For anyone that wants to know...
the stock 18" 6MT 2005 Sedan rims weigh 51LBS with tire..
the COUPE's Forged 19" weigh 48.6 and 51.4lbs (front/rear)
so,the 19" weigh the same as the 18" do.. with the coupes 245X40X19's in the rear, the speedo is 1.5% off, so when it reads 60, you are really going 60.9..
not so bad..

 

Does anyone know the rim width and weight of the stock wheel for the 2003 sedan with sport suspension? I'm trying the search function but can't seem to find it. Thanks.

 

is there a working offset caculator?

 

just wondering....will 245/35/19 front and 275/30/19 rear mess up the VDC?

 

The wheel is 17X7 and I think the weight is around 25lbs.

 

what is a safe size to go with for someone with a coupe and want to get some 18s?

 

^^What he said for me too^^

 

I have an '04 6MT coupe and want to know if the following tire replacement on the OEM 18" wheels would work.

225/45/R18 --> 245/40/R18 Front
245/45/R18 --> 275/40/R18 Rear

Main concern is to determine if the OEM rims are wide enough to accomodate the wider tires.

Thanks!!!

 

No expert here but it's only an 8" rim. 275's would most def. buldge. Not to say it won't fit BUT it will probably wear very uneven, a guy I think his screen name is IMSOLUTIONS, has the 8.5 19" OEMS and is running a 265 safely. So I would think a 255 would probably be your safest bet. Front 245's is what I had and had 0 problems on the stock 18's Just my .2

 

I put a set of Toyo 235/50/17 on my '05 G35 sedan.....Much better than stock; better ride, and handling.....

 

I just found a pretty nice offset calculator

http://www.rims-n-tires.com/rt_specs.jsp

I haven't looked at any of the other calculators yet, but this one is really nice. It shows you visually what the tire and wheel will look like together with every possible wheel/tire size.

This calculator is also a good place to go when people start talking about tire sizes (like 245/45/18) you can easily select those numbers to see a visual representation of just what they're talking about!

I didn't want to start a new thread and since this one was stickied, I thought this would be a good place to post this one.

 

Since they can't be up forever, here is how you can create your own:

In Excel place the following 2 rows of content in columns A-G (comma means new column):
Description, Width, Profile, Rim Diameter, Total Wheel Diameter, Difference From Stock, Sidewall Height
STOCK, 215, 55, 17, =((B2*(C2*0.01)*2)/25.4)+D2, =E2-$E$2, =B2*0.01*C2


Here is what you will end up with:
Description, Width, Profile, Diameter, Total Size, Difference From Stock, Sidewall
STOCK, 215, 55, 17, 26.31102, 0, 118.25
BP, 245, 35, 19, 25.75196, -0.55905, 85.75

The formula came from the 2006 Wheel & Tire guide, the resulting spreadsheet came in handy for checking sizes.

The only thing missing would be a formula for determining displayed speed at 60mph like some of the websites do. This 'should be' correct (just add these as additional columns in H-J):
Circumference, Speed Diff, Speed at 60
=PI()*E2, =H2/$H$2, =60*I2

End up with using above examples:
Circumference, Speed Diff, Speed at 60 (actual speed when speedo displays 60)
82.65851, 1, 60
80.90219, 0.97875, 58.72512


NOTE - I suggest you compare your initial spreadsheet results against the online ones for a few sizes before you rely on it to make sure all formulas entered correctly:
http://www.miata.net/garage/tirecalc.html
http://www.1010tires.com/TireSizeCalculator.asp

 

For the time being anyhow, the spreadsheet is available here (after that you'll have to create your own using instructions in previous post):

http://www.cvscc.org/TireSizeCalculator.zip

 

Thats pretty cool.!!
Thanks

 

Don't know if this one is a repost but

http://www.discounttire.com/dtcs/infoTireMath.dos

Seems to be a great comprehensive source for calculating speedo variation