Originally Posted by Crashmaster
Keep in mind that you are asking for two different things.
Tire width is measured in millimeters like P195, or P215.
Aspect Ratio is the ratio of the height of the tire's cross section to its width. For example: on a P215/65R15, the 65 means that the height is equal to 65% of the tire's width. The bigger the aspect ratio, the bigger the tire's sidewall will be.
The last part of the number 15 is the diameter of the wheel.
So to answer your question, if you want the height of your tire to be the same, keep the same aspect ratio. If you want a wider tire, go with a bigger number at the front.
1) Keep in mind that changing your aspect ration will affect your speedometer.
2) Wider tires equals wider contact patch, meaning better traction on pavement. (Not really too important with a CT).
3) Wider tires are worse on slick surfaces. This could be very important depending on your environment.
Partially true... the important number, not listed on the tire size is OD. That is what will affect your speedo..
Yes, the first number is size (width) and the second, the aspect ratio is correctly described. BUT.... a 245/65 tire will have a larger sidewall than a 225/65 tire giving it a larger OD (65% of 245 is a larger number than 65% of 225). So in order to keep the OD correct, you actually need to go down in aspect ratio as you increase width
... IE in the above example, assuming the same diameter wheel, a 245/60 tire is a closer match to a 225/65 tire in OD (within .1 of an inch). Here is a safe web link where you can see the affect of different tire sizes. https://tiresize.com/calculator/
Use the comparison tab...
Also, be very careful when upsizing wheel and tire setups. The things Crassmaster outlined are true, but there is more. Not only does getting bigger and lower profile impact ride and handling, it can actually make the performance part worse.. lowering acceleration and cornering speeds. Here is a great short article done in 2010 by Car & Driver on the topic..
Shame it came out after my stints with Accord Coupes. I learned the lesson the hard and expensive way. In short.. the 2003 Accord EX came with 16" wheels standard. I wanted to improve performance and make it look better. I installed 18" wheels with, if I can remember, 45 series tires. Well, it looked cool but drove like total garbage. Rode horribly, tracked in groves, wouldn't hold a balance... etc. But I lived with it. Then I traded it in on a year newer 5sp Coupe in silver.. this time I did the upgrade correctly. Went with just a 17" wheel and that was perfect. Rode nice, but handled better.
While I haven't answered your question directly, hopefully you and others have the tools to make the choice that works for you..
And since every thread needs pictures... LOL... here are my departed coupes.
The white one with 18's
The silver one with 17's.... much better..