• Welcome to PiBoSo Official Forum. Please login or sign up.
 
June 14, 2021, 10:08:15 PM

News:

GP Bikes beta19b available! :)


Gearing

Started by C21, November 09, 2013, 12:20:18 PM

Previous topic - Next topic

C21

i don´t know if this is the right section....

The gearing of the 125cc in demo mode (don´t know if this makes a difference) is not equal to the speed capable by the bike itself.
for example: i´ve set the 6th gear to: 31/28 Final Drive 15/34 -> 263km/h top speed , but the bike´s top speed is 221km/h out of the track and displayed in the speedo (matched by the datalogger files).
The 125cc is never able to reach the speed displayed behind the gearing  ;)
Is this a bug or is this the way it is until now?

-------------
Sorry, i´m new to this game...maybe it´s an old dumb question.
# Member of the CAWS Racing Team #


Hawk

Quote from: C21 on November 09, 2013, 12:20:18 PM
i don´t know if this is the right section....

The gearing of the 125cc in demo mode (don´t know if this makes a difference) is not equal to the speed capable by the bike itself.
for example: i´ve set the 6th gear to: 31/28 Final Drive 15/34 -> 263km/h top speed , but the bike´s top speed is 221km/h out of the track and displayed in the speedo (matched by the datalogger files).
The 125cc is never able to reach the speed displayed behind the gearing  ;)
Is this a bug or is this the way it is until now?

-------------
Sorry, i´m new to this game...maybe it´s an old dumb question.

This is something I have noticed too. I don't know if the top speed stated by the Drive Train in GP Bikes is correct? But I do know that the top speed on the longest straight of the track your riding on depends on the direction of the wind and just as important is your ability to exit the last corner onto that straight at the fastest possible exit speed for you to obtain the maximum advantage from the optimised gearing for that particular track.

Something I have not tried is under-gearing the final gear so that the top speed for that gearing should be easily attained, and therefore you should be able to see if the speed stated on the Drive Train is achievable? Give it a try.... It will be interesting..... Let us know.  :)

C21

Short answer because i´m in a hurry... ;)

No, it is not possible to achieve it. If i gear it according the displayed gear speed in the garage i have to gear the final drive to 14/37.  This equals to a 6th gear in 31/28 and 226km/h top speed.
If i drive out on the track in this config i achieve a top speed of 206km/ at 14500rpm, 6th gear.

Thank´s for your reply :)
# Member of the CAWS Racing Team #


HornetMaX

I think the gearing top speed is only a theoretical one, it does not include the aerodynamic drag.
Hence the real top speed you can achieve is lower.

MaX.

PiBoSo

Quote from: HornetMaX on November 09, 2013, 10:06:34 PM
I think the gearing top speed is only a theoretical one, it does not include the aerodynamic drag.
Hence the real top speed you can achieve is lower.

MaX.

This.
It also doesn't count rear tyre slip, that can be high even in 6th gear on a very powerful bike.
"Obviously your ambition outweighs your talent".

HornetMaX

Quote from: PiBoSo on November 09, 2013, 10:09:28 PM
Quote from: HornetMaX on November 09, 2013, 10:06:34 PM
I think the gearing top speed is only a theoretical one, it does not include the aerodynamic drag.
Hence the real top speed you can achieve is lower.

MaX.

This.
It also doesn't count rear tyre slip, that can be high even in 6th gear on a very powerful bike.
Exact. This is actually the thing that made the engineers think about the big bang engines: they were seeing unexpected differences in bike speed vs rear wheel speed (on long straights) and when they realized they were due to rear tire slippage ...

MaX.

C21

To make it short:
@Piboso
Could you explain how the maximum speed behind each gear is calculated?
Thanks for your replies.

To be honest: this way it is now did not make any sense to me....

Driving 6th gear flat out into the rev limiter at (let me guess) 14500rpm hitting 209km/h as a maximum top speed the bike can reach with this gearing but displaying 226 km/h on the gear table within the garage is far away from reality........and i did not see that in any other motorcycle game (e.g. GP500) ;-)

Even in real race life....for example: I´ve driven a 250GP Production Racer for one year on the race track and within the manual was a gearing table for each gear option with a maximum vehicle speed for each gear combination at redline. The printed vehicle speed in the manual was close to the vehicle speed the bike could reach at the fastest part of the track depending on wind and climb of the track. It was easy to get a good gearing within time only by looking into the gear/vehicle speed table.
This is not possible within GPBikes right now  ;)

I´m only looking for improvements :D
# Member of the CAWS Racing Team #


HornetMaX

How it is calculated in GPB is simple: engine RPM, gear ratio, transmission ratio, tyre radius (outer).

