Another 15x9 225vs205 Tire Thread
 

Cliff note at bottom, sorry about the ramble, lots of questions.

Hello all, I know 15x9 vs 15x8 and 205vs225 has been covered 100's of times, but reading through it all and some of the info is dated, leads to more confusion for me. My car is a 2003 NB, I just put DIY billies on it with 450/300 springs. The car is a daily driver that will see a few autocrosses and a few HPDE days a year. I only put a few thousand miles on it a year (short commute of 2 miles). I have a brand new set of 15x9 Advanti S1 rims I got for a steal waiting for this car, also a set of 15x7.5 TRMotorsport rims with BF Sport Comp 2's on it currently (I like these, but the Advanti wheels look way better and the Comp2's dont have as much grip as I imagined, perhaps i suck at driving). My budget is tight, which leads me to:

The question is tire selection. I would like to put the 15x9's on the car for ascetics, I can add more tire as my track driving improves, more grip for when I do get out on the track, but due to how limited my track driving is, I would like to stay on the more budget end of the tire spectrum. The new RS4's seem to be about $570 shipped for a set. Some people have been able to run 205's on the 15x9, but it depends on the tire selection. If I were able to drop to a 205, then the cheaper Federal 595-RR (initial reviews seem to be good on these) at $420 or the new Extremecontact Sports ($440 or so) save me $130-$150 a set that I can actually put towards track time.

The Federal section width is 8.3", and the tread width is 7.2". I assume the Conti's are comparable. How small is TOO small for a 15x9 for daily use? Also I read I think in the DIY billie thread that 15x9 wheels cannot run a 15/50 profile tire and fit when lowered? I have seen some claim they work, some say the ride is worse, or better, or the bead pops off, or you look like a stance boi pansy, etc.

Cliff notes: Guy has very tight budget, looking for a street tire he can do a few track days on, has 15x9's he desperately wants to use, and wonders which 205's would fit well and be on the cheap end of the budget. Leaning towards Federal 595RR or Conti Extremecontact Sport as both new tires have decent reviews. However both are 50 profile tires, does that work?

It's actually preferable for you to tag along an existing thread discussing this very topic rather than junk up the forum with yet another thread. Idea being it's easier to find all the data in one place.

I wouldn't be comfortable with 205's on 9's, just too stretched. It's been done but there is no good reason. The are no good for daily driver tires in 225 yet..... I got 3k miles and 9 auto x events out of my rivals I'd expect the same from the RE71's. Your best bet would be either the 245 VR1, or wait and see how the 245 RS4 turns out.

Good point on tagging an existing thread, I guess the last real discussion I saw on this was Coriftos thread about switching to a 15x8 rim.

This is where i get lost as to what direction to go. You say there is no good reason to put a 205 on the 15x9, but in Coriftos thread from 2015, https://www.miataturbo.net/wheels-ti...ch-15x8-83105/ the discussion was that a 205 can be used if no 225 is around. He just ended up buying 15x8's so the discussion didn't get much further along. Im concerned getting rid of the 15x9s and dropping to 8's for the tire selection might bite me in the ass down the line as i get more and more track time under my belt, just right now dropping $600 on a set of rivals that I'm mainly going to daily seems like wasting rubber.

If you're going to get serious about auto x then switching rim size is a waste of time......So is running one of the Uber soft Hoosiers in disguise tires such as Rivals or RE71 as a daily driver. They aren't even a good choice for a HPDE tire as they only last 4 to 6 hrs of track time.

Which is why I pointed you towards the VR1 or RS4, yeah I know it was discussed that you could run 205's on 9's but it's going to look goofy and ride like ass.

The smartest thing to do is put the cheapest hardest tires you can find on your 7.5" wheels then you can get some gumballs for your 9's and swap em for when you race. If 200$ make that big of a difference to your budget that's pretty much your only option. Think about the long game, you're looking at 5 to 8k miles for rivals/re71, 10 to 15k for second tier tires like the VR1, you can probably easily get 30k miles out of a 400 tread wear tire so you're going to go through 4 sets of rivals or 2 sets of VR1 for every set of normal street tires.

I think so long as you stay with any of the 200TW ST tires that tend to run wide, you're probably going to be fine. Them riding horrible when stretched more is a bit overblown. I doubt there's much of a difference there. There's also been a little bit of debate on a 205 being faster on an 9 over an 8. I know that holds true for Hoosiers but I've never seen a test of that theory on street tires.

