What do people think of an Aprilia RS250???

**Back Fire** · 28th March 2007, 17:48

Originally Posted by mud boy

comprenda what does that mean?

it means, that I didn't understand what you meant

**mud boy** · 28th March 2007, 17:53

who cares now forget it

**Jantar** · 28th March 2007, 18:01

Originally Posted by Back Fire

here... the GPX...

http://www.kawasakisa.co.za/details....products_id=80

"Weight dry/wet: 138/161 kg"

"Performance stats:
0--100 km/h: 5.75 s
Maximum speed: 168 km/h
Max power: 27,9 kW @ 11000 rpm
Max Torque: 24,5 Nm @ 10000 rpm"

I haven't been following this thread for a while, but when I do come back I see the same old claims and the same old arguments.

Look if you want to do 200 kmh on a GPX250 then you are going to need at least 63 HP. Without going through all the maths involved here is a simple calculation for an estimate.

Power = Force * Velocity P=FV

The force to be overcome is mainly drag due to air resistance and is
D=Cd*p*V^2 Force must exceed Drag (I dont have a proportional sign on my computer so i'll use >)
so F > f(V^2)
hence
P > V^3

If the GPX250 has been tested at 28 KW (38 HP) and achieved 168 kmh
then the power required to reach 200 kmh is simply
(200/168)^3 * 38
This gives 64 HP which is pretty close to the 63 HP I'd calculated by including the estimated all up weight at 200 kg.

So 200 kmh you need 63 HP minimum.

Good luck.

**FilthyLuka** · 28th March 2007, 18:08

Originally Posted by Jantar

If the GPX250 has been tested at 28 KW (38 HP) and achieved 168 kmh
then the power required to reach 200 kmh is simply
(200/168)^3 * 38
This gives 64 HP which is pretty close to the 63 HP I'd calculated by including the estimated all up weight at 200 kg.

err, yeah, in theory... However in automotive application, gearing, redlines, revlimiters and aerodynamics come into play... ixions post sums it up quite nicely

**Jantar** · 28th March 2007, 18:20

Originally Posted by FilthyLuka

err, yeah, in theory... However in automotive application, gearing, redlines, revlimiters and aerodynamics come into play... ixions post sums it up quite nicely

Exactly. Gearing can be altered by changing countershaft and rear sprockets and this also changes the speed at which the redline occurs. However if you are hitting the redline in top gear then the gearing is already too low. The basic calculation carried out above assumes no change to the aerodynamics from standard. However if the young lady has access to a wind tunnel to build a better aerodynamic shell, then good on her.

**FilthyLuka** · 28th March 2007, 18:29

Originally Posted by Jantar

However if the young lady has access to a wind tunnel to build a better aerodynamic shell, then good on her.

If the young lady has access to a wind tunnel, i need to stop being an arse and get some brownie points! hehe... what to wind...

**jade** · 28th March 2007, 19:42

Just so you know, I got caught out the other day for the first time like this..
coming out of long bay from the beach - coming up the hill - mate in front of me on his 250 going round this left hander, I passed him on right side and gave it some gas banked over on the left, fully spun my tyre and bucked the whole bike as I almost highsided - bucked me airbourne but holding onto the bars, thank fuck, i landed back on the bike
This was 1m in front of my mate.
pulled over straight away, thats as close as you come.
cold tyres and asking too much of them..

**2strokegirl** · 28th March 2007, 19:43

a wind tunnel... sounds fun.

like i said before i dont care how fast it goes itd just be cool to shove in peoples face if i managed to get it to 200 or atleast 180.

i think we should keep this thingy going so it becomes the bigest thingy lol.

**Mr. Peanut** · 28th March 2007, 19:46

With a different sprocket, you could do it downhill. Most I've seen on a GPX is 160.

(The NSR does that uphill

)

**2strokegirl** · 28th March 2007, 19:55

why does it say scooter boy under my name?? how do i change it its anoying me.

**Mr. Peanut** · 28th March 2007, 19:56

Lots of posts lad

**2strokegirl** · 28th March 2007, 19:57

im a girl!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !
!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!!! !!!!!!!!!!!!!!!!!!!! lol