Dial In Corvette

The 305/30/19 usually come in a little shorter that stock.
I have already seen 6600 rpm in third at the qtr mile with my
z51 geared a6. I need a little taller tire not shorter as a 30 series
would have been. Looks like I really need the nt05r and a pair of wheels
widened. The 35 series Mickey just looks too tall on paper for the computers
to handle?


Gary

dragonfly

OK, this one has been beat to death. But on a stock C-6 the rear tire is 26.85" and fronts are 25.72" tall.

stock difference is 1.13 inches

if you go with this 305/35-19 tire assuming height is 27.41 (M.T. tires may vary from this nominal size by a bit). They produce tires with English measurements and convert to metric sizing.

Use stock fronts (25.72) difference is 1.69
use 255/40-18 (26.03) difference is 1.38
use 265/40-18 (26.35) difference is 1.06
use 245/45-18 (26.68) difference is 0.73

From the other tire height threads the range is debatable but since many of you already use 255/40-18 for the front.......nannies should not have an issue or have to buy new front tires. The difference is less that the tread depth on the tires. ~0.25" which is 8/32nds and you have that on each side of the tire.

Likewise for the stock sized tire sizes New rears and bald stock sized fronts have a 1.78" tire height difference, anybody had a PCM issue with new rears replaced before the fronts? I really don't think so.

I am all game and leaning toward getting a matching pair of rear rims.... just need to find a set and a pair of these 305/35 tires!

White_Lightning

i wish MT had a 345 for a 19 to compete with the NT05R...

deecount

I'm sure it's a lot easier if someone is looking for the standard painted 5-spoke wheels. It was a major pain finding a set of front chrome gumbys. That's the hardest and most costly part of Spin's Tractionmoster mod. You need to find someone willing to sell only the fronts (usually they're a full set) that haven't been chewed up by tire machines or just outright abused. What I wound up with were a pair of forged polished gumbys that had been chromed. I ended up going with West Coast Corvettes. They have a chrome exchange program but were able to sell me a pair outright. They were pretty expensive but were still half the price of buying new GM. The chrome is pretty nice and really close to the quality of the factory GM chrome. There's no way I was going to go with repos.

FloydSummerOf68

You want a drag tire to be taller when you're making a lot of power....not shorter

Who has actually had issues with active handling when getting to different tires? So far I haven't see any issues running 26.85 (stock), 26.2 (my street tires) or 25.66 (my current drag radials)

For those worried about sidewall height, these 305/35s have about the same sidewall as my 275/40/17s (4.2 vs 4.3....stock is 3.9)

Ragtop 99

I realize that. I guess what I'd like is a 555RII in that size. I'd be willing to give up some of the advantage of sidewall flex for straight line performance to maintain excellent cornering feel.

do you push those hard in turns?

FloydSummerOf68

Not that hard...I just use them to go to and from the dragstrip.

Stang's Bane

Any new word on these? I couldn't find them on summit.

fancypants

http://www.summitracing.com/parts/MTT-3723R/

SpinMonster

The 305/19 will not perform as good as a 18"

As far as your statement of it being 550 plus the cost of the tires, you should note performance tires are always cheaper in an 18" size than a 19" size. At 33 more per tire and the fact that they will last a few months each set, You will be happier you went smaller diameter in the long run.


So you would widen a wheel to use an inferior tire?

Anyway, guys have been running the Nitto NT05r for over a year in the 345/19 and that tire is 27.5" tall. No one reports ant issue with active handling or traction control.

Same as above.

Joe_G

I'm running 295/30/18 with my 345/35/19...my research concluded that the 275/30/18's (stock z06 size and same height as 245/35/18) led to Engine Drag Control issues.

I have no such engine drag control or any active handling issues with my taller 295's.

So I would have concern that you would need to get taller front tires with the 305/35/19 drag radials.

winters97gt

I'm buying some once they are in stock. Should be a good street tire for the new mods which should put me around 675-700rwhp. Not too many people will suspect a quiet vette with stock wheels to have 700rwhp.