I ran 15x9's and 205 VR1's on my DD beater from May til it got cold in November and they seemed to work fine. Didn't really ride that bad either (and that's with Koni Race/Sports, 700/450, RB tubular front/14 mm rear bar, poly bushings, etc). That being said, I'll probably replace them next year with 225 VR1's or RS4's.


https://cimg9.ibsrv.net/gimg/www.mia...d78ec04c97.jpg
https://cimg1.ibsrv.net/gimg/www.mia...cc255172e0.jpg
https://cimg2.ibsrv.net/gimg/www.mia...6fca9d40ea.jpg

Those actually don't look too bad.

I just bought a set of 9's and when it comes time to replace tires on them I might get 205's instead of the 225's that are on there now for cost reasons. It's like a 200 dollar difference and I only drive the car sparingly in the spring/summer/fall. Depending on how much use I get out of the 225's I might get another set, but I doubt they'd last over 10k street miles.

Is there a list of the tires that tend to run wide for 205's? Yours actually look more than acceptable, but I've seen some pictures of setups I wouldn't put on my car.

https://www.tirerack.com/tires/TireS...earDiameter=17

Basically any sticky (200TW or lower) street or race tire. They all seem to advertise a 8.4" or so section width though certain ones are probably wider than others there. I think unmounted, the BFG's might run the widest of the street tires.

I have been trying to find more and more pics of 205s on 9" set ups. Not too many Ive seen yet. I picked up a set of Federal 595RS-RR tires a week or so ago. They were running a promo for $60 off, so the full set shipped was about $360. I have wanted to try these tires as a budget sticky set up for awhile, and the price point made my decision for me. If they are stretched or look goofy, I have 7.5" rims they can go on so I'm not overly worried. Once I get them mounted I will post pictures. The Federals run 8.3" section width compared to some of these others 8.4". However, every review I have read on other car forums say they always seem to be bigger.

With the spring rates you are using, an ultra 200tw tire will be grippy enough to probably put you hard on the bumpstops in a corner, depending upon your ride height.

Aside from that, you are not driving competitively in TT or w2w and you say you are on a tight budget. I'm going to suggest you pick one set of wheels to be your DD wheels and mount a good, long wearing tire on them. For the track days and autocrosses I'd pick up a set of SM takeoff Hoosier SM7's. They can be free or cost a few bucks depending upon quality. They will be 205's and will fit both the 7.5 and 9in wheels. You may find them to be faster on the narrower wheels due to less mass and possibly aero drag, but it won't matter either way because HPDE. I have run them on 6.5 wheels on a budget and they really fill out 8in 6uls. I wouldn't hesitate to put them on a 9in wheel after seeing them on an 8.

The SM7 sounds like a smart tire choice as i gain experience lapping. I only have a few sessions under my belt and have spent the last year and a half buying safety supplies for this year. The car is 90% daily driven, hence the softer spring rates. I will keep my eyes out for take off tires.

I was under the impression people were running 450/300 or 450/350 for dual duty track/daily set ups with sticky rubber? I have not driven on the new shocks/springs, I assume I might need a heavy front sway bar to help compensate.

450-f is a pretty cushy street spring rate... I ran 600/450 on Bilsteins on 205 rival-s and I was perhaps a bit under sprung, but we have really bumpy lots, so it worked. The ride was actually pretty reasonable, though I did need ISC top hats to retain enough bump travel.

205s on 9s do not ride like shit.
50/15s fit a lowered car, especially an NB.

I personally hate the stretched look, but theres no reason you cant run 205 on a 9. My NA is about 4.5" pinch height, only had to roll the front and do a slight pull on the rear. 15x9 dial ins, they don't rub anything, even at full lock.

205/50 rivals on 9s
https://cimg7.ibsrv.net/gimg/www.mia...3ff18e3bce.jpg
https://cimg8.ibsrv.net/gimg/www.mia...a8a240a342.jpg
https://cimg9.ibsrv.net/gimg/www.mia...48261d3b22.jpg
https://www.miataturbo.net/attachmen...ine=1421895039
https://www.miataturbo.net/attachmen...ine=1421895039

450 is a good 90% street rate that is still track capable, but you will need the strong front bar eventually. Just stay off the curbs at track out (outside wheels) and the car should be settled.

The car may oversteer some until you get the front bar.

Sixshooter, thanks for the input. Ill keep an eye out for a front bar.

The rivals look good on a 9, I think I should be ok with my current choice, and then upgrade to the SM7's as I find them. We just got 18-24" of fresh snow, so I think testing out the new tires is a ways away yet.....

The SM7's will work fine on your smaller wheels. I think the SM guys run 15x7's.

Thanks for the pictures!

PS: You put the konig cap on upside down!



(Jay kay!)

