bent

Hey Guys 'n Gals,

I have a 2K3 stock Max SE and am taking the plunge into suspension mods and larger rims/tires. For suspension I have ordered Tokicos and Eibachs which are due to arrive next week.

For tires I am going to 18s but am still unsure about the exact size to get. (BTW - I've read the FAQ articles and gone to discounttire.com and tirerack.com and used the miata upsizing calculator in addition to searching these forums (when it works)). They all give me different sizes for the 17 to 18 conversion so I don't know which source to trust. Here's what I have found:

Miata = 245/40/18 (0.5% too fast) or 225/45/18 (0.4% too slow)
Tire rack option 1 = 235/40/18 (1.8% too fast according to Miata)
Tire rack option 2 = 255/35/18 (3.2% too fast according to Miata)
Discount Tire opt 1 = 215/45/18 (0.9% too fast)
Discount Tire opt 2 = 225/45/18 (0.4% too slow)

For those of you who've gone to 18's, can you please tell me the following:
1) your tire specs including: make, size, load rating and how you rate them overall (comfort, performance, wear, dry, wet).
2) your rim size (7.5 or 8) and if you needed to do any special adjustments such as camber plates etc.

Also, how do you know which of the above sizes fit 7.5 rims and which fit 8 inch rims?

Any help would be great.

Kevin

LatinMax

iTrader: (1)

I have Konig 18X9 Tantrum wrapped by Dunlope 235/40ZR18 with Eiback springs and KYB AGX ajustable struts from Cattman on my 2000.
The ride is great and it handles like a champ in wet or dry climate. Oh I also am supercharged.

NyMaxedOut

iTrader: (8)

I have 18x7.5 BSA wrapped in Avon ZZ1 high performace tires. For suspension I am running KYB GR2 w/Eibach pros. First, the ride handles extremely well and the tires have super excellent road response whether wet or dry. No snow experience yet but handles like a champ in the rain. The Eibachs now that they have settled are a little harsh but still champed over stock with the GR2's. No special adjustments were required. 7.5 rims can accomodate up to 235/x/18 with no problems. Thats what I have now.

TDMAX03

bent, I have Eibach/Toks with 18x8.5 SSR GT3s on 245/40ZR18 rubber on my 2K3 SE. I love the fit and they look great.

bent

Thx guys.

Latins rims are 9 wide.
Nys are 7.5.
TDs are 8.5.

Does the size tire you picked dictate the rim width you can run or could you have picked another aspect ratio on each rim?

I am looking at 8 inch wide rims.

TDMAX03

I'm no expert on tire fitting so I recommend that if you order from Tirerack or DTD ask the rep. Tirerack seemed to know there what they were talking about. Just remember that you want to keep the over all diameter of the tire/wheel as close to stock as possible so that you don't confuse your speedometer too much.

bent

TD - this is where I get confused (OK, not only there, but that's another story). According to the size options the Tire Rack Guy recommends, the speedo will be out the most compared to what DTD and the Miata Calc say. From what I've read, this isn't good . . . but tons of guys have bought from Tire Rack so they must know what they're doing. ????????

theMax

a little difference is OK, just think as the tire wears it gets a little smaller. 3% up or down is OK

I think tire rack 235/40/18 because there are lots of tires in this size. I would go with a 235/45/18 as its a little larger and will fill in the fender better.

If you are doing autoX racing i would go with the smaller tire as it is easier to turn and thus faster off the line.

kwd2kSE

For what tire sizes are within spec for different rim width's, check the specs page on any tire on Tire Rack's site-look at Michelin Pilot Sport A/S. Next, how is the car going to be used. Daily driving only or including autoX? Good streets or pot hole infested like here in Houston? Do you like the look of a very short sidewall(and probably a stiffer ride/greater chance of bent rim), or a slightly taller sidewall? Want the widest tire that will fit without rubbing/sticking out the fender, or is a narrower tire OK?

Lots of questions you have to decide as to what you like/want on your particular car. Its all about compromises. Here's part of the chart from the Miata site to give you some choices compared to stock 17's.

Tire Size Comparison

Specification Sidewall Radius Diameter Circumference Difference
225/50-17 4.4in 12.9in 25.9in 81.2in 0.0%
235/50-17 4.6in 13.1in 26.3in 82.5in 1.5%
245/45-17 4.3in 12.8in 25.7in 80.7in -0.7%
245/40-18 3.9in 12.9in 25.7in 80.8in -0.5%
245/45-18 4.3in 13.3in 26.7in 83.8in 3.2%
255/40-18 4.0in 13.0in 26.0in 81.8in 0.7%

FYI, I'm selling the Konigs and going with 18x8.5 VOLK and 255/40/18. I want the widest tire that fits without rubbing.

Mike

HitManSE

iTrader: (1)

Just keep the % of error within 3% and you'll be fine. There is a 3% margain of error anyway so dont worry too much about it if its 0.9% off.

leungjc78

iTrader: (1)

the 6th gen maimxa uses 18x7.5 AND uses 245/45-18
so..it's do-able.

I use maxspeed/ GR-2/ with 235/40-18 on 18x7.5..seems pretty good.but I use very cheap tires and I need to change to OEM wheels when winter comes.

bent

Thanks very much for the info.

You all answered the remaining questions for me. I think for my needs 245/40/18 will be the ticket on 8 inch rims. I have a trailer to tow every now and again so I want to keep the load rating at least 93. I am looking at the Toyo Proxes T1-S and the rim range is 8 to 9.5 with 8.5 being the recommended width.

If I can just find an 8.5 rim that I like I'm in business.

Woo Cho

iTrader: (3)

I have Volk Racing GT-7's in 18x8 with Yokahama AVS 235x40x18

rob van dam

iTrader: (4)

RH C5's 18X7.5 on 225/40/18 kumbho's

Pir8 97

Luke@TireRack is the man!! He's a Nissan guy too!

busakiller

I'm running 18x8 245/40/18's w/ teins/kyb gr2's... The car handles really good...

NT2SHBBY

hey busa..can I make a request? change ur sic pic to one of those sick pix of the new rims/drop

busakiller

HAHAHAHA... What's the matter with my High Rider??? I know i need to do that... Let me see what I can do SHBBY...

HitManSE

iTrader: (1)

Ok now what kind of rims are those again, I agree with NT2SHBBY.
Those are sick!

busakiller

Wasup HitManSE... They are Enkei 1/5 S rims.. I liked the look of asu174 aka Andy's car and these are very similar.. The Ace wheel in chrome was more expensive then the Enkei... $375 Ace compare to $293 Enkei.. I was going to get the 20's but I didn't want to lose all of the hp so I want with 18's..