared. As is the rider. The other horse and rider are there to comfort them both. Wading out into that deep of water is not an easy thing for a horse first time. I used to swim with one of my horses. He loved it. Took one to the beach with 3 foot waves once. Talk about a freaked out horse.

" There is something about the outside of a horse that is good for the inside of a man '

 

[reed scott]

" There is something about the outside of a horse that is good for the inside of a man '

So true. I miss my horses terribly but after going through a couple bad deaths I just could not see ever going through anything like that again. Sold em all.

 

[steve mercier]

So true. I miss my horses terribly but after going through a couple bad deaths I just could not see ever going through anything like that again. Sold em all.

Yep ,that is why I no longer have a dog and cat. These things seem to get harder to deal with as I age ,which is the opposite of what I thought would happen.

 

[reed scott]

Yep ,that is why I no longer have a dog and cat.

Eight years ago I was at that point . Down to one cat and he was older. Then my neighbor who raises Blue Lacy dogs took his best dog and put him in the back of my truck and would not take no for an answer. He knew I needed a dog. Rio ( the dog ) was so handsome and such a wonderful dog that I just had to go with it. He's been a wonderful friend and a good watch dog which is much needed way out here in the deep country close to the southern international border. Then a little coal black long haired kitten no more than 10 weeks old showed up out of nowhere and now he's part of the family. So my life is largely dictated by my three fur babies. Now I have to worry about out living all of em.

 

[Twin Valley]

Not a cloud in the sky over old Raincouver! View attachment 84824

great Steve - that means those of us on the other side of the Rocky Mountains will look forward to that!!!

 

[steve mercier]

great Steve - that means those of us on the other side of the Rocky Mountains will look forward to that!!!

Yep, you will need a litre of sunscreen now !

 

[steve mercier]

Eight year ago I was at that point . Down to one cat and he was older. Then my neighbor who raises Blue Lacy dogs took his best dog and put him in the back of my truck and would not take no for an answer. He knew I needed a dog. Rio ( the dog ) was so handsome and such a wonderful dog that I just had to go with it. He's been a wonderful friend and a good watch dog which is much needed way out here in the deep country close to the southern international border. Then a little coal black long haired kitten no more than 10 weeks old showed up out of nowhere and now he's part of the family. So my life is largely dictated by my three fur babies. Now I have to worry about out living all of em.

View attachment 84826

View attachment 84831

Hah ! NICE.

 

[steve mercier]

Stefan I think you are right...my ride Control app for my Liv Pro said I was traveling at a record 45.7mph flying down a steep hill. Too fast...but doubt it was accurate.

Wow ...You are a speed demon Anna!