wuts the biggest rim/tires u can put on 99 neon 5 lug .. its is lowerd 3 inches if that makes any difference. i heard 17 or 18 is the biggest u can go but if u take the fender wells out u can go 20" is that true.. well anyways i havent had fender wells for a very long time. also what is the biggest width or how wide rim/tire can be.

Here is some info for you...

The first and most obvious thing to consider is the tire diameter. You want to stay fairly close to stock, or you will encounter speedometer and odometer errors. In addition, your wheels/tires act as your final drive ratio. Change the diameter significantly and you change your effective final drive ratio. There is a good tire size calculator on the main page of Neons.org to help you here: Neons.org Tire Size Calculator. Select your desired tire size and see how much speedometer error it generates. Usually anything within about 2 mph will be fine.

But to save time for the lazy folks, some of the closest common replacement tire sizes for Neons are:

195/60-14
205/60-14
195/55-15
205/50-15
215/50-15
205/45-16
215/45-16
205/40-17
215/35-18

Note that some of these are fairly unusual sizes, though, and may have a very small selection of tire brands available. For a good tutorial on what those numbers in a tire size mean, refer to this link: Tire Rack Calculating Tire Dimensions

A common misconception among many enthusiasts is that larger diameter wheels are more likely to rub on a lowered Neon that the stock size. This isn't true, assuming that the correct wheel width and offset are used. A 205/40-17 tire on a 17x7 wheel is almost exactly the same diameter as a stock 185/65-14 tire on the 14x5.5 steel wheel.


To read the whole thread, click the link...
http://forums.neons.org/viewtopic.php?t=99530