Wheels and Tires Information, Look here before asking a general question please - Hooking It Up - Performance Central - Team Focus - Come On In And Enjoy The Company!
Ok, well the common thing I see in regards to Wheels and Tires is size...what size will fit, what size do I need, what does it all mean?
So I thought I'd do my best to lighten the burden by giving you the insight.
I don't know anything about the Stock 14" wheels or tire size...so if you do, let me know by PM and I'll add it here.
The Stock 15" wheel is 15"x6" with a 4x108mm bolt pattern, it has a tire size of 195/60R15. And a 42mm offset.
The Stock 16" wheel is 16"x6" with a 4x108mm bolt pattern, it has a tire size of 205/50R16.
The Stock 17" wheel is 17"x7" with a 4x108mm bolt pattern, it has a tire size of 215/45R17. (SVT only). And a 49mm offset.
I didn't include the 18" wheels that come on the RS, though I'm certain that the typical tire size for an 18" wheel is 235/35R18.
Now, on with the aftermarket ideas. Since most people (I know not all) go with a 17" wheel when they upgrade, there are a number of different sizes that you can put on the 17" wheel. I'll start from the smallest and work my way up. All comparisons are made with the Stock 15" wheel, though they should be very close to the comparisons made with any of the other wheels.
205/40R17
If you run a 205/40R17 tire you will have a small sidewall, which doesn't typically offer your wheel much protection from the road, not to mention a very stiff ride since there isn't alot of rubber to absorb the road impact.
This size tire will hold a 7"-8" wide rim and has a section width of 205mm or ~8 inches. The sidewall height is ~82mm or 3.2 inches. The overall diameter then of the tire+wheel is 595mm or 23.5 inches. For every mile travelled the wheel will revolve 886.9 times. Your speedometer would be off by 3.235% fast. Meaning your speedometer would read 62mph when you were only going 60mph.
215/40R17
If you run a 215/40R17 tire you will have a slightly larger sidewall, as well as a wider section width, this will give you a bit better protection of your wheel, and better traction as more rubber meets the road way. Though the difference is slight it does provide a means to get a bit better ride as well. The biggest disappointment in this size is variety, as not many tire manufacturers provide this size tire and if they do they can be a bit pricey.
This size tire will hold a 7"-8.5" wide rim and has a section width of 215mm or ~8.5 inches. The sidewall height is ~86mm or 3.4 inches. The overall diameter then of the tire+wheel is 604mm or 23.8 inches. For every mile travelled the wheel will revolve 875 times. Your speedometer would be off by 1.85% too fast. Meaning your speedometer would read 61 when you were only going 60mph.
205/45R17
If you run a 205/45R17 tire you will have similar characteristics to the 215/40R17 tire, the differences mainly being that you will now have a smaller section width, but a greater sidewall, this offers better rim protection and a softer ride. Again the biggest disappointment in this size is variety, as not many tire manufacturers provide this size tire, and if they do they can be a bit pricey.
This size tire will hold a 6.5"-7.5" wide rim and has a section width of 205mm or ~8 inches. The sidewall height is ~92mm or 3.6 inches. The overall diameter then of the tire+wheel is 616mm or 24.3 inches. For every mile travelled the wheel will revolve 857 times. Your speedometer would be off by 0.21% too slow. Meaning your speedometer would read 59.8 when you were going 60mph.
215/45R17
If you run a 215/45R17 tire you will have great protection of your rim, and a softer ride, you will also have a wider section width which typically results in better lateral traction. This is the size tire that is found standard on the SVT 17"x7" wheel. It has a decent selection of tires from various manufacturers.
This size tire will hold a 7"-8" wide rim and has a section width of 215mm or ~8.5 inches. The sidewall height is ~96.5mm or 3.8 inches. The overall diameter then of the tire+wheel is 625mm or 24.6 inches. For every mile travelled the wheel will revolve 845 times. Your speedometer would be off by 1.66% too slow. Meaning your speedometer would read 59 when you were going 60mph.
Hopefully this has been helpful, other important factors to consider when choosing a tire are the speed rating, and the load bearing capacity, the worst experience ever would be to have your friends get in your pimp new ride and have the tires pop because they can't handle the load.
Multiply first number (225) by the second number preceded by a "." (.75)=168.75 X 2 (constant)=337.5 divided by 25.4 (constant)=13.28+15(the size of the rim)=28.28 inches tall
Universal Example:
A/BrC
(*=times;/=divided by)
A * .B = X
X * 2 = Y
Y / 25.4 = Z
Z + C = Tire Height
This is important when putting on bigger or smaller tires because if the height is not the same as stock it will mess up you speedometer and odometer.
