Motorcycle Racing Forum

Motorcycle Talk => Motorcycle Talk => Topic started by: DakotaCBR on October 21, 2008, 08:50:05 PM

Title: Useful Racing Equations
Post by: DakotaCBR on October 21, 2008, 08:50:05 PM
Hey guys,

I'm an engineering student and I'm currently learning the C Programming language. For my final project in the class, I am writing a program that will contain a bunch of racing/trackday equations like gearing ratios, computed top speeds, power to weight ratios, etc.

I wondered if you've got any interesting equations for me to add? I am searching for one that will calculate ball park spring rates for front and rear suspension also, if you happen to know how they figure those out (like I weigh 135 and use .9kg Racetech springs up front). How do they calculate that?

Some easy examples of the kind of info I'm looking for is:

Horsepower to weight ratio = Horsepower / Bike Weight

Computed Top Speed = ((Max RPM / Top Gear Ratio) * (Rim Size / 2 * 25.4 + (Tire Width * (Tire Depth / 100))) * 0.000377/1.6)


Got anything?

Thanks!

Title: Re: Useful Racing Equations
Post by: Xian_13 on October 21, 2008, 09:36:54 PM
One equation I can never figure out, is the Budget to tire formula.

The other one is  the ratio for Throttle to Highside, other then 100%...

:)

XIII
Title: Re: Useful Racing Equations
Post by: Super Dave on October 21, 2008, 10:09:12 PM
Front spring rates are based specifically on rider and machine weight.  Rear springs require some knowledge of the linkage ratio in addition to the rider and bike weight.

There are some charts out there that can help you with the fork thing.  Google it.  But some riders have different preferences, different conditions require different rates.
Title: Re: Useful Racing Equations
Post by: backMARKr on October 21, 2008, 10:12:54 PM
This one always seems to come in to play once traction goes away....

g = 9.8 m/s²  :biggrin:

Title: Re: Useful Racing Equations
Post by: dylanfan53 on October 21, 2008, 10:23:15 PM
Here comes McLaughlin...I can hear his footsteps...any minute now...   

Title: Re: Useful Racing Equations
Post by: Burt Munro on October 21, 2008, 11:03:14 PM
Quote from: backMARKr on October 21, 2008, 10:12:54 PM
This one always seems to come in to play once traction goes away....

g = 9.8 m/s²  :biggrin:



Don't forget to factor in the gravitational effect of the moon on a 100 kg person......

F = GMm/R² = (6.67*10-11 N-m²/kg²)(100 kg)(7.35*1022 kg)/(3.84*108 m)² = 1.67*10-3 N = 0.00167 N

Title: Re: Useful Racing Equations
Post by: HAWK on October 21, 2008, 11:28:48 PM
Quote from: Xian_13 on October 21, 2008, 09:36:54 PM
One equation I can never figure out, is the Budget to tire formula.

XIII

This one is easy X,

Tire > Budget

:banghead:
Title: Re: Useful Racing Equations
Post by: chaplain220 on October 22, 2008, 09:31:14 AM
Hmmmm.  Asking roadracers, (those of us who have struck our cranial cavities 60% more than the general population), to come up with a formula that can be translated into a testable equation...Not bloody likely.  Good seeing ya this past weekend DakotaCBR, hope the final project goes well. 
Title: Re: Useful Racing Equations
Post by: cbr600_mj on October 22, 2008, 10:37:42 AM
Quote from: HAWK on October 21, 2008, 11:28:48 PM
This one is easy X,

Tire > Budget

:banghead:
Quote from: HAWK on October 21, 2008, 11:28:48 PM
This one is easy X,

Tire > Budget

:banghead:

No it's not easy...
                     
                       
Tire > Budget  Divided by Wife

LOLOLOLOL

: )
Title: Re: Useful Racing Equations
Post by: tzracer on October 22, 2008, 02:19:48 PM
Quote from: dylanfan53 on October 21, 2008, 10:23:15 PM
Here comes McLaughlin...I can hear his footsteps...any minute now...   



Not really many equations that I use. I make gearing charts in excel (internal and external gears). Fuel consumption is about the only thing I calculate on the weekends. I used to calculate corrected RAD readings, but not any more.

Good notes are the most helpful tool for tuning.
Title: Re: Useful Racing Equations
Post by: DakotaCBR on October 22, 2008, 04:50:12 PM
Fuel consumption is one I haven't thought of.
Title: Re: Useful Racing Equations
Post by: spyderchick on October 22, 2008, 06:06:36 PM
Quote from: DakotaCBR on October 22, 2008, 04:50:12 PM
Fuel consumption is one I haven't thought of.

Fuel is weight, so you should know your average fuel consumption per lap for each track.

Now I know some pretty bright people out there who get it wrong every now and again... :rollseyes: <whistling>