HellBent

Hey can anyone offer some opinions on which brand of tire is best for autcrossing. BFG KDW looks good, but the Nitto NT 555 extreme has a great price. Any info would be helpful. Thanks.

Al

Reeves

I'm starting my shopping for auto cross tires as well. Since our weather out here is pretty dry (and my Vette isn't my commute car) I am actually considering the the BFG G-force KD (not KDW). However, in stock sizes the KD tire only comes in the SSS flavor (run flat). Anyone know how this tire compares to the KD non-SSS tire? Is it possible to get the best of both worlds (have a run flat that sticks)?

Reeves

Al, I'm curious, are you planning on using these for AutoX only or are you looking for tires that are going to be mounted on your car for daily-type use as well?

TeamZ06

Unless they just introduced something new that I'm not aware of, the Nitto Extreme is intended for drag racing, not autox.

The best autox tire for the money is the Kumho V700 DOT race tire. This is a dedicated autox tire that is generally not considered streetable. It is forgivable to both car setup - air pressures- and driver input, provides long wear, along with very good grip.

Most of the hotshoes (Kumho tire contract drivers excepted :-) run the Hoosier DOT tire; proper vehicle setup -air pressures- and excellent driver control is critical to get reasonable life, but it will wear out much sooner than the Kumho regardless, and a hell of a lot sooner if operated improperly. I would only recommend it to experienced autocrossers running on the national level.

h rocks

I agree with Team Z06's comments about the Hoosiers and Kumho's, but I was unnaware that Kumho had tires that would fit the stock sized C5 rims. Maybe they have come out with them by now?

TeamZ06

H Rocks,

18" & a few 17" sizes are now available from Tire Rack in the new Kumho ECSTA V700. More 17" sizes are available in the Kumho Victoracer V700. According to Kumho you can mix & match axle sets between the Victoracer and Ectsa DOT race tires, the tread patterns are just different.

Another tire alternative for std C5 wheel sizes (non-Z06) is the Goodyear F1 GS-CS, really used mostly as a showroom stock road race DOT legal tire that would be fairly durable as autox tires.

CaperZ28

There are two series of Nitto 555. the 555R are drag racer's while the normal 555 are street tires. That's what I use on my car and find them excellent for the price. They have a really stiff side wall. They don't handle like the KD's for sure though. Here is a link to there website. I think they have them at the Discount Tire.
http://www.nittotire.com/tire_nt555_sizes.asp

The Kumho V700 DOT would be far superior though. Any of those race tires would be acutally. I heard that Kumho's street tire isn't as good as the Nitto's for autocrossing. I almost changed over last summer, but asked the same question.

Dave

Reeves

BTW: I've come to a decision for my own needs. I'm going to get an extra set of stock-sized wheels and some BFG G-Force KDs in the SSS model (run-flat). My reasoning is that I don't yet want to spring for a trailer to pull some track tires and wheels and I like the peace of mind of having run flats. I'll continue to use my GY runflats as daily drivers for their better wet tracktion and use the BFGs on race days and weekends.

I'll give you guys a review when I've put some miles on them. :seeya

TeamZ06

A review is unnecessary. They won't touch the Hoosier or Kumho dedicated autox tire performance with the help of a 10 ft pole. The KD's are nice street performers, but aren't comparable to a real DOT race tire.

Reeves

Of course they can't compete with a track tire, I just thought people might be interested in a comparison between the BFG SSS and the Goodyear Run Flats.

CorvetteThrashers

Hi Team Z06,
I had a couple of questions for you about the Hoosier and Kumho tires if you didn’t mind taking the time.

First some brief background: The car; stock C5 except for penske coil overs and stiffer sway bars, 1.5” lower, approx Z06 size wheels, and BFG KD tires. 0.75 camber front, 0.5 camber rear. The driver – err… me; Raced bikes for 20 years to international level, one trip to a track in my car as described above (green as grass).

Some observations: The KD’s were pretty good for about 2-3 laps after coming in, then started to squirm all over the place and I lost about 2-3 secs a lap. It felt like they were overheating, but feeling them in the pits they only felt mildly warm. All four tires were between 36 and 37 PSI hot (well warmish). You cannot stand your hand on a bike slick after a good session. I know, I need a temp gauge!

Questions:
1) What’s going on with the KD’s, are they really overheating? They just didn’t feel good at the end of the session.
2) Is this typical of street tires, or are there better ones out there?
3) I’d really like to run the Hoosiers, as I wasn’t that impressed with the BFG’s even at their best, but your comment’s have put me off a little. If I get the Hoosiers heat cycled when I buy them and run more camber, say 1.5 to 2 degrees, and start out with Hoosiers recommended tire pressures are they really going to wear out extremely quickly?
4) If so what’s the secret to stopping them? (Camber, pressures?)
5) What is extremely quickly? I was sponsored by a leading tire manufacturer once and their rear slicks were good for 10 laps on an F1 bike.
6) Have you ever run the Hoosiers, and are your camber and toe settings a secret?
7) I know what road racing is, but what is autocross?
Thanks very much, Andy

h rocks

One of the first things you will notice is the tread depth of the KD's. That alone is generating a lot of heat in the tread, and the degredation of grip you're feeling after a few laps. The KD's weigh a ton. I don't have the specs, but I have lugged a few around for a friend. The Kumho's are not considered light by any stretch, but the construction and compound works phenomonally well together. Even given that however, if you take a brand new Kumho, V700 (or any tire for that matter) with full tread, which is ~ 5-6/32" after a few hard laps, event they will get greasy. That's why if you are a hard core autocrosser, road racer or plain old track ***** :D , you buy them shaved if you want to go 10/10ths right out of the chute. The Hoosiers (presuming S03) require a ton of negative camber to work and live. I used to run -2.5* neg camber on my RX7 TT. A lot of the guys running national level A-X install offset lower control arm bushings to get the required negative camber on their C4's. The Hoosiers weigh the least of the lot of the "R" tires. I don't know what the weight savings is on a 275 or a 315, but on the little 245x45x16" I ran on the RX7, it was 6# a tire compared to the R1's of the time! That's a huge difference. Frankly, unless you have a large tire budget, and the ability to dedicate the car for track use only (aggressive alignment) they would not be the tire for you. Right now, and for about the last 4-5 years, it's been hard to beat the Kumho in grip and durability. An accomplished driver *will* go faster on the Hoosier, but there are some tradeoffs. You need to be the judge. Have fun! :yesnod:

racingfast

WELL my $0.02 goes to the KUHMOS! Sizes: 275 40 17 in front and 315 35 17 in rear on Zr1 wheels. Have a set right now with 2 seasons on them and they are still good for a third...when they get hot they are unbeatable. I may try some HOOSIERS tho for the road course events. Will use my stock 01 Z06 wheels for them. :chevy