Shift Point - Sportbike Forums : Sportbikes Motorcycle Racing Forum
» Insurance
» Sponsors
Go Back   Sportbike Forums : Sportbikes Motorcycle Racing Forum > Racing > Drag Racing

Thread Tools
Old 08-08-2009, 10:58 PM   #1
Heavy's Avatar
Join Date: May 2001
Location: Anchorage, Alaska
Motorcycle: 2000 ZX-12R
<br />2001 GSX-R 1000
<br /><br /><br /> T.R.E. mod
<br /><br /><br /> K&N Filter
<br /><br /><br /> Yoshimura bolt on exhaust
Posts: 377
Default Shift Point

At what point do you shift for best accelleration? Should you shift just after your peak horsepower or just after peak torque?
A little GAS... is a good thing!!!!
Heavy is offline   Reply With Quote
Sponsored Links
Old 08-09-2009, 04:32 AM   #2
eWorld Champ
specialsymbol's Avatar
Join Date: Apr 2002
Location: Frankfurt am Meer
Motorcycle: Kawasaki Ninja ZX636C
Posts: 6,187

Depends on your engine and gearing.

The best point to shift is when you have in the higher gear more power than in the lower gear. Sounds strange, but some bikes are like that. Some will always have more power in the lower gear, so it's useful to accelerate into the limiter.

Check this out:
I stole those gearing diagrams from Norberts Motorradseiten:

First the one from a Ducati 749 R '04:

As you can see, the lower gears end all well above the higher gears. Higher means more power. That means, you'll always have more power in the lower gear than in the higher one. So it's best to rev it into the limiter (or shortly before) and shift then.

But have a look at the 5th gear: At 242km/h it intersects with the 6th gear line. From that point the 6th gear line is higher than the 5th gear line, that means it has more power. So it's best to shift there into 6th instead of staying in fifth.

Let's have a look at the Kawasaki ZX6-R '05 model (ZX636C):

As you can see all gears except first intersect with the next higher one. That means there's always a point where the next higher gear provides more power than the lower gear. This is the best shifting point. Of course the diagram can only relate to speed and not to RPM, but it's still pretty close to the rev limiter though it's not really obvious.

Let's have a look at the gearing diagram of a '06 Yamaha R1:

Here it's really obvious that there is a point (speed) where it's absolutely useful to shift into a higher gear, beginning from first. At 250km/h you'll even have more power in 6th gear than in 4th!

The point of where to shift is with the higher gears a little bit later than with the lower gears, you can see this by drawing a line through the points where they intersect, it's slightly banked (disregard the intersection between 4th and 6th).

However it's such a slight bank that it's practically the same RPM.

All you have to do is find a gearing table for your bike, calculate your gearing diagram, find the intersection points and recalculate the corresponding RPM- then you'll have the perfect shifting point.

I did this for the 05' ZX6R and found the perfect accelerating range to be between 12800 and 14600 RPM (except for first, where it's rev to the max).
Attached Thumbnails
Click image for larger version

Name:	Duc.JPG
Views:	1784
Size:	66.1 KB
ID:	12926   Click image for larger version

Name:	Kwak.JPG
Views:	1828
Size:	67.1 KB
ID:	12927   Click image for larger version

Name:	Yam.JPG
Views:	1886
Size:	70.0 KB
ID:	12928  
LUKE 22:36
In girum imus nocte et consumimur igni

The war is not meant to be won. It is meant to be continuous. The essential act of modern warfare is the destruction of the produce of human labor. A hierarchical society is only possible on the basis of poverty and ignorance.

Last edited by specialsymbol; 08-09-2009 at 04:42 AM.
specialsymbol is offline   Reply With Quote
Sponsored Links

Thread Tools

Posting Rules
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is On
HTML code is Off

Forum Jump

Powered by vBadvanced CMPS v3.2.2

All times are GMT -8. The time now is 08:28 PM.

Powered by vBulletin® Copyright ©2000 - 2016, Jelsoft Enterprises Ltd.
vBulletin Security provided by vBSecurity v2.2.2 (Pro) - vBulletin Mods & Addons Copyright © 2016 DragonByte Technologies Ltd.
Motorcycle News, Videos and Reviews
Honda Grom Forum strong>Kawasaki Z125 Forum Harley Davidson Forum Honda 600RR Forum Kawasaki Forum Yamaha R6 Forum Yamaha FZ-09 Forum
1199 Panigale Forum Honda Africa Twin Forum Roadglide Forum Honda CBR1000 Forum Vulcan Forum Yamaha R1 Forum Yamaha R3 Forum
Ducati Monster Forum Harley Forums Honda CBR250R Forum ZX10R Forum Star Raider Forum Yamaha Viking Forum
Suzuki GSXR Forum V-Rod Forums Honda Shadow Forum Kawasaki Motorcycle Forum Star Warrior Forum KTM Duke 390 Forum
SV650 Forum BMW S1000RR Forum Honda Fury Forum Kawasaki Versys Forum Drag Racing Forum Ducati 899 Panigale Forum Ducati 959 Panigale Forum
Suzuki V-Strom BMW K1600 Triumph Forum Victory Forums Sportbikes BMW NineT Forum
Volusia Forum BMW F800 Forum Triumph 675 Forum MV Agusta Forum HD Street Forum Suzuki GW250 Forum
Yamaha Motorcycles Victory Gunner Forum Victory Charger Forum Honda Vultus Forum HD LiveWire Forum Ninja H2 Forum
BMW Scrambler Forum Ducati Scrambler Forum Kawasaki Ninja 250SL Forum