Good to know. I just remembered swapping out my 400 f springs after a few weeks because my tires were kicking the springs ass and the bumpstops were doing all of the work. Given this was at autocross, so, "different springs for different things"

/end thread drift

Yeah, the 450 with the big front sway bar will still be a bit light for really sticky tires on the track but will be very compliant as a 90% DD. And he's on a budget and got them already. Lots of people have done track days on less and still had a great time. He'll be fine. And he's gonna catch a lot of slower cars and worse drivers with it on a limited budget. That's great!

This makes me excited!

(I just got a sway bar)

I just railed on 205 RC-1's on 15x9's all weekend, no issues, very responsive, but pictures make it look fairly sketchy with that amount of stretch fully loaded. Absolutely no reason to run this, I just already had 205 RC-1's and didn't want to buy another set of 8's since I plan on running 225's or 205 purple crack in the near future.

https://mohflo.photoreflect.com/stor...1&po=10&pc=127

Is section width the most important metric to go by here or is it important to consider the tread width as well if you don't want things to stretch too much?

Just for reference, the regular direzza (dz102), the S-drive, and the Direzza zII star specs all have a 8.4 section width. The respective tread widths are 7.1, 7.4, and 7.5. If someone is doing this for price reasons (like myself), it would make a lot more sense to go with the slightly more expensive S-drives if the measurements are accurate, no?

I'm sure wider treadwidth is also better there for what we're shooting for. That being said, what measurements are accurate? When 200TW stuff seems to dwarf normal 300TW street tires, I kind of wonder if there's any accuracy there for what they list. I had 195/50 S.drives on 15x6 NB wheels and 195/50 RSR's on 15x7's. I think they sat about the same on their respective wheel so I kind of doubt the S.drive runs all that wide.

You ignore all the tread and section width data and go with test results. We're lucky enough to have some very smart and we'll funded members who have run every combo under the sun so to maximize performance you run 195 on 7", 205 on 8", 225 on 9" and 245 on 10", anything else will be a compromise.

Some of us can live with that tho...

That's what I'm trying to figure out. If price is an issue, I'd rather go with the one with the best measurement if performance/metrics of importance are about the same. These are for a street car so I'm not worried about what the well funded members are doing... just looking to do what's right for me without running a stupid amount of stretch.

I've also seen 225's on 10's which should be super sketchy, but were totally fine.​

Finally got around to getting my tires and wheels to the shop to be mounted. I have been to two different places and neither can mount these things (15x9 Advanti Storm and 205 Federal 595RS-RR) They are telling me they do not have adequate air pressure to pop this on the bead. They say the sidewall is too stiff to get on.

Has anyone else had this issue? Any idea of a solution? Anyone in the Milwaukee area that knows of a shop that does this regularly?

How the hell do those stance bros get their crap on?

I am LOL'ing IRL at your screen name. :D

<---- Loudest purple NB

The Subie bros use Big Bear in Oconomowoc and I heard Endless Autosport in West Allis will as well.

Good to know, I have an appointment set up at Lake Country Alignment in Oconomowoc for next week. Those guys and Big Bear I have heard good things about and apparently have equipment to handle this set up. Sadly this is an hour drive each way just to mount tires..... Thanks for the tip.

Ether and a match I've heard works. YMMV

Defiantly more exciting than more air pressure

How about more cowbell?


OP, please post pictures of the tire/wheel combo when you have everything mounted. Thank you!

I will post pics once I have the tires on and again fitment on the car when its finished. Just got the roll bar in last night and cutting plastic trim tonight :noes:

Haha, I was so fed up with the damn thing when I finished installing my roll bar that the carpet and insulation over the rear deck area looks pretty blah. I recommend trying to be a bit more exacting with the cutting so you don't have a ton of space around the arms of the roll bar.

I completely messed up my carpet cut on one side. I have it tight around the bar legs but hacked up another area..... you're right. by the time I got to the carpet I just wanted to be done. Absolute PITA experience.

To get my 205s on 9s, I had to have someone who prefers payment in beer over cash. Luckily I already knew 'a guy'.

So you're saying that you bought yourself a 6 pack and went to town?

Not at all. Some illegal building a 1000hp m3.

Just a note to those who might not know - tire manufacturers are given a window that they have to be within for the tires to be certified (TR&A, ETRTO) and it depends on the rim. For example a 225/45R15 on a 7.5" rim can be between 216m and 232mm wide and from 577mm to 589mm in diameter. On a 8.5in rim the width window is 226mm to 242mm. So what you're really looking for is the rolling tread width if you want to know the physical size of the tire.

