How critical is side wall height on a DR ?? Example 315/35/17 vs. 315/45/16. Does the DR depend on the side wall as much as a slick ?? Will a short side wall give just as good 60ft as a DR tire with more side wall ??

Don't worry about diameter. I'm just using these as an example for side wall comparison.

Thanks ...

 

In my opinion yes, the sidewall height or thickness means a lot in a drag radial, though probably not quite as much as it does on a full (bias ply) slick.
I believe a lot of it will depend on the car's power level, type (NA, nitrous, blower etc.) of power and transmission (automatic or manual) of course but usually more sidewall is better as long as it also coincides with one's final gearing needs.

 

I'm putting together a "drag pack". I ran across a set of Weld prostar XP 16x9 with 5.5bs. The XP's are the only off the self 16's that will fit. That being said, will I be faster on a 16 or 17 with a DR ?? If I went with the 17 setup I'd run a 315/35/17 Hoosier DR @ 25lbs, so total weight being 45lbs. If I went with the XP's (which are 22lbs a piece) plus a tire, I'm in the 55lb range.

So we are talking about a 20lb difference to gain roughly 1" diameter of side wall. Basically 4.30" side wall to a 5" side wall for an additional 20lbs of rotating mass.

Which avenue is better ??

FYI, I'm '04 ZO6, 6 speed, 4.10, 3015lb with me, roughly 500rwhp N/A plus 150 shot.

Thanks....

 

I should have titled this thread "side wall vs. Rotational mass". I guess the real question is, at my power level which would better suit me. And FYI, my track is horrible (speaking of prep). So in knowing that would a taller side wall trump the weight savings ??

Thanks..

 

At your power level (especially with the harder hit from nitrous) I would likely sacrifice the slightly lighter weight and go for the taller sidewall (16s over 17s).

 

It's a 2 stage setup. Launch on 50 then roll the rest in later. If that helps.

Thanks..

 

Although sidewall height is of course important, Dave-T on here consistently goes 1.43 in the 60 foot and 10.7x's in ET on 315/35/18 BFG's in an N/A LS2. My point is the near 50/50 weight bias in the allows the C5 to launch on tires that are not seemingly up to the task.

 

A great point as well.
But I think you mean 315-30-18s?

 

Actually they are 295/35R18. I have played around quite a bit with drag radial wheel and tire combinations and I keep coming back to the BFG 295/35R18. They seemed to hook the best, be the most consistent and last the longest.

The one thing I noticed about side wall height is the effect on RT. If you are worried about RT, in my opinion, the taller Hoosiers (16 inch) really hurt RT. This is due to the very soft sidewall and the large amount of wrinkle that occurs on launch. I am sure others will disagree with me on this.

Also as far as the drag pak goes (weight savings, etc.) I basically feel going this route is a waste of money. Eric i think will agree with me on this. You gain very little for a lot of cash. With the drag pak I gained at best 0.04 sec in 1/4 mi ET. Not much. However I do like the look and the skinnies are great for keeping the car very straight on the big end.

 

A larger sidewall allows more adjustment of RT via rear tire pressure. I have found that 1lb of air pressure = .010 RT in my Hoosier QTP's vs 10 lbs air pressure = .010 RT in my 17" BFG drag radials.

Something for the bracket racers to think about.

 

So let me ask this....will a Hoosier DR 315/35/17 hold 650rwhp ?? From a standing start with a ****** track prep, I launch at roughly 3200-3600 rpm. I'm just not sure the tire will hold it, not enough meat aka; side wall.

I understand all the variables associated with this question but an educated guess would be appreciated.

Damn, when I go back and read want I wrote.... It sounds like a serious newbie question !! Haha !!

Anyways...thanks..

 

650 rwhp and a 3200 rpm launch sounds like a problem. I guess it all depends on how hard your car launches and how you finesse the clutch. I am running a lot less rwhp but my 60 foot is as good as cars with a lot more. But I do have an auto.

 

I just re-read your post as well. The other big problem I see with the 16 inch drag radials is tire width. You just simply can't get a wide tire. The 255/50/16 is all there is. I just don't think they are wide enough.

 

I employ the Ranger method. I ride the clutch (slowly letting it out) while giving more fuel. Kind of a inversely proportional deal. The more fuel the more I let the clutch out. I would say by 10-20 feet I'm totally off the clutch.

Thanks... McLeod RXT

 

i've cut a 1.41 60' with the 255/50/16

What are your 60's now employing the ranger method?

 

Oh god. Where to start. A lot of good info, just not specific enough for your setup.

-You can't go by auto's, they are different animals.
-Ranger's writeup will help everyone with a 6 speed but they are more for stock clutches.
You will need to develop a whole new launch style depending on power/clutch/track prep/tires.
So AFTER you choose the tires then we'll help dial you in with launch rpm based on your tires/pressure/track prep/clutch/suspension and a few other things.
-A lot of the fellas here are racers and therefore put a great of emphasis on reaction time. If you are out to have fun and E.T. chase then there's no need to do anything or buy anything to benefit reaction time.

