Old School Speedo

[HornetMaX]

Hi all,

just to prove I'm not totally against our old-school friends (2 strokes, bikes from the '70s, riding with leather helmets and so on), here's a suggestion that should make them happy.

On old bikes, the speedo is mechanically linked to the wheel or (more recently) electronically "linked" to it. This means that it measures the wheel's speed, not really the bike's speed.

Now that GPB takes into account the wheel radius change when leaning, if a bike has a speedo linked to the wheel (electronically or mechanically), the speed should change when you lean the bike.
In GPB the speed does not change, because the speedo is using the real bike speed (e.g the GPS-measured speed).

On "old" bikes (pre GPS era likely, pre-electronic at any rate), GPB could offer the option to modders to use the "wheel measured speed" instead of the real bike speed: this would mean that when you lean at corner entry, not only you hear the RPMs go up, but you also see the speedo speed go up (of course your real speed does not go up).

MaX.

[Hawk]

Hi all,

just to prove I'm not totally against our old-school friends (2 strokes, bikes from the '70s, riding with leather helmets and so on), here's a suggestion that should make them happy.

On old bikes, the speedo is mechanically linked to the wheel or (more recently) electronically "linked" to it. This means that it measures the wheel's speed, not really the bike's speed.

Now that GPB takes into account the wheel radius change when leaning, if a bike has a speedo linked to the wheel (electronically or mechanically), the speed should change when you lean the bike.
In GPB the speed does not change, because the speedo is using the real bike speed (e.g the GPS-measured speed).

On "old" bikes (pre GPS era likely, pre-electronic at any rate), GPB could offer the option to modders to use the "wheel measured speed" instead of the real bike speed: this would mean that when you lean at corner entry, not only you hear the RPMs go up, but you also see the speedo speed go up (of course your real speed does not go up).

MaX.

Hi Max.
Speedo's.... SPEEDO'S!!
I know I'm getting on a bit Max, but I'm not that old yet. Lol 

What era you talking about? I can't ever remember GP race bikes having a "Speedo".

Hawk.

[Klax75]

I don't want to hear old... and speedo in the same phrase.... ever...

lol

[HornetMaX]

Yeah, it's a bit unusual on race bikes, but i'm sure once you'll have had your overdose of rusty gp bikes, you'll ask for rusty road bikes ... just anticipating the need 

Ouch, you discovered my real intentions with this post ... damn you ....

MaX.

[EdouardB]

Yeah I've never seen a speedometer on real race bikes (production racers and factory racers), they were pretty much useless before electronics.

Also I want to point out that GPS systems are forbidden in MotoGP. The speed is still measured by wheel rotation (they have sensors front and rear for traction control purposes) and probably also lean angle and they can extrapolate the actual "GPS" speed of the bike.

As for modern sportbikes, the speed is almost always measured at the gearbox output (pinion). The speed actually becomes wrong if you change sproket sizes and all. And on those bikes, like I said before, the measured speed increases when you lean over of course.

[EdouardB]

And on MotoGP dashboards, when riding, they usually show RPM, Temp, gear, TCS setting, shift lights and that's about it for the main things.

[HornetMaX]

Thx EdouardB.

Even when I try to be nice to the old school gang, I can't

Also I want to point out that GPS systems are forbidden in MotoGP.

Oh strange, because I've heard and read that today in MotoGP they can tune different things on the bike (mostly the engine power delivery) depending on where exactly the bike is on the track. How do they know where the bike is on the track then ?

MaX.

[EdouardB]

I confirm, no GPS (you can find it in the MotoGP reglementation that probably can be found on the net).

They still know exactly where the bikes are on the track though. They are measuring wheel speed, lean angles, all the accelerations with all sorts of sensors and gyros (x,y,z) so with electronics you can calculate exactly where the bike is on the track (which defeats the purpose of having a GPS, but that's another story ).

