I have the stock 18" rims that i use for the track, and recently i just bought the bf goodrich kdw's 245/45 for the front. Do you guys think that this sidewall will be too tall, and will flex too much at the track? Im not able to really test them out yet as they are not broken in yet.

 

You shouldn't have any problem with the 45 series tires... especially if you're on stock or only moderately upgraded suspension.

IMHO I think you'll find them exceptional track tires... and while they may be slightly more compliant than say a 40 or a 35 series sidewall, chance are they only thing you'll notice is that they will handle surface variations a little better.

Dont think twice about it... now get out there and drive some tread off of them before your next track event!

[edit in response to Dave's post below] I used to run BFG Comp T/A all-seasons on my '90 Z32 NA AUTO and when starting out, I was very pleased with them. Had I continued on in that car, yeah, I could have quickly over-driven them. But talk about a car that wanted to understeer!

 

The KDWs are BFG's all-season performance tire. While I don't think the 45 series sidewall is of much concern, the amount of tread on a tire like that could result in some severe feathering (or worse, chunking) after prolonged track use. Since the Z is set up to understeer at the limit, the front tires are usually in for a lot of abuse. You didn't mention what kind of rear tires or suspension setup you have, but take Stack's advise and "shave" those tires with street use before you hit the track.

David Muramoto
Senior Editor
Nissan Sport Magazine

 

Im on stock suspension, and i have the same tires in the rear, but they're 255/45. My next track event is on 9/30, so im driving on them until then. Do you think they will be ready by then?

 

If you're driving more than just on the weekends, they should be fine... how many track events have you done?

All-season tires can make great track tires, if you're out there to learn, not just be the fastest one. BFG's usually have higher grip levels than most, and any will 'talk' to you a lot while out there on track. Be sure to let your instructor know what tires you are on... ask him to help you understand what the tires are telling you while you're out there... you'll be a better driver for it, and that far ahead of the game when/if you progress to a more track-oriented tire.

 

Inflate all the tires to the maximum pressure listed on the side wall and then watch each tire for rollover. You do not want the tire to roll over on the outside sidewall. Check the wear on the tread and make sure it does not go past the tip of the triangle shaped treadwear indicators on the side of the tread. If you are not getting wear to that point its safe to lower air pressures (which provides more grip) until you do get wear to that point.

 

^+1 (especially because of the all season profile differance)

 

I've been to 6 track days already, but i was using the stock potenzas. So now i expect to get a lot better traction than before. I usually run with the intermediate group. Thanks for the advice on the tire rollover.

 

I ran KDW's on a couple track days, and concur- The fronts will overheat and chunk if they have close to full tread depth and you are pushing them into understeer. I ran 33psi F, 35psi R cold, and had some rollover. (I did some drifting later in the day, which contributed to some of these issues)
They are a good tire for the track, and pretty predictable, too. They are not comparable to Falken RT-615's though.

Keep in mind that this is a front tire punished by understeer on my first day learning to drift. You can see the chunking though

 

DAYUM! I thought mine were bad from last june (below), but I think your's take the cake!

 

Those tires look so bad. My stock potenzas were starting to look like that. Do you guys think it would be a good idea to have my KDWs shaved?

 

Not sure how well they take to shaving... yeah, it would help in terms of the chunking and feathering, but you may also lose grip (I know, sounds backwards) cause most 'street' tires lose grip the more the tread is worn, as opposed to r-comps like RA1's where the grip increases as you lose tread. All depends on the tread compound.

Lets get some more info... what track is your next event at? Much of the feathering/chunking issues have as much to do with driving style and course design as they do with the type of tires you're running. Tracks with long, fast sweepers will chunk a tire quicker than tight technical courses.

You mentioned you've done 6 'track days' ... tell us more... were these Friday at the Track type events? Open track? Is that Three 2-day events or 6 single days spread out? Were you instructed at all of these?

 

I have done 4 track days with Buttonwillow themselves running the event, and 2 with speedventures. These were all one day events for me, and i had instruction for 5 out of the 6 times i have gone. Theres ususaly 3 groups when i go, (beg, int, and adv.) I have gone with the beginner group 4 times, and have run with the intermediate the last two times i have gone. Oh yea and my next event is with speedventures at Buttonwillow.

www.speedventures.net

 

Holy wack!!! What did you guys do to your tires !!!!

I've never had any of my street tires look like that, even after 45 minute sessions!

What happenend? Gave 1/2 turn of lock and let it plow ?!?

 

Tires lose grip as a result of heat cycles, not loss of tread depth. A street tire that's been run for 20,000 miles and is down to a 3/32 tread depth is slower then a comparable full tread new tire because its got thousands of heat cycles on it.

Back when World Challenge ran the Proxes TS1s they would all be shaved to 2/32s after testing showed that they were incrementally faster then when shaved to 3/32 (the more traditional shaving depth) and were at least a second per lap faster when tested against full tread depth.

Unless your racing class requires street tires (typically treadwear 140 or above) you are dollars and seconds ahead investing in a set of DOT-R tires. IMHO... the Toyo Proxes RA1 is the best street/track compromise tires when unshaved. I ran them on a few of my street/track cars and, although a bit noisy and harsh on the street, they were not as bad as the V700s or the super noisy A032s.

 

I don't know how those street tires chunked so bad. I can tell when my slip angle is too extreme causing them to chunk. The tire starts rolling over it's own rubber, and it's rough and ugly feeling. Usually, I'd have to back off the steering input, and let the car run out wide or even drop a couple wheels off if necessary. Once I reach those slip angles, though, I would be shaving off so much speed that it wasn't worth going into a turn that fast.

On another note, I saved those photos because they are truly knarly!

 

Tires with full tread and high pressures will overheat when used hard and chunk. A street tire should be shaved down to 3/32" for best results. Thats why you see DOT SCCA showroom and Touring tires are without tread not counting the two stripes around the circumfrence as required by DOT. A Kumho, Hoosier and Goodyear race tire is at its very best on laps 3 thru 5 if you start out using them hard from the first lap. Kumho, which is what i'm more familar with won't drop off very much, about 1 second on a 2 mile track, over the next 6 or 8 heat cycles. Then they will lose about 1 more second per lap. We start out with very low tire pressures as our tires are low profile and have a stiff sidewall.
Anyone looking for some 350Z 18" take-off with one weekend of qualifying and racing call my son Rob HInes at 703-989-1536 before 9pm EST. Tires located in Arlington, Va. Usually about $300 a set plus shipping.

 

I have actually even had shaved R-compound tires chunk on the Z (front tires - these were Dunlop Super Sport Race) due to the understeer. The Z needs some camber to make the tires work properly, especially R-compounds.