FASTiva Tire Choice

[Loren]

Well, crap. Got a phone call Saturday afternoon. Just kidding, sorry, we don't ACTUALLY have tires in stock. This is the second time I've had this issue with OnlineTires.com. Oddly enough, with exactly the same model of tire. How hard it is in 2016 to have accurate inventory on your website?

Anyway... nobody else seems to carry the Federal RS-R. Moving on, need to order something else.

Ben is keen on trying the Bridgestone RE-71. It's a known entity... it's the best of the best right now. Problem is that they are known to wear insanely fast (for a street tire) and might only net us 70-100 runs. Since Ben's not driving on these tires, and Steve and I are more frugal than that... we probably won't go that route.

My favorite tire for the past couple years has been the Dunlop Star Spec. Really good grip and response, very forgiving to drive on, doesn't have any weird bad habits like being sensitive to temperature, and they tend to wear very well. (154+ runs on our 185's... 205's should do better than that) They're not terribly expensive, and are another known entity. I wouldn't hesitate to buy them again.

Hankook RS-3's are another great tire. Arguably "slightly" better than the Star Spec. Probably not going to wear as well. Probably more expensive. Wouldn't hesitate to buy them again, but not really willing to pay more for them than for something like a Star Spec.

BFG Rival S is another player. They're a good performer, but we've had some pretty awful tire life experiences with them. Strange wear patterns, grooves, shortened life... not cool. Even if they claim to have fixed those problems, and even if they were cheap, I ain't going there again.

The new player in the game is the Kumho V720. Haven't heard a lot about them, but Tire Rack has tested them and they have numbers that are in the hunt with stuff like the Rival, so they should work fine for us. No idea what their wear characteristics are, though. But, they're fairly cheap.

There are a few other choices, but those are the ones I'm most enamored and/or experienced with.

So, I think the choice is mainly down to these two:

Kumho V720 - $99.10 each
Relevant facts: 21 lbs, 8.2/32 tread, 7.2" tread width, 0.96G dry, 0.81G wet, reviewed as a bit noisy and harsh. Tread is asymmetrical. (can't be flipped on the wheel to even treadwear) Very little in the way of forum chatter on these tires, but hints that they may suffer from delamination issues and/or short life.

Dunlop Star Spec - $115.02 each
Relevant facts: 19 lbs, 8/32 tread, 7.5" tread width, no G specs, reviewed as a bit noisy and harsh. Tread is symmetrical. (CAN be flipped on the wheel to even treadwear... and we DID have to do that with the current set) We already know these tires are good on the car in the 185/60-14 size... surely the same tire in a 205/50-15 will be a significant improvement?

I think this analysis has made the decision for me. Star Spec seems like the obvious choice. The "methodical experimenter" in me likes the idea of just changing the tire size (one variable) instead of going to a completely different tire. It's the best choice to be able to say "fitting wider tires helped the car THIS much".

Thoughts?

[ImpostorDan]

IMO - The v720's will basically grip and wear as fast as the RE71r's at a lower price. They come with a huge square shoulder profile. Mine wore in such a way that I don't think they would have needed a flip; the shoulders seem to be a different compound than the centers. The delam threads seem to be based more on keeping the tires hot hot hot - e.g. HPDE. Mine only gave me issue on the last mm of tread block, on a co-drive schedule, um - while possibly overdriving a touch.

I'd like to think with your finesse, you'd keep them together and get a few more runs than I did (alright, stop laughing aready).

[Loren]

Oh yeah, I forgot you had those, Dan!

FWD is weird. To keep the outside shoulder from getting eaten alive (power goes to the front wheels, no LSD, 65% of the weight is in the front, etc), we run as much camber as we can in the front. If we're successful in that endeavor (which we sort of are), then all other driving causes camber wear on the inside edge of the tire. Flipping the tires mid-life balances out the camber wear AND gives you a fresh shoulder on the outside. It really helps a lot with FWD.

For that reason alone, the Star Specs being symetrical is a big plus for us. We should be able to net at least the same 150 runs that we got out of our current Star Specs with proper rotation and a mid-life flip. I just don't see that kind of life happening with the V720.

But, let's play it out...

Star Specs = $460/set plus $45 mount & balance and another $45 mount & balance = $550 for >150 runs. Or $3.66 per run. (man, I hate looking at it that way!)

V720 = $460/set plus $45 mount & balance = $505 for <100 runs. Or $5.05 per run.

