I was wondering how wide can I get the tires for the stock rims I have? Right now I have 235s and these are the wheels I got and I know 215 is the retail recommendation.
http://www.houstoncar.org/thumbs/accord-coupe-honda.jpg

Well the picture is not showing up so I can't see what wheel you are referring to. I would go wider than 235 and if it's a 17x7" I would just stick with a 215/50 tire. Anything much beyond that and the tire is going to stick out beyond the wheel wells. To mount a 235/45/17 tire you should really be using 17x8" wheels.

how about now

I just want to know what the max width is for these kind of rims. I bought the car with 235 45 R17 on them already. I just want to know if 245s are possible for those rims.

Well the picture is not showing up so I can't see what wheel you are referring to. I would go wider than 235 and if it's a 17x7" I would just stick with a 215/50 tire. Anything much beyond that and the tire is going to stick out beyond the wheel wells. To mount a 235/45/17 tire you should really be using 17x8" wheels.

They are the 17" wheels from the 03-05 6MT coupe.

Sorry I meant to say that on a 17x7" wheel I would not go wider than a 215/50/17 tire. I think 235/35/17 is really pushing it on those wheels and I would certainly recommend that you stay away from a 245 tire on there.

the 235s I have on look pretty normal on my rim. Tire walls are not sticking out all that much if anything above normal. I guess I will just stick with 235s. The reason I asked about wider tires is because wider tires means better looking car :yes:

Use this (http://www.rims-n-tires.com/rt_specs.jsp;jsessionid=F863F34D4E504504AB2E83C3B7 409E8D?item=Wheel-Tire%20size%20comparer&showRim1=1&showTire1=1&sw1=215&ar1=45&bd1=17&rd1=17&rw1=7.0&et1=45&showRim2=1&showTire2=1&sw2=225&ar2=45&bd2=17&rd2=17&rw2=7.0&et2=40&text1=Scion%20tC%20stock&text2=) to figure out if it's too wide or not.

I always go to the tire manufacturer's web site and look up their specifications. They normally list a recommended or approved rim width. It might be a little conservative, but I figure the manufacturer should know what they are doing. I'm presuming your question is just related to rim width not clearance issues. Here's an example:

http://www.bridgestonetire.com/tireselector/SizeSpecs_BS_EN.aspx?Product_ID=1113

For what it's worth:

Calculating Tire Dimensions

Modern metric tire dimensions Example...185/60R14 85H or 185/60HR14
The first number is the width of the tire in millimeters, measured from sidewall to sidewall. To convert to inches, divide by 25.4 In the example above, the width is 185mm or 7.28".

The second number is the aspect ratio. This is a ratio of sidewall height to width. In the example above, the tire is 7.28" wide, multiply that by the aspect ratio to find the height of one sidewall. In this case, 185x0.60=111mm or 7.28"x0.60=4.36".

The last number is the diameter of the wheel in inches.
To figure the outside diameter of a tire, take the sidewall height and multiply by 2,(remember that the diameter is made up of 2 sidewalls, the one above the wheel, and the one below the wheel) and add the diameter of the wheel to get your answer.

Example...185/60R14 85H or 185/60HR14

185mm x .60=111mm x 2=222mm + 355.6mm(14")= 577.6mm or 22.74"