tires..

[mazdaspeed32007]

Diameter should also be considered since it changes your effective gear ratio and speedo/odo. Stock tires are 25.7"

?what? diameter with the 18 inch rim and 40 mm sidewall is 21.2 inches which is my current set-up with the new rims. the stock 18 inch rim and 45 mm sidewall is 21.6 inches total diameter.

i may be doing the math wrong or something but where did you get the 25.7"?

the difference inbetween the 21.2 and 21.6 has little effect on the speedo/odometer in any case.

 

[Mid_Life_Crisis]

There seem to be a lot of guys (and maybe ladies) that are puzzled by the tire manufacturers' recommended rim widths. Remember that different tires of the same size may have different sidewall designs. Some are reinforced, some aren't. This means that some can be compressed onto a smaller rim or stretched for a larger rim while others can't, because the sidewalls have different levels of flexibility.
Someone stated that the factory tires are 215/40/18. This is incorrect. The factory tires are 215/45/18.
I'm sticking with 225/40/18 as my replacements because I want to keep the suspension geometry as close to stock as possible, and these will fit the stock rims or aftermarket rims with a similar offset. They are very close in diameter to factory and there are many more options in that size than there are in the factory size.
I just put a set of Kumho (sp?) all seasons on the factory rims which will be my winter tires. As soon as I have the money, Falken 615s in the same size are going on wider (and lighter) rims for the summer.

 

[Mid_Life_Crisis]

?what? diameter with the 18 inch rim and 40 mm sidewall is 21.2 inches which is my current set-up with the new rims. the stock 18 inch rim and 45 mm sidewall is 21.6 inches total diameter.

i may be doing the math wrong or something but where did you get the 25.7"?

the difference inbetween the 21.2 and 21.6 has little effect on the speedo/odometer in any case.

Using a tire calculator, the factory size comes out to 25.6". 25.7" is close enough allowing for tread thickness variations between manufacturers.

I can't figure out what math you did to come up with 21", as adding 40mm to 18" should yield roughly 19.6". (40/25.4=1.6___18+1.6=19.6). It's moot anyway, as that isn't how it works.

The 40 and 45 are not mm, they are %. The sidewall is rated as being a certain percentage of the width of the tire. This is why a 235/40/18 is taller than a 215/40/18, because 40% of 235 is greater than 40% of 215, so the sidewall is a little bigger. It's why when we go to a wider tire, we need to drop the perentage from 45 to 40 to keep the overall diameter of the tire close to stock.

 

[mazdaspeed32007]

ahhhhh. thanks for the knowledge. i honestly thought it was based on mm to how large the sidewall was not the % of the width to sidewall.
thanks bub.

oh as adding 40mm to 18 i added the 40mm 2x because you have tire on both sides of the tire. i honestly thought thats how it worked. sorry for my slight retarded-ness. i know somethings here and there but i learn something new on cars at least once a day. im getting better everyday.

Using a tire calculator, the factory size comes out to 25.6". 25.7" is close enough allowing for tread thickness variations between manufacturers.

I can't figure out what math you did to come up with 21", as adding 40mm to 18" should yield roughly 19.6". (40/25.4=1.6___18+1.6=19.6). It's moot anyway, as that isn't how it works.

The 40 and 45 are not mm, they are %. The sidewall is rated as being a certain percentage of the width of the tire. This is why a 235/40/18 is taller than a 215/40/18, because 40% of 235 is greater than 40% of 215, so the sidewall is a little bigger. It's why when we go to a wider tire, we need to drop the perentage from 45 to 40 to keep the overall diameter of the tire close to stock.

 

[Gmac03]

just picked up a set of falkens rt615's
225/40/18
I always go to vulcantire.com typically I can't find a better price

Gmac

 

[Mid_Life_Crisis]

oh as adding 40mm to 18 i added the 40mm 2x because you have tire on both sides of the tire.

Damnit! I can't believe I overlooked that. I'm supposed to be a certified genius and I missed something very basic there, so don't beat yourself up too much.

 

[mazdaspeed32007]

just picked up a set of falkens rt615's
225/40/18
I always go to vulcantire.com typically I can't find a better price

Gmac

good luck with getting more than 12000 miles out of those tires man. thats a soft ass tire. youll be the stickiest kid in the east tho. lol.

 

[Gmac03]

yup best tires to run. best of both worlds. sticky and street.

 

[mazdaspeed32007]

yup best tires to run. best of both worlds. sticky and street.

i can get about 20000 out of mine with great traction. i travel to much for the 615's so i went with the 452's. if you put on only 12000 a year then sweetness. i get about 20000 a year so....

 

[Mid_Life_Crisis]

I told my wife RT615s are Summer tires and she should expect me to buy a new set every year. She rolled her eyes and basically said, "okay, if that's what you want." God I love that woman. Now if I can only scrape up the cash for some damn rims!
I found a set from an OZ based manufacturer that I like that weigh 19.2 pounds and the whole set with mounting kit (lugs, etc) can be had, delivered, for $570 or so, but they are 7.5 and I really want 8.0. Anybody find any seriously sweet deals on rims to go with these tires?

 

[squabbin]

I told my wife RT615s are Summer tires and she should expect me to buy a new set every year. She rolled her eyes and basically said, "okay, if that's what you want." God I love that woman. Now if I can only scrape up the cash for some damn rims!
I found a set from an OZ based manufacturer that I like that weigh 19.2 pounds and the whole set with mounting kit (lugs, etc) can be had, delivered, for $570 or so, but they are 7.5 and I really want 8.0. Anybody find any seriously sweet deals on rims to go with these tires?

I'm in the middle of picking rims as well. Its tough to find an 18x8" under 20 pounds in general, nevermind at a reasonable price.

 

[MS3077]

Where is a good place to get good wheels / tires on the cheap?

 

[tandman]

Try eastcoasttires.com they have some good deals and some even better deals through their ebay store.

 

[mazdaspeed32007]

i bought mine at stagefourmotorsports. the guy was real nice. got em quick. around 600-700 or something for some rota tarmac 3's 18x7.5. these guys sell a helluva lot of rotas i know for sure they might have what you need? (shrug)

 

[MS3077]

i bought mine at stagefourmotorsports. the guy was real nice. got em quick. around 600-700 or something for some rota tarmac 3's 18x7.5. these guys sell a helluva lot of rotas i know for sure they might have what you need? (shrug)

Do you have a pic of you MS3 with them?

 

[Gmac03]

I would say Rota or Konig, for cheap, semi decent looking rims that are moderately priced and of decent weight.

Gmac

 

[Mid_Life_Crisis]

One of the members got a set of nice looking rims made by a company called Speedy Wheels. They are light and very affordable, but does anybody know them by reputation?

 

[ericrapp]

Mine were supplied buy Element Wheels. and i must argue the East coast sticky. But if I can have the Northeast or the Stickiest old guy in the East? Spent some quality time with the new Nitto's today and they are all I hoped, Just warm them abit first. The Falken is all that too, I bet. That Sppedy thread must still exist, I do recall the subject being discussed.

 

[MS3077]

Thanks for all the feedback dudes!

 

[blacksheepms3]

u guys tell me....rota wheels P1 18x8 with kumho ecsta spt, mounted, balanced, shipped, lug nuts included for 1300...is that a good deal? that's what i have.