Doing 5 runs (or more) per event, we're looking at a difference of $7 per event. For what might amount to a half second faster per run... not really worth it to me.

Edit: Plus the inconvenience of having to buy tires again... and the guilt that comes from being more wasteful than I need to be.

[Native]

Nitto NT05 - $102.
200 tw (if not W-speed-rated) 7/32 tread depth 8.4 section width (probably more important than tread width, given fitment concerns). Couldn't find a weight.
http://www.discounttiredirect.com/direc ... 3879892cac

Azenis 615K $120
21 lbs. 8/32 tread depth. 7.6 tread width. Couldn't find section width. Most of them are about 8.4 anyway
http://www.discounttiredirect.com/direc ... =15&cs=205

Kumho XS $111
19 lbs. 8/32 tread 8.4 section
http://www.tirerack.com/tires/tires.jsp ... &tab=Sizes

[ImpostorDan]

For what might amount to a half second faster per run... not really worth it to me.

A half second would have Rob Ledwell under pressure as you vied for a top 20 finish by the .001's and .002's. Based on my RS3 wear at 50 runs (compared to my kaput 52 run kumhos), you'll easily get 50-100% more life on the star specs.

And you may have math'd wrong if the price is really $100 a tire for the v720's; as such, $4 premium to start chasing the R1 times...

[Loren]

For what might amount to a half second faster per run... not really worth it to me.

A half second would have Rob Ledwell under pressure as you vied for a top 20 finish by the .001's and .002's. Based on my RS3 wear at 50 runs, you'll easily get 50-100% more life on the star specs.

And you may have math'd wrong if the price is really $100 a tire for the v720's; as such, $4 premium to start chasing the R1 times...

Yeah, I was mathing on "best case" for the V720 to give it a fair shake. Going from 185 to 205 should make the car considerably faster if we can keep up with the steering. I'm guessing probably about a second per run faster. I'm not itching to get greedy in search of yet another half second just yet. (we have some weight reduction to do yet!)

[ImpostorDan]

You would get the 100 runs for sure, especially if you skip the dog track and downs days.

[Loren]

The XS was a decent tire, as I recall, but they're currently on closeout. My experience with closeout tires is that they're usually a couple years old. Even though TR stores them properly, they still "age out". Gave a set a shot once and was sorely disappointed. For that reason, I didn't even consider that tire.

Azenis are "okay", but have been surpassed by many of the newer tires. Worth considering in 14" sizes where there are precious few options. But, for 205/50-15 where there are plenty of options in the same price range... meh.

I was turned off by the NT05 at a glance because it's got those HUGE voids in the middle. What's the point of a wider tire if THAT MUCH of it isn't going to have rubber on the road? (we'll get wider track and some other advantages... but, net grip?) That said...

Discount Tire has free shipping, which Tire Rack does not. That's $60+ per set, or about $15/tire.

So, the NT05 will cost us $408 + $0 shipping. (and they're asymmetrical, so we can flip them if we need to)

Star Specs will cost $460 + $60 shipping, $520 total.

The NT05 would be considerably less expensive. Unless having 12.5% less tread is a factor that results in less useful life. (and it probably is)

Not much autocross-specific info on them. Track day guys seem to like them, and they're popular with the muscle car crowd (probably because they're decent and cheap... and they burn through tires even quicker than we do). This review/test is rather damning, though: http://www.hotrod.com/how-to/wheels-tir ... ires-test/

Over 2 seconds slower than Star Specs on the same car, same driver, same course, same day. Not good. I won't chase a half second with tire money. But, 2 seconds? That's significant.

And then there's this thread by Emilio (well-known Miata tuner and aftermarket guy) on Miata.Net: http://forum.miata.net/vb/showthread.php?t=318701

I think that basically indicates that it's a really good track tire. For our purposes, I don't like that it's "less forgiving" than the Star Spec. And one of the statements bugs me for autocross: "We found that the NT05 does need to be heated up to at least 150° to really start working."

That all points to "great track day tire", but not necessarily "great autocross tire".

[Carracer]

Well, my vote would be either the RE71R or the Star Specs. If you are going for grip why not have all of it. So get the RE71Rs. They have a $70 Visa rebate right now so the are actually really cheap for what you get. If not, the Star Specs seem like a good compromise between grip and tread wear. Also the car has been setup for the driving style of Star Specs.

[Loren]

Didn't see the $70 rebate. That brings a set of RE71's down to $388 + shipping.

