Recommended external GPS for us on a Motorbike

Discussion related to external and internal GPS / GLONASS / Galileo / BeiDou sensors
CR_Biker
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Recommended external GPS for us on a Motorbike

Post by CR_Biker »

I recently got Harry's Laptimer Grand Prix edition and want to hook it up to an external GPS for better accuracy (I have a Samsung A8 2018 android phone)

I want to use the lap timer on a track on my Triumph Street Triple - so a motorbike. Do other bikers out there do you have a external GPS you like and is easy to install and remove as needed? Ideally I want one I can install under the seat or somewhere and leave it there all the time.

Thanks
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Harry
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Re: Recommended external GPS for us on a Motorbike

Post by Harry »

The options are listed here: http://www.gps-laptimer.de/compatibility/android

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Re: Recommended external GPS for us on a Motorbike

Post by CR_Biker »

I saw those and was thinking about getting the XGPS160 but was not sure if it was ok for motorbike use. It also brought up another issue. I have the OBDlink MX bluetooth which works fine but the XGPS 160 is Bluetooth as well. As far as I can find out my phone, a Samsung A8 2018 cannot connect to two different bluetooth devices at the same time. The GoPro is ok because that is wifi but how does it work with the OBD and the GPS?

Another thing I did a test today and must have got something wrong.

I had the phone mounted basically flat as seen in this photo

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But the test video I did came out like this - https://youtu.be/afKLtrfNLoI

As you can see the lean angle indicator does not seem to work. I checked out the accelerometer being used and it is the samsung SM-530F which when I enter it in the app seems to work fine if I hold the phone flat as iI had it in the photo.

What am I doing wrong? How should I mount the phone for the lean angle and braking and acceleration to register correctly?
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Harry
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Re: Recommended external GPS for us on a Motorbike

Post by Harry »

Hello,

You can connect multiple BT devices at the same time. Complexity of the setup is certainly going up, but it will work. The GPS is mounted best to the tail. This area is not shielded by your body.

Measuring lean using acceleration on a motorbike is a sensible thing. Please see illustration #4 for the correct mounting angles for a motorbike. Make sure you select a vehicle of type Motorbike to make LapTimer use the motorbike specific calculation. You. An verify the angle by watching Analysis / Real-time / Acceleration while in the pits. You should see near zero acceleration when sitting in the bike. Acceleration view is just for testing, return to Timer before driving.

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Re: Recommended external GPS for us on a Motorbike

Post by CR_Biker »

I used the acceleration screen in real time to set the phone position exactly and it does seem better. The only thing now is that if I lean the bike left the icon leans right!
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Re: Recommended external GPS for us on a Motorbike

Post by Harry »

That should be right ;-) When leaning the bike left, you will usually go through a left corner. This means lateral acceleration (which is shown in Acceleration View) is pointing to the outside of the corner, which is right. When showing a bike lean like in an overlaid video, the lean is always the opposite of the direction of lateral acceleration.

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Re: Recommended external GPS for us on a Motorbike

Post by CR_Biker »

I see - that makes sense if you are not a biker! As a biker if I am going left I lean the bike left and so seeing it lean the other way in the graphic looks a little odd but obviously it is not a big deal. maybe in a future release you can have the motorbike mode mirror the acceleration so it switches from left to right.

So in fact it is not showing lean angle as such but g force?
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Re: Recommended external GPS for us on a Motorbike

Post by Harry »

Take care my friend, you are taking to a biker. ;-)
When lean is shown (i.e. a leaning motorbike), the lean is correct. When lateral acceleration is shown, it is correct too. It is probably a question of how you read a G-G diagram. It is showing forces, not lean. Even for a motorbike, going around a corner to the left, with a left lean, the lateral acceleration is pulling to the right or outside of the corner. This is what a G-G diagram is showing. Try to interpret it like this and you will be fine.

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Re: Recommended external GPS for us on a Motorbike

Post by CR_Biker »

OK great so as long as I just mentally switch sides the lean angle should approximate the g force and be a decent guide. Perfect thanks very much.

I plan on another test run tomorrow and will report back. A road test not on the track sadly. Here in Costa Rica there is only ONE - yes ONE track - and so I only get to go out maybe 3 or 4 times a year. Still the mountains are beautiful and the twisties are fun in the mean time
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Re: Recommended external GPS for us on a Motorbike

Post by rbono459890 »

Old thread but worth commenting for future reference - the XGPS160 seems to be a popular choice among bikers, velcro on your tail is all you need (very light) and the logging ability lets you use it w/out a phone realtime if needed.
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