Got the Federal 595RS-RR tires mounted on the Advanti Storm S1 in 15x9. Two local tire shops were not able to set the bead as the standard air pressure couldn't get the stiffer side walls to set. I had to take it to a guy who had a... I think it was called a Cheetah bead blaster. That set them right on. Pics on fitment:
http://i66.tinypic.com/f9dsaq.jpg
http://i66.tinypic.com/2igzw4w.jpg
http://i67.tinypic.com/2lbia77.jpg
http://i64.tinypic.com/30ax85u.jpg

HPDE UPDATE:

I do not have a lot of on track experience, I autocross every summer, and did a track day 2 years ago in a 1990 miata. Just had these on the Milwaukee Mile course for 3 20 minute sessions in 60 degree weather. These things grip..... General road noise is a bit higher, most reviews say it sounds like there is a small plane following you, this is pretty accurate, but on the track they were fantastic. Slight squealing when you're getting to the limit, sharp turn in response, Grip immediately out of the paddock and I never felt them lose any grip through the 20 minute sessions. I paid $360 shipped for this set earlier this year, absolutely great for the price. I am hoping to get in as many driving events as possible, so I will have to see how they do long term.

Quick question for guys with the Spec Miata take off tires: Are you able to run the SM6 or SM7 on the street to and from events? I dont think they are technically legal on the road, I just mean is it going to be like driving on wooden wheels on the highway or is it feasible? I do not have a trailer but might have a way to snag a set of hoosiers to try out this season.

As long as there's no standing water see no reason why you can't. I've driven RC-1's to the track (~2 hours) and around town a handful of times. The only problem is rcomps are less puncture resistant from what I understand.

It seems most SM7 tires are considered DOT rated, so technically they can be on the road from what I'm seeing. Unless this is inaccurate I answered my own question. Thanks for the tipcobowabo.

They are DOT rated but say for competition use only on the sides.

They heat cycle every time you use them so they are terrible to use on the street. If they are already heat cycled a couple of times before and you use them for a commute for a few days they have lost 80% of whatever made them special versus a performance street tire. They get harder quickly. If they freeze they are ruined.

My SM7 takeoffs have also done an entire track weekend as well as a SM race so test driving across town yesterday to check fitment and feel once wasn't a big deal. They're already a shadow of their former selves.

The SM takeoffs, I assume most people are getting these with 4-6 heat cycles or so on them. I have read that life expectancy is maybe 8-10? Does that sound right? So does that mean you're only getting 1-2 weekends of HPDE (3 sessions each) max out of a full set before you need to swap another set on? It might not even be worth me getting these if a full set only lasts a weekend or so.

For HPDE you should get fresh RC1/NT01 and be done with it. I just got fresh SM7's for NASA TT, but am only going to run them 1-2 sessions per day hunting time, then swapping back to RS4's to keep HC's off the SM7s. A buddy ran SM7 take off's on his kswap a couple of events ago and was slower than on his 225 (possibly 245?) RC1's.

Hmmm. NASA Florida gives six 20min and two 25min sessions a weekend, or about 2 3/4 hours. Performance Driving Group gives 6 30 minute sessions in one day and then sometimes some open lapping at the end of the day, so 3+ hours. That's a pretty good day for one set of tires. I usually bring a couple of spare sets to the track in case of a flat spot, a puncture, or a bent wheel. Usually doesn't happen but nice to have spares. But, yeah, performance does fall off.

When I worked for a Spec Miata team we cycled out tires anywhere from 3-6 hours of use depending on the driver. Though it would be legal to drive SM7's on the street, if your event is two hours away and the tires had 5 solid heat cycles on them already, they would be completely toast by the time you got to your event, and I wouldnt trust them to hold air on the way back home.

Ok, this makes more sense. People are able to get about 3 hours of track time on a set of take offs, give or take. In the Milwaukee region our HPDE are 3 20 minute sessions for an hour total. So if the tires are swapped at the event, I SHOULD be able to squeeze 2, maybe 3 events out of a set before they are garbage. And driving them on the street destroys them. Got it.

This is good info. Makes the decision if its worth getting a set to try or not easier, vs just running a sticky street tire. Thanks all.

FWIW I recorded tire temps with a pyrometer after 3+ hours of highway driving on NT01s and the tire temp didnt get above ~90degF in 80ish degF ambient. I'm not convinced you could heat cycle tires just with normal highway driving.

I currently run Federal 595RS-RR tires on my 15x9 wheels on the street. I maybe put on 3k miles a year, so daily driving these and doing track days (5 a year) isn't outrageous, I should get 2-3 years out of a set. I just dont know if it makes sense to go after slicks for HPDE just to shave a few seconds and deal with hauling tires/swapping every event. I do have a spare set of rims, but the pay off doesnt seem to be there.

Doesn't sound worth it for you.

To my understanding it is cycles and not actually usage time that Harden of the rubber and cause the tire to be less grippy. This seems to be the case in my experience as well as what I have read.

If you're just doing track days probably not. Timed events are another thing.