: Rims, Tires and all that good stuff



nethic
02-01-13, 11:23 PM
Can some one tell me if I can get after market rims for the 98 catera as long as there 16' or can I go bigger? I know that if I do go bigger there is something I need to 'hack' so the speedometer works properly, now my tire size is 225/55R16 and I have the stock chrome rims on there right now, but since winter is pretty damn rough up here my all seasons are not cutting it so I need to put winters on right away and need a set of winter rims as well and kinda conflicted about not getting the right size or bolt pattern, also TCS lights up and stays on when I slip not sure whats with that( I know its supposed to come on when you slip but not stay on ). Another question is, in the summer can I expect to be able to put some sickly rims on it or do I need to stick with stock and get low profiles, or can I even put low profiles on this car? whats the deal with the rims and tires :suspense:

MoistCabbage
02-01-13, 11:56 PM
"The deal" with rims and tires is, regardless of rim diameter, you need to keep the outside diameter of the tire to within about 1/4 inch of the stock tire size.

Putting low profile (short sidewall height) tires on stock size rims, will make the wheels look too small for the car, and cause speedometer/odometer errors.

Putting larger rims on the car, without using lower profile tires, will make the car look like a tractor with sagging suspension, cause rubbing, and cause speedometer/odometer errors.

Both scenarios will also change your final drive ratio, which means your transmission gear ratios will no longer be correct at any given speed, and acceleration will be effected.

Again, you can install larger rims, as long as the new tires have an OD within 1/4 inch of the stock ones. Keep in mind that the larger you go, the less sidewall height there will be, and the ride will be harsher. Go TOO big, and the extra shock can begin to prematurely wear steering and suspension components.

The reduced sidewall height will increase steering response and improve handling slightly, but only to a point. Again, go TOO big, and the excess weight and rotational mass will begin to REDUCE performance (both handling and acceleration).

In general, 18" is a good choice.

The numbers you need to know are stock tire OD, wheel back spacing/offset, and bolt pattern.

Grandmaster B
02-03-13, 12:57 PM
The easiest way to figure out tire size is by using the "plus 1" method. I'll try to explain. For every 1 inch in rim size you go larger you also go 10mm wider on the tire width and go down 10% on the height. What? Here are some examples. Factory is 225/55R16 right? You want a 17" rim? You need a 235/45R17 tire. 18" rim? 245/35R18 tire. 19" rim? 255/25R19 tire. Problem is I really don't know how wide a Catera will fit. I agree an 18" is about as large as I would go. I'm pretty sure the bolt pattern is a 5x110mm but you'll want to verify that. I know it's not a super common bolt pattern but other cars do use it. Mostly German cars. Maybe try Tire Rack for more recomendations.

MoistCabbage
02-05-13, 02:51 AM
Factory is 225/55R16 right?.....18" rim? 245/35R18 tire.There's an inch difference in overall diameter between two sizes. ~Four times the max recommended variation from stock.

The term "plus one" means to increase the diameter of the rim by 1 inch (there's also plus two, plus three). It is not a method of calculating tire size. You can't just guess. You also can't just add width with every 1 inch increment in rim diameter, you'll end up with rub before full lock.

The stock tire size on a '98 Catera is 225/55/16, the OD is 25.8".

With an 18" rim, you'd need a 225/45/18, the OD is 25.9. If you wanted a slightly (10mm) wider tire, 235/40/18 is the closest at 25.4, it's just a tad smaller than recommended.

BTW, if you're going to have 2 sets of rims, I'd use the 16's for the snow tires, and use the larger ones the rest of the year.

Grandmaster B
02-05-13, 12:53 PM
That is correct. I over simplified it.
http://autorepair.about.com/od/buyingtires/a/plus_tires_red.htm
225/55/16 = 25.8
235/45/17 = 25.4
At 18" in this application it changes.
235/40/18 = 25.4
245/40/18 = 25.7
255/40/18 = 26
Moistcabbage is correct. You want to keep the overall dia. as close to stock as possible. Variations will affect all kinds of things. Speedometer, odometer, A.B.S., etc...
The wider the section width the wider the tire will be. This can also lead to problems with rubbing. Backspacing or offset can help correct this to a point. It all can be pretty complicated.

98Catera_2010
02-05-13, 03:55 PM
Since were talking tire size, I put 225/60/16 on my 98 for winter. Will that effect anything?

Grandmaster B
02-05-13, 07:37 PM
Your tires will be slightly larger than stock. Your speedometer and odometer will read slightly lower than your actual speed and distance traveled. I'm not real sure how sensitive to changes the Catera's are but I doubt it will affect anything else. It's really not a huge change. The tires you have now should be around 26.6" when new.

MoistCabbage
02-05-13, 07:39 PM
That's a little less than a half inch taller than stock. Ideal is less than 1/4 inch, but it's not the end of the world.

98Catera_2010
02-05-13, 08:38 PM
I know its not much but it sure does make a difference on how much the wheel well is filled and looks nice too.

JohnJJO
02-06-13, 03:03 PM
Guys! What tires u recommend to get. My size is 235/45R17. Im looking for quiet, smooth ride. And prefer tire to be flat on the side wall, not like round on regular tires, so basically its performers tires. Buy need quit ones. What tires u have?
Thank you

MoistCabbage
02-06-13, 05:15 PM
Everyone's going to have a different opinion on tires, but:

Smooth and quiet aren't generally qualities that are associated with performance tires.

Sidewall shape is mostly determined by sidewall height, and tire vs rim width. There's no way you're going to have anything near a flat looking sidewall (there's no such thing as a flat sidewall) on your car, with 17's.

Get in touch with TireRack, and tell them what you're looking to get out of the tires.

CateraMV6
02-06-13, 07:17 PM
Wheel size also needs to be matched to the particular thread size.

I run 245/40/18 on my 18x7.5" wheels. At that size its recommended to run 8" wheels or larger.
On my 17" sport wheels I run 245/45/17 tires both winter and summer sets. Each of those are 17 x 7.5"
On the other BBS wheels I have 245/45/17 but on a 17x8" wheel and those look a bit more stretched however not too much.

All my sets of wheels the sidewall looks straight but if you go to a 225/55/16 and you have a 6" wide rim you will get a nice size belly. Most sports cars try to reduce tire flex so they would run a 225 tire on a 8.5" wheel or even larger and as a result the sidewall leans in. Im not a fan of that look nor do I need such wild tire set up therefore I think the 245/7.5" combo wokrs extremely well.