need advice on rims

goingganzo
goingganzo Posts: 2,793
edited March 2003 in Car Audio & Electronics
i am thinking of getting some rims for my 2 door alero gls. i have 16 and want to go to 18. my queston is will i have a problem with bending my rims with a 40 series tire on them. i have a frend with a car with 17 with 45 series tires on them 245/45/17zr

will i have a problem with going form a 225/60/r16 to a 245/40/r18



thanks.
Post edited by goingganzo on
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  • Jstas
    Jstas Posts: 14,820
    edited March 2003
    Currently you have a 26.6 inch tall tire. Subtract 16 from that you have a 10.6 inch tall sidewall but, you have to divde that by 2 so in actuality you have a 5.3 inch tall sidewall.

    Going to 18" tall tires, to maintain that over all diameter, you need to go plus 2 sizing. I will demostrate.

    Plus 0: 225/60R16

    Plus 1: 245/50R17

    Plus 2: 265/40R18

    You 245/40ZR18 tire gives you an overall diameter of 25.7 inches. Subtract 18 and that gives you 7.7 inches tall. Divide 7.7 inches by 2 and you have a 3.85 inc tall sidewall. That is quite small and leaves little room for flex when contacting irregularities in the road surface. It's a pretty good chance of denting a rim and it will throw your speedo and possible your ABS system out of whack.

    the 265/40R18 gives you a 26.3 inch tall tire. That is only .3 off from your stock size and within allowable range of tire sizes. Subtract 18 from that size and you end up with 8.35 inches. Divide by 2 and you have a roughly a 4.2 inch tall sidewall. That half an inch will make a huge difference in pothole negotiation.

    However, the 265/40R18 will be a wider tire, by probably 1-1.5 inches so you would need to check clerance to use that tire. The 245/40R18 will most likely put you in the same boat. So make sure you measure properly and get your backspacing right so you don't rub.

    Also, with the 265/40R18, you will have a sidewall that will bulge slightly vs the 245/40R18 which might be thinner than the wheel you are mounting it on. This is important from two reasons. Number one, the sidewall bulge will help protect your wheels from being rubbed and marred badly if you happen to rub a curb or something. It won't stop it 100% but you have a much better chace of your expensive wheels surviving. Number 2, the bluge acts as a cushion for the wheel when negotiating bumps. Since the tire isn't as skinny as the 245/40R18, the rim actually sits over teh cushion of air inside the tire and not one the edge of teh sidewall. Tires should be chosen in size so that when mounted, the bead of the tire is in line with the tread pattern of the tire. That ensures proper tire alignment on the wheel for proper wear and mileage.

    I think you will be much happier if you go for th 265 instead of the 245. It will fill out the wheel well more because it will be close tothe stock size. If you can't get a 265/40, go for a 255/40 or a 275/40.
    Expert Moron Extraordinaire

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  • PoweredByDodge
    PoweredByDodge Posts: 4,185
    edited March 2003
    not that this is importatnt or anthing, but if your alero is the right color (navy blue / black / silver) (white also works if its spotless and limo tint)...

    see if you can get the yellow letter goodyear Eagle 1 tires... i'm pretty sure they come int he sizes that Jstas and you mentioned. They're the best damn "look at me my tires look better than yours" i've seen in 3 years.
    The Artist formerly known as PoweredByDodge
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  • goingganzo
    goingganzo Posts: 2,793
    edited March 2003
    i have a metalic blue the dark blue with my back tinted to limo and dr amd passanger window with a light tint also have vinal on front and back window.


    thanks for all the advice. i was told by a frend with a grand am that he could not fit 18 on his. but know i know. just have to watch out for the rub.

    here a few rims i have considering

    http://www.victoriatire.com/wheels.html?cart=10477905596429031&PICNUM=1078A&&checkAvailable=F&make=OLDSMOBILE&model=ALERO%2099-02&size=18
    http://www.victoriatire.com/wheels.html?cart=10477905596429031&PICNUM=1088&&checkAvailable=F&make=OLDSMOBILE&model=ALERO%2099-02&size=18
    http://www.victoriatire.com/wheels.html?cart=10477905596429031&PICNUM=1265&&checkAvailable=F&make=OLDSMOBILE&model=ALERO%2099-02&size=18
    http://www.victoriatire.com/wheels.html?cart=10477905596429031&PICNUM=1298B&&checkAvailable=F&make=OLDSMOBILE&model=ALERO%2099-02&size=18

    i am looking for simple and easy to clean.
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  • PoweredByDodge
    PoweredByDodge Posts: 4,185
    edited March 2003
    get the last one or the first one -- personally i'd do the last one... i like the blackish chrome... and i think it would look tough as hell with the right tires -- even if u dont go yellow letter, white letter would still make the car just scream "i am Dr. Pimp"
    The Artist formerly known as PoweredByDodge
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