WIDTH of RIM matched to WIDTH of TIRE [Archive] - GrandAmGT.com Forum

PDA

View Full Version : WIDTH of RIM matched to WIDTH of TIRE


IMICEMAN
09-15-2003, 06:09 PM
OK, I went to a reputable speed shop here and wanted them to put 235/45/17 TIRES onto a 17x7 RIM.
They told me that it would not work well, and that it would not LOOK good either.
They said that even the 225mm width tires that I have now (stock RSA's) should be on at least a 7.5" WIDE Rim.
I was told that, at a MINIMUM, I should be looking for a RIM size/WIDTH of 7.5 inches.
They said that it is better that the RIM is WIDE to avoid the "sidewall bulge" that happens when the Tire is wider than the Rim.

So then, you experts: (keeping in mind a 17" diameter)
-What is the WIDEST RIM that we can put on our GA's (WITHOUT any rubbing at all) ?
-What TIRE WIDTH would FIT/LOOK the BEST on "that" Width of Rim ?

Ideally, I want a "non-bulging" look for the wheel/tire combo.

For example:

RIM WIDTH..........MIN Tire width..........MAX Tire Width
17x7......................???/45/17...................???/45/17
17x7.5...................???/45/17...................???/45/17
17x8......................???/45/17...................???/45/17
17x8.5...................???/45/17...................???/45/17

Thanks !
Kent

mfuller
09-15-2003, 07:18 PM
Sure you can put a 235mm tire on a 7" wide rim. It'll bulge out fair amount, but it will work.

About the widest rim you can use is 8", providing you can find an offset that'll work (look for +35mm to +38mm). Either a 225 or 235 tire will look great on 8" wide rim, but the 225 will have a bit less bulge.

But rim width should always be less than a tire's section width.

Here's a decent pic of a 225/45R17 tire on a 8" wide rim:

http://www.aleroupgrades.com/Baer.jpg

RAZE
09-15-2003, 07:55 PM
Originally posted by mfuller
(look for +35mm to +38mm

I may be wrong, but I thought our offset was 38mm to 42mm :confused:

AMRAAM4
09-15-2003, 08:26 PM
Originally posted by RAZE
I may be wrong, but I thought our offset was 38mm to 42mm :confused:
When you increase the width of your rim you generally want to decrease your offset a tad to make up for that small increase in rim width.

However, for example..an RX7 has an 8" wide rim and 50 mm offset, but in the rear, you can fit a 10" wide rim and still keep a 50mm offset. It's all about how much space you have, and in teh GA, we don't have much.

SpyhunteR
09-16-2003, 10:23 AM
Originally posted by AMRAAM4
When you increase the width of your rim you generally want to decrease your offset a tad to make up for that small increase in rim width.

However, for example..an RX7 has an 8" wide rim and 50 mm offset, but in the rear, you can fit a 10" wide rim and still keep a 50mm offset. It's all about how much space you have, and in teh GA, we don't have much.

WHICH FREAKIN BLOWS!!!

I wanted an 8.5 rim.. but they came in the crappiest of offsets... simply they wouldn't fit.

IMICEMAN
09-16-2003, 12:03 PM
Originally posted by mfuller
Sure you can put a 235mm tire on a 7" wide rim. It'll bulge out fair amount, but it will work.

About the widest rim you can use is 8", providing you can find an offset that'll work (look for +35mm to +38mm). Either a 225 or 235 tire will look great on 8" wide rim, but the 225 will have a bit less bulge.

But rim width should always be less than a tire's section width.

Here's a decent pic of a 225/45R17 tire on a 8" wide rim:

http://www.aleroupgrades.com/Baer.jpg

Hey that looks good !
So you don't have any troubles of rubbing, etc with the 8" Rim all around the car ?
Also, are those Konig Tantrums ?
Kent

AMRAAM4
09-16-2003, 12:48 PM
uhmm, tons of people here run 8" wide rims. You can run a 235 or 225 tire with them. I prefer the 225 which doesn't give you the rounded sidewall..and that is what you want from what I can tell.

mfuller
09-16-2003, 01:05 PM
Nope, no rubbing problems....although it did get close at full-lock. Those are 17x8" Konig Tantrums with a +35mm offset and 115mm BCD.

zhd1000
09-16-2003, 07:37 PM
*offtopic* what do each set of numbers mean?? like 225/45/17? i know the 17 is the diameter.. what do the other numbers stand for??

IMICEMAN
09-16-2003, 07:52 PM
Originally posted by mfuller
Nope, no rubbing problems....although it did get close at full-lock. Those are 17x8" Konig Tantrums with a +35mm offset and 115mm BCD.

Its kind of weird the way GM would put 6.5" rims on the GAGTs when we can fit (up to) an 8" rim on there ! Especially since (from your picture), it looks a helluva lot better to run the 225mm width tires on the wider rims.

Just one last question....what do you mean when you say "it did get close at full-lock" ? Will 8" rub or cause any other problems ?

95-GT
09-16-2003, 08:40 PM
Originally posted by zhd1000
*offtopic* what do each set of numbers mean?? like 225/45/17? i know the 17 is the diameter.. what do the other numbers stand for??

The first number is the width of the tire in MM.

The second number is the profile, or aspect percentage of the tire width. Example: Say the width is 225, and the aspect ratio is 45.....its actually 45% of 225. So the profile hight of the tire is 45% of 225...or 101.25.

The 3rd number is the size rim in inch's it can fit on. Thus, this tire would fit a 17" rim.

mfuller
09-17-2003, 07:30 AM
Originally posted by IMICEMAN
Just one last question....what do you mean when you say "it did get close at full-lock" ? Will 8" rub or cause any other problems ?