Now on tires. As Dave T said the Hoosier 255 50 16's are great drag radials but are narrow.
They help with gearing(if necessary), hook great, roll great, and are good for some mid 1.3x's but mainly with an auto.
You can expect some 1.4x's with those tires with the right launch technique with a 6 speed vette like yours. I'm betting once you get the launch down that you'll cut low 1.5x's most regularly with a tire like that.
They will work well for you n/a with practice but will be a handful on the spray to launch especially on a track that is not well prepped. This would be my top pick for a drag radial if you were to run n/a a lot and occasionally nitrous progressively. If your planning on spraying all the time then we'll have to have a more in depth discussion. But keep in mind, if the tires are spinning you're not breaking and you have more fun when your car's in one piece. The 315 35 17's will likely hook similarly.

Surprisingly the shorter sidewall drag radials of today have been proven to get the job done on corvettes with big power. Again, much easier to hook for the auto but as Eric F. mentioned the balance/suspension of the corvette makes it possible.
So, you can go with a wide 17 or even 18 and get traction on the spray with a 26" tire.
You can also step it up to 27" or 28", but personally I would start with a 26" for many reasons, better left for another discussion.

As for slicks and your 6 speed, they will be the most consistent, and the best way to learn and dial in your set up with, especially the launch. You will need skinnies then.
I would start with the old proven, 'bread-n-butter' combo; 26x11.5x16 with skinnies up front. This tire combo will allow you to launch aggressively n/a and will work with the spray and allow you to go deep into the nines if the car has the gumption.

In summary, if you will go to the strip alot and want to really dial in the car and run with and without nitrous equally then I would get a drag pack with slicks (26x11.50x16 MT et streets) as my first set of tires. If your running n/a more so and nitrous occasionally and only want a drag radial then I would choose the Hoosier 255 50 16 and still go with a drag pack.
If you plan to run nitrous all the time and want the best et possible and don't car if you blow up stuff here and there then we'll add a bunch of other players to the mix.
Try and figure out realistically how and how often you'll be running this car as that will make the choice more clear.

Also don't forget about diameter and trap speed. Figure out what rpm you are comfortable going thru the traps at. Then figure around 132-134mph for 500+rwhp. Factor in rear diff. gearing and make sure it all makes sense. But this can be done after you have the car dialed in and that may take a set of tires.

 

That was the case up until more recently, Hoosier has since released a 295-50-16 but unfortunately it's 28" tall.
M/T has a wider 16" available as well.

 

Thank you guys for all the great info.

To clarify, the main duty of this car is chasing an great ET and of course the Saturday night grudge matches (midnight drags).

I'm really not interested in slicks, this car is not a trailer queen. I drive it to work on nice Fridays and cruise it on Friday night, so DR make the most sence to me.

That being said, I'm worried that the 255/50 is to narrow for s**tty track conditions. I'm leaning towards either the Hoosier 315/35/17 or the 315/30/18. I would consider the 16" setup but the performance (side wall) does not offset the weight in my opinion.

And I'd really like to stay under 27" diameter for gearing reasons. And I'm comfortable spinning this thing to 7100. And about the spray, once I get the progressive conroller dailed in I will only spray it when the "need" arises (grudge).

Basically, it will be cruised Saturday night then head out to the track for midnights. Which is heads up clock off (lots of gambling) grudge racing.

FYI, I put about 1200 miles on the car last year. So she doesn't see lots of time. Just the summer weekends.

Thanks a bunch guys for all the support here on the forum. You guys have saved me an immeasurable amout of time (trail and error) and money on wrong parts for my combo.

Thanks...Forgive me for any typos, my laptop is in the shop, I'm doing all of this from my phone.

 

I've had 18's 17's and 15's on my car and my best 60' by far was with the 15" DR's. Side wall is important, but more important is contact patch. You want to have as tall of a tire as you can with as wide of a footprint as you can while keeping as much side wall as you can.

I would make sure that the 16" rim won't limit you to a 26" tall tire. That would be worse than loosing side wall.

You need to have a minimum of a 28" tall tire on a Corvette and if you can squeeze it in, a 30" tall tire will hook WAY better and give you more gear for the big end.

keep these things in mind while you decide on a rim.

 

Hey mr atomicfusion, I'm not sure if I'm putting down enough HP to use the tire your referring to.

When you say you tried 18, 17 and 15 and had the best sucsess with the 15's. Was that all with the same combo ?? And if so what kind of HP are we talking ?? I know your way up there now but when you were playing around with 18's and 17's what were you putting down ??

Thanks..