To start this off, I did a brief search and found a few answers, but some I did not. I'm just looking for some straight answers, hopefully I can get some help.

Need some tires to wrap the new 17x9 Advans that I got.

I was originally looking into the RE01R's but the Dunlop Z1's seem to be getting excellent performance ratings as well as an affordable price.

I'm looking for mostly street driving and some track days during the summer. My questions.

1) What is the main difference between the Z1 and the Z1 Star Spec? Is it just the compound of the tire? Is the star spec the better tire?

2)How can I tell the difference between the Z1 and the Z1 Star Spec(like if I bought them how could I be sure they're the right tire)?

3) I've heard the Z1's run wide. Should I have any fitment issues with 255/40/r17's if I have rolled fenders? (or should I stick with 245's)

4) Lastly, what is the recommended cold tire pressure. I have seen 34 front 36 rear. Does this sound good?

Thanks in advance,
Nick

 

1) Softer compound - slightly better performance.
2) There is a Star on the tire where the word "Spec" is
3) I got 255/40 and put them on my stock 17X8 BBS rims. They bulge a little more than my 255/40 RT-615s, so I'd agree that they run wider at the same size. The problem with 245/40 is it's shorter than stock, which isn't good for gearing. 245/45 is taller than stock. 255/40 is the closest to stock diameter and fit just fine on the stock rims.
4) Cold pressure for what? Different pressures for different situations. The ones you posted are just fine for DD and maybe 4psi here on both for track.

 

Thanks for the help Warrtalon

the cold numbers are for DD not track.

Also thanks for explaining the size vs. diameter. To be more specific I meant will the 255/40 fit my Advan 17x9 well? (They shouldn't bulge at all correct?)

Also if anyone knows of any reputable places to get fenders rolled on Long Island, post up or send a PM. Thanks again

 

1) The old regular Z1s are no longer being made. Star Specs are the current Z1 tire. Compound is very similar to the old tire but Goodyear improved the heat up properties of the tire (aka they heat up quicker without losing ultimate grip).

2) Yep, just that 1 inch star.

3) On 17x9s - 255/40s should be nice. If OE I have to go with 245/45.

4) Look like my numbers. I run that psi for track (but different sized tires and setup all together). They are a good place to start and adjust from there.

 

i run the star specs. love em.

 

Oh hell yeah. On 17X9s, the 255/40 will fit beautifully. You should have no rubbing unless you maybe you're lowered a lot.

 

yea im lowered alot so unfortunatly my 245's on my stock rims rub my fenders on ocasion

 

I can't wait to get these on my car

 

I have used and abused my first set of Star specs on the street, slalom courses, E-town's roadcourse and Pocono North and I have to say they are my new benchmark beating out PS2's for best all around summer tire.
My 245/40-18 tires rub the inside of the wheel well due to lowering...

 

The primary enhancement in the Star Spec version is the tread compound, which comes up to operating temperature faster than the original while retaining the same ultimate performance levels.
There is a star branded after the Z1 on the tire's sidewall.

Haven't seen any sizes in the Z1 that are wider than a couple tenths of an inch vs. other tires. Basically no noticeable/fitment difference between those and other tires in the same size. Many use the 245's with great results.


Best to stick with the door placard/owners manual to start. You need at least that amount to support the car weight properly. Anything between recommendation and the max psi on the tires sidewall is fine. More pressure will increase handling but reduce ride.

 

Some of the autocross guys are running this tire in STU and the results so far are pretty good. I plan on picking up a set real soon. One race on my all season Bridgestones was enough to convince me to get off my *** and get serious about this race season. I can still hear them screaming

 

They aren't just doing "pretty good," but rather winning National events with them over and over. They are the top street tire currently.

 

Even better! Just ordered them today. Will post back up after the next race.

 

^^ Thanks!

 

After reading all the reviews on tire rack and comparing these to the Bridgestone RE-01R's I think these are a great tire, worthy of mounting on my Buddy Club rims.