Andy Neuman
Andy Neuman HalfDork
5/24/16 3:54 p.m.

Last year at the challenge I feel like I failed myself miserably in the drag racing portion of the event. I blame part of that to my suspension setup and lack of a LSD. For us that have run the challenge we know the Hoosier A/R7 just don't hook when it comes to drag racing. Running a 15.9 at 94mph is just sad. If we would have had a burnout contest I'm sure I could have spun one tire for the whole track but that wasn't the goal, actually pretty sure I did it one run but that is besides the point.

I know the best thing would be to find take off autocross tires or drag slicks, buy the other set new and have two sets of wheels. I really want to avoid doing that.

My questions are...
How much time will be lost by running Hoosier A7s up front with a Drag radial in the rear?
Has anyone tried this approach?
Which Drag Radials will be the best compromise for both events?
Tire pressure for autocross on drag radials?
Should I stagger my setup? front or rear biased?
Is this just a really poor idea?

This years car should be a 200-230 rwhp 3000 lb car. Might even throw "some" nitrous at it. Feel free to give your opinion. I wish I had the time and money to test all my options but that won't be the case this year.

SVreX
SVreX MegaDork
5/25/16 1:02 p.m.

The ratty street tires that came on it are a better option for the drags than autocross tires (at least the fronts).

AutoX tires get really squirrely at 100 mph. The Texas A&M car was almost undriveable last year with autocross tires on the drags. I recommended they switch to their street tires and some suspension changes (and then they beat me).

I never made the top 10 until I started getting serious about tires, and bringing 2 sets.

Real drag tires really make a difference on the drags (assuming you have the power to turn them).

The problem is that, as a minimum, you need stiff sidewalls for autocrossing, and flexible sidewalls for drag racing (on your drive wheels). They are not interchangeable.

I did something interesting 2 years ago with the MINI S- I staggered the tires, and ran the bigger tires on the rear for the autocross, and ran them on the front for the drags. It wasn't about traction, it was about gearing. It changed the final drive ratio just enough to make a big difference. (Note: those same staggered tires got used at the Skidpad Challenge with the bigger tires on the outside, and the smaller tires on the inside).

Robbie
Robbie SuperDork
5/25/16 2:10 p.m.

I'd be really interested in autoxing a car with a drag tire on the drive axle (or all 4 corners). Here's why:

  1. I think that the launch is super-important in autox, especially in a car that accelerates slowly. Better launch = faster speed on the whole course up to the first point you have to brake.
  2. If the drag tires still grip in the turns but just have lots of sidewall flex, conceivably you would end up with a car that feels squirmy and squishy but you could drive through it with earlier inputs.
  3. It's a genius move to get an advantage in the challenge.
SVreX
SVreX MegaDork
5/25/16 3:51 p.m.

In reply to Robbie:

It would appear that our own David Wallens disagrees with you:

David's test of Nitto drag radials

Andy Neuman
Andy Neuman HalfDork
5/25/16 4:01 p.m.
SVreX wrote: In reply to Robbie: It would appear that our own David Wallens disagrees with you: David's test of Nitto drag radials

Quoting things from 1999. The theory is two A7's in the front two drag radials in the back. Air up the drag radials for the autocross and dump the air for the drags. One set of new tires for the whole event, only one set of wheels to budget into the event.

I think we should request a tire test in the magazine.

SVreX
SVreX MegaDork
5/25/16 4:11 p.m.

I like your idea of using 1 set, just question whether it will be an advantage.

The tires we ran on were road racing takeoffs- they actually were free (plus shipping). Monstrous grip- lightweight shell.

Robbie
Robbie SuperDork
5/25/16 4:29 p.m.

hmmm, the Nitto 555R might actually make a really good compromise tire. I hadnt been thinking about Nitto...

Andy Neuman
Andy Neuman HalfDork
5/25/16 4:32 p.m.

I'm obviously not going to place in the top 5 so I'm not too worried. I'm just thinking of ideas to take best advantage of the rules. Really how much time would be lost vs a new set of either drag tires or autocross tires. People using two sets are generally compromising by using old used tires during one portion of the event. I believe the purple neon used this strategy last year.

I'm getting bad, I asked my father if he would "sponsor" my car to pay for new tires.

Antihero
Antihero Reader
5/25/16 6:58 p.m.

This thread makes me feel good about my plans for using nitto drag radials for everything on my challenge car lol

SVreX
SVreX MegaDork
5/25/16 8:22 p.m.
Andy Neuman wrote: I'm just thinking of ideas to take best advantage of the rules.

Right. That's the game. But there are many, many ways to take advantage of the rules.

So, for example, the rules I looked at were:

  • In spite of the SCCA rules, DOT legal are not required. That means full race rubber is legal. I used full race rubber that would be speced for a much lighter car (FSAE) in longer heat cycles. My heavier car heated them more quickly, and they worked well for autocross.

  • We paid $17 for the shipping. The tires were given to us by Lee Graser (former Challenge competitor who dealt in used race tires, and made an open offer to all Challenge competitors). (although we used this set for our "free" tires)

  • The wheels that came with the car were traded straight up for the wheels we used.

  • Our drag tires/ wheels were given to me a few years ago. They have good rubber, but the beads were broken, and we glued them to the rims. I bag them and store them when we are not using them. They are still hanging on.

So, all my wheels and tires were legitmately free, but I put an FMV in the budget for the drag tires.

I could have put a new set of autocross tires on the car, but we did a lot of testing, and decided the race takeoffs were better- size, weight, grip, width, compound, etc.

I like your idea of using 1 set- it's grassroots. But I would spend some time testing it before committing.

I don't think there is a more important choice in the Challenge then what tires you wear, if you are going to be competitive.

Opti
Opti HalfDork
5/26/16 9:52 a.m.

Why not just use a really good set of street tires, Ive had good luck drag racing especially at low power levels with just good street tires, the vette does fine with Re760s at about 340whp.

Years ago I talked to a guy who was using 275/40/17 Nitto 555R 1 (the Drag Radial version) with a like 40 or44 psi for road course use, said they worked well. Never done it myself though.

I know some of the newer nitto DRs are way better, might shoot them an email and ask them about using a DR for road course work.

Andy Neuman
Andy Neuman HalfDork
5/26/16 7:03 p.m.

In reply to SVreX:

I'll probably give it a shot. I don't mind screwing up, need to do something to be different at the event anyways. Testing everything would be excellent but time and money become a factor for me. I'll probably only take off 12-14 days between now and leaving for the event.

Andy Neuman
Andy Neuman HalfDork
5/26/16 7:04 p.m.

In reply to Opti:

From what I've read, I'll probably end up with Nitto drag radials and hoosiers. What is the worst that could happen?

drdisque
drdisque HalfDork
5/26/16 7:37 p.m.

Years ago my friend brought his SN95 on Nitto Drag Radials to an autocross and it wasn't awful.

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