My 'new' 17's

[96Familia]

My 'new' 17's. Second hand off an auction site. NZD$755 (around USD$530).

Have to go out and pick them up. Won't put them on until I get my skirts done. Which could be a few more weeks. It will lower my car 3.36cm.

My current mags are 185/60 R14
These mags are 205/40 R17

[Mazda96Protege]

Congrats man they look awesome! very nice choice

cant wait to see your car with them on and of course the skirts as well!

[beetle_orange]

very nice, put them on!

[Intruder]

Are you getting lowering springs too?

[96Familia]

Are you getting lowering springs too?

I don't think I will be, not in the near future. Problem is my driveway is too steep. The skirts and the mags will make it appear lower anyway and it's got interplay x coils in it so it aint too granny atm. Maybe I'll change my mind later.

[Intruder]

You're saying the skirts will lower the car, but that's only your ground clearance. It's not going to do **** for your wheel gap. I think those 17's are going to look terrible with the stock springs.

[96Familia]

You're saying the skirts will lower the car, but that's only your ground clearance. It's not going to do **** for your wheel gap. I think those 17's are going to look terrible with the stock springs.

I know the wheel gap will decrease 3.36cm. It won't look half-bad. My mate worked it out for me, though I'm not sure how to. I'll need to ask him, or unless you guys can tell me.

[Intruder]

I don't see how installing side skirts can decrease your wheel gap.

[96Familia]

I don't see how installing side skirts can decrease your wheel gap.

Nor do I see how installing side skirts will decrease the wheel gap. What I'm saying is installing the 17's will decrease the wheel/arch gap by 3.36cm. Obviously all the side skirts will do is decrease ground clearance.

[DeanSweetP5]

tire size must be a little bigger?

[95pro]

even with the 17's, the gap is still going to be there. bcause the overall diameter of the wheel and tires is still going to be the same.

[Intruder]

He's saying that the overall diameter has grown by 6.72 cm (2.6") which eats away some wheel gap but throws the speedo off.

[95pro]

that's not going to eat up the gap. maybe a little, and at the same time, it's going to push the car up a bit.

[MazdaRacer]

**** man who cares, homie's got some VERY nice wheels. Good Find!

http://www.miata.net/garage/tirecalc.html

from that page

185/60/14 = 22.7" (577.6mm)
205/40/17 = 23.5" (595.8mm)

1.2" (18.2mm) taller

[goldstar]

Nor do I see how installing side skirts will decrease the wheel gap. What I'm saying is installing the 17's will decrease the wheel/arch gap by 3.36cm. Obviously all the side skirts will do is decrease ground clearance.

I don't see this-what am I missing?
From: http://www.1010tires.com/TireSizeCalculator.asp

185/60-14 wheel/tire combo = 22.74" diameter, 71.43" circumferance
205/40-17 wheel/tire combo = 23.45" diameter, 73.67" circumferance

Diameter difference = 23.45" - 22.74" = .71" (1.8034 cm)
Circumferance difference = 73.67" - 71.43" = 2.24" (56.9 mm, 5.69 cm)

Therefore, how can your new tire/wheel setup decrease wheel/arch gap by 3.36 cm?

Also, the speedo reading will be 3.123% too slow and the diameter difference is 3.03% larger.

FWIW, 1010 Tire states, "Warning! When changing tire sizes, we recommend staying within 3% of the diamter of the original tire. Any more than this and you face the risk of brake failure."