widest tire u put on your 2000 grand am gt?

[Norco]

wonderin what the biggest anyone has gone width wise without any mods, my stock tires are 225/50-16 goodyear eagle RS-A's and stock rim 16x6.5, thinkin about gettin new rims for summer but wonderin if can go any wider than 225 for tires, thanks

[DontPassTheFence]

on 6.5'' wide rims up to 235 would be pushing it, I think (Im too lazy to do the calculations) However, if you get a wider rim, up to 245 could be used with minimal tire rubbing (maybe at full steering input)

[Norco]

from what i been readin, width of the rim doesnt change the width of the tire, example is my eagle tires, they can be used on rims 6.5 to 9 inches wide or something but i think the width of them woudl still be 225 unless im wrong :roll2: i wouldnt want any rubbing so 235 would be the widest prolly? or should stick with 225

[Mendoza]

245/35/19 here

[DontPassTheFence]

I know full well the width of the rim doesnt change the width of the tire, Im just stating the optimum for each rim width. For example, if you had a 185mm wide tire on an 8in wide rim, it would look pretty off, and you'd have your rims poking out on the sides there, and once you rolled over the sidewall, OH NOES! there goes your rims. Conversely, if your tires are too wide for the rim, say a 245 tire on a 6in wide rim, then your sidewall will stick WAYY out in front of your rim, which does protect the rim quite well if you like to rub curbs; BUT it also increases your likelihood of rolling over the sidewall under heavy cornering, which may not be exactly 'safe'

[antirice]

you shouldn't be able to run wider than a 235 or a 245 because of the coil spring cup on the strut

personally, on a stock rim, the 225's look too wide

[gold dragon]

you do know that the 225 is the rolling radius not the width the width of your tire is 6.5 in wide and if you want to be able to use your speedometer you need to stay with in 10% of your stock roling radius or are you asking what size so you can fill your wheel well gap stay within 10% of your stock rolling radius

[antirice]

Originally posted by gold dragon
you do know that the 225 is the rolling radius not the width

wrong, 225 refers to the tire being 225 mm's wide, second number refers to the aspect ratio, the sidewall being 50% of 225 mm's, and the third being the rim size

[gold dragon]

sorry i got that from a morron friend of mine thanx for correcting me.

[antirice]

yup



I've done enough sets of tires to know a couple things about them

[TA^Guy]

Originally posted by Norco
from what i been readin, width of the rim doesnt change the width of the tire, example is my eagle tires, they can be used on rims 6.5 to 9 inches wide or something but i think the width of them woudl still be 225 unless im wrong :roll2: i wouldnt want any rubbing so 235 would be the widest prolly? or should stick with 225
From a performance and saftey aspect each rim width has a certain tolerance for tire width than can saftly be used.

For example I have personally see people put 295s on 7" wide wheels Is this safe? No. A Sidewall that is extensively pull in to meet the rim at the bead (too wide) or pulled out(too narrow) is not safe. A) it's excess stress on the bead which can cause leaks or even blow outs. B) It's also excess stress on the sidewall of the tire which will breakdown the sidewall's durability and over time can cause shifted belts, cords or even bubbles. C) It also effects the handling of your car. A sidewall pulled in at the wheel (tire too wide) may have more of a tendancy to break loose and slide without warning, as where one too pulled out (tire too narrow) maybe plow the front end throw a corner and ride on the sidewalls under hard cornering.

On average a wheel of 7"s is good for a 225 or 235 tire. However this may not always be the case. The aspect ratio (sidewall height) can change that. A shorter sidewall height (lower aspect ratio) will not have as much flex or give to saftly meet the proper width of the wheel.

For example a typical 225/60R16 can be used on wheels between 6"-8"s wide. Where a typical 225/40R18 works well on wheels between 7.5"-9"s. The shorter sidewall has less flex and works better when mated to a rim closer to the tire's width.

If mm to inches is tough for you all you need to do is devide the tire's width by 25.4 (the ammount of milimeters in a inch) and you get the tire's widthin inches. (225 / 25.4 = 8.8 inches). Remember this is the tires full width, not it's width at the bead. For a good ride and handling tire you want it to taper slightly at the rim, so you want the tire slightly larger than the wheel width (maybe 2"s of difference).

Finding the best tire size for your vehicle and driving style can be a long game of trial and error. On my '92 Z28 I tired out several different setups for ideal handling. The car, a '92 Z28 with factory 16x8" wheels, Eibach springs and Monroe Sensitrac struts/shocks. Stock tire size is either 235/55R16 or 245/50R16 depending on what package was ordered with it. I tried many different combinations. 235/55 all around, 245/50s all around, 225/50 front and 245/50 rear, 225/50 front and 255/50 rear, 245/50 front and 255/50 rear... My conclusion was the 225/50 and 245/50 was the most responsive setup but traction was limited in the front under highspeed cornering. The 245/50 and 255/50 setup was the best for me as held a high speed corner alot harder. So for a low speed auto-x, the narrower shorter tire works well, but for faster, longer corners the wider tires were best.
Originally posted by gold dragon
you do know that the 225 is the rolling radius not the width the width of your tire is 6.5 in wide and if you want to be able to use your speedometer you need to stay with in 10% of your stock roling radius or are you asking what size so you can fill your wheel well gap stay within 10% of your stock rolling radius
The messurement commonly used for speedometer calibrations and speed sensors for say the ABS system isn't messured in rolling circumfrance but mor ecommonly messured as the tire's overall diameter in inches. For example the overall diameter of a 225/50R16, as used on stock '99+ GAGTs has a overall diameter of or 25.1"s (each brand of tire may vary slightly. To keep the speedo and ABS in calibration the tire size may change as long as the overall diameter is close. So to replace a 225/50R16 with a 18" wheel and tire, the best tire size would be 225/40R18 with a overall diameter of about 25.1". Or I could use a 17" wheel and run a 225/45R17 (25.1") or a 245/40R17 (24.8").