Go Back   EcoModder Forum > EcoModding > General Efficiency Discussion
Register Now
 Register Now
 


Reply  Post New Thread
 
Submit Tools LinkBack Thread Tools
Old 01-08-2021, 08:24 PM   #1 (permalink)
Eco Rodder
 
Join Date: Nov 2014
Location: Walnut Creek, CA
Posts: 53
Thanks: 14
Thanked 24 Times in 12 Posts
Tire/wheel weight and mpg

How much will rotational weight reduction help with fuel economy? I have to assume that it would help more than the same weight reduction elsewhere in the car.

My current front tire/wheels weigh 47 lbs each, 94 lbs total
The current rears weigh 55 lbs each, 110 lbs total

The new fronts Iím considering would weigh 41 lbs each, 82 lbs total
The new rears would weigh 48 lbs each, 96 lbs total.

While it not a lot of weight off the the entire car, itís a pretty good chunk off the rotating stock.

Should I see this in my mpg recordings?

__________________
1966 Chevelle w/ 3.6L (217 ci) 4 cam direct injected V6, 6 speed double OD auto trans and 3.07 rear end. 3260 lbs with full tank of gas.
  Reply With Quote
Alt Today
Popular topics

Other popular topics in this forum...

   
Old 01-09-2021, 12:02 AM   #2 (permalink)
Master EcoModder
 
Ecky's Avatar
 
Join Date: Dec 2011
Location: Vermont
Posts: 4,148

Gaptooth (retired) - '00 Honda Insight
Team Honda
Gen-1 Insights
90 day: 54.26 mpg (US)

Such Fit - '07 Honda Fit Sport
90 day: 41.27 mpg (US)

Connect - '15 Ford Transit Connect XL
90 day: 23.4 mpg (US)

K-sight - '00 Honda K-sight
Team Honda
90 day: 44.31 mpg (US)
Thanks: 1,953
Thanked 1,748 Times in 1,125 Posts
Some back of the envelope math suggests the rotational inertia of your wheels is around 6.5% of your total vehicle's inertia (I made what I felt were some reasonable assumptions about wheel moment of inertia). The wheels themselves are also, surprisingly, just about 6.5% of the total vehicle mass, so you're looking at affecting approximately 13% of the energy need to accelerate and decelerate. Or, in other words, my math supports that taking a pound out of the wheels is like taking two pounds out of the car.

Looks like the total inertial savings is ballpark 1.5% from the entire vehicle. I can only guess at how that would relate to fuel consumption. Maybe 1/3 to half that in mixed driving?

  Reply With Quote
Reply  Post New Thread


Thread Tools




Powered by vBulletin® Version 3.8.11
Copyright ©2000 - 2021, vBulletin Solutions Inc.
Content Relevant URLs by vBSEO 3.5.2
All content copyright EcoModder.com