What you are basically asking is to factor in the other factors (aerodynamic drag and rear tyre slip).
I suspect your tables only keep the aero thing into account (and in an approximate manner).

But is it a big deal ? I mean, usually you go out with the default gearing, a couple of laps and then you've a good idea of what the right gearing should be ...

MaX.

C21

QuoteBut is it a big deal ? I mean, usually you go out with the default gearing, a couple of laps and then you've a good idea of what the right gearing should be ...

No it isn´t  ;)
But it is easier to set each gear acc. to the speed   ;D
You´re right.... been to the race track, driving a final ratio of 15/35 (for example only), hitting brake point at the longest straight in 6th 1500 rpm below redline and i know to gear the final ratio 15/37 or 15/38 to get it in the right way.....vehicle speed doesn´t matter  ;)
# Member of the CAWS Racing Team #


PiBoSo

November 12, 2013, 11:51:27 AM #9 Last Edit: November 12, 2013, 12:38:41 PM by PiBoSo
Quote from: C21 on November 12, 2013, 10:51:09 AM
To make it short:
@Piboso
Could you explain how the maximum speed behind each gear is calculated?
Thanks for your replies.

To be honest: this way it is now did not make any sense to me....

Driving 6th gear flat out into the rev limiter at (let me guess) 14500rpm hitting 209km/h as a maximum top speed the bike can reach with this gearing but displaying 226 km/h on the gear table within the garage is far away from reality........and i did not see that in any other motorcycle game (e.g. GP500) ;-)

Even in real race life....for example: I´ve driven a 250GP Production Racer for one year on the race track and within the manual was a gearing table for each gear option with a maximum vehicle speed for each gear combination at redline. The printed vehicle speed in the manual was close to the vehicle speed the bike could reach at the fastest part of the track depending on wind and climb of the track. It was easy to get a good gearing within time only by looking into the gear/vehicle speed table.
This is not possible within GPBikes right now  ;)

I´m only looking for improvements :D

At the moment the estimation of top speed for each gear is very simple:
engine redline * engine internal ratio * gearbox ratio * sprockets ratio * rear wheel unloaded radius

This very simple formula doesn't account for aerodynamic resistance, track slope, rear tyre slip and even rear tyre radial deformation.
Maybe the code should at least use an estimated loaded radius. The loaded radius is lower than the unloaded one, making the tyre smaller and reducing the top speed a lot.
"Obviously your ambition outweighs your talent".

C21

Thank you Piboso.
That will answer my question!  :)
# Member of the CAWS Racing Team #


PiBoSo

Quote from: C21 on November 12, 2013, 10:51:09 AM
Even in real race life....for example: I´ve driven a 250GP Production Racer for one year on the race track and within the manual was a gearing table for each gear option with a maximum vehicle speed for each gear combination at redline. The printed vehicle speed in the manual was close to the vehicle speed the bike could reach at the fastest part of the track depending on wind and climb of the track. It was easy to get a good gearing within time only by looking into the gear/vehicle speed table.
This is not possible within GPBikes right now  ;)

I´m only looking for improvements :D

It would be great if you could share something from that manual, if you still can access it.
"Obviously your ambition outweighs your talent".

Alby46

i've met 2 days ago "someone" who owns 2 bmw 1000 in the CIV champ, i showed him gp bikes and he liked it.
Still riding a 50cc, but enjoying it :)

PiBoSo

Quote from: Alby46 on November 13, 2013, 10:09:51 PM
i've met 2 days ago "someone" who owns 2 bmw 1000 in the CIV champ, i showed him gp bikes and he liked it.

8)
"Obviously your ambition outweighs your talent".

C21

November 14, 2013, 09:21:34 AM #14 Last Edit: November 14, 2013, 09:38:42 AM by C21
@ Piboso
I don´t have the manual because i sold the 250 years ago but i can attach some images from another one...
will do it over the weekend.
I´ve attached an example..so you get an opinion what i´m speaking of..
The second 5th gear is of course the 6th gear but the japanese guys don´t take it too seriously  ;)
# Member of the CAWS Racing Team #