Tire Size / Offset Explained! - Acura Forum : Acura Forums
FAQ Frequently Asked Questions for all models.

 
LinkBack Thread Tools Display Modes
post #1 of 7 (permalink) Old 04-09-02, 03:29 AM Thread Starter
That's my girl
 
Edub's Avatar
 
Join Date: Jan 2002
Location: Bay Area, CA
Age: 42
Posts: 3,068
Send a message via AIM to Edub
Cool Tire Size / Offset Explained!

It's actually pretty simple..

Compared to Stock
TLS/CLS = 215 * 50 = 107.5mm
TLP/CLP = 205 * 60 = 123mm

Total tire height = * 2

But you have to consider the diameter of the wheel as well, since wheels are given in standard, but tires are in metric, it gets a bit confusing.. so just convert everything to metric..
given 1 inch = 25.4mm

17 inch = 431.8mm + 2(107.5)mm = 646.8mm total wheel hight
16 inch = 406.4 + 2(123) = 652.4 total

225/40/18
just means:
225mm * 40% = 90mm sidewall height

18(25.4) + 2(90) = total
457.2 + 180 = 637.2mm

so 225/40/18 is 9.6mm shorter than stock TLS/CLS height

for 225/45/18 calc
225 * 45% = 101.25
457.2 + 202.5 = 659.7 total height.

224/45/18 is 12.9mm taller than stock TLS/CLS

The same formula can be used for TL/CL 16 inch stock as well

D + 2(ar * tw) = total height..
where:
D = Diameter of wheel
ar = aspect ratio of tire
tw = tire width

all in metric (mm) measurements..
Here is a website that is good for calculating it for you:
http://www.miata.net/garage/tirecalc.html

***********************

Ok, now that you understand wheel/tire sizes.. lets go into how offset plays a part in it..
Okay, here it goes.. This is for TLS/CLS

Stock offset is +55 on a 7 inch wheel
Not sure about clearence, but we all know it's 4x4

Think of offset as two independant rings, one smaller inside of the larger..
the outer ring is your wheel, and the inner ring is your mounting surface.. how even with the wheel the mounting surface is, that is your offset..

http://www.tirerack.com/wheels/images/tech/offset.gif

0 offset means that the inner ring is exactly in the middle of the outer ring..

so our stock +55, makes the mounting surface closer to the outside of the wheel, effectively making the whole wheel tucked into the middle of the car..

by reducing the offset to +42, you are moving the mounting surface closer to the centerline, effectively making the whole wheel stick out away from the car. In this case, by 13mm. You could probably get away with it if your tire size stayed the same..

but if you are thinking of 225 tires.. which is 10mm wider than stock.. but you take half of that for either side of the wheel giving you only 5mm wider on tires.. add that to the 13mm you have already moved the wheel out and you have 18mm total from the stock position. Again, probably ok if you do not lower it..

So with a higher offset, the wheel will stick out less, or more correctly, not move from the stock position as much.. It seems that +45 is probably the lowest you could go without too much rubbing..

On a 7inch wheel, 225 is 47.2mm wider overall than the wheel itself, 23.6mm on either side.. but it seems that a skinny wheel will make the tire sidewall not perfectly flat and will cause it to bulge out a little bit.. which is fine for a lower profile..
People get wider tires to get more of the tire surface to the ground for better traction, and also to help protect the wheel from getting scratched as easily..

And if you are going to lower with Comptech, wich is 1.75 closer to the fenderwell. So everytime the springs compress, you'll even have less room for the suspension to move causing the tire to rub against the fenderwell or the bumper tab, or the shocks, etc..

With wider wheels, you have to worry about rubbing not only on the outside, but also the shocks..

with wider tires you really only have to worry about the fenderwell..

