tmak26b

Here is your first, I hate these tires. They are better than the RE040, but not by much. If you are used to leaning on the R compounds at the track, it's almost suicidal to drive the 615s after. The tires are also bugging me on the road now as they are extremely bumpy and noisy. I drove them on a 300 miles trip, they are a lot more noisy and bumpy than the RA-1s. I would gladly take my RA1 1000 miles across the country than the 615s. The drone on the 615s nearly put me to sleep, I hate these tires. I have 50% tread on these things, I would gladly trade them for a set of new brake pads!!!

My rear tire wear on the 615s are very close to the RA1 because of their tendency to spin. I live on a steep hill, so it's almost a given the 615s will spin up the hill.

I have tons and tons of videos of me nearly losing it on the 615s, I can hardly think of 3 or 4 on the RA1s. Driving the 615 is like doing a drift show rather than being able to drive the car like what I can do on the RA1s.

Z1NONLY

iTrader: (2)

RA-1's = 100 treadwear
615's = 200 treadwear

Apples and oranges. I have driven the NT01's (100) the VictoRacers (50) and a couple of "slick" type competition tires (30) they all have varying degrees of grip and it's important not to take more than a tire can give.

The RA-1 is a DOT competition tire and the 615 is an aggressive street tire.

I think you may be asking too much of street tires (615's) if your yard stick is a competition tire. (RA-1's)

tmak26b

That is also the difference between FTD vs being in the mid pack in the standing. It's not for everyone, but it works for me. As a user of both tires, I can tell you what is better. Also with the massive torque and the understeer prone car like the Z, having a grippy tires really help. When I did a fun run in my car yesterday, all it did was plow into and at the mid corners, power oversteer exiting the turns, what a mess...

MSR350Z

My recommendation and one that I make to all my students. Wear out at least two sets of high performance tires... Hankooks, Kumhos, 615, etc. Forget about mods, forget about times. Only focus on modding that nut behind the steering wheel.

Money spent on improving oneself is always money well spent.

Get out there and drive and drive and drive and drive. The fastest always spend the most time at the track.

NA&CH

iTrader: (74)

Hey guys. I know there is a thread, which I am searching for , anyway,

What size tires are you guys putting on your stock 03 track rims? I once read that some guys were buying another set of rears for the front. I am a beg. and want to start with auto-x then move into the world of road racing. I don't feel like messing my Advans up, even though they are lighter...

Thanks guys. Sorry for off-topic.

Kolia

iTrader: (2)

235/40R18 front
255/40R18 Rear

Back on topic now

The HACK

What is your experience level?

When you mention track, is it for DE or time trial? Open track?

Suspension? Any work done? Alignment settings?

How much are you looking to spend per tire?

What sort of brake and brake compound do you have?

Don't mean to pry, but the more information you can give the easier it is to give a better and more objective suggestion. For example, unless you're on track pads like Hawk DTC-60s or Cobalt Spec VR/XR series, real track pads, you probably shouldn't run an R-Comp. Reason being that the R-comps (Pilot Sports Cup, Toyo RA-1...etc) will allow you to go so fast that your brake pads will be overwhelmed quickly. Especially if you're just doing DE or open track days where the money for R-comps just doesn't justify itself. Now, if you're doing Time Trials, you should consider ONLY R-comps and make sure you upgrade your brakes.

Certain tires respond better to additional camber, whereas certain tires will wear really fast with camber. For example, Bridgestone Potenza Pole Position S-02 and S-03s don't need a lot of camber to work well and seems to be rather indifferent to camber settings, except when you have more than 2 degrees of negative camber it'll start wearing out the Potenzas really quick. R-comps, especially, are sensitive to camber settings. Make sure you have a tire temperature gauge to take temps if you're running R-comps and adjust your camber accordingly to even out temperature distribution.

Experience level...Usually I say no to R-comps unless you've got a few events (like 15-20) under your belt. But that's hard to determine sometimes. If you've got 3-5 events, I'd say run what your OE comes with, if you need to replace, replace with OE. If you've got 5-10 events under your belt, look to something like Bridgestone Potenza Pole Position RE050A or Michelin Pilot Sport 2 or equivalent street tires. After that but before R-comps, try Yokohama Advan Neova or Bridgestone RE-01Rs. They're street tires with near r-comp grip. Then when you've pretty much maximized your own ability to handle the car, move up to R-comps like Michelin Pilot Sport Cups or Toyo RA-1s or Nitto NT-01R. But be sure to upgrade your brake and suspension hardware when you move up to R-comps.