Stang's Bane

Spinmonster, will you please substantiate your claim to.why the 18 is a better tire than the 19.

MARSC6

I've been using 315/30/20 Toyo R888s with a diameter of 27.6 for the past year. There has been absolutely no rubbing but I did increase the diameters of the front tires as well just to make sure I didn't have any active handling issues.

Joe_G

To a person, all the fast drag racers I know choose the shortest tires possible as they give the gearing advantage you need to get out of the hole quickly. The taller drag radials slow you down. Plus you want as much sidewall as you can get to absorb the shock of the launch.

IMHO these are not good for serious drag racers.

However, if you need drag radials for street use for your 700+ hp car and don't want to buy new wheels, these are a great option.

FloydSummerOf68

Why do you think it won't perform as well (by perform as well I mean be able to 60')?

The 305/35/19 will have similar sidewall and more overall height while being the same compound as the 305/30/18, so I don't see where the straight line performance is going to suffer.

If the 19" wheel is automatically inferior to the 18" wheel then I don't understand why everyone wouldn't just run 17s out back who have stock or Z51 brake setups. There are a lot of combinations of wheels/tires that will get the job done, and 19's will start doing just that I believe.

It would be a long time before the cost of the wheels to widen versus running these 19" wheels would be a wash for me. I would first have to purchase front wheels, get them widened, and then buy tires. It's a lot more cost effective to go with what will already fit my current wheel setup. My XLR-V is my daily driver, so the tires would last considerably more than a couple months. Running the 18's isn't a better or cheaper option in ever case.

Stang's Bane

If a car is limited on gear ratio, a shorter tire is a great way to gain a mechanical advantage. If not, a taller tire always works better, to a reasonable extent.
FWIW, race classes that are tire limited always limit tire circumference, never do they give a minimum, because there is no need.

winters97gt

Exactly.

That is why I will be buying these. 275/40/17's will still be for track duty.

SpinMonster

Its pretty common and basic knowledge.

Sidewall is where traction comes from. You dont see drag cars running 20" wheels, you see 15" on the fastest cars. There is no demand for a 19" radial because it doesnt help. Those who think wider is better should talk to guys like dennis who will tell you it helps up front and slows you down on the end.

ECS sells kits to allow a 15 or 16" rim to work by shrinking down the brakes in the back. Why would someone do this if a 19" 345 tires is available? 18 is better than 19, 17 is better than 18....ect.

Anyway, traction, especially the launch comes from the sidewall. If it came from width, you would see drag cars running 20" wheels with 345's out back instead of really tall wrinkle walls.

This is drag racing 101. Dont take my word for it. Ask a drag racer.

By the way, the gains you will get from a 19" tripple zero compound with a soft sidewall like the tire this thread is about, loses 2x the handling in exchange for the traction it gains. You will be cringing at .8g's. Stiff sidewalls is where handling comes from. You car will break lose on even moist ground on turns. An SUV can match your cornering with a soft sidewall mickey thompson. I have them. Rain = 30mph max with the hazzards on.

Did you think it was some technological breakthrough to make a 19" drag radial? Track guys wont use it if they want max performance and street guys wont use it twice once they get caught in the rail 50 miles from home and they will see just how bad the handling is. By the way, even the C6R uses 18's all around. 19's and 20's wouldnt be considered optimum on a real race car.

Stang's Bane

Sidewall height is the same on a 305-35-19 as on a 305-35-18. In effect the only real difference is the tire is an inch taller. The advantage of going smaller on rim diameter is to allow for more sidewall height in relation to a relative ceiling of overall tire height. Actually, there is a valid argument to be made for the 19" version of the tire to be better for traction because the contact patch will be greater.
Iirc, top fuel cars run a 17" rim, because their total allowable tire height is much greater.