Super quick Tire question
 

Hello to all. i have been shopping for summer tires over the past few days and just had a quick question so i can make sure before i sink a bunch of money into rubber. tirerack says the stock rubber is a 215/45/18 but they have very limited options in this size. can i get away with a 225/45/18 on stock MS6 rims without modifying anything?

Thanks for the help.

Go with 225/40 18. When you increase the tire width like that you want to decrease the percentage of said width to make the sidewall height the same. I know that probably doesn't make sense, but go w/ the 225/40 18, its whats on my car now.

i thought 225/45/18s fit as well on stock wheels / springs and no obese folks in the back.

if i go with the 225/40/18 will i have to reclock my speedo?

nope...no change of speedo. Honestly in either case its going to be slightly off.

Stock sidewall height is 96.75

225/45 sidewall is 101.25

225/40 sidewall is 90

so as you can see, either tire size is off. I guess it comes down to what look you want. The 40 series will have more of a low profile look than the 45 series.

neither of those tires is the same height. the 225/45 is closer to stock.

the only way to change the speedo is to use a dash hawk. you can input the diameter of the tire.

I did not know that...does that change the speedo in the car, or just on the dashhawk readings?

just on the DH. its gona be off by about 2% in each case which isent going to matter because your speedo is ALREADY off by about 3% at speeds above 60 anyway

Ok...so maybe this wasnt super quick as the title suggests...but one more quick one...

What about a 235/40/18? Is that too wide for the stockers?

They'll fit on stock rims, I even think a couple guys on here run those and don't have any issues w/ rubbing...


http://www.mazdaspeedforums.org/foru...40-18-a-50202/

I went to the dealer to see what their options were and ended up leaving extremely satisfied, here's how:

Tire Rack wants anywhere from $117 to $250+ per tire for our cars, pick your style. Add $40-$50 for tax if you're in the shipping state and $40-$50 for delivery. Minimum cost out the door is going to hover $550 minimum from Tire Rack for the cheapest tires I saw, Kumho Ecsta ASX's, which are currently on backorder.

After I asked Mazda what their replacement option was, they surprisingly did not say the Potenza's. They sell Pirelli PZero Nero All-Season's at $136 a pop. I read a lot of reviews and they were highly rated for traction, life, road noise, etc.

Decided to bite the bullet and went with the Pirelli's.

Costs were: $544 ish for all four tires, $32-ish in tax for the tires, and the mount and balance was $80 ($20 per tire). That's $656 for dealer installed tires. I happened to also go ahead with a full suspension alignment and the nitrogen in the tires, $50 for the alignment and $40 for the nitrogen instead of oxygen inside (one time fee for free lifetime checks/refills for the life of the car for any tire in the future). Came out to around $750 total.

Impressions:

This is a different car. Bumps are fine to take now, forget all the suspension complaints I had before, loving it! Road noise is down at least 50% from my old Potenzas. The alignment is, well, very aligned. I got new OEM valve stem caps since I was missing one, and they have the nifty "N" on the end for nitrogen (very hard to see, not ricey at all and I am a stickler about that stuff). Assuming the tires last as they should, I'm sold for the rest of the vehicle lifetime on these Pirelli's. Keep in mind this is my DD and fun car, not an autoX car.

On a nice side note, I whined about a dash rattle and received the TSB fix under warranty without any questions with the felt pads under the cowl to eliminate dash rattles. Works like a charm, no more dash rattle and did not cost me a penny. Also got the updated EGR system via a TSB for cold start trouble difficulties, gotta love that warranty, and it seems to have really improved how smoothly the car accelerates, not sure why but its been 150+ miles and its still a lot better. They said the old versions tend to get stuck open and hurt performance and cold starts.

Last TSB on the list is the updated PCV system, which again will be installed under warranty as soon as it comes out, dealer promised. :) Happy days for my car!