changing wheels and tire sizes - Hot Rod Forum : Hotrodders Bulletin Board
Hotrodders.com -- Hot Rod Forum



Register FAQ Search Today's Posts Unanswered Posts Auto Escrow Insurance Auto Loans
Hot Rod Forum : Hotrodders Bulletin Board > Tech Help> Hotrodding Basics
User Name
Password
lost password?   |   register now

Reply
 
LinkBack Thread Tools
  #1 (permalink)  
Old 02-23-2013, 08:45 PM
68 firebird's Avatar
Registered User
 
Last photo:
Join Date: Feb 2013
Posts: 19
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
changing wheels and tire sizes

hi im new here and have a question about how to measure for new tires . i have a 68 firebird 350 i have 14 inch wheels and tires on it now but im putting 15s on it soon .how would i go about measuring for new tires? im looking for an agressive look .wide in back and alittle narrower in front. i will be using pontiac rally wheels.im not sure if it matters bu i have 2 inch drop spindals in front with disk brakes and drums in rear..any help you can offer would be great thank you verry much.

    Advertisement
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2 (permalink)  
Old 02-23-2013, 09:27 PM
LATECH's Avatar
Hotrodders.com Moderator
 

Last journal entry: Motor - vator
Last photo:
Join Date: Jul 2010
Location: Northeast Pennsylvania
Posts: 5,338
Wiki Edits: 0

Thanks: 222
Thanked 276 Times in 256 Posts
If you run 14 inch rally 2 on the front you need to check that the wheel fits and clears the calipers. Some of the early rally2 14 wont fit around the calipers. Somewhere around 1970 the 14s were made to fit the small rotor disc setup. Wheels have codes and you can check that out to find the correct ones.
I would think a 195-60-14 for the front or 195 -50-15
a 255-60-15 for the rear could look pretty boss.
Go to the Tire Rack website and look into the "Tech" section. It will have articles on tire dimesions and size .You can get a good idea of the meaning of the numbers.
From there you can come up with your own numbers and tire brand tread design etc. Good luck
__________________
Fact is stranger than Fiction
Reply With Quote Quick reply to this message
  #3 (permalink)  
Old 02-23-2013, 09:47 PM
68 firebird's Avatar
Registered User
 
Last photo:
Join Date: Feb 2013
Posts: 19
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
thanks for your help im going to be running 15inch wheels on all 4 corners so i shouldnt have to worry about the wheels fitting with the disk brakes. i will definatly check out tire rack for the dimentions thanks again
Reply With Quote Quick reply to this message
  #4 (permalink)  
Old 02-24-2013, 09:59 AM
sedanbob's Avatar
Registered User
 
Last photo:
Join Date: Oct 2008
Location: St. Louis
Age: 66
Posts: 626
Wiki Edits: 0

Thanks: 61
Thanked 80 Times in 77 Posts
Here's a link that will also help you with wheel and tire sizes, and will let you compare to what you have now making it easier to measure. Custom rims, wheel tire packages for your ride - RIMSnTIRES.com
Reply With Quote Quick reply to this message
  #5 (permalink)  
Old 02-24-2013, 10:17 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,467
Wiki Edits: 0

Thanks: 348
Thanked 826 Times in 792 Posts
You did noy say if you want factory wheels or after market wheels?The factory 15x8s fit the back and some 15x8s fit the front.My 67 Camaro used 15x8 and 15x7 Corvette rally wheels.Ive used 15x10 on the rear with 235x60x15s,Ive used 15x4 on the front when racing,,,horrible street manners with skinnys up front. For after market wheels you can measure clearances and have custom offset wheels ordered.Go conservative with back spacing.
REMEMBER: the car was designed to have a certain size wheel/tire,straying too far causes other issues.For full explanation look up S.A.I.
steering axis inclination,get someone with road race experience to explain to you what happens when tire height is greatly changed,then get a custom wheel alignment quote
Reply With Quote Quick reply to this message
  #6 (permalink)  
Old 02-24-2013, 10:19 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,467
Wiki Edits: 0

Thanks: 348
Thanked 826 Times in 792 Posts
PS: re 68 firebird..
the frame horns are known to spread with age,check to see how many alignment shims you have in both sides of the car now. Get the frame measured and consider subframe connectors and bending if required
Reply With Quote Quick reply to this message
  #7 (permalink)  
Old 02-24-2013, 10:23 AM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 36
Thanked 105 Times in 95 Posts
Quote:
Originally Posted by 68 firebird View Post
.... i will be using pontiac rally wheels.....
1968 Firebird eh? Nice!

Since you have already chosen the wheels you will be using I'd jack up the car, remove the exisiting tires and wheels from one side and then set the car down using jackstands under the suspension. Then bolt on the bare Pontiac rally wheels. You should now be able the measure how much space you have for tires.

The problem with using the Tire Rack website is you're dealing with a vehicle that is 45 years old. Unless it's bone stock chances are components have been replaced. Your best bet is to measure what you have. In the rear the shocks will likely limit the tire width. If needed you can trim the fender lip for some additional clearance, or roll the fender lip under.

I have a stock '69 Camaro and there is a lot less space than you would think for rear rubber, unless you make some modifications. In my case the car is so nice I didn't want to cut or alter it. I ended up using the following:
(4) American Racing#286-309-5761 Torq-Thrust TTO Series 309 Wheel
Size: 15'' x 7''
Bolt Circle: 5 x 4-3/4''
Rear Spacing: 3-3/4''
(2) BFG Radial T/A 255/70SR15
(2) BFG Radial T/A 215/60SR15

Hope that helps.. good luck to ya and post up some photo's of your car.