Save true competition tires like Hoosiers when you're competing.

Kolia

iTrader: (2)

+1
Very important thing to keep in mind!

tmak26b

My car still works fine with the stock suspension and the stock braking system other than pads and a bent dust shield. Only upgrade whatever the driver is capable of.

Kolia

iTrader: (2)

The car works well on r-comps with stock suspension. Untill you hit a bump in a fast curve...

The OEM damper's lack of rebound damping combined with the front bumpsteer characteristics will make things interresting as the car darts left and right...

The HACK

On R-Comps?

dnguyent

iTrader: (5)

I'm pretty sure that you'll need a brake upgrade if you run r-comps and do Laguna Seca. Although not a precise measurement of heat capacity, I still managed to change the color of my stoptech calipers to mud red on street tires at that track; and I have the 355mm kit.

I experienced brake fade with the stock non-brembo oe braking system on my second track day, and I decided that I was just going to make the jump to bbk instead of risking the repeat of very unpleasant experience. I don't see how anyone can manage to make the non-brembo brake system work with r-comps + northern CA summer heat....maybe at Sears Point...but even so, you don't ever want fade approaching T11.

dnguyent

iTrader: (5)

Yeah, once you hit a bump, it wavers like an old school cadillac. I'm also running the koni yellows now, and like them very much.

tmak26b

Yes sir, you just have to change your driving to counter for it. I can bounce over bumps all day long, I just have to compensate for it. I have no problem pushing the car to the limit, my lap times can back me up on it. Heck, I can make it through Lime Rock on the RA1 with stock suspension, what are you guys complaining about? There are not many tracks that are bumpier with the exception of Sebring.

Kolia

iTrader: (2)

A fun car is a car that's easy to drive.

A car that darts over bumps doesn't fall in the "Easy to drive" category. With the costs involved in tracking a car, I'd rather have a setup that's balanced so I can have my share of fun track time instead of wrestling with the car.

Otherwise, I'd go lapping on a bone stock Z shod with winter tires...

The HACK

No fade? On stock 350Z brakes?

I would suggest putting on a set of track pads, and try altering your braking so that you brake later and harder into your braking zone. You are leaving A LOT of time on the table if you're not on track pads, especially with R-comps.

The HACK

The stock non-Brembo on the 350Z (heck, even the stock brembo brakes) are the worst brakes I've ever had on any car(s) that I've ever tracked. My E46 323Ci and my Z4 3.0 both had much better performance at Buttonwillow and California Speedway. Heck my E30 318is' brakes held its own at Sears Point.

I wouldn't take a stock 350Z to the track without some basic brake work to allow for better cooling that's for sure. I tried just about everything too, slotted rotors from Rotora, various compounds (Axxis Ultimate, Nismo R compound, Hawk HPS), and ultimately had to pony up to a RacingBrake 4 piston front/OE caliper big brake kit with Hawk DTC-60s that solved my problems.

Car was on Yokohama A032R soft compound. Tried tons of different braking technique too, it would either fade or completely chew up an entire set of pads on 2 sessions.

tmak26b

Huh, driving a Z fast on street tire is a work out. I feel much more comfortable and confident with the race tires.

These are bad videos, but same track on street tires and race tires. This is from Lime Rock, not exactly glass pavement.

http://www.youtube.com/watch?v=vICXp_KOJC8

http://video.google.com/videoplay?do...11961269&hl=en

Not every car in the world drives like this, http://www.youtube.com/watch?v=zbRElM3JUZU

tmak26b

I said my braking system is stock except for a set of Carbotech XP10, modified heat shield and Wilwood fluid. I was only able to do 3 laps on the stock pads. The car stops fine, they just get heat soaked and pedal goes to the floor. Maybe weather is cooler here, but I have plenty of brakes for a 10 min session. 15 min. you start to notice the difference with my current setup. I can get 200 miles on the pads, that's my max.

I have been using RA-1s and Rt-615 Azenis (used RE040 and Rt-215s), the car stops just fine with either tires.

The HACK

Well, more power (no pun intended) to ya.

The few times I was at Buttonwillow and California Speedway the ambient temperature were in excess of 115 degrees F.