That means when the front wheels are turned all the way to the right or left - that is what we call full-lock. It gets a bit close, but no rub.

PontiacGTboy
09-18-2003, 08:45 AM
Just to give you an idea of how close it is,,, my wheels couldnt balance with the stick on weights on the inside of the wheel... they simply wouldnt do it. I had a Pontiac Vibrator for a good while. I finally asked them to put hammer on weights (crazy i know) and the inner weight on the back rim tapped my strut every time the rim went around! the fix? 10 thin washers from Lowes,,, one for each stud. it was just enough to pull the rim out MAYBE half of a centimeter and no rubs what so ever. I also run 225 45 17 on my 17x8s.

snwman
09-19-2003, 09:57 AM
ive got 245's on a 7.5 inch wide wheel with no problems.

AMRAAM4
09-19-2003, 10:20 AM
Originally posted by snwman
ive got 245's on a 7.5 inch wide wheel with no problems.

What the hell do you have those balloons on there for?? What is the point of going to a larger rim if you are going to increase tire size?

mfuller
09-19-2003, 10:26 AM
I can't really fathom how you managed to squeeze 245s in there, but I suppose with the correct offset......I'm still of the opinion that things are pretty tight down there.
The point of going to a wider rim with a wider tire is so that you maximize the tire's contact patch (the small square-shaped part of the tire that is in contact with the road). If you put a wide tire on too narrow of a rim, the tire will have a more rounded (instead of flat) contact patch, effectively decreasing available traction. 245mm tires really need a 8.5" wide rim.

My 2 cents.

snwman
09-19-2003, 01:03 PM
Originally posted by mfuller
I can't really fathom how you managed to squeeze 245s in there, but I suppose with the correct offset......I'm still of the opinion that things are pretty tight down there.
The point of going to a wider rim with a wider tire is so that you maximize the tire's contact patch (the small square-shaped part of the tire that is in contact with the road). If you put a wide tire on too narrow of a rim, the tire will have a more rounded (instead of flat) contact patch, effectively decreasing available traction. 245mm tires really need a 8.5" wide rim.

My 2 cents.

things are really tight down there, lol. I bought the wheels used from another member with 245's already mounted on them. now knowing this I may replace them with 235's when the time comes.

EDIT: while the wheels were off today i mesured and they must be at least 8" wide. i guess thats what happens when you buy used items not correct details.

IMICEMAN
03-12-2005, 11:48 PM
ive got 245's on a 7.5 inch wide wheel with no problems.

What is your "offset" ?

rennation
03-13-2005, 07:47 AM
Hey guys while we are on the topic....17x8, 5x115, offset of 38 will work right?

xxbackhillxx
03-13-2005, 08:15 AM
yes

AaronGTR
03-13-2005, 01:06 PM
I have 235/45-17's on 17x7" wheels with a 42mm offset and they fit just fine. I've had only a tiny bit of tire rub on the drivers side. Back edge of tire on the inner frame, and only during cornering at speed with full steering lock. In other words, it almost never touches. I do have a bit too much tire bulge though. I was trying to fit the widest possible tires on the lightest wheels I could afford to maximize the contact patch. The fact that they are an all season compound though and the amount of roll over they get doesn't help traction. They start to slide when they get hot. I'm going to switch this year to a 225/45-17 summer only tire. That should square up the sidewall a little and give me more traction, as well a slightly smaller rolling diameter for better acceleration. Eventually I plan to use an 18x8" wheel with 245/35-18's.

Like Matt said, you don't ever want your tires to be narrower than your wheel. You'll have a really bumpy ride, less traction, and possibly damage the wheel. The general rule is, the bigger the wheel and the shorter the sidewall you use, the closer the width of the tire needs to be to the width of the wheel, because you have less sidewall to play with. Most online tire sites have info on what size wheel a certain tire will fit, and what size is best.

Trancer
03-15-2005, 04:26 PM
[QUOTE=AaronGTR]Eventually I plan to use an 18x8" wheel with 245/35-18's. QUOTE]

Just curious... Why going with the 245/35/18 instead of the 245/40/18s? The 40 series tire is the closest tire size to stock. If you run the 35 series tire you are 1.3% too slow. If you run the 245/40, you are running .1% too fast. It would also help fill in the wheel gap a little more. Only reason I can think of is that you have your car lowered. True? :)

AaronGTR
03-15-2005, 06:25 PM
[QUOTE=AaronGTR]Eventually I plan to use an 18x8" wheel with 245/35-18's. QUOTE]

Just curious... Why going with the 245/35/18 instead of the 245/40/18s? The 40 series tire is the closest tire size to stock. If you run the 35 series tire you are 1.3% too slow. If you run the 245/40, you are running .1% too fast. It would also help fill in the wheel gap a little more. Only reason I can think of is that you have your car lowered. True? :)


Actually the 245/35-18 is closer to stock tire diameter than the 245/40-18. Not the other way around. Stock size is 225/50-16. A 245/35-18 would read 59.7mph at 60mph or .4% fast. A 245/40-18 would read 62.1mph at 60mph or 3.5% too slow so it's further from the stock size.

My car is lowered, but that has nothing to do with it.

PACE
03-15-2005, 06:33 PM
I have 18x8 32 or 35 offset with a 235/40/18 Kuhmo MX = Perfection

Trancer
03-15-2005, 08:28 PM
[QUOTE=Trancer]


Actually the 245/35-18 is closer to stock tire diameter than the 245/40-18. Not the other way around. Stock size is 225/50-16. A 245/35-18 would read 59.7mph at 60mph or .4% fast. A 245/40-18 would read 62.1mph at 60mph or 3.5% too slow so it's further from the stock size.

My car is lowered, but that has nothing to do with it.

Oh damn, I thought the stock size was 225/55.... my bad.