*sigh* the Bridgestone RE050S are the factory tire for the coupe 19s.

 

Don't know about Indy but this is probably the reason for using those ballon tires:

Also Indy wheels are only 15" so they have to run a higher profile tire.

 

No, you just proved that you know nothing about racing. Road racing, indy, and nascar are three way different racing classes. You cant even compare an open wheel indy car and a cts cadillac. Cant even compare nascar either considering they only drive in a circle, they dont need a strong sidewall tire thats why they use those huge sidewall slicks.

These dont look like low profile ghetto race cars to me...

http://www.world-challenge.com/gallery/#

scroll through the gallery and define "ghetto" for me, please!

-sean

 

Opps. lol

 

Like I said, if wheels being large and tires being lower profile was a better thing it would be on there. But it is not. That is why you see SCCA all these miatas, etc with small wheels and larger tires.

If it was safety, then the Nascar tires wouldn't be as large as they are either. lol

 

You proved nothing. So they run almost all the same wheel/tire on every car. Looks to be the same wheels too. I bet they don't have a choice. Coming from racing experience and trying 19s and 18s on cars, I know that 18s are better for racing. More flex, less hop over bumps, more stability. 19s are way to skinny on the G35 to race in.

Again, this goes back to why the 350z on the track package has smaller wheels.

No, I proved my point. That is why professional racers do not use small profile tires.

If you look at those pictures, most of those wheel/tires are no more than max 18" in size on those cars. Like I said 19" is too much and is not for racing purposes.

 

Not necessarily. You couldn't have low pro tires and FIT the safety systems required for the series. There is a difference inbetween the performance benefits of low profile tires AND RULES REGULATIONS for any particular race series. You don't get to run any tire/wheel combo in every race series. You should know this

 

I have Wedsports SA-70 18 inch rims
and they are only 17lbs each and are way stronger then any volk rim lol and most other rims out on the market, but thats what you pay for, any loss of wieght in the rim area helps lol

 

Did you even read my post thoroughly before saying something you think is smart. I said to go faster...RIM size needs to be reduced or lighter material.

 

Yes your absolutly correct. I know the 19" wheel is not a wheel size that anyone races in. I was proving to you from your previous statement that the cadillac isnt the only one that uses that size tire and that the cars arnt "ghetto". I was also proving to you that nascar, indy, and scca GT series are not in the same class. I know you are right about the 18 inch wheel being better for the road course or whatever.

Im just simply setting up an experiment at school to prove everyone that thinks the 19" wheel is better for acceleration wrong, but i cant do it without mathmatic evidence to back it up. Atleast on this forum. sorry if we are not talking about the same thing.

-sean

 

Okay I guess we were both talking about the same thing but a bit off from each other.

 

IIRC, there was a thread discussing the difference between stock 18" vs stock 19" wheels. I was one of the first people to switch from the 18" to the 19" so I did quite a bit of research on it. The result I found out was that....

1) OEM 19" rims are lighter than OEM 18" rims by appx 3lbs.

2) OEM 19" Potenza RE050A tires are much heavier than OEM 18" Michelin Pilot Sport

3) Handling with the 19" is definitely sharper and has less roll.

4) 18" feels lighter on the feet and helps with acceleration more.

It's true that the 19" Rays are lighter than the 18" cast. It's also true that the OEM 19" rays actually have less rotational mass than most aftermarket 19" rims. Take a look at the lip design of the OEM 19", they are actually very similar to a 18" rims with lip extension to make them into 19" rims. This particular lip design helps reducing the rotational mass on the OEM 19" compared to traditional 'fat lip' design on aftermarket wheels.

I think with the right tires the OEM 19" are very very competent rims for performance purposes. OEM 19" with Toyo tires (245 front / 255 rear) would probably yield very good performance on the track) As it stands, the weight of the Potenza RE050A makes the weight saving from the forged 19" pointless compared to OEM 18". (Why Infiniti, Why!?)

 

Thanks Sukairain. That about sums up my info as well as adding the lip info.

I just switched back to my oem 215-55-17s on stock wheels because of the snow. I noticed the accerlation is better as well as the gas mileage. But I don't know if it's because the 19s are heavier (I imagine they are heavier than the 17s/tires) or if the bigger dia rear tires are fudging my navi gas calculations.

I noticed the tire thing also when I was researching the wheel weights and tire weights. The RE050s are ROCKS! Would have been much better to go with the Michelin Pilots for the oem 19s. That would save 3-4 lbs right there!

 

You know, the easiest test you can do to test this out right? I know it isn't very scientific, but it'll work. What you do is, get two tires (the OEM 18's and 19's), put it on an incline, at the top, and let them both roll down the incline and see which one rolls down faster. I did this way way back in College Physics Class and it works. The key here is that even though diameter are different on the tires, it'll give you an approximation as to which one has less rototational torque, or whatever it is called.

 

Except they will fallover/ angle at any significant distance that would be required to actually determine a differene. Easy to do in a class, not so easy in real life