Go Back   EcoModder Forum > EcoModding > Aerodynamics
Register Now
 Register Now

Now available from EcoModder: ScanGauge II fuel economy gauge.  Click for details.  

Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-02-2013, 06:53 PM   #1 (permalink)
rav
EcoModding Lurker
 
Join Date: Sep 2008
Location: albany, NY
Posts: 38

Gas HOG - '08 JEEP LIBERTY SPORT
Thanks: 5
Thanked 5 Times in 4 Posts
effect of wheel offset on mpg

I am planning to swap the steel wheels on my Honda fit with a 55 mm offset with lightweight alloy wheels with a 45 mm offset. If i understand offset correctly, my wheel will stick out by about 10 mm from the fender. Will the gain in mpg by lighter wheels (low rolling resistance) be more then the additional drag caused by the wheels sticking out or I am just being paranoid and 10 mm will be barely anything at all.

  Reply With Quote
Old 01-02-2013, 11:24 PM   #2 (permalink)
Sport Compact Driver
 
Join Date: Apr 2012
Location: Lolo Mt
Posts: 623

The Bee - '96 Mazda B4000 4x4 Base
Pickups
90 day: 20.39 mpg (US)

Celica Gts - '84 Toyota Celica Gts
Sports Cars
90 day: 26.32 mpg (US)
Thanks: 56
Thanked 62 Times in 55 Posts
I dont think it will be a problem, 10mm is only a touch more than a 1/3rd of a inch. Aero shouldn't be affected esp if the rims and tires are still in the fenders.
  Reply With Quote
Old 01-03-2013, 01:02 PM   #3 (permalink)
EcoModding Apprentice
 
Join Date: May 2012
Location: Indiana, US
Posts: 132

TheCav - '04 Chevy Cavalier LS
Thanks: 13
Thanked 21 Times in 17 Posts
What about when you go over an unexpected bump, won't your tires wack the crap out the top of your fender? Don't think you'll avoid all bumps because all it takes ia one good wack to leave a pretty dent.
  Reply With Quote
Old 01-03-2013, 03:49 PM   #4 (permalink)
Master EcoModder
 
mcrews's Avatar
 
Join Date: Oct 2009
Location: Texas
Posts: 2,893

The Q Sold - '02 Infiniti Q45 Sport
90 day: 23.08 mpg (US)

Kia - '06 Kia Sportage EX
90 day: 23.63 mpg (US)
Thanks: 1,091
Thanked 449 Times in 337 Posts
THe 10mm is not from the fender.
THe 10mm is added to the current outside edge of the tire. I dont think it will rub, but you should measure. Again, from the outside edge of the tire.
__________________
MetroMPG: "Get the MPG gauge - it turns driving into a fuel & money saving game."

ECO MODS PERFORMED:
First: ScangaugeII
http://ecomodder.com/forum/showthrea...eii-23306.html

Second: Grille Block
http://ecomodder.com/forum/showthrea...e-10912-2.html

Third: Full underbelly pan
http://ecomodder.com/forum/showthrea...q45-11402.html

Fourth: rear skirts and 30.4mpg on trip!
http://ecomodder.com/forum/showthrea...tml#post247938
  Reply With Quote
The Following User Says Thank You to mcrews For This Useful Post:
Sven7 (01-04-2013)
Old 01-03-2013, 04:18 PM   #5 (permalink)
Master EcoModder
 
Join Date: Oct 2012
Location: Carson City, Nevada
Posts: 575

Jimmy - '00 GMC Jimmy SLT
90 day: 21.18 mpg (US)

The White Gnat - '99 Suzuki Swift
Team Suzuki
90 day: 64.34 mpg (US)
Thanks: 171
Thanked 97 Times in 80 Posts
Whoa! Just gave me an idea: get offset wheels the OTHER direction for the rears & then can do a more "complete" fender skirt!!!
  Reply With Quote
The Following User Says Thank You to wmjinman For This Useful Post:
Sven7 (01-04-2013)
Old 01-03-2013, 05:36 PM   #6 (permalink)
Master EcoModder
 
mcrews's Avatar
 
Join Date: Oct 2009
Location: Texas
Posts: 2,893

The Q Sold - '02 Infiniti Q45 Sport
90 day: 23.08 mpg (US)

Kia - '06 Kia Sportage EX
90 day: 23.63 mpg (US)
Thanks: 1,091
Thanked 449 Times in 337 Posts
Quote:
Originally Posted by wmjinman View Post
Whoa! Just gave me an idea: get offset wheels the OTHER direction for the rears & then can do a more "complete" fender skirt!!!
there you have it!
__________________
MetroMPG: "Get the MPG gauge - it turns driving into a fuel & money saving game."

