If you have a question about:
This is to avoid making different threads everytime someone has a question (Seen 3 in the last week)
Also any information posted in here I will start adding to the respected wiki page for the information.
Just thought this might be a good thing to add to the start of this thread to give everyone a better understanding of what info they have/need to have before you get too lost in the world of numbers. Bit of a Wheels 101 ty Mods
NB When changing your wheel/tyre combo it is important to similarly match the original diameter of your standard wheels.
- Your wheels are a part of the final drive, the last "gear" in the car and this will effect your speedometers accuracy as well as acceleration and top speed by using a different outer diameter.
For the sake of keeping it simple going to be using the stock base model CE size wheel/tyre as an example
Tyre Size Found on the Tyre Sidewall
175 Tyre Width in MM
70 Aspect Ratio (Used to calculate the height of your sidewall)
R Tyre Construction - All tyres now for the road are Radial (R)
13 Rim Diameter in Inches
82 Load rating (How many KG the tyre can withstand) You'll need a chart like THIS to understand what your number means
T Speed Rating (Max speed capable of the tyre) again you'll need THIS chart (or similar) to understand what your letter means
Rim Size Found on the inside of the wheel often on the back of a spoke
5 Rim Width in Inches
J Rim Flange Style
x
13 Rim Diameter in Inches
ET37 Offset in MM (Also prefaced by IS instead of ET by some wheel manufacturers)
Different manufacturers use different methods and orders of stamping and labeling as seen in the picture below. The code in this is even written on separate spokes. Your best bet is to try and find any numbers that look similar to the code written above.
(Mirage stockies weren't marked, these are my CH Enkei's)
Random bits of info to note (Feel free to add)
* To find the thickness of your side wall in MM multiply the width by the ratio and then divide by 100
- ie (175 x 70) ÷ 100 = 122.5MM
* By keeping the exact same offset with wider rims, the wheels will be exactly half the extra width either side of your current wheels.
* At an offset of 0 your rim will poke exactly half of its width either side of the hub.
* Positive offset puts more of the wheel inside the car
* Negative offset pokes more of the wheel outside the car
(Pic via www.lesschwab.com)
Will I scrub?
A method I like to use is a thorough visual inspection by using your current wheels as a base.
Firstly, lift up one corner of your car, best to do one front and one rear to see how both ends of the car line up.
Mark the center of your tyre width with chalk.
You can use a tape measure for visually inspecting poke and clearances by first calculating the difference in the two offsets to find the 'center'of the new rim.
Lets say currently you have an offset of +40 and the new wheels are +20, you would measure and mark
20mm towards the inside of the car from the center of your current wheel.
This second mark is the effective centre of your new wheels.
(New tyre centre demo)
Take half of the width of your new rim and lay your tape measure that distance for the centre to either outside of the wheel.
This is a rough but near accurate estimate of how your new rims will sit on the car
An adaption to this is using measured length of dowel cut to the new rim width. The centre of this can be taped to the second mark you made on the current tyre - with that wheel raised off the ground you can rotate freely to inspect any clearances. If you have a second jack, you can raise the wheel back into the arch at ride height and freely turn the wheel to inspect clearance better.
(Tape measure under car - too hard to show this in the wheel arch with the car on the ground)
(1" Poke with a tape measure)
- Rims
Wheels
Tyres
Offset
Width
Size
Scrubbing
Anything To Do With Those round things that spin to make you go forward
This is to avoid making different threads everytime someone has a question (Seen 3 in the last week)
Also any information posted in here I will start adding to the respected wiki page for the information.
Just thought this might be a good thing to add to the start of this thread to give everyone a better understanding of what info they have/need to have before you get too lost in the world of numbers. Bit of a Wheels 101 ty Mods
NB When changing your wheel/tyre combo it is important to similarly match the original diameter of your standard wheels.
- Your wheels are a part of the final drive, the last "gear" in the car and this will effect your speedometers accuracy as well as acceleration and top speed by using a different outer diameter.
For the sake of keeping it simple going to be using the stock base model CE size wheel/tyre as an example
Tyre Size Found on the Tyre Sidewall
175 Tyre Width in MM
70 Aspect Ratio (Used to calculate the height of your sidewall)
R Tyre Construction - All tyres now for the road are Radial (R)
13 Rim Diameter in Inches
82 Load rating (How many KG the tyre can withstand) You'll need a chart like THIS to understand what your number means
T Speed Rating (Max speed capable of the tyre) again you'll need THIS chart (or similar) to understand what your letter means
Rim Size Found on the inside of the wheel often on the back of a spoke
5 Rim Width in Inches
J Rim Flange Style
x
13 Rim Diameter in Inches
ET37 Offset in MM (Also prefaced by IS instead of ET by some wheel manufacturers)
Different manufacturers use different methods and orders of stamping and labeling as seen in the picture below. The code in this is even written on separate spokes. Your best bet is to try and find any numbers that look similar to the code written above.
(Mirage stockies weren't marked, these are my CH Enkei's)
Random bits of info to note (Feel free to add)
* To find the thickness of your side wall in MM multiply the width by the ratio and then divide by 100
- ie (175 x 70) ÷ 100 = 122.5MM
* By keeping the exact same offset with wider rims, the wheels will be exactly half the extra width either side of your current wheels.
* At an offset of 0 your rim will poke exactly half of its width either side of the hub.
* Positive offset puts more of the wheel inside the car
* Negative offset pokes more of the wheel outside the car
(Pic via www.lesschwab.com)
Will I scrub?
A method I like to use is a thorough visual inspection by using your current wheels as a base.
Firstly, lift up one corner of your car, best to do one front and one rear to see how both ends of the car line up.
Mark the center of your tyre width with chalk.
You can use a tape measure for visually inspecting poke and clearances by first calculating the difference in the two offsets to find the 'center'of the new rim.
Lets say currently you have an offset of +40 and the new wheels are +20, you would measure and mark
20mm towards the inside of the car from the center of your current wheel.
This second mark is the effective centre of your new wheels.
(New tyre centre demo)
Take half of the width of your new rim and lay your tape measure that distance for the centre to either outside of the wheel.
This is a rough but near accurate estimate of how your new rims will sit on the car
An adaption to this is using measured length of dowel cut to the new rim width. The centre of this can be taped to the second mark you made on the current tyre - with that wheel raised off the ground you can rotate freely to inspect any clearances. If you have a second jack, you can raise the wheel back into the arch at ride height and freely turn the wheel to inspect clearance better.
(Tape measure under car - too hard to show this in the wheel arch with the car on the ground)
(1" Poke with a tape measure)
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