Occasionnaly a bike is "confused" on the track, which happened to Nicky Hayden a few years ago on Ducati and ruined his GP...

[EdouardB]

Extract from the regulation: "15. Only DORNA can supply GPS unit just for entertainments such as TV broadcasting, which can't connect to CPU unit by any kind of system."

[tseklias]

As for modern sportbikes, the speed is almost always measured at the gearbox output (pinion). The speed actually becomes wrong if you change sproket sizes and all. And on those bikes, like I said before, the measured speed increases when you lean over of course.

<-this is completely right

this is a nice post and i agree with it. ofcourse race bikes didnt have a speedo but all other old road bikes 2 or 4 stroke measured the speed from the front wheel(except from leaning-who wouldnt enjoy doing a wheelie and have a speed indicate of 60km/h[and falling] and when he lands the front wheel the speedo go instantly to the actual speed)

also all the small cc bikes even nowadays measure the speed from the front wheel. it will be a very nice addon if it became available.

[HornetMaX]

I confirm, no GPS (you can find it in the MotoGP reglementation that probably can be found on the net).

They still know exactly where the bikes are on the track though. They are measuring wheel speed, lean angles, all the accelerations with all sorts of sensors and gyros (x,y,z) so with electronics you can calculate exactly where the bike is on the track (which defeats the purpose of having a GPS, but that's another story ).

Occasionnaly a bike is "confused" on the track, which happened to Nicky Hayden a few years ago on Ducati and ruined his GP...

Hmm, very interesting and, once again, pretty silly from dorna (but then, that's not a big news).

I'm not sure they know exactly where the bike is: even using gyros and all sort of sensors it's pretty hard to get good precision over a significant lapse of time. But maybe they need only a rough position along the track, so it's ok.

I still hate the concept though, even if it's not GPS based, I hate automagic stuff varying things knowing where you are.

MaX.

[EdouardB]

I'm not sure they know exactly where the bike is: even using gyros and all sort of sensors it's pretty hard to get good precision over a significant lapse of time. But maybe they need only a rough position along the track, so it's ok.

The thing is, motoGP riders do lap after lap after lap exactly the same way so it becomes very repetitive so I think the system is probably extremely precise. They have processors in there that can calculate all sorts of things and, considering how many sensors they have and how the input is almost always the same I suspect it's very precise.

For example on a lot of tracks you have specific bumps at the apex that the rider always hits and the sensors feel so you have a lot of ways to tell the bike where it is on the track.

All of this research s**t is probably more expensive in ressources than simply putting a GPS on the bike, but viva la dorna

[EdouardB]

Even in World Supersport they have turn by turn tuning with no GPS (and riders say it's surprisingly precise) so, considering MotoGP is even more evolved, I think this is precise stuff

[HornetMaX]

But you can still do some unexpected stuff (like go wide for once, take a different line to overtake, etc).
With only bike sensors (including gyros, accelerometers and so on) it's a bit of a nightmare (I played with all this stuff for space applications).
It is definitely possible to know that you are approaching turn 5, 50m away from it, but exact position on track ... sounds hard.

GPS would need these sensors too as it's likely to be not quick enough and probably not even precise enough by itself.
But yes, it would be far easier than doing the same thing without GPS.

MaX.

[EdouardB]

Yeah I guess when you go wide it becomes less precise but after a few turns you're back to normal again. It's complicated I know that in Nicky Hayden's case the bike got completely confused and thought he was all over the track lol.

And when I say "super precise", it's not 10cm. I think "approaching turn 5, 50m from it" is really precise already considering you have no GPS!

And yes, a GPS would be used with the other sensors if it was allowed. They use everything they can...

I don't like the overall concept of knowing where the bike is on the track honestly, it adds so much complexity while the improvement on the lap time is there but not THAT significant.

In Formula 1 I remember that at some point in the 80s the pits could communicate with the F1s to change the setup live without the driver doing anything It quickly was forbidden but it's the same sort of electronics non sense.