[Supras] 18" or 19"

[cthommes at adelphia.net]

Enter 4x 14" rotors and 20 pistons.

My car with 18's seems to stop ok.

It's the part about getting it going anywhere (without pushing) that's tricky.

-Craig

---- Jeff Mohler <speedtoys.racing at gmail.com> wrote: 
> Simple, more mass farther from the hub, creating tons more rotational
> momentum for the brakes to now try to stop as WELL as stopping the moving
> mass of the car.
> 
> Thats why for performance we want the lightest wheels & tires we can find,
> and also..the smallest diameter.
> 
> Wider diameters have a higher %age of rotational mass farther from the hub
> as compared to a smaller diameter wheel/tire combination.
> 
> That 19" will weight more as well, resulting in a slower performing
> suspension, which will force the tire to accept more road bumps and
> holes..than the suspension itself, because it will accelerate up & down
> slower than a lighter combination...and thats why you see more split
> sidewals and bent wheels on larger sizes compared to smaller ones.  Of
> course, a strong-ass 19" wheel would also weigh about 35lbs..if not more,
> which makes things even worse.  The tire will weigh 25-30 as well.
> 
> Rotational mass hurts WAY WAY more than dead weight in the chassis.
> 
> Also, a wider diameter wheel/tire combination with a higher %age of weight
> towards the outside of the total diameter will act as a much more powerful
> gyroscope than a smaller tire/wheel combination, which will affect high
> speed cornering and transitional handling.
> 
> Four 50lb gyroscopes at 50mph is a powerful tool that either works for you,
> or against you.
> 
> 
> Basically, theres no gain to a larger wheel over a narrower one, except for
> brake fitment.
> 
> If I could run 13x9 wheels and STILL have enough braking to handle the
> heat/friction requirements that I could USE with a 275 wide tire on the
> racetrack..I could.
> 
> But the penalty is I need more brake to use all of a 275 tire than a puny
> 1983 rx7 rotor and caliper can deliver, so the tradeoff is I would need a
> larger heavier and momentum-hungry wheel to fit it.
> 
> 
> 
> 
> 
> On 4/9/07, C Fernandez <fernande at internet1.net> wrote:
> >
> > Jeff,
> >
> > How would bigger diameter rims put more stress on the brakes?  Larger
> > diameter tires, yes, but rims?
> >
> > Chad Fernandez
> > Michigan, USA
> >
> > Jeff Mohler wrote:
> > > Bigger wheels will strain your suspension and braking system a lot more
> > as
> > > well.
> >
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