Here is an offset calculator:
http://toy4two.home.mindspring.com/offset.html
Edub is offline  
Sponsored Links
Advertisement
 
post #2 of 7 Old 04-09-02, 03:40 AM
Banned
 
Join Date: Jan 2002
Location: CHICAGO
Age: 38
Posts: 14,326
Send a message via AIM to Crazy Quattro
copy and paste is your friend.
Crazy Quattro is offline  
post #3 of 7 Old 06-25-02, 05:21 PM
NO AMG, NO CARE
 
iridium130's Avatar
 
Join Date: Jan 2002
Location: Denver, CO
Age: 36
Posts: 10,527
Send a message via AIM to iridium130
This deserves a sticky IMO

Current hotness:
2003 Mercedes C32
2003 Subaru Impreza WRX

What I miss:
2001 3.2CLS (Comptech Springs and Sways, Xephyr CAI, SSR GT1 18x7.5+45, Bridgestone S03 235/40/18, Door Sills)
iridium130 is offline  
 
post #4 of 7 Old 06-27-02, 01:46 PM
Just Another Mutt
 
Tuff Gong's Avatar
 
Join Date: Jan 2002
Location: A Place Full Of Nasty SOB's......NY
Posts: 4,309
Hey hey hey!!! I own the copyright on this!!!

http://www.tirerack.com/wheels/images/tech/offset.gif

Just playin brother. A great write up, period
Tuff Gong is offline  
post #5 of 7 Old 06-28-02, 12:21 AM Thread Starter
That's my girl
 
Edub's Avatar
 
Join Date: Jan 2002
Location: Bay Area, CA
Age: 42
Posts: 3,068
Send a message via AIM to Edub
Quote:
Originally posted by Tuff Gong
Hey hey hey!!! I own the copyright on this!!!

http://www.tirerack.com/wheels/images/tech/offset.gif

Just playin brother. A great write up, period
OK, fine.. I'll post another one..
https://www.acuraworld.com/forums/att...=&postid=81885
Attached Images
 
Edub is offline  
post #6 of 7 Old 06-29-02, 10:22 PM
Just Another Mutt
 
Tuff Gong's Avatar
 
Join Date: Jan 2002
Location: A Place Full Of Nasty SOB's......NY
Posts: 4,309
Quote:
Originally posted by Edub

OK, fine.. I'll post another one..
That diagram is so much nicer Eric. I was only messing with ya man, it was just good to see the thread again and I remembered the diagram.....my bad.

A well written thread should stay around for a loooong time then to fade away....
Tuff Gong is offline  
post #7 of 7 Old 07-08-02, 06:03 PM
Registered User
 
patrick's Avatar
 
Join Date: May 2002
Location: Vancouver, BC
Posts: 1,963
Send a message via MSN to patrick
We should put this in FAQ.

1999 Satin Silver Acura 3.2TL
Performance Upgrades:
Blitz Short Ram Intake | Stone Racing Headers | AJR Custom Throttlebody Upgrade | UR Crank Pulley | Outlaw Engineering ThermoBlok Spacers | Axle-Back Magnaflow Exhausts and Y-Pipe

Suspension and Braking Upgrades:
H&R Race Springs (stage 3) | Tokico Blue HP Shocks | SPC Rear Camber Kit | Cusco Front Lower Tie Bar | Front & Rear Rotora Slotted Rotors | Endless Type NA-M Front Brake Pads | Comptech Stainless Steel Brakelines | Endless Dot 4 Brake Fluid

Interior & Exterior Upgrades:
Acura TL Door Sills | Inspire Fog Light Switch with PIAA 912 Stealth auxilary lighting | PIAA Silicon Wipers | OEM Bodykit

2001 Starlight Silver Honda Odyssey EX
PIAA Silicon wipers
Tranny #1 replaced at 55,420 KM
patrick is offline  
Sponsored Links
Advertisement
 
 

  Acura Forum : Acura Forums > Shop Talk > FAQ

Quick Reply
Message:
Options

Register Now



In order to be able to post messages on the Acura Forum : Acura Forums forums, you must first register.
Please enter your desired user name, your email address and other required details in the form below.

User Name:
Password
Please enter a password for your user account. Note that passwords are case-sensitive.

Password:


Confirm Password:
Email Address
Please enter a valid email address for yourself.

Email Address:
OR

Log-in











Currently Active Users Viewing This Thread: 2 (0 members and 2 guests)
 
Thread Tools
Show Printable Version Show Printable Version
Email this Page Email this Page
Display Modes
Linear Mode Linear Mode



Posting Rules  
You may not post new threads
You may not post replies
You may not post attachments
You may not edit your posts

BB code is On
Smilies are On
[IMG] code is Off
HTML code is Off
Trackbacks are On
Pingbacks are On
Refbacks are On

 
For the best viewing experience please update your browser to Google Chrome
 

Ad Management plugin by RedTyger