ECO MODS PERFORMED:
First: ScangaugeII
http://ecomodder.com/forum/showthrea...eii-23306.html

Second: Grille Block
http://ecomodder.com/forum/showthrea...e-10912-2.html

Third: Full underbelly pan
http://ecomodder.com/forum/showthrea...q45-11402.html

Fourth: rear skirts and 30.4mpg on trip!
http://ecomodder.com/forum/showthrea...tml#post247938
  Reply With Quote
Old 01-04-2013, 12:44 PM   #7 (permalink)
PSmodder lurker
 
botsapper's Avatar
 
Join Date: Jan 2009
Location: Chino
Posts: 1,017
Thanks: 14
Thanked 363 Times in 227 Posts
..so you can tuck in all the wheels inside all the skirts...

http://s.images.boldride.com/saab/19...197314-304.jpg

http://images.thetruthaboutcars.com/...97a-119008.jpg
  Reply With Quote
Old 01-04-2013, 06:09 PM   #8 (permalink)
Ride your bike!
 
Sven7's Avatar
 
Join Date: Aug 2011
Location: Warren, MI
Posts: 2,081

Ren - '92 Honda Civic DX
90 day: 48.4 mpg (US)

Boo Radley - '65 Ford F100
90 day: 13.7 mpg (US)
Thanks: 658
Thanked 466 Times in 284 Posts
crews is right.


Offset (wheel) - Wikipedia, the free encyclopedia

It should not make a discernible difference in fuel economy.
__________________
Experimenting with car-less living- human power only!
  Reply With Quote
Old 01-04-2013, 06:32 PM   #9 (permalink)
(:
 
Frank Lee's Avatar
 
Join Date: Jan 2008
Location: up north
Posts: 10,259

Blue - '93 Ford Tempo
Last 3: 27.29 mpg (US)

ShWing! - '82 honda gold wing Interstate
90 day: 33.65 mpg (US)

F150 - '94 Ford F150 XLT 4x4
90 day: 18.5 mpg (US)

Sport Coupe - '92 Ford Tempo GL
Last 3: 69.62 mpg (US)

Moon Unit - '98 Mercury Sable LX Wagon
90 day: 21.24 mpg (US)
Thanks: 1,023
Thanked 1,828 Times in 1,221 Posts
The Bonneville speed guys carefully place the wheel offset for minimum drag. That said, I don't know if you can do it by eyeball, and furthermore at highway speeds I doubt it makes a detectable difference. But if you are going whole hog, it should be investigated via tuft tests or ?
__________________


  Reply With Quote
Old 01-04-2013, 06:37 PM   #10 (permalink)
Ride your bike!
 
Sven7's Avatar
 
Join Date: Aug 2011
Location: Warren, MI
Posts: 2,081

Ren - '92 Honda Civic DX
90 day: 48.4 mpg (US)

Boo Radley - '65 Ford F100
90 day: 13.7 mpg (US)
Thanks: 658
Thanked 466 Times in 284 Posts
Quote:
Originally Posted by Frank Lee View Post
The Bonneville speed guys carefully place the wheel offset for minimum drag. That said, I don't know if you can do it by eyeball, and furthermore at highway speeds I doubt it makes a detectable difference. But if you are going whole hog, it should be investigated via tuft tests or ?
Or go to one of those speed runs at airports and do coast-down testing from 100mph. You'd need to have the same tires on each set of wheels, though, for consistency.

__________________
Experimenting with car-less living- human power only!
  Reply With Quote
Reply  Post New Thread

Tags
alloy, drag, offset, steel

Thread Tools





Powered by vBulletin® Version 3.8.7
Copyright ©2000 - 2014, vBulletin Solutions, Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com