Use this formula to make sure the tires you are looking will be okay.
Blurry wrote: For an SVT 5-spoke or Euro wheel it is 49mm...42mm sounds right for ZX3.
Thanks Blurry, I'll add that to the main post. Anyone else know any other numbers, offsets, etc...
wait, how does ofset measure? Ive heard it both ways. that the smaller the number the further it sticks out and of course vice versa. I have a 38 offset on my enkeis and they stick out too damn far.
I believe you are right, the higher the number the more tucked in the wheel will be...at least that is what I have seen, the SVT sits in snugger to the hub and thus further under the fender well, but the common offset for the ZX3 or other non-svt vehicles is 42mm from everywhere I've seen, I think this is to prevent problems with rubbing, since these cars weren't meant to have larger wheels. If the offset didn't push the wheel further out, then it would rub on the fender well.
Alright here is to add to this, I did some research...offset is a pain in the butt apparently because it varies depending on changes in the wheel width...but for example...
to calculate offset, you divide the overall width of the wheel by 2 to find the centerline...
Overall Width/2 = Centerline
then you subtract the backspace from the centerline...
Centerline-backspacing = offset
If the number is negative then the offset is towards the outer part of the wheel (the part the faces you when you put the wheel on). So more of the wheel would be surrounding the hub, and in essence be closer under the fender well.
If the number is positive then the offset is towards the inner part of the wheel. More of the wheel is now further away from the hub, and further out from under the fender well.
So working backward, a 42mm offset on a 7" wheel means that the centerline is 3.5" or 88.9mm and then the backspacing is 46.9mm.
On a 39mm offset on a 7" wheel, the centerline is still 3.5" or 88.9mm but the backspacing would have changed to 49.9mm. This means that it is now 49.9mm from the inner edge of the rim, to the bolt up face of the wheel, which means it now sits 3mm out from where the 42mm wheel sat.
Last edited on Wed Jun 2nd, 2004 08:35 pm by RPIJG
wow. the old man and I were arguing about offset. I want to explain it to him but I can see this is going to be hard. Oh well, time to teach the old dog a new trick.
So...I did find out this little bit of information...the SVT wheel has 5.94" backspacing which if by following my formula correctly is...3.5"-5.94"=-2.44" offset...which is...negative 62mm? Either the backspacing listed by MFP.com is wrong, or something else isn't making any sense...
in regards to the 205/45/17 will this tire scrub the fenderwell w/ a 2in. drop in the front and 1.75 drop in the rear? or do you think im on my own w/ this?your help would be greatly appreciated!
I don't think this would. gr33nlemon had a drop like that and ran on 15's...I know you're talking a completely different tire set up, but what you'll need to worry about is the bottom. Scaping is something you'll need to think of. Look into skidplates.
Hey Mikey - What's your idea on this?
____________________ Get in, Sit down, Shut up and HANG ON!
n2focus wrote: in regards to the 205/45/17 will this tire scrub the fenderwell w/ a 2in. drop in the front and 1.75 drop in the rear? or do you think im on my own w/ this?your help would be greatly appreciated!any idea what the offset on the wheel is? if you go lower than the 42mm offset found stock zx3 (SVT offset is 49mm), i think you might see a problem..you may be able to squeak a 38 offset on, since its not even 1/4 difference in offset. i had this discussion with the guy im most likely buying wheels off of soon, and going from my stock 49mm offset to the new wheels 42 mm offset is approx 0.28" difference, there would be no problems for rubbing. from doing a little bit of mental math, well assume that every 6mm less offset you have, your wheels will stick out approx .25" further.
Good effort on posting info but the offsets for both 15" and 16" OEM wheels is 52.5mm. Look at the info cast into the back of the hub. It will be "ETxx" with xx being replaced by the offset, in millimeters. That's 2.07" in good old american units.
Thanks I'll take a look at that, but any information is good information, especially if I'm disseminating the wrong information. Perhaps the 42mm is just for when someone with stock 15" wheels upgrades to 17" wheels. Obviously the width makes a significant difference.
RPIJG wrote: Thanks I'll take a look at that, but any information is good information, especially if I'm disseminating the wrong information. Perhaps the 42mm is just for when someone with stock 15" wheels upgrades to 17" wheels. Obviously the width makes a significant difference.yes, the offset would be near impossible to find in a 52.5 on an aftermarket wheel because of the rim width. good asumption joe
joe, so glad you have the patience to do the work on this...I couldn't have done it.
!
