OH2Z06

ok, so I want to order some forgestar f14s for my Z, but am unsure which size wheels or tires I should go for and want some opinions. I really want to use MT ET Streets as tires which gives me two options (305/35/18 or 305/35/19). I'd rather run a 19" rim in the rear, but with this size tire it would make the rear rim over 1" bigger in diameter than stock and would throw off the speedo. So here are my options that get me close to the right stagger. which would you go for?

18/18 with 275/35/18 front and 305/35/18 rear

18/19 with 275/35/18 front and 305/35/19 rear ( this might give me active handling issues because of size difference front and rear)

19/19 with 265/35/19 front and 305/35/19 rear ( this gap may be too big as well)


Any recommendations would be helpful. My car is head/cam car with 150 shot makes around 630 on nitrous. This is why i'm looking for a MT tire. What do you suggest?

2003corvettez06

go with

275-30-19
305-30-19

or

275-35-18
305-30-19

OH2Z06

Mickey thompson only makes the ET street in 305/35/18 or 305/35/19. I want to use this tire. So each option I listed is in one of those sizes. 305/30/19 tires will limit my traction because they don't make a drag radial in that size

2003corvettez06

makes sense. look this here torque is putting down 471whp and looks like these tires could be worth the try or u wanna run strictly MT's

http://forums.corvetteforum.com/c5-g...5-30-19-a.html

OH2Z06

Thanks for the info! I'm putting down 471 on the motor as well. I'm just not sure id keep traction with the 150 shot. I've heard really good things about the MT et street. My car is not daily driven so not worried about bad weather or tire life either.

OH2Z06

anybody know if the 18/19 or 19/19 sizes i listed would throw off the active handling?

Gregster

as long as overall diameter of tire in rear is bigger than .5" than you will have no problems. Wheel diameter play no role in AH

Toque

These are the typical sizes that people go with on 18/19, or 19/19 combo's.

471 at the motor, or at the rear wheels ? Im at 471 at the rear wheels, and approx 555 at the motor.




See my web site for figuring out how to size your tires.

www.ToqueZ06.com

How to Determine the correct "Tire Size" for new wheels on a C5 and C5 Z06:

Stock C5 has a 1.0" larger rear tire diameter
Stock C5 Z06 has a 0.7" larger rear tire diameter

.
.
.

275/35/18 front - 25.6" diameter
305/35/18 rear - 26.4" diameter
Rear tire is 0.8" larger in diameter. This is OK !

275/35/18 front - 25.6" diameter
305/35/19 rear - 27.4" diameter
Rear tire is 1.8" larger in diameter. This is OK ! Quite LARGER than stock though.

265/35/19 front - 26.3 diameter
305/35/19 rear - 27.4" diameter
Rear tire is 1.1" larger in diameter. This is OK !


Keep in mind that the larger tire you go with (larger than stock) ... your speedo will be off. If your speedo reads 60mph, your actual speed will be 61, or 62, or 63... depending on how large a tire you go with.

You can also have issues with the tire being TOO large. Especially in the front where turning can hit the inner fender liner. A large rear tire can also hit the fender liner before it hits the suspension bump stops.

I would try not to go too large when over sizing your tires in general.


Stock C5 (97-04):
Front
Rim size = 17x8.5" rim
Tire Size = 245/45/17
Diameter = 25.7"
Rear
Rim Size = 18x9.5"
Tire Size = 275/40/18
Diameter = 26.7"

Stock C5 Z06 (01-04):
Front
Rim size = 17x9.5" rim
Tire Size = 265/40/17
Diameter = 25.4"
Rear
Rim Size = 18x10.5"
Tire Size = 295/35/18
Diameter = 26.1"

Toque

OH2Z06

Toque - thanks for all the info! Much appreciated

I am at 471 to the wheels all-motor as well. 632 with the 150 shot.

I'm thinking the 18/19 or 19/19 combo would look the best, but 18/18 would keep me at the closest to stock tire sizes. I wish they made a DR in 305/30/19. Worthless having all that power if you can't put it to the ground so going the MT ET Street route for sure.

Great site btw Toque. I've done the anti-venom mod and plan on using your site when I finally bite the bullet and buy coilovers as well!

Toque

Thanks ! Glad to hear my site is of some help to you.

With all that power a 18" drag radial is likely your best bet !

Toque

markab

i want to go all 18's around any suggestions

OH2Z06

275/35 or 265/35 front
295/35 or 305/35 rear

Depends on tire choice. I ended up going 18/18 and went with 265/35 front and 305/35 rear

WannaC5Z

I think the first is your only real option. When you change a rim size up one inch you have to lower your tire side wall height by 5%. Thus going from a 40 to a 35 will keep it very close as long as you keep the tire width (millimeters) the same. Making your tire height taller or shorter by probably more than 5-8mm total, I would think can throw off the balance of the car, in addition to your speedo.

GenerationX1

Toque... would a 275/40/17 for the stock front rim work with a 295/35/18 stock rear rim, or would that be to close causing problems with the AH/TC? Thanks!!

WannaC5Z

Maybe I can help. That tire height would be approximately 25.6-7" tall if I did my math right. Multiply the tire track width by the tire sidewall height, or 275 x .4 = 110. Multiply that by 2 for top and bottom of rim, 110 x 2 = 220mm. Convert that to inches (8.6-7") and add the size of rim (17"). I hope that helps. You can Google aspect ratio also.

GenerationX1

Hmmm... thanks.. that's right there at it being 0.5 and 0.4 respectively at the 25.6 and 25.7 measurments.

The reason that I was wanting to know is that I want to keep the stock rims on my Z for now and my front tires are going to need replacing soon since my back tires are practically brand new when I bought my car 2 years ago. The stock size tires are hard to come by and they are quite expensive compared to the 275/40/17 variants that are out there.

WannaC5Z

The guy I recently bought mine from had just put Falkens on the front.

GenerationX1

thank you brother!!!

WannaC5Z

Glad I could help. I am a total newb to the Corvette world and am soaking up everything I can learn about these cars. But I do have about 8 years of wrenching on my '97 Cobra which gives me some general knowledge.

Toque

Sorry for the delay.... my lap top crashed hard and I don't have the time on a puter like I normally do. Should have a new lap top soon though.

Front - 275/40/17 = 25.7"
Rear - 295/35/18 = 26.1"

Thats a difference of 0.4" (rear is only larger than the front by 0.4")

Thats a risk.... you may or may not have issues with AH/TC.
I would personally lean towards the "do not do it".
I could be wrong though.
Some folks may have tried it and not had issues.

Check out the tire calculator here.
Its on my web site too under the section talking about sizing your tires.

http://www.rimsntires.com/specs.jsp

Hope this helps !
Toque