Last edited by lakeroadster; 02-24-2013 at 10:36 AM.
Reply With Quote Quick reply to this message
  #8 (permalink)  
Old 02-24-2013, 10:30 AM
sedanbob's Avatar
Registered User
 
Last photo:
Join Date: Oct 2008
Location: St. Louis
Age: 66
Posts: 626
Wiki Edits: 0

Thanks: 61
Thanked 80 Times in 77 Posts
Quote:
Originally Posted by vinniekq2 View Post
...REMEMBER: the car was designed to have a certain size wheel/tire,straying too far causes other issues.For full explanation look up S.A.I.
steering axis inclination,get someone with road race experience to explain to you what happens when tire height is greatly changed,then get a custom wheel alignment quote
Excellent reminder! I set up my alignment following what several sources suggested and it was 'skitish' at speed. Always felt like it was on the edge of out of control. I found a real alignment shop (not a tire store with computer alignment setup). It was not cheap, and took several hours. The result is a very stable ride and excellent handling. Changes in ride height, wheel/tire size, chassis rake, all factor into getting that alignment right.
Reply With Quote Quick reply to this message
The Following User Says Thank You to sedanbob For This Useful Post:
vinniekq2 (02-24-2013)
  #9 (permalink)  
Old 02-24-2013, 10:39 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,467
Wiki Edits: 0

Thanks: 348
Thanked 826 Times in 792 Posts
lakeroadster
Nice 69,350 or 396?
My 67 had the bumblebee stripe. They are and will always be icons,67/68&69s
Reply With Quote Quick reply to this message
  #10 (permalink)  
Old 02-24-2013, 11:12 AM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 36
Thanked 105 Times in 95 Posts
Vinnie,

350, 3-speed Muncie. It has lived here in Colorado it's entire life, and the dry climate has been kind to it.
Reply With Quote Quick reply to this message
  #11 (permalink)  
Old 02-24-2013, 11:25 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,467
Wiki Edits: 0

Thanks: 348
Thanked 826 Times in 792 Posts
lakeroadster
thats a beautiful car
I would still have my 67 if it wasnt stolen,,,,
I will always be close to those cars,guard yours with w/e it takes to keep it safe
Reply With Quote Quick reply to this message
  #12 (permalink)  
Old 02-24-2013, 11:37 AM
lakeroadster's Avatar
Hot Rods are Built, not Bought
 

Last journal entry: Lakeroadster's '31 Model A Tudor
Last photo:
Join Date: Dec 2001
Location: High Plains - Rocky Mountains
Age: 53
Posts: 695
Wiki Edits: 0

Thanks: 36
Thanked 105 Times in 95 Posts
Thanks Vinnie, good advice. Got any old photo's of your '67 you could post up?
Reply With Quote Quick reply to this message
  #13 (permalink)  
Old 02-24-2013, 11:48 AM
Registered User
 
Join Date: Dec 2012
Posts: 77
Wiki Edits: 0

Thanks: 9
Thanked 8 Times in 8 Posts
I also have a 68 Bird. I have replaced the rear leaf springs with heavy duty leafs (5 leafs) which raised the car up from the old factory leafs, which were worn out. I run a 295/50/15 BFG radial T/A in the rear and a 235/60/14 in the front. I have seen other folks runs a 275/60/15 in the rear with no clearance issues.
Reply With Quote Quick reply to this message
  #14 (permalink)  
Old 02-24-2013, 11:55 AM
vinniekq2's Avatar
Registered User
 
Join Date: Jun 2012
Location: BC,Canada
Age: 56
Posts: 8,467
Wiki Edits: 0

Thanks: 348
Thanked 826 Times in 792 Posts
all analogue pictures

Quote:
Originally Posted by lakeroadster View Post
Thanks Vinnie, good advice. Got any old photo's of your '67 you could post up?
I will scratch up some pics if I can.
Reply With Quote Quick reply to this message
  #15 (permalink)  
Old 02-24-2013, 03:12 PM
68 firebird's Avatar
Registered User
 
Last photo:
Join Date: Feb 2013
Posts: 19
Wiki Edits: 0

Thanks: 0
Thanked 0 Times in 0 Posts
hi everybody thanks for your comments and advise. thats a gorgous camaro Lakeroadster your combo looks good.i would like to go just alittle wider in rear though..rite now i have an old set of pro track 50s they measure 10 inches wide but they are real short i want to fill my wells up thats why im going to 15 inch.not to meantion cant find that wide a tire in 14.i was thinking 70s in front
Reply With Quote Quick reply to this message

Recent Hotrodding Basics posts with photos

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Hot Rod Forum : Hotrodders Bulletin Board forums, you must first register.
Please enter your desired user name (usually not your first and last 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:

Log-in

Human Verification

In order to verify that you are a human and not a spam bot, please enter the answer into the following box below based on the instructions contained in the graphic.




Currently Active Users Viewing This Thread: 1 (0 members and 1 guests)
 
Thread Tools

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

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


Similar Threads
Thread Thread Starter Forum Replies Last Post
Tire Sizes joeford Hotrodding Basics 2 11-23-2007 07:02 PM
Tire Sizes sha_ba_do_bang General Rodding Tech 1 10-20-2005 11:36 PM
Tire Sizes Jag Daddy General Rodding Tech 10 06-11-2003 11:21 PM
tire sizes CARGUY Suspension - Brakes - Steering 1 03-14-2003 10:28 AM
HELP!!! with tire sizes and such. i got a few ?s tony350ss Suspension - Brakes - Steering 2 10-26-2002 04:56 PM


All times are GMT -6. The time now is 08:29 PM.


Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Search Engine Optimization by vBSEO 3.6.0 PL2
Copyright Hotrodders.com 1999 - 2012. All Rights Reserved.