Steve Sanders

There is a significantly larger selection of 18" track tires at this time.

kujo

that's another great reason to stick with 18's for the track !!

NIEMALS FOLGEN S4

Side wall is to short for the track, as the tire rolls in hard cornering you can mess up the edge of the rim especially when running over gators. Also higher risk of rims bending/breaking completely, bring spare set to the track. Higher cost of 19" rims and tires my falkens are done with one hard event and 3 parade lap drives at highway speeds.

My conti's have 5 events, 10 days, 25 hours on track and 30min on a dry skid pad with center tread still good, side blocks are gone but they still have 3-5 events in them before I get R compounds, even though they are getting louder with each event. And new tires are cheaper in 18" and more choices in R compound than 19"

JD ran his HRE's at VIR and had a horrible time, running far slower than most even with PS2's. A big issue was the reverse lip collecting water and causing vibrations. Wes was running the stock Conti's and going 40-50mph faster than JD.

BergeyRPI

Basically, if you want to accelerate the same as an 18" rim, the 19" rim has to be 1.5 lbs lighter. Torque = Moment of Inertia * acceleration. Therefore, acceleration = Torque / Moment of Inertia. Thus, the smaller the moment of inertia, the larger the acceleration. Don't worry about understanding the units of inertia. Since you are comparing apples to apples, it doesn't matter. All you need to know is the 19" wheel has to be about 1.5 lbs lighter to have the same moment of inertia so that the car will accelerate the same.

Approximations include:
1) Ignoring the spoke weight
2) Assuming each wheel was a 1 inch thick donut that averaged around the 18 or 19 inch diameter

I believe it would be relatively accurate to ignore spoke weight since the only error in ignoring spoke weight is the small amount of weight in the spokes at the last extra 1/2-inch that exists around the circumference of a 19" diameter wheel.

As for assuming the rest of the wheel is a 1 inch thick donut 17.5-18.5 for the 18" rim and 18.5-19.5 for the 19" rim, I looked at pictures on tirerack and decided that should be pretty accurate. To be more accurate, I'd need to create a 3D Ansys model.

Download the file here:<ul><li><a href="http://members.***.net/bergey/18%20vs%2019%20inch%20wheels%20moment%20of%20inert ia.xls">http://members.***.net/bergey/18%20vs%2019%20inch%20wheels%20moment%20of%20inert ia.xls</a</li></ul>

bla4ck

i'll hook you up with a good deal (no tax too)

Orangeblood

Or pick up a set of cheap wheels that you don't mind flogging the crap out of. There are many options for you. I suggest having more than one set of wheels though. Different jobs take different tools,so to speak.But make sure you get what makes you happy and fits your needs, not other peoples(don't feel pressured to fit in with what is popular).You can spend big money on wheels and it won't improve the value of your car and in alot cases improve the performance either.

kujo

shoot me an email and I can tell you what I have going on....

kujo

I'm selling my 19" DTM's and getting some lighter 19's for everday use.

I WILL be getting some light 18's that I don't mind kickin the shiz outta at the track though.

I agree that wheel choice is personal.
this was more a performance question than anything else...

kj