They are symmetrical, so we can flip them. Total life analysis:

RE71 = $388/set plus $45 mount & balance and another $45 mount & balance = $478 for >100 runs. Or $4.78 per run.

Star Specs = $460/set plus $45 mount & balance and another $45 mount & balance = $550 for >150 runs. Or $3.66 per run.

The $70 rebate makes a little difference. But, probably still not enough.

I'm still feeling the Star Specs.

Also the car has been setup for the driving style of Star Specs.

Bwaaaaahahaha! If we were in trash talk mode, I'd agree emphatically. The setup of the FASTiva is a marvel of race car engineering that warrants your respect and admiration, and our competitors should be afraid... very afraid. But, the reality is that the car is just thrown together for the most part, and tweaked to sort of work "well enough", and course workers should be afraid... very afraid.

[Native]

Star Specs!

[Loren]

Star Specs!

On it!

[puncturina]

I suppose I'm late to the tire party discussion here, but here's our two cents...We've driven the Hankooks, Star Specs, and now the Bridgestones.
We got a new set of Star Specs when we got the new car last year, but I was very disappointed in the handling of the car. It didn't seem that much better than those funky Prius tires the car came with. I don't know if they were just old when we got them or what, but they really liked to break loose. I believe Jamie and Steve will testify to how easy it was to spin out with those. When we got the Bridgestones, it was like getting a new car. Aside from my recent excursion into the agricultural elements, we rarely spin out anymore. You guys are better drivers, but for us, I would never want to go back.

[Loren]

The RE-71's are phenomenal tires. Pretty much on-par with a race tire of 10-15 years ago.

But, the Star-Specs have proven to be pretty darned good. I'm wondering if maybe you did get an old set, or maybe you just never got the tire pressure to a happy place? (I'll admit that I've been guilty of letting my co-driver worry about that lately... I think we're running around 38 psi, and the FASTiva isn't too picky about tire pressure)

[Loren]

True to form, the Tire Rack delivered tires within two days. (I think they actually showed up the afternoon after I ordered them) They are presently over at Carl's for mounting.

Thanks for the discussion. We opted to stick with the "known entity" of the Star Specs. They may not be "the best", but we know they are good and we can reasonably expect them to last us through at least 6 months. (that's 2 FAST events per month with two drivers for 6 months...)

[aw614]

I missed this thread earlier doh!

I don't know what it is, but I never got used to the Z2SS either when I ran the 195/55 version on my Integra for 2015, it could have been setup dependent, but I preferred the way the car drove on my previous RE-11A and even the Kumho V720 I had briefly after I corded the dunlop. I will say this the Z2 SS did last a very long time, probably over 120 runs and 4,000 street miles on them without flipping them. I felt like I couldnt get the car to rotate like I wanted.

But I did get the tread delamination on my Kumhos after around 50 runs and 1,500 street miles. So I went with RE-71R's instead after talking to Tire Rack and sending my two delaminated tires back. Sucks because I thought they felt great at the dog track event and the few brooksville events I took them to.

[aw614]

Well, my vote would be either the RE71R or the Star Specs. If you are going for grip why not have all of it. So get the RE71Rs. They have a $70 Visa rebate right now so the are actually really cheap for what you get. If not, the Star Specs seem like a good compromise between grip and tread wear. Also the car has been setup for the driving style of Star Specs.

What kind of driving style does the star specs prefer? I've read this before on other sites and heard the same from word of mouth, but don't recall hearing the driving style

[Loren]

I've found the Star Specs to be pretty flexible.

But, I had this discussion with Philip the other day. I'm not a driver that's good for picking out subtle details of things like tires and suspension. I can tell you when something is grossly wrong and usually what you can adjust to fix it... but, for minor stuff, I just adapt and drive the car the way it wants to be driven.

[Carracer]

Well, my vote would be either the RE71R or the Star Specs. If you are going for grip why not have all of it. So get the RE71Rs. They have a $70 Visa rebate right now so the are actually really cheap for what you get. If not, the Star Specs seem like a good compromise between grip and tread wear. Also the car has been setup for the driving style of Star Specs.

What kind of driving style does the star specs prefer? I've read this before on other sites and heard the same from word of mouth, but don't recall hearing the driving style

They don't like slip angle. When I drove my all seasons and even to an extent the Azenis, I could slide the car and still get good times. The Star Specs don't like sliding much at all.

[Loren]

Generally speaking, the more grip a tire has, the less progressive it breaks loose. That's probably what you're feeling.