Swapping 20's for 18's with 3.55 - Ford Powerstroke Diesel Forum
General 6.7 Discussion General 6.7 Discussion

Powerstroke.org is the premier Diesel Truck Forum on the internet. Registered Users do not see the above ads.
Reply
 
LinkBack Thread Tools Display Modes
  #1  
Old 09-21-2012, 08:41 AM
Member
 

Join Date: Apr 2010
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Swapping 20's for 18's with 3.55

Like the title says I am looking at going down to 18's from my 20" wheels. I just like the look of 18's better than 20's. Will I sacrifice mpg by doing so? Will I need to get the speedo recalibrated?

Thanks
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
  #2  
Old 09-21-2012, 11:50 AM
Compression Ignition Addict
 

Join Date: Oct 2011
Location: Kings River Nevada
Posts: 1,100
Thanks: 56
Thanked 10 Times in 9 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by chongo View Post
Like the title says I am looking at going down to 18's from my 20" wheels. I just like the look of 18's better than 20's. Will I sacrifice mpg by doing so? Will I need to get the speedo recalibrated?

Thanks
Doesn't matter wheel size for speedometer recalibration. What matters is whole wheel and tire diameter.

Sent from my DROID RAZR using AutoGuide.Com Free App
Reply With Quote Quick reply to this message
  #3  
Old 09-21-2012, 11:54 AM
Member
 

Join Date: Apr 2010
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
So if I go with a 285/75/18 (34.8") tire I should be fine?

Any issues or concerns with that much sidewall?


Sent from my Autoguide iPhone app
Reply With Quote Quick reply to this message
  #4  
Old 09-21-2012, 01:39 PM
Premium Member
 

Join Date: Jun 2008
Posts: 22
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
My truck came with 18''s. I just put on 305/70r18's and now my speedo is almost right. When my speedo says 55 and I pass a laser speed sign it will say 56.

The 305/70r18 is 34.8" tall.
Reply With Quote Quick reply to this message
  #5  
Old 09-21-2012, 09:30 PM
Compression Ignition Addict
 

Join Date: Oct 2011
Location: Kings River Nevada
Posts: 1,100
Thanks: 56
Thanked 10 Times in 9 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by chongo View Post
So if I go with a 285/75/18 (34.8") tire I should be fine?

Any issues or concerns with that much sidewall?


Sent from my Autoguide iPhone app
What size diameter is on your truck? If these new wheels and tires are bigger then your original ones. Your actual speed will be faster then your what your speedometer says.

Sent from my DROID RAZR using AutoGuide.Com Free App
Reply With Quote Quick reply to this message
  #6  
Old 09-21-2012, 09:39 PM
Member
 

Join Date: Apr 2010
Posts: 60
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
I currently have 275/60/20

34.1 or 34.8 -whatever comes factory.
Reply With Quote Quick reply to this message
  #7  
Old 09-21-2012, 10:17 PM
Powerstroke.org Fanatic
 

Join Date: Sep 2012
Posts: 109
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by coryz71 View Post
My truck came with 18''s. I just put on 305/70r18's and now my speedo is almost right. When my speedo says 55 and I pass a laser speed sign it will say 56.

The 305/70r18 is 34.8" tall.
For the 305's did you change the rim width size to be more than the stock 8?
Reply With Quote Quick reply to this message
  #8  
Old 09-22-2012, 12:03 AM
Premium Member

 

Join Date: Jun 2012
Location: Frederick, Maryland
Posts: 202
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
the oem 20's are 20 x 8 " the tire is a 275/65/20 275 MM wide by 65 % for sidewall hight

so do 275mm divided by .65 = actual sidewall height. convert to inches 25.4 mm = 1 inch

or convert the 20" wheel to MM

Take the wheel dia plus add the sidewall height x 2 and thats the over all rolling diameter

take the overall rolling dia and subtract that from the overall diameter on the 18" wheel/ tire combo. You then have your answer
Reply With Quote Quick reply to this message
  #9  
Old 09-22-2012, 11:26 AM
Premium Member
 

Join Date: Jun 2008
Posts: 22
Thanks: 0
Thanked 0 Times in 0 Posts
Feedback Score: 0 reviews
Quote:
Originally Posted by Adventure Rider View Post
For the 305's did you change the rim width size to be more than the stock 8?
No, stock wheels.
Reply With Quote Quick reply to this message
  #10  
Old 09-22-2012, 06:50 PM
Member
 

Join Date: Jan 2012
Posts: 76
Thanks: 0
Thanked 1 Time in 1 Post
Feedback Score: 0 reviews
Where r u located I want 20s and I have 18s

Sent from my LS670 using AutoGuide.Com Free App
Reply With Quote Quick reply to this message
Sponsored Links
Advertisement
 
Reply

Quick Reply
Message:
Options

Register Now

In order to be able to post messages on the Ford Powerstroke Diesel Forum 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:

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.



Thread Tools
Display Modes

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



All times are GMT -8. The time now is 07:34 PM.


Powered by vBulletin® Copyright ©2000 - 2014, Jelsoft Enterprises Ltd.
Search Engine Optimization by vBSEO 3.6.1
Garage Plus, Vendor Tools vBulletin Plugins by Drive Thru Online, Inc.

vB.Sponsors